KFU. Card publication. 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

Form of presentation

Articles in international journals and collections

Year of publication

2012

Authors, employees of KFU

Garipov Ruslan Shavkatovich, author

Gilyazetdinov Eduard Makhmutovich, author

Zhuravleva Yuliya Igorevna, author

Zakharov Aleksey Vasilevich, author

Krutikov Aleksandr Aleksandrovich, author

Mukhtarov Anvar Sharafulislamovich, author

Bibliographic description in the original language

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

Annotation

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.

Keywords

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The name of the journal

DALTON T

URL

http://kpfu.ru

Please use this ID to quote from or refer to the card

https://repository.kpfu.ru/eng/?p_id=94367&p_lang=2

Full metadata record

Field DC	Value	Language
dc.contributor.author	Garipov Ruslan Shavkatovich	ru_RU
dc.contributor.author	Gilyazetdinov Eduard Makhmutovich	ru_RU
dc.contributor.author	Zhuravleva Yuliya Igorevna	ru_RU
dc.contributor.author	Zakharov Aleksey Vasilevich	ru_RU
dc.contributor.author	Krutikov Aleksandr Aleksandrovich	ru_RU
dc.contributor.author	Mukhtarov Anvar Sharafulislamovich	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/eng/?p_id=94367&p_lang=2	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	��	ru_RU
dc.subject	��(II)	ru_RU
dc.subject	��-��	ru_RU
dc.subject	��	ru_RU
dc.subject	��	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	Articles in international journals and collections	ru_RU