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Correlation of intra and intermolecular hydrogen bridges in bis(dimethylglyoximato)cobalt(III)complexes

2000; De Gruyter; Volume: 215; Issue: 4 Linguagem: Inglês

10.1524/zkri.2000.215.4.260

2196-7105

Ulli Englert, M. Kirch, N. Knur,

Enzyme Structure and Function

The solid state structures of the complexes Co(Hdmg) 2 (NCS)(NH 3 ) (Hdmg = dimethylglyoximate) and CoCl(Hdmg) 2 (H 2 O) were determined by single crystal X-ray diffraction. The thiocyanato complex crystallizes in the orthorhombic space group Pnma with lattice constants a = 14.626(3) Å, b = 9.222(3) Å, c =11.575(3) Å, V = 1561.2(7) Å 3 and Z = 4 while the chloro complex is monoclinic, space group P2 1 /m with lattice constants a = 7.572(2) Å, b = 8.820(4) Å, c = 10.351(5) Å, β=96.29(3)º, V = 687.2(5) Å 3 and Z = 2. In these coordination compounds the pseudooctahedral molecules are located on crystallographic mirror planes; both bridging hydrogen atoms in each complex are close to one of the chelating ligands whereas chemical intuition would rather suggest two monoprotonated Hdmg moieties. This conflict is resolved when the correlation between intra and intermolecular hydrogen bonds is taken into account.