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Exhibition of induced mesophases in the binary systems where both the components are non-mesogenic
Binary systems of two non-mesogens exhibiting mesomorphism are rare. In the present study few binary systems of non-mesogens exhibiting smectic and/or nematic mesophases are reported. One of the components is Schiff base having terminal isopropyl group and the other component contains an ester linkage. The binary systems of non-mesogens with terminal isopropyl group having identical structures (homologues) also exhibit induced mesomorphism. Some of the binary compositions exhibit smectic phase at ambient temperature. The phase diagrams of the present study are discussed in detail and the common features emerging from the overall study are outlined.
Prajapati,Pandya, Himanshu M.
p. 43 - 54
(2001)
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Bradfield,Jones
p. 2660
(1929)
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Design, synthesis, and biological studies of novel 3-benzamidobenzoic acid derivatives as farnesoid X receptor partial agonist
Farnesoid X receptor (FXR), a bile acid-activated nuclear receptor, regulates the metabolism of bile acid and lipids as well as maintains the stability of internal environment. FXR was considered as a therapeutic target of liver disorders, such as drug-induced liver injury, fatty liver and cholestasis. The previous reported FXR partial agonist 6 was a suitable lead compound in terms of its high potent and low molecular size, while the docking study of compound 6 suggested a large unoccupied hydrophobic pocket, which might be provided more possibility of structure-activity relationship (SAR) study. In this study, we have performed comprehensive SAR and molecular modeling studies based on lead compound 6. All of these efforts resulted in the identification of a novel series of FXR partial agonists. In this series, compound 41 revealed the best activity and strong interaction with binding pocket of FXR. Moreover, compound 41 protected mice against acetaminophen-induced hepatotoxicity by the regulation of FXR-related gene expression and improving antioxidant capacity. In summary, these results suggest that compound 41 is a promising FXR partial agonist suitable for further investigation.
Hu, Lijun,Ren, Qiang,Deng, Liming,Zhou, Zongtao,Cai, Zongyu,Wang, Bin,Li, Zheng
supporting information

(2020/12/25)

Synthesis and mesomorphic characterization of some novel steroidal mesogens: A structure–property correlation
The steroidal derivatives are found to be extremely good mesogens since their inception. Because of their inherent chirality, they have the potential to induce a wide variety of liquid crystalline phases, including frustrated phases depending upon the structure of the steroidal skeleton and the substituents attached. In this report, a series of novel monoalkoxy and dialkoxy benzoate derivatives of ergosterol and a few monoalkoxy derivatives of stigmasterol have been synthesized and their mesomorphic property has been investigated. The derivatives exhibited various mesophases including SmA, SmC*, N*, TGB and blue phases. Also, the gelation ability of some of these derivatives with various organic solvents has been examined. Furthermore, the mesomorphism of these derivatives has been compared with the analogous cholesteryl counterparts.
Bhat S, Vanishree,Kumar, Sandeep,Raghunathan, V. A.
(2021/08/25)

Binary systems of non-mesogens with naphthalene derivatives
Binary mixtures with both the components are non-mesogenic becomes an interesting and enlighten feature when they exhibit mesomorphism at ambient temperature. In the present study, we report five binary systems where two non-mesogenes exhibit smectic and/or nematic mesophases at ambient temperature over a certain range of concentration. All the binary systems contain one non-mesogenic naphthalene derivative. The study provides many binary systems of non-mesogens which exhibit mesophases at ambient temperatures. The terminal nitro chain is found to be responsible for the induction of both the nematogenic and smectogenic tendency in the present investigation of binary systems with two ‘compatible' component.
Yao, Yong fang,Patel,Prajapati, Ashish Kumar,Sangani, Chetan B.,Duan, Yong-Tao
p. 31 - 42
(2021/04/14)

Synthesis and mesomorphic properties of bis ester derivatives of coumarin containing chalcone linkage
Bis ester derivatives of coumarin containing chalcone linkage with various terminal alkoxy groups were designed, synthesized and characterized. Compounds 11a-m were studied for their mesomorphic properties using polarizing optical microscope & differential scanning calorimetry and photophysical properties using UV-vis & fluorescence spectroscopy. In this particular homologous series, compounds having lower flexible alkoxy chains showed very good mesogenic property with nematic mesophase formation, while analogues with higher chains failed to show any liquid crystalline property. Compound 11a with methoxy group showed very good absorbance and fluorescence as compared to higher chain length analogues.
Shah, Priyanka,Soni, Rina,Soman, Shubhangi S
(2021/05/04)

Synthesis, mesomorphic properties and biological evolution of calamitic-shaped chalcone-based LCs: effect of lateral and terminal group
The mesomorphic properties of linear shaped homologous series based on two linkage group have been designed and synthesized with different side chain substituents (-OR) on the one end of terminal side with presence of lateral nitro group and second terminal iodo substituted group. Novel series consists thirteen members (C1 to C8, C10, C12, C14, C16, C18). Compounds (C1 to C6) showed nonliquid crystalline properties while compound (C7 to C18) displayed smectic and nematogenic mesophase properties. The textures of smectic C and nematic phase are fan, schlieren and droplets type. All these compounds were characterized by spectroscopic techniques such as [FTIR] and 1H Nuclear magnetic resonance [NMR] spectroscopy. The mesomorphic properties of these compounds were observed by POM and further confirmed by DSC and XRD. Chalconyl ester based compounds (C3 to C12) shows good antibacterial as well as antifungal activity compared with corresponding standard drugs.
Dwivedi, Durgesh J.,Thakor, Akshay,Desai, Vipul,Sharma, Vinay S.,Patel
p. 16 - 32
(2021/05/26)

λ-shaped to T-shaped azo diester mesogens having methyl (–CH3)/methoxy(–OCH3) terminal substituents with trisubstituted benzene
A two new homologous series of λ-shape to T-shape mesogenic azo diesters were synthesized, and their thermotropic properties were studied by differential scanning calorimetry and a hot-stage polarizing optical microscope. The difference between these two series is in the structure of terminal substituents methyl (–CH3) for series I and methoxy (–OCH3) for series II at one terminus. Structure variation from λ-shape to T-shape as we go from lower members to higher members is discussed. In the series I, methoxy to n-pentyloxy derivatives are non-mesogenic. n-hexyloxy derivative exhibits only monotropic nematic mesophase. n-heptyloxy to n-dodecyloxy derivatives exhibit monotropic smectic C mesophase. n-tetradecyloxy derivative exhibits enantiotropic SmA mesophase, whereas n-hexadecyloxy derivatives exhibit monotropic Smectic A mesophase. In series II, methoxy to n-hexyloxy derivatives are non-mesogenic. n-heptyloxy and n-octyloxy derivatives exhibit monotropic smectic C mesophase. Smectic A mesophase commences from the n-decyloxy derivative as a monotropic and persists up to the last member synthesized. The mesomorphic properties of the present series were compared with each other and with the structurally related mesogenic homologous series to evaluate the effect of methyl (–CH3)/methoxy (–OCH3) substituents as well as variation in the shape of the molecule by varying the alkoxy chain length of the bulky lateral substituent on mesomorphism.
Duan, Yongtao,Koshti, Rohit R.,Kumar Ameta, Rakesh,Patel, H. N.,Sangani, Chetan B.,Tarpada, Umesh P.,Vyas, Akshay,Yao, Yongfang
(2021/07/12)

1,3-Oxazine-2-one derived dual-targeted molecules against replicating and non-replicating forms of Mycobacterium tuberculosis
The high mortality rate and increasing prevalence of resistant Mtb are the major concerns for the Tuberculosis (TB) treatment in this century. To curtail the prevalence of resistant Mtb, we have prepared 1,3-oxazine-2-one based dual targeted molecules. Compound 67 and 68 were found to be equally active against replicating and non-replicatiing form of Mtb (MICMABA 3.48 and 2.97 μg/ml; MICLORA 2.94 and 2.15 μg/ml respectively). They had found to suppress the biosynthesis of alfa, methoxy and keto-mycolate completely, as well as inhibit enzymatic activity of MenG (IC50 = 9.11 and 6.25 μg/ml respectively for H37Ra; IC50 = 11.76 and 10.88 μg/ml respectively for M smegmatis).
Velappan, Anand Babu,Kesamsetty, Dhanunjaya,Datta, Dhrubajyoti,Ma, Rui,Hari, Natarajan,Franzblau, Scott G.,Debnath, Joy
supporting information

(2020/10/02)

2-Aryl benzazole derived new class of anti-tubercular compounds: Endowed to eradicate mycobacterium tuberculosis in replicating and non-replicating forms
The high mortality rate and the increasing prevalence of Mtb resistance are the major concerns for the Tuberculosis (TB) treatment in this century. To counteract the prevalence of Mtb resistance, we have synthesized 2-aryl benzazole based dual targeted molecules. Compound 9m and 9n were found to be equally active against replicating and non-replicating form of Mtb (MIC(MABA) 1.98 and 1.66 μg/ml; MIC(LORA) 2.06 and 1.59 μg/ml respectively). They arrested the cell division (replicating Mtb) by inhibiting the GTPase activity of FtsZ with IC50 values 45 and 64 μM respectively. They were also capable of kill Mtb in non-replicating form by inhibiting the biosynthesis of menaquinone which was substantiated by the MenG inhibition (IC50 = 11.62 and 7.49 μM respectively) followed by the Vit-K2 rescue study and ATP production assay.
Datta, Dhrubajyoti,Debnath, Joy,Franzblau, Scott G.,Ghosh, Kalyan Sundar,Hari, Natarajan,Ma, Rui,Rana, Shiwani,Velappan, Anand Babu
(2020/09/04)

Hydrogen bonding and the design of twist-bend nematogens
The phase properties of equimolar mixtures consisting of a hydrogen bond donor, a 4-alkoxybenzoic acid (nOBA), and one of two different stilbazole-based hydrogen bond acceptors, either 4-[(E)-2-(4-{[6-(4′-methoxy[1,1′-biphenyl]-4-yl)hexyl]oxy}phenyl)-ethenyl]-pyridine (1OB6OS) or 4-[(E)-4′-(6-{4-[(E)-2-(pyridin-4-yl)ethenyl]phenoxy}hexyl)-[1,1′-biphenyl]-4-carbonitrile (CB6OS) are reported. Neither hydrogen bond acceptor exhibits liquid crystal behaviour whereas the nOBA compounds show smectic and/or nematic behaviour depending on the length of the alkyloxy chain. For the complexes of an nOBA with n = 1–5, both conventional nematic and twist-bend nematic phases were observed, while for n ≥ 6 smectic phases emerged and the twist-bend nematic phase was extinguished. The CB6OS-nOBA mixtures may exhibit the heliconical smectic CTB phase. The local molecular arrangement in the two sets of mixtures are similar and changes on increasing n but this is not reflected in the nematic-isotropic transition temperatures. Birefringence studies of the mixtures are reported. In general the behaviour of the hydrogen-bonded mixtures is similar to that of their covalently bonded counterparts.
Crawford, Catriona A.,Gorecka, Ewa,Imrie, Corrie T.,Pociecha, Damian,Storey, John M. D.,Walker, Rebecca
(2020/02/13)

Synthesis and characterization of novel rod-like ester-based liquid crystalline homologous series: Effect of tert-butyl tail on mesomorphism
A new rod-like homologous series consisting twelve compounds with central ester linkage and terminal tert-butyl group, tert-butyl [4-(4’-n-alkoxybenzoyloxy)benzoates] has been synthesized and characterized through standard spectroscopic techniques like UV, FT-IR, 1HNMR, DSC, POM, and XRD. Methoxy and ethoxy derivatives are nonmesogenic. Nematic mesophase commences as enantiotropy from propyloxy derivative and persists up to the octadecyloxy derivatives. Smectic A mesophase commences as monotropy from propyloxy to the octadecyloxy derivatives. The mesomorphic properties of present series are compared with other structurally related series to evaluate the effect of terminal tert-butyl group on mesomorphism. Two derivatives are subjected to in?vitro antimicrobial activity.
Thakur, Shavi,Patel, Hemant N.
p. 76 - 89
(2021/04/14)

“Effect of the linking unit on the calamitic-shaped liquid crystal: a comparative study of two homologous series of benzoate and cinnamate linked compounds”
Two homologous series based on three linking groups have been synthesized and well characterized by elemental analyses and spectroscopic techniques such as Fourier transform infrared [FT-IR] and proton magnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by using optical polarized microscopy (POM) and confirmed by differential scanning calorimetry (DSC) analysis. In this present investigation, we have synthesized two homologous series viz. (E)-4-(3-(4-(tetra decanoyloxy) phenyl) acryloyl) phenyl-4-n-alkoxy benzoate (Series-1) and 4-((E)-3-(4-(((E)-3-(4-n-alkoxy phenyl) acryloyl) oxy) phenyl)-3-oxo prop-1-en-1-yl) phenyl tetradecanoate (Series-2). Both of the series are differing with respect to the first linking group. All the homologous in following series displays LC properties on heating as well as cooling condition except first four homologous (C1 to C4) in series-1 and six homologous (C1 to C6) in series-2. To get more insights, the HOMO, LUMO studies are carried out which supports intramolecular charge transfer interactions in this class of mesogens.
Kashyap, Dinesh,Patel, Sunil,Prajapat, Varsha,Sharma, Vinay,Vasava, Dilip
p. 58 - 70
(2019/08/28)

“Synthesis, Mesomorphic and DFT Studies of Chalcone Derived Room Temperature Liquid Crystal with Presence of Lateral Nitro and N, N-Dimethyl Amino Terminal Group”
In this present article, we wish to report on the liquid-crystalline properties of chalcone-ester based homologous series of compounds having aliphatic chain length in n-alkoxy group (n = 1 to 10, 12, 14, 16, 18). The present series consisted thirteen compounds, in which comp.C1 and C2 shows nonliquid crystalline properties, while comp.C3 to C7 display SmC phase and comp.C8 to C18 exhibits only nematic phase. Textural pattern of presently synthesized compounds are schlieren and threaded type. All this compounds were well characterized by elemental analysis, FT-IR and 1H NMR. Phase transition temperatures of present synthesised compounds were determined by optical polarising microscopy (POM), differential scanning calorimetric (DSC). Detailed XRD investigation endorses the presence of the nematic phase in higher homologues and SmC phase in lower homologues. It is shown that chalcone with ester as linking unit favors a calamitic liquid crystalline behaviour in molecules. To get more insights, the DFT based HOMO, LUMO studies are carried out which supports intramolecular charge transfer interactions in this class of mesogens. Chalconyl ester based compounds C3 to C12 shows antibacterial as well as antifungal activity compared with corresponding standard drugs.
Shukla, Devendra K.,Sharma, Vinay S.,Prajapat, Varsha,Patel
p. 8 - 26
(2019/10/14)

Design, synthesis and biological activity evaluation of benzoate compounds as local anesthetics
Tetracaine and pramocaine were used as the lead compounds to design benzoate compounds. The combination principle was used to design the target molecule, and the target molecule was modified by bioisostere formation and modification with alkyl groups. In this research, a total of 16 compounds were designed and synthesized. In the process of synthesis, we selected a route with high total yields, mild conditions and simple operation. Three steps were used in the synthesis of the new target compounds, namely, alkylation, esterification and alkylation. The newly designed target compounds were evaluated via surface anesthesia, infiltration anesthesia, block anesthesia and acute toxicity tests. The results of biological activity experiments showed that compounds 4d, 4g, 4j, 4k, 4n, and 4o had a good local anesthetic effect, and the results of acute toxicity tests showed that the target compounds had low toxicity.
Zou, Huiying,Chen, Guangying,Zhou, Shiyang
p. 6627 - 6635
(2019/03/14)

Dependence of mesomorphism on terminal polar group in novel azoester series
Novel homologous series 4-(4′-n-alkoxy benzoyloxy) napthyl azo 4″–bromo benzenes, consisted of 11 members of a series. All the 11 members (ethoxy to hexadecyloxy) except hexadecyloxy are only enantiotropically nematogenic without exhibition of any smectogenic character. Transition temperatures and the textures are determined by an optical polarizing microscopy equipped with a heating stage. Textures of a nematic phase are threaded or schlieren. Analytical and spectral data supported the molecular structure of homologs. Transition curves viz., solid-nematic and nematic-isotropic showing phase behavior of the mesophase in a phase diagram behave in normal manner. Alternation of transition temperatures is exhibited by N–I transition curve. Thus, novel series is entirely nematogenic and high ordered melting type. Thus, synthesis of a novel azoester homologous series is carried out with a view to understand and establish the effect of molecular structure on Liquid crystal (LC) behaviors of a substance.
Kher, Seema N.,Prajapati,Makwana,Chandra, Raviprakash S.
p. 44 - 53
(2019/10/14)

Preparation, structure and optical properties of thermochromic liquid crystal compounds containing (?)-menthyl with selective reflection
A series of new chiral liquid crystal compounds named MOPnB containing (?)-menthyl group has been prepared and characterized by FT-IR and 1H NMR spectra. The thermal properties and optical textures were investigated by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Increasing the length of the terminal alkoxy group tended to decrease the clearing points and narrow the temperature range of the N* phase as well as favored the development of SmC* phase. Furthermore, Bragg selective reflection spectra of the compounds were measured by ultraviolet/visible spectrometer (UV/Vis). All compounds MOPnB (n = 2, 4, 6, 8, 10) revealed the thermochromic property or selective reflection of visible light in the N* phase. Additionally, only MOP10B and MOP12B in the SmC* phase had the thermochromic phenomena and gave red-saffron colour.
Luo, Cong-Cong,Wang, Xin-Jiao,Han, Lu-Juan,Jia, Ying-Gang,Ying, Shao-Ming,Wang, Ji-Wei
p. 241 - 250
(2018/11/27)

Structure-Function Evaluation of Imidazopyridine Derivatives Selective for δ-Subunit-Containing γ-Aminobutyric Acid Type A (GABAA) Receptors
δ-Selective compounds 1 and 2 (DS1, compound 22; DS2, compound 16) were introduced as functionally selective modulators of δ-containing GABA type A receptors (GABAAR). In our hands, [3H]EBOB-binding experiments with recombinant GABAAR and compound 22 showed no proof of δ-selectivity, although there was a minimally higher preference for the α4β3δ and α6β2/3δ receptors with respect to potency. In order to delineate the structural determinants of δ preferences, we synthesized 25 derivatives of DS1 and DS2, and investigated their structure-activity relationships (SAR). Four of our derivatives showed selectivity for α6β3δ receptors (29, 38, 39, and 41). For all of them, the major factors that distinguished them from compound 22 were variations at the para-positions of their benzamide groups. However, two compounds (29 and 39), when tested in the presence of GABA, revealed effects at several additional GABAAR. The newly synthesized compounds will still serve as useful tools to investigate α6β3δ receptors.
Yakoub, Kirsten,Jung, Sascha,Sattler, Christian,Damerow, Helen,Weber, Judith,Kretzschmann, Annika,Cankaya, Aylin S.,Piel, Markus,R?sch, Frank,Haugaard, Anne S.,Fr?lund, Bente,Schirmeister, Tanja,Lüddens, Hartmut
p. 1951 - 1968
(2018/03/21)

New chalcone based liquid crystals with allylidene amino linking unit: Synthesis and characterization
In this study, the synthesis, structural characterization and mesomorphic properties of newly thirteen calamitic shaped compounds derived from allylidene amino chalcone and 4-n-alkoxy benzoyloxy benzoic acid. Comp.H1 to H3 exhibited nonliquid crystalline nature, while comp.H4 to comp.H18 displayed enantiotropical smectic C phase. Phase transition temperatures of present synthesised compounds were determined by optical polarising microscopy (POM), differential scanning calorimetric (DSC) and powder X-ray diffraction (PXRD) techniques. Thermal stabilities of smectic to isotropic phase are 150.0 °C and temperature range of mesophase is in decreasing order from comp.H3 to comp.H18 respectively. The presences of SmC phase are the type of broken fan and needle type in present synthesized series. It is also shown that presence of chalcone amino allylidene central linking group favors a calamitic liquid crystalline behaviour in molecules with lower member to higher member aliphatic side chain in alkoxy group (-OR).
Sharma, Vinay S.,Sharma, Anuj S.,Jadeja, Upendra H.,Suthar, Deepak
p. 64 - 81
(2019/02/24)

λ-Shaped mesogens based on chalconyl ester core having variable side chain: Synthesis and characterisation
In present study, we have synthesized two newly chalconyl-ester core LCs having variable side chain and fixed disubstituted butoxy group at another terminal end. All this compounds were well characterized by elemental analysis, FT-IR, 1H NMR. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and also confirmed by using differential scanning calorimetry (DSC) and X-ray diffraction pattern (XRD). Detailed XRD investigation endorses the presence of the nematic phase in higher angle region and SmC phase in lower angle region. In addition, it is found that all the prepared materials display enantiotropic LCs phases except first four members in series-1 and first member in series-2. Thermal stability of SmC and nematic phase of series-1 is higher as compare to series-2. To get more insights, the DFT based HOMO, LUMO studies are carried out which supports intramolecular charge transfer interactions and stability in this class of mesogens.
Sharma, Vinay S.,Suthar, Deepak,Sharma, Anuj S.
p. 100 - 118
(2019/02/24)

Metal-Free Etherification of Aryl Methyl Ether Derivatives by C-OMe Bond Cleavage
A general and efficient protocol was developed for the synthesis of aryl alkyl ethers through metal-free C-OMe bond cleavage under mild reaction conditions. This process displays a wide scope of methoxyarenes and alcohols, including primary, secondary, and tertiary alcohols, as well as natural products, pharmaceuticals, and biologically active alcohols. DFT calculations and experimental results simultaneously confirm that a potassium ion plays a critical role in the activation of methoxy group via binding with the nitrile and provide support for an SNAr mechanism.
Wang, Xueqiang,Li, Chenchen,Wang, Xia,Wang, Qingli,Dong, Xiu-Qin,Duan, Abing,Zhao, Wanxiang
p. 4267 - 4272
(2018/07/29)

Study of Y-shaped liquid crystalline materials with polar nitro substituent
A new homologous series of Y-shaped liquid crystals namely 4-Nitro-[2′4′bis (4″-n-alkoxybenzoyloxy)] phenyl bisazobenzenes have been synthesized and its thermotropic properties studied on the hot stage of a polarizing microscope. The compounds consist four phenyl rings joined through ester and bisazo linkages with alkoxy and nitro as terminal substituents. The structures of synthesized compounds were confirmed by spectroscopic techniques such as FTIR, 1HNMR as well as elemental analysis. The compounds were found to exhibit enantiotropic nematic and smectic mesophases. The role of molecular shape, size and polarity of functional groups in the mesophases formation is discussed.
Dixit, Sandhya
p. 77 - 84
(2018/06/27)

Mesomorphism dependence on terminal polar group in the nonlinear novel azoester series
Synthesis of a novel azoester homologous series is carried out with a view to understand and establish the effect of molecular structure on liquid crystal (LC) behaviors of a substance. Novel series consists of ten LC substances. All the homologs are enantiotropically nematogenic without exhibition of smectic property. Transition and melting temperatures, textures of LC are determined by an optical polarizing microscopy equipped with a heating stage. Textures of nematic phase are threaded or schlieren. Transition curves of a phase diagram behaved in normal manner. Nematic–isotropic transition curve exhibited odd–even effect. Analytical and spectral data supported and confirmed the structures of homologues.
Kher, Seema N.,Prajapati,Chandra, Raviprakash S.,Makwana
p. 1 - 9
(2019/02/24)

Study of the molecular structure on liquid crystal properties with reference to thermotropic azoester derivatives
An azoester homologues series: RO?C6H4?COO?C10H6?N?N?C6H4?OC5H11 (para) as novel liquid crystalline (LC) materials has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on LC properties with reference to laterally substituted phenyl ring and terminally substituted ?OR and ?OC5H11 (n) groups; including ?COO? and ?N?N? central bridges. Novel homologous series of thermotropic LC variety consists of thirteen homologues (C1 to C18). C1 to C3 derivatives are nonliquid crystal (NLC); C4 is only nematogenic and C5 to C18 are smectogenic plus nematogenic. All the mesogenic homologues (C4 to C18) are enantiotropically nematogenic or/and smectogenic as confirmed by a polarizing optical microscopy (POM) equipped with a heating stage. Transition curves Cr-I/M, Sm?N, and N?I behaved in normal manner in a phase diagram. Odd-even effect is exhibited by Sm?N and N?I transition curves. Analytical, spectral and thermal data confirms the molecular structure of novel homologues. Novel azoester series is predominantly nematogenic and partly smectogenic whose mesogenic temperatures ranges minimum to maximum from 79.0°C to 162.0°C. Thermal stability for smectic and nematic are 128.2°C and 147.7 °C, respectively. Thus, it is a middle ordered melting type of novel series whose total mesophaselength ranges from 20.0°C to 56.0°C. Textures of nematic are threaded or schlieren and that of smectic are smectic A or C.
Sharma, Vinay S.,Jadeja,Patel
p. 28 - 39
(2017/03/08)

Molecular flexibility operated mesomorphism by end groups in azoester series
A novel azoester homologous series, RO?C6H4?COO?C6H4?N = N?C6H4?OC7H15(n) (para) has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on mesomorphic properties with reference to tthe flexible terminal chain. The novel azoester series consists of thirteen (C1–C18) members. Mesomorphism commences from C5 homologue. C1–C4 homologues are nonmesomorphic, C5 homologue is only nematogenic and C6–C18 homologues are smectogenic and nematogenic. All mesogenic homologues are enantiotropically mesomorphic. Transition temperatures and textures were determined by polarizing optical microscopy (POM) and a heating stage. Cr-M/I transition curve follows a zigzag path of rising and falling values and behaves in a normal manner. The Sm-N and N-I transition curves of a phase diagram behave in the normal established manner except for a small deviation for the higher homologues (C14 and C16). An odd-even effect is exhibited by Sm-N and N-I transition curves. Analytical spectral and thermal data support the molecular structures. Smectic and nematic thermal stabilities are 93.62°C and 114.3°C, respectively. Smectic and nematic mesophas elengths range from 12.0°C to 18.0°C and 11.0°C to 31.0°C. The series is predominantly nematogenic and partly smectogenic and of middle order melting type. Group efficiency order derived for smectic and nematic. Smectic and nematic: ?OCH3 > ?OC4H9 > ?OC7H15(n).
Jain,Jadeja,Patel
p. 1 - 9
(2017/10/27)

Dependence of mesomorphism on geometrical shapes of isomeric and nonisomeric series of chalconyl esters
A meta substituted chalconyl ester homologous series: RO?C6H4?COO?C6H4(meta)?CO?CH?CH?C6H4?OC12H25(n)(para) is synthesized and studied with a view to understanding the effect of molecular substitution at meta position in a molecular structure on thermotropic liquid crystal properties. The novel homologous series consists of thirteen homologues (C1 to C18). All the homologues except the nonliquid crystal homologues C1, C2, C3 are enantiotropic nematic with the absence of smectic properties. The transition and melting temperatures were determined by an optical polarizing microscopy (POM) equipped with a heating stage. Textures of a nematic phase are threaded or Schlieren. Transition curves (Cr-N/I and N-I) behave in normal manner except homologues between C10 and C14 of N-I curve, which show negligible deviation from normal and a smooth descending tendency. The N-I transition curve exhibits an odd-even effect up to C10 homologue and then the odd-even effect disappears for higher homologues. Analytical and the spectral data support the molecular structures. Thermal stability for nematic is 107.3°C and the mesophase lengths range between 13.0°C and 35.0°C at the C18 and C12 homologues respectively. Group efficiency order for nematic is derived on the basis of thermal stability as ?OC12H25(n) (linear) > ?OC12H25(n) (nonlinear) > ?OC16H33 (nonlinear).
Patel, Priya K.,Shah
p. 168 - 177
(2017/03/08)

Identification of highly potent N-acylethanolamine acid amidase (NAAA) inhibitors: Optimization of the terminal phenyl moiety of oxazolidone derivatives
N-acylethanolamine acid amidase (NAAA) is a cysteine hydrolase that participates in the deactivation of fatty acid ethanolamides, such as palmitoylethanolamide (PEA). NAAA inhibition may provide a potential therapeutic strategy for the treatment of diseases in which higher PEA level is desired. In the present study, we reported the structure-activity relationship (SAR) studies for oxazolidone derivatives as NAAA inhibitors. A series of substituents or alkyl replacements for the terminal phenyl ring of oxazolidone derivatives were examined. The results showed that the inhibition potency of these oxazolidone derivatives towards NAAA depends on the sizes, flexibility, and lipophilicity of the terminal groups. SAR results suggested that small lipophilic 3-phenyl substituents or hydroxy-containing 4-phenyl substituents were preferable for optimal potency. Furthermore, the distal aliphatic replacement is also preferred for high inhibitory potency. Rapid dilution and kinetic analysis suggested that oxazolidone derivatives with different terminal phenyl moieties inhibited NAAA via different mechanisms. This study identified several highly potent NAAA inhibitors, including 1a (F215, IC50 = 0.009 μM), 1o (IC50 = 0.061 μM) and 2e (IC50 = 0.092 μM), and also determined structural requirements of oxazolidone derivatives for potent inhibition against NAAA.
Li, Yuhang,Chen, Qi,Yang, Longhe,Li, Yanting,Zhang, Yang,Qiu, Yan,Ren, Jie,Lu, Canzhong
supporting information
p. 214 - 221
(2017/08/16)

Calamitic-rod-shaped mesogens based on chalcone esters comprising varying alkoxy and lauryl ester chains: Synthesis, mesomorphism and computational study
In this studywe have synthesized a new class of compounds incorporating of chalconyl-ester and terminally substituted lauryl group. A series of new chalcones with three aromatic rings is synthesized and characterised by elemental analyses and spectroscopic techniques such as Fourier transform infrared [FT-IR] and proton magnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and confirmed by differential scanning calorimetry (DSC). It is found that all the prepared materials display enantiotropic LCs phases except first two homologue in present series. The lowermember comp. (C3 to C6) display only SmC phase while comp. (C7 to C12) shows smectic C as well as nematic phase. The higher member comp. (C14 to C18) display only nematic phase in heating and cooling condition. To get more insights, the HOMO, LUMO studies are carried out which supports intramolecular charge transfer interactions in this class of mesogens. (Figure presented.).
Sharma, Vinay S.,Patel, Sunil B.,Sharma, Anuj S.,Patel
p. 32 - 47
(2017/12/26)

Role of molecular structural flexibility on mesomorphism
A homologous series of novel chalconyl ester derivatives: RO.C6H4.COO.C6H4.CO.CH:CH.C6H4.OC6H13(n) shave been synthesized and studied for its thermotropic liquid crystal (LC) properties with a view to understanding and establishing the relation between molecular structure and LC properties. The homologous series consists of eleven members whose, mesomorphism commences from C3 of the series and continues up to the C16 homologue. The C1 and C2 homologues are nonliquid crystals. All the LC homologues are enantiotropically nematogenic with absence of smectogenic character. Transition temperatures were determined by an optical polarizing microscope (POM) equipped with a heating stage. Textures of a nematic phase are threaded or Schlieren. Analytical and spectral data confirms the molecular structures of homologues. Transition curve Cr-N/I behaved in normal manner. N-I transition curve exhibits an odd even effect; descended at C10 homologue and then again rises at C12 and descended from and beyond C12 homologue. Thus it partly deviates from normal behaviour. Thermal stability for nematic is 95–89°C and nematogenic upper and lower mesophase lengths are 41.0°C and 07.0°C respectively. Group efficiency order for nematic on the basis of thermal stability is –OC8H17(n)> -OC6H13(n) > -OC10H21(n) and it is a low order melting type series.
Pandya,Patel
p. 1 - 8
(2017/02/15)

Mesogenic naphthyl derivatives
Two new mesogenic homologous series of liquid crystalline naphthalene derivatives with different central linkages: 2- Naphthyl-4-n-alkoxybenzoates (I) and trans-2-Naphthyl -4-n –alkoxycinnamates(II), have been synthesized and characterized by a combination of elemental analysis and standard spectroscopic methods. Twelve compounds have been synthesized in both the series I and II. In series I, methoxy to n-pentyloxy derivatives are non mesogenic, n-hexyloxy to n-hexadecyloxy derivatives exhibit monotropic nematic mesophase. Smectic A mesophase commences from n-decyloxy derivatives as a monotropy and persist up to the last member synthesized. All the 12 compounds of series II exhibit mesomorphism. Methoxy to n-propyloxy derivatives exhibit monotropic nematic mesophse, and n-butyloxy to n-tetradecyloxy derivatives exhibit enantiotropic nematic mesophase. n-Hexayloxy to n-hexadecyloxy derivatives also exhibit enantiotropic smectic A mesophase. The mesomorphic properties of present series were compared with each other and with a structurally related mesogenic homologous series to evaluate the effects of central linkage on mesomorphism.
Patel,Prajapati
p. 106 - 115
(2017/03/08)

Effect of alkyl chain in the terminal ester group on mesomorphic properties of new rod like homologous series: Synthesis and characterization
The mesomorphic properties of linear chalconyl ester homologous series can be tuned in a predictable fashion with tail groups (–OC5H11) substituents on the terminal side and nitro group substitute at lateral position. Novel series consisted 13 members (C1 to C8, C10, C12, C14, C16, C18). C1 to C5 homologues are nonliquid crystal, C6 to C18 homologues display smectic and nematic mesophase enantiotropically manner except C5 homologue, which show only nematogenic mesophase. The texture of the nematic mesophase is of fan-shaped, Schlieren, and nematic droplets type. All these compounds were characterized by elemental analyses and spectroscopic techniques such as [FTIR] and 1H Nuclear magnetic resonance [NMR] spectroscopy. The mesomorphic properties of these compoundswere observed by optical polarized light microscopy (POM) and differential scanning calorimetry (DSC).
Sharma, Vinay S.,Patel
p. 62 - 75
(2017/03/08)

Mesomorphism in chloro substituted isomeric series including chalconyl central bridge
A novel homologous series of thermotropic liquid crystals α-4-(4′-n-alkoxy benzoyloxy phenyl) β-2″-chloro benzoyl ethylenes have been synthesized and studied with a view to understand and establish the effect of molecular structure on liquid crystal (LC) properties with reference to molecular flexibility in isomeric series with differing positional status of same functional group. Novel homologues series consist of 12 homologues C1 to C16. C1, C2, and C3 homologues are nonliquid crystals (NLC) and rest of the homologues are liquid crystals. C10 to C16 homologues are enantiotropically smectogenic plus nematogenic and C4 to C8 homologues are enantiotropic nematic. The texture of nematogenic derivatives is threaded or schlieren and that of the smectic mesophase are focal conic of the type smectic A or C. Analytical, thermal and spectral data supported molecular structures of novel homologues. Transition temperatures as determine by a hot stage polarizing optical microscopy (POM) were plotted against number of carbon atom present in n-alkyl chain ‘R’ of left n-alkoxy (-OR) group and the phase transition curves Cr–I/M, Sm–N, N–I were obtained on linking like or related points. The odd–even effect is observed for the N–I transition curve and thus transition curves behaved in normal manner. The even-membered nematic transition curve occupied higher position than the odd-membered transition curve. Present series is predominantly nematogenic and partly smectogenic with middle-ordered melting type.
Namera, Dipti L.,Ranchchh, Avani R.,Bhoya
p. 233 - 240
(2017/03/08)

New hockey stick shaped amino allylidene (?N?CH?CH?CH) based compounds: Effect of linkage group on mesomorphic properties
Two nonlinear hockey stick shaped homologous series based on three linking groups have been synthesized and characterized by elemental analyses and spectroscopic techniques. The mesomorphic properties of these compounds were observed by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). In this present investigation, we have synthesized two homologous series viz. 2-((3-phenyl allylidene) amino) phenyl 4-((4-n-alkoxy benzylidene) amino) benzoate (series-1) and 4-((2-((3-phenyl allylidene) amino) phenoxy) carbonyl) phenyl-4-n-alkoxy benzoate (series-2). Both the series are differing with respect to first linking group. In series-1, comp.C4-C18 shows nematic as well as smectic phase while in series-2, comp.C10-C16 shows smectic and nematic phase while comp.C4-C18 shows only nematic phase.
Sharma, Vinay. S.,Vekariya, Rajesh. H.,Sharma, Anuj. S.,Patel
p. 84 - 98
(2017/09/25)

Synthetic pathway for a new calamitic series of liquid crystal: Comparison with corresponding linkage group
Reduction-responsive cystamine-incorporated gelatin microspheres were prepared by an emulsification method. On SEM micrograph, the microsphere, prepared at pH 9.0 and at the carboxyl/amino group molar ratio of 1:1, was sphere-like and its diameter was a few to 100 μm. The gelatin to cystamine ratio of the microsphere was about 1:0.2 (w/w), determined by energy dispersive X-ray spectroscopy. Two endothermic peaks were observed around 92°C and 126°C, which were thought to be the melting point of gelatin-rich phase and that of cystamine-rich phase, respectively. The microsphere released its payload (FITC-dextran) in dithiothreitol (a reducing agent) concentration-dependent manner.
Sharma, Vinay S.,Vekariya, Rajesh H.,Sharma, Anuj S.,Patel
p. 143 - 157
(2017/10/27)

Synthesis and mesomorphic properties of calamitic shaped molecules with chalconyl-ester and lateral fluoro substituents
In this study we have synthesized a new class of compounds incorporating of chalcones and laterally substituted fluoro group. A series of new chalcones with five aromatic rings is synthesized and characterised by elemental analyses and spectroscopic techniques such as Fourier transform infrared [FT-IR] and proton magnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and confirmed by differential scanning calorimetry (DSC). It is found that all the prepared materials display enantiotropic LCs phases except first three homologue in present series. The lower homologues (n = 4 to 12) display SmC and nematic phase while, in higher homologues (n = 14 to 18) only SmC phase were seen in heating and cooling condition.
Sharma, Vinay S.,Sharma, Anuj S.,Vekariya, Rajesh H.,Patel
p. 32 - 44
(2018/03/21)

The effect of position of octadecyloxy tail on the formation of liquid crystal with chalconyl-ester and chalconyl-vinyl ester series: Comparison with corresponding linkage group
Two series of chalconyl-based liquid crystals which differ from each other in the position of the first linking group have been synthesized and characterized by elemental analyses and spectroscopic techniques such as Fourier transform infrared and proton magnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and differential scanning calorimetry (DSC). We have synthesized two homologous series viz. 3-(3-(4-(Octadecyloxy) phenyl) acrylonyl) phenyl 3-(4-n-alkoxyphenyl) acrylate (series-1) and 3-(3-(4-(Octadecyloxy) phenyl) acryloyl) phenyl 4-n-alkoxy benzoate (series-2). Series-1 has chalconyl-ester central linkage group while in series-2 chalconyl-vinyl ester group is present and tail octadecyloxy side chain is common in both homologous series. All the homologous in present series display LC property in enantiotropical manner except first three homologous in both series.
Solanki,Sharma, Vinay. S.,Patel
p. 216 - 232
(2017/03/08)

Synthesis and characterization of rigid rode shape homologous series: Effect of tail iodo group
In this study, the synthesis, structural characterization andmesomorphic properties of newly thirteen calamitic rod-shaped compounds derived from chalcone and 4-n-alkoxy benzoic acid. Here we present, chalcone as central group and terminal side substituted iodo (-I) group containing homologous series. Comp.C1 displayed nonmesogenic nature, while comp.C3 to comp.C18 shows enantiotropic smectic plus nematic property except comp.C2 which show only nematic phase. It is shown that chalcone as central linking unit favors a calamitic liquid crystalline behaviour in molecules. Phase transition temperatures of present synthesised compoundswere determined by optical polarisingmicroscopy (POM), differential scanning calorimetric (DSC). Thermal stabilities for smectic and nematic mesophases are 150.18 and 163.58 respectively.
Sharma, Vinay S.,Sharma, Anuj S.,Patel
p. 158 - 171
(2017/10/27)

Synthesis and properties of new calamitic-shaped liquid crystal compounds with disubstituted octadecyloxy (?OC18H37) tail groups
In present study, we have synthesized such newly chalcone-ester linking group based homologous series containing disubstituted octadecyloxy tail part. A series of new chalcones with having three aromatic rings is synthesized and characterised by elemental analyses and spectroscopic techniques such as Fourier transform infrared [FT-IR] and proton magnetic resonance magnetic resonance [1H NMR] spectroscopy. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and confirmed by differential scanning calorimetry (DSC). It is found that all the prepared materials display enantiotropic LCs phases except first three homologue in present series. Comp. C1 to C12 exhibits only enantiotropic nematic phase. However, in higher member comp.C14 to C18 shows enantiotropic SmC and nematic phase. Thermal stability of smectic and nematic phase of present series is found to be 51.33°C and 109.0°C.
Sharma, Vinay S.,Sharma, Anuj S.,Patel
p. 45 - 58
(2018/03/21)

Study of mesomorphism dependence on molecular flexibility of an azoester series containing a napthyl unit
A novel azoester homologous series of liquid crystalline (LC) compounds: RO?C6H4-COO?C10H6-N:N-C6H4?OC4H9(n) without lateral substitution has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on thermotropic LC substances with reference to tailed-end group. The novel homologous series consists of 13 homologs (C1 to C18) whose nematogenic and smectogenic mesomorphism commences enantiotropically from C6 and C12 members of the series, respectively. The C12–C18 homologs are smectogenic and C6–C18 are nematogenic, of which C12–C18 homologs are smectogenic plus nematogenic. The C1–C5 homologs are nonmesogenic. Transition temperatures and the textures of the homologs were determined and identified by an optical polarizing microscope (POM) equipped with a heating stage. Textures of a nematic phase are threaded or Schlieren and that of the smectic phase are of the type A or C. Transition curves Cr-M/I, Sm-N and N-I of a phase diagram behaved in normal manner except N-I transition temperature of C10 homolog which deviated by 9°C–10°C from normal behavior. N-I transition curve exhibited odd-even effect. Analytical, spectral, and thermal data confirms the molecular structures of homologs. Thermal stability for smectic and nematic are 115.5°C and 138.5°C, respectively whose corresponding mesophaselengths are varied from 10.0°C to 16.0°C and 13.0°C to 24.0°C, respectively. Group efficiency order for smectic and nematic are derived from comparative study of structurally similar analogous series; as smectic: ?OC4H9 (n) > ?CH3 > ?H; Nematic: ?H > ?OC4H9 (n) > ?CH3
Jadeja,Patel
p. 10 - 18
(2016/11/21)

Dependence of LC state on molecular flexibility
A novel azoester homologous series of liquid crystals (LCs) viz. RO?C6H4COOC10H6-N?N(ortho)-C6H4?OC4H9(para) has been synthesized and studied with a view to understanding and establishing the effect of molecular structure on LC properties. Homologous Series consists of thirteen members (C1 to C18). C1 to C3 members are nonliquid Crystals and the rest of the homologues are LC in an enantiotropic manner. C7 to C18 are smectogenic in addition to nematogenic whereas C4, C5, and C6 are only nematogenic. The Sm-N and N?I transition curves behave in a normal manner with the usual exhibition of an odd–even effect. The Cr-M/I curve also behaves in a normal manner. Analytical and spectral data confirm the molecular structures of homologues. The average smectic and nematic thermal stabilities are 60.31°C and 79.6°C, respectively, with total mesophase length varying minimum to maximum is 21°C to 57°C at the C6 and C14 homologue, respectively. Thus, present novel azoester homologous series is partly smectogenic and predominantly nematogenic with low ordered melting type and useful to construct LC devices workable at low temperatures or room temperature.
Jadeja,Sharma, Vinay S.,Jain,Patel
p. 144 - 153
(2016/07/14)

Mesomorphism dependence on the combined effect of molecular rigidity and flexibility
A novel liquid crystalline (LC) homologous series of azoesters with a laterally substituted methoxy group RO-C6H4-COO-C6H3-(-OCH3)-N═N-C6H4-COO-C4H9(n) has been synthesized and studied with a view to understanding the effect of molecular structure on thermotropic mesomorphism. The novel homologous series consists of thirteen homologues (C1–C18). The C1–C5 homologues are nonliquid crystals. The C6 and C7 homologues are only enantiotropically nematogenic and the rest of the mesomorphic homologues (C8–C18) are enantiotropically smectogenic and nematogenic. Transition temperatures and the textures of the mesophases were determined using an optical polarizing microscope (POM) equipped with a heating stage. The novel azoester homologues were characterised and confirmed using their analytical, spectral and thermometric data. Transition curves Cr-M/I, Sm-N and N-I behaved in normal manner without (Sm-N) and with (N-I) exhibition of odd-even effect respectively in a phase diagram. Thermal stabilities for smectic and nematic are 100.0°C and 127.7°C whose, mesomorphic phase length vary from 13.0°C to 24.0°C and 11.0°C to 33.0°C, respectively. The mesomorpism is compared with other known series.
Jadeja,Patel
p. 17 - 26
(2016/11/21)

Mesomorphism dependence on central bridge (-COO-CH2-) and terminal end group (-Br)
A novel series of liquid crystalline (LC) ester materials has been synthesized and studied with a view to understanding the effects of molecular structure on LC behavior. The homologous series of eleven members is entirely enantiotropically smectogenic without exhibition of a nematic phase. Transition temperatures and the texture of smectic phase was determined by an optical polarizing microscope equipped with a heating stage (POM). Transition curves (Cr-Sm and Sm-I) showing phase behavior in a phase diagram behave in a normal manner. Textures of smectic phase are focal conic fan shaped of the type Smectic-A or Smectic-C. An odd-even effect is exhibited by the Sm-I transition curve. The average thermal stability for smectic is 91.2°C and the mesogenic phase length ranges between 3.6°C and 39.3°C. Thus, the novel smectogenic homologous series is a middle-ordered melting type whose LC phase is relatively middle ordered. The LC properties of the present series are compared with a structurally similar homologous series. Analytical and spectral data support the molecular structures.
Marathe, Rajesh B.,Doshi
p. 122 - 131
(2016/02/19)

Study of mesomorphism and its relation to molecular structure with special reference to central bridges viz. -COO- and -CH=CH-COO- of the homologous series
Two ester homologous series of mesogens, viz., Methyl-p-(p′-n-alkoxy benzoyloxy) cinnamates (X) and Methyl-p-(p′-n-alkoxy cinnamoyloxy) cinnamates (Y) being structurally similar are discussed. Both (X) and (Y) differ in respect of central bridges linking two phenyl rings. Only enantiotropic nematogenic character is observed without exhibition of any smectic character by all members of series (X) and (Y). Thermal stability of series (X) is relatively low as compared to (Y), but nematogenic mesophase lengths are of reverse order. Solid-nematic/solid-isotropic and nematic-isotropic transition curves in the phase diagrams behave in normal manner.
Sharma,Solanki,Patel,Patel
p. 137 - 145
(2016/03/01)

Mesomorphism Dependence of Chalconyl Derivatives on Position of -CH=CH- Unit
A novel homologous series of heterocyclic chalconyl esters (C1 to C16) has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on liquid crystal (LC) properties and the degree of liquid crystallinity. The C1 to C6 homologues are not liquid crystals, the C7 homologue is enantiotropic nematic, the C8 to C16 homologues are smectogenic in addition to nematogenic (C8 & C10 monotropic smectic). The texture of nematic phases are threaded or Schlieren and that of the smectic phase are fan-shaped smectic-A or smectic-C type. Transition temperatures and the textures of mesophases were determined by an optical polarizing microscope equipped with a heating stage. Transition curves Cr-I/M, Sm-N/N-Sm, and N-I showing phase behaviors of series in a phase diagram behave in normal manner. Thermal stability for smectic and nematic are 115.66°C and 126.83°C and their mesophase lengths minimum to maximum are 6.3 to 12.9°C and 6.9°C to 17.4°C, respectively. Analytical and spectral data confirms the molecular structures of homologues. LC properties of present novel series are compared with structurally similar other reported series.
Rakhasia,Bhola,Bhoya
p. 81 - 89
(2016/04/05)

Mesomorphism of azo-esters and chalcone-esters
AOne chalcone-ester homologous series of mesogens α-4-[4/-n-alkoxybenzoyloxy phenyl β-4//methoxy benzoyl ethylenes (A) and one azo-ester homologous series of mesogens p-(p/-n-alkoxybenzoyloxy) phenyl azo-p//-methoxy benzene (B) being structurally similar are discussed. Both series (A) and (B) differ in respect of central bridges linking two phenyl rings. Mesomorphic properties start from 6th and 1st member of series (A) and (B) respectively. In series (A), 6th to 12th members show both smectogenic and nematogenic properties, and the 14th and 16th members show only nematogenic property. While in series (B), 1st to 10th members show nematogenic properties, 11th member shows both smectogenic and nematogenic properties, while 12th member shows only smectogenic property. Thermal stability of series (A) is relatively high as compared to series (B). Transition temperatures are observed through hot stage polarizing microscope by the miscibility method. Analytical data support the structure of molecules. Textures of series (A) in nematic are threaded and Schlieren in SmecticSmectic A type, while that of series (B) in nematic are threaded in SmecticSmectic A and smectic C.
Jain,Sharma, Vinay S.,Chauhan,Patel
p. 102 - 111
(2016/07/14)

Dependence of thermotropic mesomorphism on flexible tail group
A novel homologous series RO-C6H4-COO-C6H4-CO-CH:CH-C6H4-OC12H25 of chalcones have been synthesized and studied with a view to understand and establish the effects of molecular structure on liquid crystal (LC) properties of a substance. Liquid crystal properties of a novel series commences from C6 homologue and continue upto the last C18 homologue derivative of a series, as enantiotropically nematogenic without exhibition of smectogenic characteristic. The rest of the homologues (C1 to C5) are nonliquid crystals (NLC). Transition temperatures of homologues (C1 to C18) are determined by an optical polarizing microscopy equipped with a heating stage. Textures of a nematic phase are threaded or schlieren. Transition curves of a phase diagram behaved in normal manner except for C18 member of a series, which drastically behaved with abnormal manner. N-I transition curve exhibits odd–even effect. Average thermal stability for nematic is 110.25°C and mesophase length ranges from 10°C to 39°C. Analytical and spectral data supported the molecular structures of homologues. LC properties of present novel series are compared with structurally similar other known homologous series. Thus, present novel series of chalcones is partly nematogenic and of middle-ordered melting type.
Patel, Priya K.,Shah
p. 130 - 138
(2016/07/14)

The effect of molecular rigidity and flexibility on the mesomorphism of azoesters
ASBTRACT: An Azoester novel homologous series RO-C6H4-COO-C6H4-N?N-C6H4-OC4H9(n) (para) of liquid crystalline (LC) materials are synthesized and studied with a view to understanding and establishing the effects of molecular structure on liquid crystal behavior with reference to lateral, terminal, or central group or groups on the basis of molecular rigidity and/or flexibility. The novel homologous series consists of thirteen (C1 to C18) homologues. C1 to C5 homologues are nonmesogenic and the rest of the homologues are enantiotropically mesogenic. C8 to C18 homologues are smectogenic plus nematogenic and the remaining two C6 and C7 homologues are only nematogenic without exhibition of smectic property. Analytical, thermal and spectral data confirms the molecular structures. Textures and transition temperatures of homologues were determined by an optical polarizing microscope (POM) equipped with a heating stage. Textures of a nematic phases are threaded or Schlieren and that of a smectic phase are of the type of A or C. The average thermal stabilities for smectic and nematic are 111.3°C and 124.7°C, respectively. The smectic and nematicmesophase lengths from 10.0°C to 28.0°C and 7.0°C to 16.0°C, respectively. The transition temperatures are compared with known series.
Jadeja,Patel
p. 28 - 36
(2016/11/21)

Mesomorphism dependence on molecular rigidity with reference to -CH=CH- unit of central bridge
A novel ester homologous series of rich mesomorphism and low temperatures with unexpected phase behaviors of eleven homologues was synthesized and studied with a view to understanding and establishing the relation between mesomorphic behaviour and the molecular structure of a series 4-(4′-n-alkoxybenzoyloxy)-4″-chlorobenzyl cinnamates. All the members of the novel series are enantiotropically smectogenic and the octyloxy (C8) to hexadecyloxy (C16) homologues are enantiotropically nematogenic, in addition to smectogenic. Odd-even effect is observed for Sm-I/Sm-N transition curve but it is absent for N-I transition curve. Textures of nematic phase are threaded or Schlieren and that of the smectic phase are fan shaped or batonates of smectic-A type phase or Smectic-C type for C16 homologues as judged directly from a heating stage of an optical polarizing microscopy. Analytical and spectral data confirmed the molecular structures of novel homologues. Mesomorphic properties of present series are compared with the structurally similar other known series. The average smectic and nematic thermal stabilities are 92.78°C and 100.8°C, respectively. Mesophase length minimum to maximum for smectic and nematic are 21.0°C to 31.1°C and 8.4°C to 42.6°C respectively. Thus, the present novel series is partly nematogenic and fully smectogenic with considerable degree of mesomorphism and low melting type.
Marathe,Doshi
p. 81 - 92
(2016/03/08)

A series of 2, 4, 5-trisubstituted oxazole: Synthesis, characterization and DFT modelling
A new series of 2,4,5-trisubstituted oxazole were synthesized with good yields using simple methodology. All the compounds were thoroughly characterized by IR, NMR (1H and 13C) and mass spectrometry and structures of 2-(4-butyloxyphenyl)-4,5-dimethyloxazole (5b) and 4,5-dimethyl-2-(4-(octyloxy)phenyl)oxazole(5e) were unambiguously determined by X-ray crystallography. Evidently, the crystal structures of these compounds showed C-HaN and C-HaO intermolecular interactions. The electronic structures of these compounds were also studied by DFT at B3LYP/6-311G ++ level of theory.
Kadam, Vinay S.,Shaikh, Saminaparwin G.,Patel, Arun L.
p. 181 - 188
(2016/03/12)

Dependence of thermotropic mesomorphism on molecular flexibility of changing tail group
A novel chalconyl ester homologous series of liquid crystals has been synthesized and studied with a view to understanding and establishing the effect of molecular structure on liquid crystalline properties. Novel series consisted of 13 members (C1–C18) of a series. C1–C4 member of a series is nonliquid crystals and, the rest of the homolog members (C5–C18) are enantiotropically nematogenic with absence of smectogenic property. None of the homolog is monotropically mesomorphic. Transition and melting temperatures were determined by an optical microscope equipped with a heating stage. Textures of nematic phase are threaded or schlieren. Spectral and analytical data of selected members of a series confirms the molecular structures of homologues. Cr-N and N-I transition curves of a phase diagram behaved in normal manner with exhibition of odd-even effect of very short range as observed for N-I transition curve. Thermal stability for nematic is 122.0°C and the nematogenic mesophase ranges from 7.0°C to 38.0°C. Liquid crystal properties of a present series are compared with the structurally similar known homologous series.
Solanki, Ravindra,Sharma, Vinay,Patel, Roshan
p. 107 - 115
(2016/07/21)

Study of mesomorphism and laterally substituted nitro group
A novel thermotropically mesomorphic, meta-substituted nitro group of chalconyl ester series, RO-C6H4-COO-C6H3-(NO2)-CO-CH=CH-C6H4OC12H25(n) (para) is synthesized and studied with an aim to establish the relation between molecular structure and the mesomorphism with reference to changing molecular flexibility in presence of nitro lateral group. Novel homologous series consist of thirteen homologs (C1–C18) whose mesomorphism commences from C5 homolog as enantiotropic nematogenic with absence of smectic property, even in the monotropic condition. Transition temperatures of novel substances were determined by an optical polarizing microscope, equipped with a heating stage (POM). Textures of a nematic phase are threaded or Schlieren. N-I transition curve exhibited narrow, sharp and short odd-even effect; with deviating trend in a phase diagram. Analytical, spectral and thermal data confirmed the molecular structures of homologs. Thermal stability for nematic is 182.89°C, whose mesophase lengths minimum to maximum ranges from 17°C to 45°C and it is an upper middle ordered melting type series. Group efficiency order for nematic is series 1 > series Y > series X, as derived from comparative study of structurally similar analogous series.
Patel, Priya K.,Shah
p. 41 - 49
(2016/10/04)

Study of novel thermotropic liquid crystals with lateral nitro substituent
In this article, we report synthesis and characterization of a novel thermotropic liquid crystals, namely, 4-bromo-[3′-nitro-4′(4″-n-alkoxybenzoyloxy)] phenyl azobenzenes. The first member of a homologous series is nonmesogenic in nature. The n-ethyl to n-decyl homologues exhibit enantiotropic nematic mesophases, while the n-dodecylton -hexadecyl homologues exhibit only smectic mesophases. The synthesized compounds were characterized by a combination of elemental analysis and standard spectroscopic methods. The mesogenic behavior of present series is explained by comparing each homologue of the related mesogenic series. The impact of the lateral nitro group on mesomorphism is also discussed.
Dixit,Intwala
p. 1 - 8
(2016/07/21)