An experimental and quantum-chemical study of the Raman spectra and rotational isomerism of thiophosphites (RS) n PCl3 - N (R = Me, Et; N = 1, 2)

The Raman spectra of different conformations of CH3SPCl 2, C2H5SPCl2, and (C 2H5S)2PCl are studied within the framework of the density functional theory (B3LYP/6-31G*and B3LYP/6-31+G*) using the method of scaling of force fields. Comparison of the calculated and experimental spectra makes it possible to interpret the latter and to establish the existence of trans and gauche conformers of these molecules, which are formed due to internal rotation about the P-S and S-C bonds. This comparison also shows that, for the prediction of the degrees of depolarization of Raman lines to be correct, it is necessary to introduce diffuse functions into the basis set. © Nauka/Interperiodica 2006

Novel amphiphilic conjugates of: P-tert -butylthiacalix[4]arene with 10,12-pentacosadiynoic acid in 1,3- alternate stereoisomeric form. Synthesis and chromatic properties in the presence of metal ions

© 2018 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. For the first time amphiphilic receptors based on the 1,3-alternate stereoisomeric form of thiacalix[4]arene, bearing carboxyl/sulphonate polar headgroups on one side and 10,12-pentacosadiynoic acid (PCDA) residues on another side of the macrocyclic plane, were synthesized. It was shown that embedding of synthesized macrocycles in PCDA vesicles results in stable colloids with a size around 300 nm. The temperature of ultrasonication before UV irradiation has a critical impact on the packing of vesicles for better polymerization. The increase of calixarene content in PCDA vesicles causes a decrease in the degree of PCDA polymerization. Nevertheless, calixarene additives dramatically change the colorimetric response of photopolymerized PCDA vesicles toward metal ions. Vesicles with 10 mol% content of calixarene have significant colorimetric response toward lanthanide ions with a detection limit up to 8 μM. The colorimetric response in the series of lanthanide ions depends on the ionic radius, and the greatest response was found for the largest La(iii) ion. It was found that binding of calixarene-PCDA vesicles with lanthanide ions results in the formation of large 1 μm aggregates followed by sedimentation. Thus, the mechanism of colorimetric response of calixarene-decorated polydiacetylene vesicles toward lanthanide ions includes the distortion of the calixarene cavity provoking perturbation of the PDA backbone accompanied by metal-induced aggregation of functionalized vesicles with sedimentation of particles. Therefore, calixarene-PCDA vesicles have great potential for the future design of bifunctional colloids with sensor and separation applications

Germylene complexes of tungsten pentacarbonyls W(CO)5{double bond, long}GeCl2 and W(CO)5{double bond, long}Ge{double bond, long}W(CO)5: Electrochemical synthesis and quantum-chemical computations

Convenient synthetic route to prepare the germylene complexes of tungsten pentacarbonyls, W(CO)5{double bond, long}GeCl2 and W(CO)5{double bond, long}Ge{double bond, long}W(CO)5, electrochemically is developed. Combined quantum-chemical/IR spectroscopic approach is used for identification of the synthesized compounds. Good agreement between theoretical and experimental spectra can be regarded as one of the proofs of their supposed structures. © 2007 Elsevier B.V. All rights reserved

First neutral dinuclear cobalt complex formed by bridging [μ-O2P(H)R]- ligands: Synthesis, X-ray crystal structure and quantum-chemical study

© 2015 Mendeleev Communications. Published by Elsevier B.V. The reaction of cobalt dibromide hexahydrate with 2,2′-bipyridine (bpy) and 9-anthrylphosphinic acid AntP(O)(OH)H (Ant = 9-anthryl) leads to the first example of a neutral dinuclear cobalt(ii) complex {Co2Br2[μ-O2P(H)Ant]2(bpy)2} formed by two bridging [μ-O2P(H)Ant]- ligands. The complex has been characterized by X-ray diffraction analysis and quantum-chemical calculations

Synthesis, X-ray crystal structure and quantum-chemical study of new dinuclear cobalt complex {Co2[mmm-O2P(H)Mes] 2(bpy)4}Br2

The reaction of cobalt dibromide hexahydrate with 2,2'-bipyridine (bpy) and mesitylphosphinic acid MesP(O)(OH)H (Mes = = 2,4,6-trimethylphenyl) under solvothermal synthesis conditions leads to a new dinuclear cobalt(ii) complex {Co2[μ-O2P(H)Mes]2- (bpy) 4}Br2 formed by two bridging {μ-O2P(H)Mes}- ligands. X-ray crystal structure analysis of the complex displayed that cobalt ions have distorted octahedral coordination and are doubly bridged by two mesitylphosphinato ligands. © 2013 Mendeleev Communications. All rights reserved

Spectroscopic studies of compounds containing a P —H bond: 4. Vibrational spectra and conformational multiformity of di- tert-butylphosphorous acid molecules

IR and Raman spectra of liquid di- tert-butylphosphorous acid and its two low-temperature crystalline modifications are studied. It is found that at least three stable conformations of acid molecules can exist in the liquid state. © 1995, Plenum Publishing Corporation. All rights reserved

Conformational analysis of mono-and bis(dimethoxyphosphoryl)benzenes

Conformational analysis of mono-and bis(dimethoxyphosphoryl)benzenes with substituents in the benzene ring was performed by the method of dipole moments, IR spectroscopy, and quantum-chemical calculations (DFT B3LYP/6-31G*). Comparison of all calculated and experimental data shows that the compounds studied exist as equilibrium mixtures of conformers with preferred gg orientation of the phosphoryl and methoxy groups. © Pleiades Publishing, Inc., 2006

IR and NMR spectra, intramolecular hydrogen bonding and conformations of mercaptothiacalix[4]arene molecules and their para-tert-butyl-derivative

It is demonstrated that the introduction of p-tert-butyl groups dramatically influences the conformational behaviour of the mercaptothiacalix[4] arene molecules. Quantum-chemical computations in combination with IR and NMR spectroscopy prove that, in contrast to closely related calixarenes, the 1,3-alternate becomes a dominant conformer of p-tert-butyl-mercaptothiacalix[4] arene not only in crystal, but also in solutions and in vacuum. It is shown that the title molecules form essentially non-cooperative intramolecular hydrogen bonds: their SH groups are intramolecularly H-bonded solely to the sulfide groups bridging thiophenolic units. The enthalpy of this bonding, evaluated from Iogansen's rule, amounts to ca. 1.5 kcal mol-1 per one SH•••S bond, which about four times smaller than the enthalpies of cooperative intramolecular H-bonds formed by related calixarenes and thiacalixarenes. © 2007 Springer Science+Business Media B.V

IR and NMR spectra, intramolecular hydrogen bonding and conformations of para-tert-butyl-aminothiacalix[4]arene in solid state and chloroform solution

It is demonstrated that dissolution of aminothiacalix[4]arene in chloroform results in transformation of 1,3-alternate conformation, adopted in single-crystal and bulk polycrystalline solids, to the pinched-cone form. This conformer is stabilised by the intramolecular hydrogen bonds of two distal amino-groups acting as H-donors with another two amino moieties that appear as H-acceptors. The H-bonds cause quite small (ca. 10-20 cm-1) red shift of the IR bands of the NH2 stretching vibrations, which suggests rather weak NH⋯N hydrogen bonding. This latter is sufficient to stabilize the pinched-cone conformation in the chloroform solution, but the energy gap between the pinched-cone and other conformations is small, and solid-state intermolecular forces easily overcome it, leading to realisation of the 1,3-alternate conformer. The comparison of the DFT computed and experimental vibrational and NMR spectra demonstrates good quality of present quantum-chemical computations, allows complete interpretation of the spectra and reveals simple IR and NMR spectroscopic markers of the conformers of aminothiacalix[4]arenes. © 2009 Elsevier B.V. All rights reserved

Thermal stability of primary and secondary phosphine oxides formed as a reaction of phosphine oxide with ketones

© 2016 Taylor & Francis Group, LLC.We present the study of reactivity of electrochemically generated in situ from white phosphorus P4 phosphine oxide H3PO toward various ketones (acetone, methylethylketone, methyl-n-propylketone). This interaction was found to give a selective formation of mono- and bis-(α-oxyalkyl)phosphine oxides RRʹC(OH)P(O)H2 (1) and (RRʹC(OH))2P(O)H (2) where R = Me; Rʹ = Me, Et, n-Pr. Thermal properties of the formed primary and secondary phosphine oxides have been studied and quantum chemical calculations of thermodynamic stability of these compounds were performed