- Experimental and theoretical studies of 2-Mercaptobenzothiazole with 2-Bromomethylmesitylene and 1,4-Bis(bromomethyl)durene
-
Biologically important 2-(2,4,6-trimethylbenzylthio)benzo[d]thiazole[BTM1] and 2-(4-((benzo[d]thiazol-2-ylthio)methyl)-2,3,5,6-tetramethylbenzylthio)benzo[d]thiazole [BTD2] were synthesized and characterised using FT-IR, NMR and single-crystal XRD (SCXRD). SCXRD revealed that both compounds were crystallized as a triclinic system and were associated through weak intermolecular interactions like H-bondings (CH…N, sp3-, and sp2-CH…π), π-π stackings and Vander Waals interactions. These weak intermolecular interactions in BTM1 and BTD2 were studied using Crystal Explorer and Gaussian. The interaction of title compounds with epidermal growth factor receptor (EGFR)tyrosine kinase protein was performed using AutoDock Vina. Molecular docking study revealed an efficient interaction of compounds with the protein resulting in good anti-cancer activity. DNA binding studies were explored against calf thymus (CT) DNA using a spectrophotometric titration method and was found that benzothiazole compounds showed hyperchromism and good binding efficiency. In-vitro anti-microbial activities against some bacterial and fungal strains were investigated. BTM1exhibited a better inhibition against bacterial (Bacillus subtilis and Staphylococcus aureus) and fungal (Aspergillus niger) strains than BTD2.
- Asha, R. Nandini,Bhuvanesh, N.,Daisy, Caroline,Kumar, G. S. Suresh,Nayagam, B. Ravindran Durai,Vadivel, E.
-
-
Read Online
- Intervalence (Charge-Resonance) Transitions in Organic Mixed-Valence Systems. Through-Space versus Through-Bond Electron Transfer between Bridged Aromatic (Redox) Centers
-
Intervalence absorption bands appearing in the diagnostic near-IR region are consistently observed in the electronic spectra of mixed-valence systems containing a pair of aromatic redox centers (Ar+/Ar) that are connected by two basically different types of molecular bridges. The through-space pathway for intramolecular electron transfer is dictated by an o-xylylene bridge in the mixed-valence cation radical 3.+ with Ar = 2,5-dimethoxy-p-tolyl (T), in which conformational mobility allows the proximal syn disposition of planar T.+/T redox centers. Four independent experimental probes indicate the large through-space electronic interaction between such cofacial Ar.+/Ar redox centers from the measurements of (a) sizable potential splitting in the cyclic voltammogram, (b) quinonoidal distortion of T.+/T centers by X-ray crystallography, (c) "doubling" of the ESR hyperfine splittings, and (d) a pronounced intervalence charge-resonance band. The through (br)-bond pathway for intramolecular electron transfer is enforced in the mixed-valence cation radical 2a.+ by the p-phenylene bridge which provides the structurally inflexible and linear connection between Ar.+/Ar redox centers. The direct comparison of intramolecular rates of electron transfer (kET) between identical T.+/T centers in 3.+ and 2a.+ indicates that through-space and through-bond mechanisms are equally effective, despite widely different separations between their redox centers. The same picture obtains for 3.+ and 2a.+ from theoretical computations of the first-order rate constants for intramolecular electron transfer from Marcus-Hush theory using the electronic coupling elements evaluated from the diagnostic intervalence (charge-transfer) transitions. Such a strong coherence between theory and experiment also applies to the mixed-valence cation radical 7.+, in which the aromatic redox S center is sterically encumbered by annulation.
- Sun,Rosokha,Lindeman,Kochi
-
-
Read Online
- Preparation, crystal structures and conformations of six complexes based on 1,4-bis(benzimidazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene
-
Reaction of ligands (L or LA) with metal salts affords six new metal complexes {[Mn(L)3](ClO4)2}n (1), [Cu(L)(SO4)(H2O)]·1.5H2O (2), [Co(L)(LA)(CH3OH)2]·2CH3OH (3), [Co(L)(DMF)(NO3)2]n (4), [Cd(L)(DMF)(NO3)2]n (5) and [Cu(L)(DMF)(NO 3)2]n (6) (L = 1,4-bis(benzimidazol-1-ylmethyl) -2,3,5,6-tetramethylbenzene, LA = fumarate). These complexes are structurally characterized by X-ray diffraction analyses. Analyses of crystal structures of complexes 1 and 2 show that 2D layers with metallomacrocycles are formed via ligand L and metal atoms (Mn(ii) for 1 and Cu(ii) for 2). The 2D layer with metallomacrocycles in complex 3 is formed via ligand L, fumarate groups and Co(ii) atoms. 1D polymeric chains in complexes 4-6 are formed via ligand L and metal atoms (Co(ii) for 4, Cd(ii) for 5 and Cu(ii) for 6). In the crystal packing of complexes 1-6, 3D supramolecular frameworks are formed via intermolecular weak interactions, including π-π interactions and C-H...π contacts. π-π interactions between benzimidazole rings are compared. The conformations of metal complexes based on dibenzimidazolyl bidentate ligands with flexible or semi-rigid linkers are described and compared. Additionally, the fluorescence emission spectra of ligand L and metal complexes and the magnetic properties of complexes 2-4 are reported. This journal is the Partner Organisations 2014.
- Liu, Qing-Xiang,Zhao, Zhi-Xiang,Zhao, Xiao-Jun,Bi, Yue,Yu, Jie,Wang, Xiu-Guang
-
-
Read Online
- Synthesis, structural, spectral, antidiabetic, DNA interactions and molecular docking investigations of a piperidine derivative
-
A new organic piperidine derivative named as 4‐methyl‐1‐({2,3,5,6‐tetramethyl‐4‐[(4‐methylpiperidinyl)methyl]phenyl}methyl)piperidine (D24MP) was synthesized and characterized by single crystal X-ray diffraction (SCXRD) and diverse spectroscopic (1H &13C NMR and FT-IR) techniques. The monoclinic structure of D24MP crystallises with the space group P-1. Density Function theory (DFT) using the B3LYP/6–31++G(d,p) level basis set was used to get the optimised geometry and non-linear optical properties. MEP surface analysis was used to investigate the crystal's nucleophilic and electrophilic reactive sites. The molecular shape and intermolecular interactions in the crystal structure were determined using Hirshfeld surface analysis and fingerprint plots. The physicochemical, pharmacokinetic and toxicological properties of D24MP have been evaluated by using drug-likeness and insilico ADMET studies. The molecule's first hyperpolarizability (β) estimation is 3.65 times higher than urea. Antidiabetic, antioxidant and DNA binding ability of D24MP were investigated by experimental and theoretical techniques. The obtained results suggest that D24MP possesses better antidiabetic, antioxidant and DNA binding abilities. Gel-electrophoretic method results suggest that D24MP has better cleaving capability against CT-DNA at higher concentrations (100 μg).
- Asha, Radhakrishnan Nandini,Bhuvanesh, Nattamai,Nayagam, Balasingh Ravindran Durai,Sankarganesh, Murugesan
-
-
- Refining the model to design α-chymotrypsin superactivators: The role of the binding mode of quaternary ammonium salts
-
A number of quaternary ammonium salts with bulky hydrophobic moieties are known to provoke the superactivation of α-chymotrypsin (α-CT) in aqueous solution. In particular, benzyl-substituted ammonium and dicationic ammonium-based salts have recently emerged as promising classes of compounds to induce α-CT superactivation and stabilization. Preliminary in silico modelling suggested the α-CT residue tryptophan 215 to be the major anchor point of these additives. In order to achieve a broader knowledge of the enzyme-additive interactions and to validate the modelling studies, new ammonium-based additives were designed and tested. The hydrophobic interaction resulted in being critical to improving superactivation, with [(2,3,5,6-tetramethyl-p-phenylene)dimethylene]bis[triethylammonium bromide] (bisEDuEAB) resulting as the most effective quaternary ammonium superactivating agent studied so far. Finally, a general agreement between in silico outcomes and kinetic parameters was observed, and data interpretation is discussed based on the proposed α-CT/additive binding modes. This journal is
- Gabriele, Francesco,Goracci, Laura,Germani, Raimondo,Spreti, Nicoletta
-
p. 20823 - 20833
(2020/12/28)
-
- Asymmetric epoxidation of unfunctionalized olefins with C2-symmetrical diphenol-derived axially coordinated homogeneous chiral bi-Mn(III) salen complexes
-
A novel type of C2-symmetrical diphenol-derived and axially coordinated homogeneous chiral bi-Mn(III) salen complexes are synthesized and their catalytic effects in asymmetric epoxidation of unfunctionalized olefins are investigated in details. The results show that excellent enantioselectivities and high activities are achieved (enantioselectivities up to >99% in 99.9%) in the absence of expensive NMO. Compared with Jacobsen's catalyst, the configuration of C2-symmetrical homogeneous chiral bi-Mn(III) salen complex contribute to the catalytic reactivity and stability. Furthermore, these new homogeneous catalysts could be easily recovered and reused for 5 cycles without significant loss of their properties.
- Dong, Tianyi,Wu, Xiaoju,Cai, Jiali,Huang, Jing
-
-
- Cyclic bis-benzimidazole hexafluorophosphate compound as well as preparation method and application thereof
-
The invention discloses a preparation method of a cyclic bis-benzimidazole hexafluorophosphate compound and application thereof. The preparation method comprises the following steps: taking 2,3,5,6-tetramethylbenzene as a raw material in an organic solvent, and reacting with paraformaldehyde, glacial acetic acid, concentrated sulfuric acid and potassium bromide so as to obtain 1,4-bisbromomethyl-2,3,5,6-tetramethylbenzene; reacting with benzimidazole to obtain an intermediate (Y), reacting with 1,8-bis(2-bromoethoxy) anthraquinone so as to obtain a bromide (1) of a cyclic bis-benzimidazole salt; and exchanging the cyclic bis-benzimidazole salt and hexafluorophosphate, thereby obtaining the cyclic bis-benzimidazole hexafluorophosphate compound (2). The cyclic bis-benzimidazole hexafluorophosphate compound disclosed by the invention has the advantages of being simple in preparation and obvious in fluorescent sensitization effect, can be used for manufacturing a fluorescent molecular recognition system and is mainly applied to the technical field of fluorescent recognition.
- -
-
Paragraph 0015
(2018/03/26)
-
- Macrocyclic Receptor for Precious Gold, Platinum, or Palladium Coordination Complexes
-
Two macrocyclic tetralactam receptors are shown to selectively encapsulate anionic, square-planar chloride and bromide coordination complexes of gold(III), platinum(II), and palladium(II). Both receptors have a preorganized structure that is complementary to its precious metal guest. The receptors do not directly ligate the guest metal center but instead provide an array of arene π-electron donors that interact with the electropositive metal and hydrogen-bond donors that interact with the outer electronegative ligands. This unique mode of supramolecular recognition is illustrated by six X-ray crystal structures showing receptor encapsulation of AuCl4-, AuBr4-, PtCl4-2, or Pd2Cl6-2. In organic solution, the 1:1 association constants correlate with specific supramolecular features identified in the solid state. Technical applications using these receptors are envisioned in a wide range of fields that involve precious metals, including mining, recycling, catalysis, nanoscience, and medicine.
- Liu, Wenqi,Oliver, Allen G.,Smith, Bradley D.
-
supporting information
p. 6810 - 6813
(2018/05/31)
-
- Chiral and achiral basket-handle porphyrins: Short synthesis and stereostructures of these versatile building blocks
-
Both, chiral and achiral basket-handle porphyrins were synthesized via a short, reliable, and efficient route in multigram quantities. Standard synthetic protocols such as metalation of the macrocycle, halogenation, and borylation of the porphyrin core or alkyl- and arylation with lithium organyls were successfully adapted. The planar-chiral representatives were resolved into their enantiomers, whose absolute configurations were determined by comparison of experimental CD spectra with TDCAM-B3LYP calculated ones.
- Gehrold, Andreas C.,Bruhn, Torsten,Schneider, Heidi,Radius, Udo,Bringmann, Gerhard
-
p. 210 - 213
(2015/03/05)
-
- Zinc metal-organic frameworks based on a flexible benzylaminetetracarboxylic acid and bipyridine colinkers
-
Three new metal-organic frameworks (MOFs), [Zn2(L)(H 2O)]·3DMF·1.5H2O (1), [Zn 2(L)(4,4-bpy)1.5(H2O)2] ·2DMF·2H2O (2), and [Zn2(L)(2,2-bpy) 2(DMF)2]·2DMF·4H2O (3) [H 4L = 5,5-(2,3,5,6-tetramethyl-1,4-phenylene)bis(methylene) bis(azanediyl)diisophthalic acid, 4,4-bpy = 4,4-bipyridine, 2,2-bpy = 2,2-bipyridine, DMF = N,N-dimethylformamide], were synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction analysis, elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). The L4- ligands in 1-3 display different coordination modes, and the introduction of bipyridine colinkers brings significant structural variation into the frameworks. Complex 1 is constructed from dinuclear carboxylate [Zn2O(COO)4] secondary building units (SBUs) and H4L ligands and exhibits a binodal (4,4)-connected pts net with 54.6 % solvent-accessible void. Complex 2 exhibits an unprecedented tetranodal (3,4,4,4)-connected net, which is constructed from two types of crystallographically independent ZnII ions, H4L ligands, and the 4,4-bipyridine colinker. Complex 3 is constructed from parallel 1D molecular ladders stacked along the a axis that generate 1D channels (7.8 × 10.4 A?) and are hydrogen bonded to form 2D layers. The thermal stabilities and luminescence properties of 1-3 have also been studied in detail. Copyright
- Wang, Chao,Tang, Sifu,Lv, Xiaoxia,Li, Liangjun,Zhao, Xuebo
-
supporting information
p. 3133 - 3139
(2014/07/21)
-
- Zinc Metal-Organic Frameworks Based on a Flexible Benzylaminetetracarboxylic Acid and Bipyridine Colinkers
-
Three new metal-organic frameworks (MOFs), [Zn2(L)(H2O)]·3DMF·1.5H2O (1), [Zn2(L)(4,4′-bpy)1.5(H2O)2]·2DMF·2H2O (2), and [Zn2(L)(2,2′-bpy)2(DMF)2]·2DMF·4H2O (3) [H4L = 5,5′-(2,3,5,6-tetramethyl-1,4-phenylene)bis(methylene)bis(azanediyl)diisophthalic acid, 4,4′-bpy = 4,4′-bipyridine, 2,2′-bpy = 2,2′-bipyridine, DMF = N,N-dimethylformamide], were synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction analysis, elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). The L4- ligands in 1-3 display different coordination modes, and the introduction of bipyridine colinkers brings significant structural variation into the frameworks. Complex 1 is constructed from dinuclear carboxylate [Zn2O(COO)4] secondary building units (SBUs) and H4L ligands and exhibits a binodal (4,4)-connected pts net with 54.6% solvent-accessible void. Complex 2 exhibits an unprecedented tetranodal (3,4,4,4)-connected net, which is constructed from two types of crystallographically independent ZnII ions, H4L ligands, and the 4,4′-bipyridine colinker. Complex 3 is constructed from parallel 1D molecular ladders stacked along the a axis that generate 1D channels (7.8 × 10.4 ?) and are hydrogen bonded to form 2D layers. The thermal stabilities and luminescence properties of 1-3 have also been studied in detail.
- Wang, Chao,Tang, Sifu,Lv, Xiaoxia,Li, Liangjun,Zhao, Xuebo
-
p. 3133 - 3139
(2015/04/27)
-
- Enantioselective epoxidation of nonfunctionalized alkenes catalyzed by recyclable new homochiral bis-diamine-bridged bi-Mn(salen) complexes
-
Three new homochiral bis-diamine-bridged bi-Mn(salen) complexes were synthesized. Their catalysis on asymmetric epoxidation of α-methylstyrene, styrene and indene was studied with NaClO and m-CPBA as oxidants respectively. This homogeneous catalyst exhibited comparable catalytic activity and enantioselectivity to the Jacobsen's catalyst in the asymmetric epoxidation of unfunctionalized olefins. Furthermore, the catalyst could be conveniently recovered and reused at least five times without significant losses of both activity and enantioselectivity. Specially, it also could be efficiently used in large-scale reactions with superior catalytic disposition being maintained at the same level, which provided the potential for the applications in industry. The effect of axial bases, temperature and solvent on activity and enantioselectivity of the catalytic system were also studied.
- Huang, Xuemei,Fu, Xiangkai,Jia, Ziyong,Miao, Qiang,Wang, Guoming
-
p. 604 - 611
(2013/07/19)
-
- Novel bis-Salen Mn(III) chiral complexes of rigid structure axially coordinated with bis-diphenolate and bis-diamine for epoxidation of unfunctionalized olefins
-
A series of bis-Salen Mn(III) chiral complexes of rigid structure axially coordinated with bis-diphenolate and bis-diamine ligands were synthesized and their catalytic performances in asymmetric epoxidation of indene and α-methylstyrene were investigated in detail. Compared with Jacobsen's catalyst and the corresponding monomer salen Mn(III) catalyst, bis-Salen Mn complex showed higher activity and enantioselectivity under the same reaction conditions. A point worth emphasizing was that the bis-diphenolate axially coordinated bis-Salen Mn catalysts afforded remarkable increases of ee values in the absence of axial base NMO for the asymmetric epoxidation of olefins, especially for the epoxidation of indene (ee: from 55% to 100%), however, the axial base is indispensable for the bis-diamine axially coordinated bis-Salen Mn(III) catalysts, these performance might attribute to the rigid difference of the structure. Furthermore, the catalyst could be conveniently recovered and reused at least five times without significant losses of both activity and enantioselectivity. Specially, it could also be efficiently used in large-scale reactions with superior catalytic disposition being maintained at the same level, which possessed the potentiality for application in industry.
- Huang, Xuemei,Fu, Xiangkai,Wu, Xiaoju,Jia, Ziyong
-
p. 4041 - 4044
(2013/07/25)
-
- Synthesis, crystal structure and luminescence properties of lanthanide complexes with a new semirigid bridging furfurylsalicylamide ligand
-
We present here new lanthanide coordination polymers based on a semirigid bridging furfurylsalicylamide ligand which were synthesized and characterized by elemental analysis, X-ray powder diffraction and IR measurements. The coordination polymer [Pr2L3(NO3) 6]∞ displays a two-dimensional honeycomb-like framework, which can be regarded as a (6,3) topological network with praseodymium atoms acting as "three-connected" centers. The photoluminescence analysis indicates that there is an efficient ligand-to-LnIII energy transfer in TbIII complex and the ligand is an efficient "antenna" for TbIII. From a more general perspective, the results demonstrated herein provide the possibility of controlling the formation of the desired lanthanide coordination structure to enrich the crystal engineering strategy and enlarges the arsenal for developing excellent luminescent lanthanide complexes of salicylamide derivatives.
- Song, Xue-Qin,Wang, Li,Zheng, Qing-Fang,Liu, Wei-Sheng
-
scheme or table
p. 171 - 178
(2012/10/08)
-
- Lanthanide radii controlled one-dimensional polymer and dinuclear complexes and their fluorescent properties
-
A bi-phosphonate ligand tetraethyl-(2,3,5,6-tetramethyl-1,4-phenylene) bis(methylene)diphosphonate has been designed and synthesized. The bi-phosphonate as a bridging ligand reacts with lanthanide nitrates forming four different types of 1D coordination complexes: ribbon polymer (type I), semi-ribbon polymer (type II), zigzag polymer (type III),1 and dinuclear-triligand short chain (type IV), which changed according to the decrease of the radius of the lanthanide. They have been characterized by IR spectroscopy, elemental analysis, and X-ray diffraction spectroscopy. The photophysical properties of Sm3+, Eu3+, Tb3+ and Dy3+ complexes at room temperature were also investigated. They exhibit strong fluorescence by excitation of the Ln3+ ion absorption bands and the quantum yield values of Eu3+ and Tb3+ complexes are no less than 20%.
- Hu, Xiong,Dou, Wei,Xu, Chan,Tang, Xiaoliang,Zheng, Jiangrong,Liu, Weisheng
-
experimental part
p. 3412 - 3418
(2011/06/18)
-