Thiocyanate, bridging ligand

Using a triazole-/pyrimidine-containing hybrid ligand, terminally coordinated in a thiocyanate-bridged copper(II) dimer, Haasnoot et al. reported250 the structure of the f3 isomer of complex (288), revealing that the Cu-SCN distance is relatively short compared to other Cu-SCN... 

Vahrenkamp and co-workers formed a number of chelate-stabilized ketone complexes with pyridylphenyl ketone. Octahedral complexes formed with a 2 1 ratio of ligand to zinc were formed with trifluoromethanesulfonate, chloride, and bromide anions. 1 1 reactions resulted in the formation of square pyramidal [ZnL2X]+ with X = Br, I, and a trigonal-bipyramidal dimer [L2Zn(NCS)2]2 with thiocyanate bridges.350... 

The structure determination of Zn(en)(NCS)Cl reveals monomeric tetrahedral zinc coordinated to thiocyanate via nitrogen.179 A structure determination of Cd(en)(N02)2 reveals a polymer containing cadmium in a seven-coordinate pentagonal prismatic environment the en functions as a bridging ligand, as does one of the nitrites.180... 

The solvent influences on the complex formation and stability have been reviewed by Golub et al.194 Several monomeric complexes of Hg(SCN)2 with N, O, P, As and S donor ligands are known with terminal Hg—SCN bonds.224-2 Some thiocyanate-bridged dimeric complexes of mercury(II) are also known.225,226 Recently the isolation of a mercury(II) thiocyanate complex with hexamethylenetetramine with exclusively N-bonded SCN groups has been published (Figure 9).233 The compounds (CH2)6N4-Hg(SCN)2 and (CH2)6N4-2Hg(SCN)2 exhibit covalently bonded Hg—s.394,595... 

The basic process can be exemplified by the reaction of the cobalt(III) complex [Co(NH3)5(NCS)]2+ (the oxidant) with the chromium(II) complex [Cr(OH2)6]2+ (the re-ductant), where thiocyanate acts as the bridging ligand. The overall reaction in aqueous acidic solution is shown in Equation (5.58). 

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