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

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

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

Complex formation of d-metal ions at the interface of Tb III-doped silica nanoparticles as a basis of substrate-responsive TbIII-centered luminescence

The complex formation of d-metal ions at the interface of Tb III-doped silica nanoparticles modified by amino groups is introduced as a route to sensing d-metal ions and some organic molecules. Diverse modes of surface modification (covalent and noncovalent) are used to fix amino groups onto the silica surface. The interfacial binding of d-metal ions and complexes is the reason for the TbIII-centered luminescence quenching. The regularities and mechanisms of quenching are estimated for the series of d-metal ions and their complexes with chelating ligands. The obtained results reveal the interfacial binding of CuII ions as the basis of their quantitative determination in the concentration range 0.1-2.5 μM by means of steady-state and time-resolved fluorescence measurements. The variation of chelating ligands results in a significant effect on the quenching regularities due to diverse binding modes (inner or outer sphere) between amino groups at the interface of nanoparticles and FeIII ions. The applicability of the steady-state and time-resolved fluorescence measurements to sense both Fe III ions and catechols in aqueous solution by means of Tb III-doped silica nanoparticles is also introduced. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Vibrational spectra, co-operative intramolecular hydrogen bonding and conformations of calix[4]arene and thiacalix[4]arene molecules and their para-tert-butyl derivatives

The IR and Raman spectra and conformations of calix[4]arene, thiacalix[4]arene and their p-rerf-butyl derivatives have been analysed within the framework of scaled quantum mechanics (SQM). It is shown that the introduction of four p-tert-Bu groups into the calixarene molecules influences the relative energies of their conformers and the enthalpy of the cooperative intramolecular H-bonding (ΔHintra) almost negligibly. ΔHintra, evaluated from Iogansen's rule, amounts to ∼ 26-28 kcal mol-1 for the calixarenes and ∼20-21 kcal mol -1 for the thiacalixarenes, which essentially exceeds the enthalpies of non-cooperative H-bonds formed by related phenols. As a result of this strong bonding, bands of stretching, bending and torsion vibrations of an eight-membered cyclic system (OH ⋯)4 arise, e.g., two δ(OH)4 bands are observed in the IR spectra of the most highly symmetric C4 cone conformations of calix[4]arene and thiacalix[4]arene. The "duplication" of the number of OH infrared bands is a good new indicator of cooperativity of intramolecular H-bonding of the calixarenes. © The Royal Society of Chemistry 2005

IR and UV study of reversible water-induced structural transformations of poly(manganese 1,1′-ferrocenediyl-bis(H-phosphinate)) and poly(cobalt 1,1′-ferrocenediyl-bis(H-phosphinate))

© 2018 Elsevier B.V. Recently new flexible and hydrolytically stable metal-organic framework [M(H2O)2(Fc(PHOO)2)·2H2O]n, M = Co has been synthesized by the use of synthetic technique, described earlier for M = Mn [1]. The heating of both complexes leads to elimination of water molecules and in the case of Co complex is accompanied by change of its color from orange to dark blue. The corresponding structural changes are reversible and are reflected in vibrational and electronic absorption spectra. Analysis of IR, Raman and UV–vis spectra of complexes shows the same structures of Mn and Co complexes before and after heating and suggests that both Mn and Co coordination polyhedra undergo reversible changes under heating from octahedral to tetrahedral form with ferrocene part remaining unchanged