КФУ. Карточка публикации. Complex formation, chemical exchange, species structure, and stereoselective effects in the copper(II)- L/DL-histidine systems

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COMPLEX FORMATION, CHEMICAL EXCHANGE, SPECIES STRUCTURE, AND STEREOSELECTIVE EFFECTS IN THE COPPER(II)- L/DL-HISTIDINE SYSTEMS

Форма представления

Статьи в зарубежных журналах и сборниках

Год публикации

2012

Авторы, сотрудники КФУ

Гарипов Руслан Шавкатович, автор

Гилязетдинов Эдуард Махмутович, автор

Журавлева Юлия Игоревна, автор

Захаров Алексей Васильевич, автор

Крутиков Александр Александрович, автор

Мухтаров Анвар Шарафулисламович, автор

Библиографическое описание на языке оригинала

Dalton Trans. – 2012. – V. 41, N 4. – P. 1216–1228.

Аннотация

ABSTRACT: The formation of copper(II) complexes with L- and DL-histidine (HisH) has been studied by means of pH-potentiometry and spectrophotometry over a wide range of pH (2-14), ligand-to-metal ratio (1 : 1-15 : 1), and temperature (15-55 ?C) in aqueous solutions with 1.0 mol dm(-3) KNO(3) as background. Formation constants and spectral characteristics of 13 complex types were found. Fine stereoselective effects have been detected with preferential coordination of two ligands with identical configuration in Cu(His)(HisH)(+) and opposite configuration in Cu(His)(2). The stereoselective effect for Cu(His)(HisH)(+) is explained by hydrogen bond formation between the carboxyl and imidazolyl groups of neighboring ligands at cis-arrangement of amino groups (3N(eq)-form). The opposite sign of stereoselective effect for Cu(His)(2) is derived from favourable axial coordination of the imidazole group in meso-form with cis-structure (3N(eq)N(ax)-form). A significant tetrahedral distortion was revealed for the first time in the prevalent cis-isomer of the Cu(L-His)(2) 4N(eq)-form. These findings were confirmed by EPR data and DFT computations at the B3LYP/TZVP level. The prevalence of cis-isomers for these complexes has been assigned to the rather strong trans effect of the amino groups. The structures of other detected complexes are briefly discussed on the basis of spectroscopic data. Chemical exchange reactions in the copper(II)-L/DL-hishidine systems have been investigated by the NMR relaxation of water protons. A unique proton exchange reaction with short-term proton dissociation from the coordinated imidazolyl group catalyzed by hydroxide ion was characterised for the first time. The discovered enantioselective effects in the ligand exchange reactions between Cu(His)(2) and HisH or His(-) species were attributed to the associative substitution mechanism.

Ключевые слова

координационные соединения, медь(II), ЯМР-релаксация, химический обмен лигандов, механизмы реакций

Название журнала

DALTON T

URL

http://kpfu.ru

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https://repository.kpfu.ru/?p_id=94367

Полная запись метаданных

Поле DC	Значение	Язык
dc.contributor.author	Гарипов Руслан Шавкатович	ru_RU
dc.contributor.author	Гилязетдинов Эдуард Махмутович	ru_RU
dc.contributor.author	Журавлева Юлия Игоревна	ru_RU
dc.contributor.author	Захаров Алексей Васильевич	ru_RU
dc.contributor.author	Крутиков Александр Александрович	ru_RU
dc.contributor.author	Мухтаров Анвар Шарафулисламович	ru_RU
dc.date.accessioned	2012-01-01T00:00:00Z	ru_RU
dc.date.available	2012-01-01T00:00:00Z	ru_RU
dc.date.issued	2012	ru_RU
dc.identifier.citation	Dalton Trans. – 2012. – V. 41, N 4. – P. 1216–1228.	ru_RU
dc.identifier.uri	https://repository.kpfu.ru/?p_id=94367	ru_RU
dc.description.abstract	DALTON T	ru_RU
dc.description.abstract	ABSTRACT: The formation of copper(II) complexes with L- and DL-histidine (HisH) has been studied by means of pH-potentiometry and spectrophotometry over a wide range of pH (2-14), ligand-to-metal ratio (1 : 1-15 : 1), and temperature (15-55 ?C) in aqueous solutions with 1.0 mol dm(-3) KNO(3) as background. Formation constants and spectral characteristics of 13 complex types were found. Fine stereoselective effects have been detected with preferential coordination of two ligands with identical configuration in Cu(His)(HisH)(+) and opposite configuration in Cu(His)(2). The stereoselective effect for Cu(His)(HisH)(+) is explained by hydrogen bond formation between the carboxyl and imidazolyl groups of neighboring ligands at cis-arrangement of amino groups (3N(eq)-form). The opposite sign of stereoselective effect for Cu(His)(2) is derived from favourable axial coordination of the imidazole group in meso-form with cis-structure (3N(eq)N(ax)-form). A significant tetrahedral distortion was revealed for the first time in the prevalent cis-isomer of the Cu(L-His)(2) 4N(eq)-form. These findings were confirmed by EPR data and DFT computations at the B3LYP/TZVP level. The prevalence of cis-isomers for these complexes has been assigned to the rather strong trans effect of the amino groups. The structures of other detected complexes are briefly discussed on the basis of spectroscopic data. Chemical exchange reactions in the copper(II)-L/DL-hishidine systems have been investigated by the NMR relaxation of water protons. A unique proton exchange reaction with short-term proton dissociation from the coordinated imidazolyl group catalyzed by hydroxide ion was characterised for the first time. The discovered enantioselective effects in the ligand exchange reactions between Cu(His)(2) and HisH or His(-) species were attributed to the associative substitution mechanism.	ru_RU
dc.language.iso	ru	ru_RU
dc.subject	координационные соединения	ru_RU
dc.subject	медь(II)	ru_RU
dc.subject	ЯМР-релаксация	ru_RU
dc.subject	химический обмен лигандов	ru_RU
dc.subject	механизмы реакций	ru_RU
dc.title	Complex formation, chemical exchange, species structure, and stereoselective effects in the copper(II)- L/DL-histidine systems	ru_RU
dc.type	Статьи в зарубежных журналах и сборниках	ru_RU