Composition and structure of heteroassociates formed in a binary liquid system HF-CH3CN

Tarakanova, E. G.; Yukhnevich, G. V.

doi:10.1007/s10947-008-0094-4

Cited by 16 publications

(5 citation statements)

References 16 publications

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“…Based on these re sults (which are consistent with the results of the corre sponding calculations for the (HF) m •(CH 3 CN) n (see Ref. 31) and (HF) m •((C 2 H 5 ) 2 O) n systems 32 ), only centro symmetric (HF) 8 •(DMF) 2 associates consisting of cyclic moieties were considered in the third group. A compari son of the enthalpies of formation of the associates of interest showed that the associate that is formed by the binding of two (HF) 3 chains, which are closed through the hydrogen atoms of the methyl groups, to the C 2h sym metry tetramer (11) are much more stable than purely cyclic HA (12).…”

Section: Quantum Chemical Calculations Of Heteroassociates (Hf) M •(Dsupporting

confidence: 81%

“…Actually, the mutual arrangement of the experi mental points at molar ratios of the solution components higher than 3 : 1 is such that the maximum of the second Lorentzian is shifted to larger values ln(N HF /N Solv ) and corresponds to the 4.5 : 1 stoichiometric ratio of the mole cules. ** The earlier studies 30, 31 have shown that such a considerable deviation from the 4 : 1 ratio may be a con sequence of the absorption of large HA, which was not directly detected.…”

Section: Resultsmentioning

confidence: 81%

“…31 According to this procedure, the absorbance spectrum of each solution was normalized to the number of Solv molecules per square centimeter of the layer under study (S). Then the A/S spectrum of a solution of the lower concentration was subtracted from the spectrum of each subsequent concentration (which is of interest for a particular consideration).…”

Section: Experimental Data Processingmentioning

confidence: 99%

“…This explains the difference between the mechanism of the complex formation in the HF-DMF system and the corresponding mechanism in the HF-CH 3 CN binary mixture. 31 According to the results of quantum chemical calculations, 32 there is an inter mediate case in the HF-(C 2 H 5 ) 2 O system, where the pro ton transfer to the solvent molecule occurs in certain branched structures, whereas no proton transfer is observed in other structures.…”

Section: Quantum Chemical Calculations Of Heteroassociates (Hf) M •(Dmentioning

confidence: 99%

“…[25][26][27][28][29][30][31][32] In these studies, new methodological approaches were developed. For example, two procedures adequate to the law of mass action 33 were developed for the determination of the sto ichiometric HF : Solv ratios in these HA.…”

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confidence: 99%

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Composition and structure of heteroassociates formed in the HF-N, N-dimethylformamide binary liquid system

Tarakanova

Yukhnevich

2011

Russ Chem Bull

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The concentration dependence of the normalized (to the total number of moles of the components per liter) absorbance of HF solutions in DMF in ratios from 1 : 12 to 7 : 1 was analyzed. In the binary liquid system (BLS) under consideration, there are molecular complex es with stoichiometric ratios of 1 : 1 and ≥ ≥ ≥ ≥ ≥10 : 1 along with heteroassociates (HA) with the HF to DMF ratio of 4 : 1, which have been found earlier. For each HA, the concentration range, in which HA is formed in BLS, was estimated, and the positions of the stretching bands of HF were determined. The optimal configurations and the vibrational frequencies of the molecular complexes (HF) m •(DMF) n (m = 1, 2, 4, 8; n = 1, 2) with different topologies were calculated using the density functional theory (B3LYP/6 31++G(d,p)). The relative stability and struc tural features of the latter complexes were investigated. The complex formation in the HF-DMF system was analyzed. The structures of HA with stoichiometric ratios of 1 : 1 and 4 : 1 were determined by comparing the results of calculations and experimental data.Hydrogen fluoride has the unique ability to form sol vates and complexes. 1 Its molecules are involved in nu merous stable heteroassociates (HA) with different struc tures, 1-32 which determine the chemical, physicochemi cal, and spectroscopic properties of HF containing sys tems. Comprehensive studies of these HA are of funda mental and practical interest due, in particular, to the fact that some HA can act as fluorinating agents. 1,3-6,14, 18 One of important goals in the solution chemistry is to determine the composition, structures, and the mecha nism of the formation of stable hydrogen bonded molecu lar complexes (HF) m •(Solv) n (Solv is an organic solvent) in the liquid phase. Chemical and physicochemical meth ods, 1,3-6,14,18,25-30 IR spectroscopy, 2,22,26-32 X ray dif fraction, and differential thermal analysis 12,13 are em ployed to obtain relevant information.The structural features and conditions of the forma tion of heteroassociates (HF) m •(Solv) n in binary liquid systems (BLS) were considered in experimental and com putational studies having common logic. 25-32 In these studies, new methodological approaches were developed. For example, two procedures adequate to the law of mass action 33 were developed for the determination of the sto ichiometric HF : Solv ratios in these HA. 25,26 One of these procedures is based on measurements of the concentra tion dependences of the normalized (to the total number of moles of the components of BLS per liter of the solu tion) excess density of the solution (Δρ/N, g mol -1 ) and the fact that, according to the law of mass action, the maximum in this dependence will be observed at the mo lar ratio of the components in the binary mixture corre sponding to the stoichiometric composition of HA. An alternative procedure 26 involves measurements of a series of normalized absorbance of solutions (A/N, L mol -1 ), the determination of the frequency regions, in which the absorption of molecular...

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Section: Quantum Chemical Calculations Of Heteroassociates (Hf) M •(Dsupporting

confidence: 81%

Section: Resultsmentioning

confidence: 81%

Section: Experimental Data Processingmentioning

confidence: 99%

Section: Quantum Chemical Calculations Of Heteroassociates (Hf) M •(Dmentioning

confidence: 99%

mentioning

confidence: 99%

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Composition and structure of heteroassociates formed in the HF-N, N-dimethylformamide binary liquid system

Tarakanova

Yukhnevich

2011

Russ Chem Bull

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Structure of heteroassociates formed in the HF-(C2H5)2O liquid system

Tarakanova

Yukhnevich

2010

J Struct Chem

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Exploration of the СH₃CN^…HF complex in the gas phase with high-resolution FTIR spectroscopy and computational methods

Amonov

Murodov

Jumabaev

et al. 2022

Molecular Crystals and Liquid Crystals

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Composition and structure of heteroassociates formed in a binary liquid system HF-CH3CN

Cited by 16 publications

References 16 publications

Composition and structure of heteroassociates formed in the HF-N, N-dimethylformamide binary liquid system

Composition and structure of heteroassociates formed in the HF-N, N-dimethylformamide binary liquid system

Structure of heteroassociates formed in the HF-(C2H5)2O liquid system

Exploration of the СH₃CN^…HF complex in the gas phase with high-resolution FTIR spectroscopy and computational methods

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Composition and structure of heteroassociates formed in a binary liquid system HF-CH3CN

Cited by 16 publications

References 16 publications

Composition and structure of heteroassociates formed in the HF-N, N-dimethylformamide binary liquid system

Composition and structure of heteroassociates formed in the HF-N, N-dimethylformamide binary liquid system

Structure of heteroassociates formed in the HF-(C2H5)2O liquid system

Exploration of the СH3CN…HF complex in the gas phase with high-resolution FTIR spectroscopy and computational methods

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Exploration of the СH₃CN^…HF complex in the gas phase with high-resolution FTIR spectroscopy and computational methods