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Crystal structures of strontium and barium ethylenediaminetetraacetato cobaltates(III), Sr[CoEdta](2) center dot 9H(2)O and Ba[CoEdta](2) center dot 8H(2)O: Comparison of the structures of complexes in the series M '[CoEdta](2) center dot nH(2)Oстатья
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
- Авторы: Zasurskaya L.A., Polyakova I.N., Rybakov V.B., Polynova T.N., Poznyak A.L., Sergienko V.S.
- Журнал: Crystallography Reports
- Том: 51
- Номер: 3
- Год издания: 2006
- Издательство: Maik Nauka/Interperiodica Publishing
- Местоположение издательства: Russian Federation
- Первая страница: 448
- Последняя страница: 458
- DOI: 10.1134/S1063774506030138
- Аннотация: Cobalt(III) complexes, namely, Sr[Co Edta](2) center dot 9H(2)O ( I) and Ba[CoEdta](2) center dot 8H(2)O (II) ( where Edta(4-) is the ethylenediaminetetraacetate ion), are synthesized. The crystal structures of these compounds are determined using X-ray diffraction. Crystals of compound I are triclinic, a = 6.514( 1) angstrom, b = 11.410( 2) angstrom, c = 12.317( 2) angstrom, alpha = 67.87( 1)degrees,beta = 88.73( 2)degrees gamma = 84.22( 2)degrees, V = 843.6( 3) angstrom(3), Z = 1, space group P1, and R = 0.0295 for 4130 reflections with I > 2 sigma ( I). Crystals of compound II are monoclinic, a = 6.543( 2) angstrom, b = 12.895( 3) angstrom, c = 19.489( 4) angstrom, beta = 95.24( 3)degrees, V = 1637.5( 5) angstrom(3), Z = 2, space group P2(1), and R = 0.050 for 3016 reflections with | F | > 3 sigma( | F |). The structures of compounds I and II are compared with those of the previously studied complexes Mg[ CoEdta](2) center dot 10H(2)O ( III) and Ca[ CoEdta](2) center dot 7H(2)O ( IV). The crystal structure of the cobalt( III) complex with the strontium cation ( I) is topologically similar to the crystal structure of cobalt( III) complex with the calcium cation ( IV). The former structure is built up of the two symmetrically independent homochiral anionic complexes [ CoEdta](-) (A(I) and B-I), the aqua cations [Sr(H2O)(8)](2+), and the molecules of crystallization water w(cr). The structure of compound II involves two independent anions [CoEdta](-) (A(II) and B-II) with different chiralities (i.e., they are kryptoracemates). The A(II) anions are linked via the barium cations into {Ba(H2O)(7)[CoEdta]}(1 infinity)(+) chain agglomerates due to the incorporation of two terminal oxygen atoms O-u of the anions neighboring in the chain into the coordination sphere of the barium atom. All four structures ( I - IV) contain stacks composed of the [ CoEdta] - homochiral anions forming layers aligned parallel to the ( 001) plane. The aqua cations [ Sr( H2O)(8)](2+), [ Mg(H2O)(6)](2+), and [Ca(H2O)(7)](2+) or the partially hydrated barium cations [Ba(H2O)(7)(O-u)(2)](2+) ( in structure II), as well as water molecules wcr, are located between the anion layers. The octahedral environment of the cobalt( III) atoms consists of donor atoms (2N and 4O) of the Edta(4-) ligand. The Co - N bonds in the A(I), B-I, A(II), and B-II anions [ the mean bond lengths are 1.927( 4), 1.921( 4), 1.910( 6), and 1.921( 6) angstrom, respectively] are considerably longer than the Co - O bonds [ the mean bond lengths are 1.908( 5), 1.902( 5), 1.904( 6), and 1.908( 6) angstrom, respectively]. The mean distances Sr - O-w and Ba - O-w in the strontium and barium polyhedra are 2.609( 4) and 2.834( 8) angstrom, respectively. The mean distance Ba - O-u is 2.814( 7) angstrom.
- Добавил в систему: Засурская Лариса Александровна