- Crystal structure, vibrational spectra, optical properties and density functional theory approach of a picrate salt based on substituted triphenylphosphinium
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A new organic crystal, [BzTPP][PIC](1) ([BzTPP]+ = benzyl triphenylphosphinium, [PIC]- = picrate), has been grown by slow evaporation solution growth technique. Single crystal XRD reveals that it belongs to monoclinic system with P21/c. The two neighboring [BzTPP]+ cations from a dimer through C-H···π interaction while anions stack into a columnar structure through N?O, O?O and π···π interaction. The anions and cations form a column structure alternately in ···AC-AC-AC-AC··· sequence through C-H?O hydrogen bonds. The experimental vibrational bands (IR and Raman) have been discussed and assigned based on DFT calculations. The HOMO-LUMO energy gap explains the charge transfer interactions in the molecule. The thermal stability of the hybrid crystal was analyzed by TG-TDA-MS technique and revealed that the title crystal was stable up to 290 °C. The fluorescence spectra reveal three main emission peaks at 295, 388 and 543 nm upon excitation at 250 nm in solid state at room temperature. The energy of weak interactions in the molecule and nonlinear optical properties were studies using DFT calculations.
- Li, Ting,Gan, Zhi-Hao,Liu, Cai-Hong,Zhou, Jia-Rong,Liu, Xiao-Ping,Yang, Le-Min,Ni, Chun-Lin
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Read Online
- Buckyball-Based Spherical Display of Crown Ethers for de Novo Custom Design of Ion Transport Selectivity
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Searching for membrane-active synthetic analogues that are structurally simple yet functionally comparable to natural channel proteins has been of central research interest in the past four decades, yet custom design of the ion transport selectivity still remains a grand challenge. Here we report on a suite of buckyball-based molecular balls (MBs), enabling transmembrane ion transport selectivity to be custom designable. The modularly tunable MBm-Cn (m = 4-7; n = 6-12) structures consist of a C60-fullerene core, flexible alkyl linkers Cn (i.e., C6 for n-C6H12 group), and peripherally aligned benzo-3m-crown-m ethers (i.e., m = 4 for benzo-12-crown-4) as ion-transporting units. Screening a matrix of 16 such MBs, combinatorially derived from four different crown units and four different Cn linkers, intriguingly revealed that their transport selectivity well resembles the intrinsic ion binding affinity of the respective benzo-crown units present, making custom design of the transport selectivity possible. Specifically, MB4s, containing benzo-12-crown-4 units, all are Li+-selective in transmembrane ion transport, with the most active MB4-C10 exhibiting an EC50(Li+) value of 0.13 μM (corresponding to 0.13 mol % of the lipid present) while excluding all other monovalent alkali-metal ions. Likewise, the most Na+ selective MB5-C8 and K+ selective MB6-C8 demonstrate high Na+/K+ and K+/Na+ selectivity values of 13.7 and 7.8, respectively. For selectivity to Rb+ and Cs+ ions, the most active MB7-C8 displays exceptionally high transport efficiencies, with an EC50(Rb+) value of 105 nM (0.11 mol %) and an EC50(Cs+) value of 77 nM (0.079 mol %).
- Li, Ning,Chen, Feng,Shen, Jie,Zhang, Hao,Wang, Tianxiang,Ye, Ruijuan,Li, Tianhu,Loh, Teck Peng,Yang, Yi Yan,Zeng, Huaqiang
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supporting information
p. 21082 - 21090
(2020/12/21)
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- Tuning the intramolecular charge transfer (ICT) process in push-pull systems: Effect of nitro groups
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The intramolecular charge transfer (ICT) process in donor-acceptor systems has tremendous importance in various physical and biological systems. Three nitrophenolate salts were synthesized and studied here. The ICT and π → π? transition processes were identified in these derivatives using UV-Vis spectroscopy and theoretical calculations. It was observed that by simple substitution with nitro groups, one can generate and control the ICT process by regulating the charge distribution over the molecule. While for a monosubstitute nitro derivative, only one ICT band was observed, additional ICT processes can be generated at will by introducing a second nitro group. The intensity of this second ICT channel can be regulated with introduction of a third nitro group. Further, the association constants and solvation processes for these potassium nitrophenolate derivatives were found to be drastically dependent on the number of ICT channels present in the molecule. Theoretical studies (MEP analysis) support the experimental observations presented here. The results show that by simply introducing additional acceptor groups to the system, one can tune the ICT band efficiently in a conjugate system.
- Panja, Sumit Kumar,Dwivedi, Nidhi,Saha, Satyen
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p. 105786 - 105794
(2016/11/18)
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- Synthesis, binding properties and theoretical studies of p-tert-butylhexahomotrioxacalix[3]arene tri(adamantyl)ketone with alkali, alkaline earth, transition, heavy metal and lanthanide cations
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p-tert-Butylhexahomotrioxacalix[3]arene tri(adamantyl)ketone (1b) was synthesized for the first time. Compound 1b was obtained in a cone conformation in solution at room temperature, as established by NMR spectroscopy (1H and 13C). The binding properties of ligand 1b for alkali, alkaline earth, transition, heavy metal and lanthanide cations have been assessed by phase transfer and proton NMR titration experiments. Molecular mechanics and ab initio techniques were also employed to complement the NMR data. The results are compared to those obtained with other closely related homooxacalixarene derivatives. Although triketone 1b is a weak extractant, it shows a strong peak selectivity for Na+ and also some preference for Ag+. Proton NMR titrations indicate the formation of 1:1 complexes between 1b and the cations studied, and also that they should be located inside the cavity defined by the phenoxy and carbonyl oxygen atoms. Although the molecular mechanics results show little correlation with the NMR data, a good agreement was obtained with the ab initio models.
- Marcos, Paula M.,Ascenso, José R.,Segurado, Manuel A.P.,Bernardino, Raul J.,Cragg, Peter J.
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experimental part
p. 496 - 503
(2009/04/07)
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- Self-assembled ionophores
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Ionophores having the capacity spontaneously assemble in solution and composed of hydrogen bonded monomers of 5′-(t-butyl-dimethylsilyl)-2′,3′-O-isopropylidene-isoguanosine, 5′-(t-butyl-dimethylsilyl)-2′,3′-O-isopropylidene-thio-isoguanosine or 2′,3′-Di-O-acetyl-5′-(t-butyl-dimethylsilyl)-isoguanosine are used to remove 137-cesium ions (137Cs+) from nuclear waste.
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- Concerted mechanisms of the reactions of methyl aryl carbonates with substituted phenoxide ions
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The reactions of 4-nitrophenyl, 2,4-dinitrophenyl, and 2,4,6-trinitrophenyl methyl carbonates (NPC, DNPC, and TNPC, respectively) with substituted phenoxide ions are subjected to a kinetic study in water at 25.0 °C, ionic strength 0.2 M (KCl). Production of the leaving groups (the nitro derivatives) is followed spectrophotometrically. Under excess of the phenoxide ions pseudo-first-order rate coefficients (kobsd) are found throughout. Plots of kobsd vs substituted phenoxide concentration at constant pH are linear, with the slope (kN) independent of pH. The Broensted-type plots (log kN vs pKa of the phenols) are linear with slopes β = 0.67, 0.48, and 0.52 for the phenolysis of NPC, DNPC, and TNPC, respectively. The magnitudes of these Broensted slopes are consistent with a concerted mechanism. In the particular case of the phenolysis of NPC the expected hypothetical curvature center of the Broensted plot for a stepwise mechanism should be pKa0 = 7.1 (the pKa of 4-nitrophenol). This curvature does not appear within the pKa range of the substituted phenols studied (5.3-10.3), indicating that these reactions are concerted. The phenolysis of DNPC and TNPC should also be concerted in view of the even more unstable tetrahedral intermediates that would be formed if the reactions were stepwise. The reactions of the same substrates with pyridines are stepwise, which means that substitution of a pyridine moiety in a tetrahedral intermediate by a phenoxy group destabilizes the intermediate perhaps to the point of nonexistence. The kN values for the title reactions are larger than those for the concerted phenolysis of the corresponding ethyl S-aryl thiolcarbonates. The kN values found in the present reactions are subjected to a dual regression analysis as a function of the pKa, of both the nucleophile and leaving group, the coefficients being βN = 0.5 and βig = -0.3, respectively. These coefficients are consistent with a concerted mechanism.
- Castro,Pavez,Santos
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p. 3129 - 3132
(2007/10/03)
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- A study of C-F···M+ interaction: Alkali metal complexes of the fluorine-containing cage compound
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The C-F···M+ interaction was investigated by employing a cage compound 1 that has four fluorobenzene units. The NMR (1H, 13C, and 19F) spectra and X-ray crystallographic analyses of 1 and its metal complexes showed clear evidence of the interaction. Short C-F···M+ distances (CF···K+, 2.755 and 2.727 A; C-F···Cs+ 2.944 and 2.954 A) were observed in the crystalline state of K+ ? 1 and Cs+ ? 1. Furthermore, the C-F bond lengths were elongated by the interaction with the metal cations. By calculating Brown's bond valence, it is shown that the contribution of the C-F unit to cation binding is comparable or greater than the ether oxygen in the crystalline state. Representative spectroscopic changes implying the C-F···M+ interaction were observed in the NMR (1H, 13C, and 19F) spectra. In particular, 133Cs-19F spin coupling (J = 54.9 Hz) was observed in the Cs+ complex.
- Takemura,Kon,Kotoku,Nakashima,Otsuka,Yasutake,Shinmyozu,Inazu
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p. 2778 - 2783
(2007/10/03)
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- Design and synthesis of a new class of nonmacrocyclic alkali metal host compounds
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A new class of nonmacrocyclic metal ion hosts has been examined that features a polyspirocyclic framework that offers a 1,3,5-triaxial presentation of ligating centers. These compounds are easily synthesized and exploit stereoelectronic influences to preorganize the metal ion binding site. While compounds bearing oxygen substituents (X = OH, OMe) failed to show appreciable binding of alkali metals, the aminated host (X = NHBn) exhibitied strong binding with association constants (Ka) greater than 107-108 as measured by picrate extraction analysis.
- McGarvey, Glenn J.,Stepanian, Marshall W.,Bressette, Andrew R.,Sabat, Michal
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p. 3453 - 3456
(2007/10/03)
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- Guest inclusion properties of calix[6]arene-based unimolecular cage compounds. On their high Cs+ and Ag+ selectivity and very slow metal exchange rates
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The reaction of 1.3.5-tri-O-alkylated calix[6]arenes with 1,3,5- tris(bromomethyl)benzene yielded capped calix[6]arenes (2 with ten-butyl groups on the upper tim and 3 without tert-butyl groups) in unexpectedly high yields (80 - 91%). Combined studies of 2 and 3 by MM3 computation, X-ray analysis, and 1H NMR spectroscopy established that these calix[6]arenes feature a unique structure consisting of alternately-arranged three flattened mesitylene-linked phenyl units and three stand-up anisole units. Particularly, compound 2 possesses a closed ionophoric cavity: the upper hemisphere is closed by three ten-butyl groups of anisole units and the lower hemisphere is closed by a mesitylene cap and three anisole methoxy groups. The 1H NMR spectrum was scarcely changed at wide temperature range (30 ~ 130 °C), indicating that the structure is extremely rigidified. Both solvent extraction and spectroscopic studies established that this cavity shows the high selectivity toward Cs+ among alkali metal cations, the high affinity with Ag+, and the moderate affinity with RNH3+. Very surprisingly, the association-dissociation processes for 2 and cesium picrate was so slow that the rate could be followed by a conventional spectroscopic method. The thermodynamic parameters determined by kinetic studies disclosed that the major driving-force for Cs+ inclusion is the entropy term based on the desolvation.
- Otsuka, Hideyuki,Suzuki, Yoshio,Ikeda, Atsushi,Araki, Koji,Shinkai, Seiji
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p. 423 - 446
(2007/10/03)
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- New supramolecular hosts: Synthesis and cation binding studies of novel Troger's base-crown ether composites
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A simple and straightforward synthesis of a novel class of supramolecular hosts containing the Troger's base moiety is reported. The cation binding properties of these macrocycles were investigated using Cram's picrate extraction method.
- Manjula, Alla,Nagarajan, Madhavarao
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p. 11859 - 11868
(2007/10/03)
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- Chloro- and bromo-demethoxylation of methoxypolynitroaryl systems
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Various reagents for effecting halogenodemethoxylation of methoxy substituted polynitrophenyl and -biphenyl systems have been investigated, and the preferred procedures for achieving chloro- and bromo-demethoxylation in high yield have been identified.
- Bellamy, Anthony J.,Hudson, P. Nick
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p. 5639 - 5642
(2007/10/03)
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- Kinetically stable complexes of alkali cations with calixspherands: An evaluation of shielding
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Three new calixspherands (2-4) were synthesized in good yields (>60%) via a new method; p-tert-butylcalix-[4]arene (6) is bridged with a m-terphenyl (7-9) and subsequently alkylated. 1H NMR spectroscopy and X-ray crystallography showed that all the complexes are in a partial cone conformation. All the calixspherands form kinetically stable complexes with Na+, K+, and Rb+. The kinetic stability was determined both by 1H NMR spectroscopy, in CDCl3 saturated with D2O, and by a new method based on the exchange of radioactive rubidium or sodium in the complexes for nonradioactive sodium in different solvents. Both methods showed that the kinetic stability of the different complexes is strongly increased when the size of the group on the central aromatic ring of the m-terphenyl is increased. This effect is most pronounced for the rubidium complexes. The half-life times for decomplexation, in CDCl3 saturated with D2O, increased from 2.8 h for [1·Rb]+ to 139 h and 180 days for [2·Rb]+ and [3·Rb]+, respectively. The 'exchange method' shows that the rate of decomplexation is the rate-limiting step in the exchange of rubidium in the complex for sodium present in solution. These results can be explained in terms of increased shielding of the cavity from solvent molecules. The kinetic stabilities of the complex of 3 with Na+, K+, and Rb+ are the highest ever reported.
- Iwema Bakker, Wouter I.,Haas, Marijke,Khoo-Beattie, Corinne,Ostaszewski, Ryszard,Franken, Sybille M.,Den Hertog Jr., Herman J.,Verboom, Willem,De Zeeuw, Dick,Harkema, Sybolt,Reinhoudt, David N.
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p. 123 - 133
(2007/10/02)
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- Regioselectivity in the reaction of ambident phenoxide ion and methoxide and hydroxide ions with 2,4,6-trinitroanisole. Kinetic and thermodynamic control
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2,4,6-Trinitroanisole (TNA, 1), as the archetypal electron-deficient aromatic that possesses a leaving group, reacts with alkoxide ions, including methoxide, in media that contain appreciable amounts of dipolar aprotic solvents to yield a 1,3 anionic σ-adduct as the product of kinetic control; the 1,3 adduct gives way over time to the thermodynamically more stable 1,1 adduct. This behavior, in which an initial 1,3 adduct isomerizes to a 1,1 adduct, is now classified as TC-1,1 (therrnodynamic control favoring the 1,1 adduct) and has generally been taken to be ubiquitous. The present studies challenge this view. The salient features of the reaction of TNA with the ambident (O- and C-)nucleophile phenoxide, as studied by 400-MHz NMR spectroscopy, include initial formation of a 1,1 O-adduct, which only gives way at long times to a 1,3 para-bonded C-adduct of phenoxide. TNA is also intercepted by methoxide and hydroxide ions formed in situ through solvolytic pathways, which adhere to the TC-1,1 behavior. No 1,3 O-adduct of phenoxide is formed either prior to the 1,1 species or later in the reaction sequence. This fact is emphasized by low-temperature (-40 °C) NMR studies made possible by the introduction of the novel CD3CN-glyme-d10 solvent system, where the 1,1 adduct is the only species observed (3 min after initiation of reaction). These observations are in accord with a system that obeys K.C-1,1 regioselectivity (kinetic control favoring the 1,1 adduct), in which the 1,1 phenoxide O-adduct is both kinetically and thermodynamically favored. Four limiting TC and KC cases are considered, and the factors that favor one pattern of regioselectivity as compared to another are discussed with regard to the following: F-strain associated with approach of the nucleophile to C-1; stabilization afforded adducts by charge-separated canonical forms; stabilization of a later transition state for PhO- attack at C-1, due to relief of strain in that transition state; ion pairing; geminal electronegative disubstitution; and, in particular, steric and stereoelectronic effects in antiperiplanar rotameric forms of the 1,1 O-adducts.
- Buncel, Erwin,Dust, Julian M.,Jo?czyk, Andrzej,Manderville, Richard A.,Onyido, Ikenna
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p. 5610 - 5619
(2007/10/02)
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- Kinetically Stable Complexes of Alkali Cations with Rigidified Calixarenes: Synthesis, X-ray Structures, and Complexation of Calixcrowns and Calixspherands
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Selective 1,3-dialkylation of the phenolic groups of p-tert-butylcalixarene (3) with methyl or benzyl tosylate yields 7a (75percent) and 8 (95percent), respectively.Subsequent bridging of the two remaining phenolic groups in 7a or 8, by reaction with polyethylene glycol ditosylates, gives p-tert-butylcalixarene crown ethers (4b, 4c, and 4e).Reaction of 7a with 3,3''-bis(bromomethyl)-2,2',2''-trimethoxy-5,5',5''-trimethyl-1,1':3',1''-terphenyl (10) in the presence of NaH or KH produces the corresponding NaBr and KBr complexes of the calixspherand 6.Decomplexation of the6*NaBr and 6*KBr complexes in H2O/CH3OH (4:1) requires long reaction times and high temperatures, indicating a high kinetic stability.The X-ray structure of 6*NaPic confirmed the flattened partial cone conformation of the calixarene moiety in this complex.The free energies of complexation (ΔG0) of the calixcrown ether alkali picrate (MPic) complexes vary from -6 to -12 kcal*mol-1 (CDCl3).The calixspherand 6 forms kinetically "stable" complexes with Na(1+) (kd298 = 6.0*1E-9 s-1), K(1+) (kd298 =1.0*1E-8 s-1), and Rb(1+) (kd298 = 6.9*1E-5 s-1).The rates of complexation vary between 1.3*1E4 and 2.5*1E5 M-1 s-1.The calculated free energies of complexation of 6 with MPic salts in CDCl3 at 298 K are -16.8 , -18.1 , and -13.0 kcal*mol-1, respectively.The high thermodynamic and kinetic stabilities of these complexes are explained in terms of a high degree of preorganization of the calixspherand and the highly hydrophobic collar around the molecular cavity.This prevents solvent molecules to assist in the decomplexation process.
- Dijkstra, Pieter J.,Brunink, Jos A. J.,Bugge, Kjell-Erik,Reinhoudt, David N.,Harkema, Sybolt,et al.
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p. 7567 - 7575
(2007/10/02)
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- Complexation of Diaza Crown Compounds with Some Alkali Metal Ions in Acetonitrile and in Methanol at 25 deg C
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Conductometric measurements of lithium and potassium picrate in pure methanol, in pure acetonitrile, and in the presence of 1,7,10,16-tetraoxa-4,13-diazacyclooctadecane and N-methyl-N'-dodecyl-1,7,10,16-tetraoxa-4,13-diazacyclooctadecane macrocyclic ligands have been carried out at 25 deg C.The analysis of the results obtained with the different systems shows that the interaction forces, correlated with the molecular details of ions, solvents, and ligands, are, in most cases, superimposed on the ion-dipole forces acting between cations and macrocyclic cavities to such an extent as to prevent the cation macrocyclic ligand complexation.The effect of side chains attached to the main diazo crown ether ring on the complexation process is also discussed.
- D'Aprano, Alessandro,Sesta, Bianca
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p. 2415 - 2422
(2007/10/02)
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- REACTIONS OF AROMATIC NITRO COMPOUNDS. LVII. REACTION OF GLYCOL ETHERS OF PICRIC ACID WITH NUCLEOPHILIC AGENTS
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In the reaction of the glycol ethers of picric acid, containing 2-4 methylene units, with alkali-metal methoxides, tert-butoxides, and glycolates the intermolecular 1,1-?-complexes are formed in addition to the intamolecular spirocyclic anionic ? complexes.Thus, irrespective of the nature of the solvent and the nucleophilic agent, 1-(β-hydroxyethoxy)-2,4,6-trinitrobenzene undergoes intramolecular spirocyclization to a ? complex with a 1,3-dioxolane spirocycle.For 1-(δ-hydroxybutoxy)-2,4,6-trinitrobenzene only the formation of intermolecular 1-methoxy-1-hydroxyalkoxy- and 1,1-dihydroxyalkoxy-2,4,6-trinitrocyclohexa-2,5-dienides is observed, whereas 1-(γ-hydroxypropoxy)-2,4,6-trinitrobenzene can give ? complexes of both types, depending on the polarity of the solvent.
- Mel'nikov, A. I.,Gitis, S. S.,Kaminskii, A. Ya.
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p. 1336 - 1343
(2007/10/02)
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- FORMATION OF PICRATES IN THE REACTIONS OF PICRYL HALIDES PicX (X = F, Cl, I) WITH ORGANOMETALLIC SALTS R3EM (E = Se, Ge AND M = Li, K, Cs), BORATES, AND CARBANIONS. POSSIBLE REACTION MECHANISMS
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The reaction of picryl halides PicX (X = F, Cl, I) with organometallic compounds Me3SnM (M= Li, K, Cs), Et3GeK, borates Me4NBR4 (R = Bu, CH2SiMe3, CH2GeMe3), and 9-fluorenylpotassium was investigated.It was shown that for picryl fluoride and picryl chloride the reaction leads to the corresponding picrate.In the case of picryl iodide 1,3,5-trinitrobenzene is formed in addition to the picrate.The formation of the picrate also accompanies the reaction of PicX (X = F, Cl, I) with potassioacetoacetic ester, the main product from which is picrylacetoacetic ester.Possiblemechanisms are considered for the reaction leading to the picrates.
- Artamkina, G. A.,Egorov, M. P.,Beletskaya, I. P.,Reutov, O. A.
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p. 1649 - 1659
(2007/10/02)
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- Ion Association. Comparison of Spectroscopic and Conductance Values of Association Constants
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Molar conductances of potassium, rubidium, and cesium picrate and of cesium tetraphenylborate have been determined in 2-butanone at 25 deg C over a concentration range of 0.1-1.6 mmol L-1.These Λ,C data together with those for lithium and sodium already determined in this laboratory were fitted by using the Lee-Wheaton (LW), the Pitts (P), the Fuoss 78 (F), and the Justice (J) conductance equations to obtain values of ion association constants, KA, and limiting molar conductances.Spectrophotometric absorbance changes were measured for sodium and cesium picrate and remeasured for lithium and tetra-n-butylammonium picrate at 380 nm and 25 deg C over a concentration range of 0.02-1.4 mmol L-1.Values of the cesium-133 NMR chemical shifts of cesium picrate were determined over a concentration range of 0.1-3 mmol L-1 while those for cesium tetraphenylborate were determined over a range from 0.25 to 10 mmol L-1.We calculated values of ion assiciation constants for the various salts using this spectroscopic data.The values of KA determined spectroscopically and the values determined conductimetrically are the same within experimental error with one exception; for cesium tetraphenylborate, the NMR value depends on the concentration range of data included in the analysis.
- Gilkerson, William R.,Kendrick, Katherine L.
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p. 5352 - 5359
(2007/10/02)
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- Crown Ethers of Low Symmetry. Spiro Crown Ethers and 16-Crown-5 Derivatives
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Spiro crown ethers 3a-c, spiro bis(crown ethers) 5a-e, and the related 16-crown-5 derivatives 6a-d were synthesized and their cation binding abilities were evaluated by study of the extraction of aqueous alkali picrates.Crown ethers carrying 13-crown-4 and 16-crown-5 skeletons showed significant changes in cation selectivity as compared with the corresponding 12-crown-4 and 15-crown-5.Spiro-13-crown-4 3a and spiro-bis 5a showed extremely low extractabilities for all cations examined, while the 16-crown-5-derivatives, including spiro-bis 5b and spiro-bis 5c, showed anomalously high Na+ selectivity.In a quantitative study of extraction equilibrium constants (Kex), 16-crown-5 was again found to have much higher selectivity for Na+ than 15-crown-5.This result is attributed to the less symmetrical spatial arrangement of donor oxygen atoms in 16-crown-5; the symmetry-extractability relationship is discussed on the basis of the size-fit concept.
- Ouchi, Mikio,Inoue, Yoshihisa,Sakamoto, Hidefumi,Yamahira, Atsushi,Yoshinaga, Masanobu,Hakushi, Tadao
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p. 3168 - 3173
(2007/10/02)
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- REACTION OF METHYL AND PHENYL PICRATES WITH NUCLEOPHILES
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The reactions of 2,4,6-trinitroanisole with various nucleophiles Me3SnM, Me3SiLi, BuLi, Me4NBBu4, PhMgI, CN-, lithium (potassium) succinimide, F-, Cl-, Br-, SCN-, NO2-, NO3-, HCO3-, PhSO2-,AcO-, S2- were investigated.It was found that the final products are the picrate and the corresponding methyl derivatives.The formation of intermediate ? complexes was detected in a series of the reactions (Me3SnLi, potassium succinimide, Bu4B-, CN-, NO2-, PhSO2-).Possible mechanisms for the reaction are examined.Reactions of 2,4,6-tricyanoanisole and phenyl picrate with certain nucleophiles were also investigated.
- Artamkina, G. A.,Egorov, M. P.,Beletskaya, I. P.,Reutov, O.A.
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- REACTIONS OF AROMATIC NITRO COMPOUNDS. LII. ALKALINE CLEAVAGE OF ? COMPLEXES OF 2,4,6-TRINITROANISOLE WITH ALKALI-METAL METHOXIDES IN THE PRESENCE OF NEUTRAL SALTS
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The kinetics of the alkaline cleavage of ? complexes of 2,4,6-trinitroanisole with lithium, sodium, and potassium methoxides in the presence of the chlorides of these metals were investigated.The nature and concentration of the salt have a significant effect on the reaction rate.The reason for such an effect lies both in the formation of ion pairs and triplets in the reaction system and in the salt effect.Disruption of the framework structure of water by the bulky cations also has a significant effect on the process rate.
- Golopolosova, T. V.,Gitis, S. S.,Glaz, A. I.,Kaminskii, A. Ya.,Savinova, L. N.
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p. 898 - 901
(2007/10/02)
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