МОНО- ВА ДИАЛМАШИНГАН M-ФЕРРОЦЕНИЛБЕНЗОЙ КИСЛОТАЛАР СИНТЕЗИ, СПЕКТРАЛ ТАДҚИҚОТЛАР ҲАМДА КВАНТ-КИМЁВИЙ ТАҲЛИЛИ

Мақолада м-аминобензой кислота билан ферроцен орасидаги диазотирлаш реакциясига асосланган такомиллаштирилган усулни қўллаган ҳолда моно- ва диалмашинган ферроценилбензой кислоталар синтези бўйича олинган натижалар баён қилинган. Ҳосил қилинган маҳсулотлар таркиби ва тузилишини аниқлаш мақсадида амалга оширилган масс-спектрометрик, потенциометрик, инфра-қизил спектроскопик ва квант-кимёвий ҳисоблаш тадқиқотларидан олинган натижалар ва уларнинг таҳлили келтирилган. Ҳисоблашлар “Gaussian 98” дастурлар пакети DFT/B3LYP гибрид методининг турли базислари ёрдамида амалга оширилган.

В данной статье представлены полученные результаты по синтезу моно- и дизамещенных ферроценилбензойных кислот с применением усовершенствованного способа, основанного на реакции диазотирования ферроцена и м-аминобензойной кислоты. Проведен детальный анализ данных исследований синтезированных соединений, проведенныхс целью установления их состава и структуры с применением масс-спектрометрических, потенциометрических, ИК-спектроскопических и квантово-химических расчетныхметодов.Расчёты осуществлены с использованием различных базисов гибридного метода DFT/B3LYP пакета программ “Gaussian 98”.

This article presents the results of studies on an improved method for the synthesis of mono- and di-substituted ferrocenylbenzoic acids, which are products of the reaction of diazotization of ferrocene and m-aminobenzoic acid. The work also describes the mass-spectrometric, titrimetric, IR spectroscopic, quantum-chemical calculation datas in detail for the products obtained, as well as the results of the analysis of the experimental and theoretical studies got to determine their composition and structure.

The basis of the improvement of the method for the synthesis of mono- and di-substituted ferrocenylbenzoic acids is the diazotization reaction in chloroform, in place of traditional diethyl ether. As a result, the yield of mono- and di-substituted ferrocenyl benzoic acids increases by 8-10% compared with the method in which diethyl ether is used.

Mass spectrometry analysis of the products was carried out in a Perkin Elmer AxION 2 TF mass spectrometer. It has been established that the main lines found in the mass spectrum of isolated in solid form and purified by recrystallization of m-ferrocenylbenzoic acid and 1,1'-bis-(3-carboxyphenyl)-ferrocene correspond to molecular ions and fragments that are formed as a result of cleavage from molecular ions of the proton, -OH, -COOH, -C₆H₄COOH, etc.

Determination of the molar mass equivalent of the synthesized acids was carried out by potentiometric titration of their solutions, with a known concentration of solutions of lithium, sodium and potassium hydroxides in methanol on an Mettler Toledo Easy pH automatic titrator. It is established that the difference between the calculated by the formulas of mono- and di-substituted ferrocenylbenzoicacids, and the found molar mass of the equivalent does not exceed 0.5%.

The IR spectra of the synthesized substances in potassium bromide were measured on an Agilent IR spectrophotometer. For the purpose of detailed interpretation of the measured IR spectra, the molecular structures of m-ferrocenyl acid and possible isomers of the di-substituted derivative are optimized, and their theoretical vibrational spectra are calculated using the 6-31G(2d) basis of the DFT/B3LYP hybrid method in “Gaussian” software. Based on the comparison and analysis of the obtained experimental and theoretically calculated IR spectroscopic data, it was established that the molecular structure of the di-substituted derivative corresponds to the structure of the 1,1'-bis-(3-carboxyphenyl)-ferrocene.

In order to check the adequacy of the IR output of spectroscopic studies from the energetic point of view, computational work was carried out to calculate the Hartree energy of possible isomers of mono- and di-substituted ferrocenylbenzoic acids using the 3-21G basis of DFT / B3LYP method in program Gaussian 98. Analysis of the obtained results proves that the most energetically favourable of all isomers is 1,1′-bis-(3-carboxyphenyl)-ferrocene. One of the main reasons for the energy stability of this compound as compared to its other isomers is the occurrence of favourable conditions for the formation of intramolecular hydrogen bonds between the adjacent hydrogen and oxygen atoms of the neighbouring carboxyl groups.