INTERMOLECULAR HYDROGEN BONDING BETWEEN N-SUBSTITUTED CAPROAMIDES AND TETRAHYDROFURAN

hydrogen bonding N-substituted caproamide tetrahydrofuran DFT

КРИСТАЛЛИЧЕСКАЯ СТРУКТУРА и МАГНИТНЫЕ СВОЙСТВА НОВОГО ГЕТЕРОМЕТАЛЛИЧЕСКОГО КОМПЛЕКСА Pd(II)—Cu(II) С 1-АМИНОЭТИЛИДЕН-1,1-ДИФОСФОНОВОЙ КИСЛОТОЙ, МОЛЕКУЛЯРНАЯ СТРУКТУРА 3,7-ДИМЕТИЛ-9-ТИА-3,7-ДИАЗАБИЦИКЛО[3.3.1]НОНАН-9,9-ДИОКСИДА, ...

The B3LYP functional with 6-31G** basis set has been used to calculate the structural parameters of the studied hydrogen bonded complexes. <...> It can be assumed that both inductive and steric effects play an important role in the stability of these hydrogen bonded complexes. <...> Knowledge of N—HĥO interactions of N-substituted amides contributes to a better understanding of the structure of polypeptides and proteins. [ 4 ]. <...> In our laboratory, during continuous and extensive research of N-substituted amides and their interactions in solutions, N—HᄷO, [ 5—8 ] hydrogen bonded complexes were investigated using IR techniques. <...> In the present work, we investigated the N—HĥO interactions of newly synthesised N-alkyl caproamides in order to provide better insight into the nature of the hydrogen bonding of secondary amides. <...> EXPERIMENTAL Various N-monosubstituted caproamides (NsCA) of general formula CH3(CH2)4CONHR, wherein R is n-propyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, and n-pentyl (NPrC, NBuC, NsBC, NiBC, NtBC, NPeC), were synthesised by Schotten-Baumann reaction, by acylation of the corresponding amines with alkyl chloride. <...> The purity of these N-monosubtituted amides was checked by GC and mass spectrometry. <...> Tetrahydrofuran was obtained from commercial sources (Fluka, > 97 %) and was used without further purification. <...> In order to avoid self-association, amide concentrations in carbon tetrachloride solutions were beInfrared spectra were obtained using a Thermo-Nicolet Nexus 670 instrument. <...> IR spectra of N-substituted caproamides in the presence of tetrahydrofuran: a) N-propyl caproamide, b) N-butyl caproamide, c) N-iso-butyl caproamide, d) N-sec-butyl caproamide, e) N-tert-butyl caproamide, f ) N-pentyl caproamide within 0.2 and 1 cm–1, respectively. <...> The integrated molar absorption coefficients were obtained within Ĕ5 %. <...> The equilibrium constants were determined with average relative standard deviation of 6.6 %. <...> Geometrically optimized hydrogen bonded complexes of N-substituted caproamides with tetrahydrofuran a) N-propyl caproamide, b) N-butyl caproamide, c) N-iso-butyl caproamide, d) N-sec-butyl caproamide, e) Ntert-butyl caproamide, f ) N-pentyl caproamide the Beceker method. <...> The equilibrium constant values and accuracy parameters for the equilibrium constants determination are given in Table 2. <...> Comparison of the equilibrium constants as well as the frequency shift values for the series of examined <...>

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