Cobalt tris(mercaptoimidazolyl)borate complexes: synthetic studies and the structure of the first cobaltaboratrane

The paramagnetic complexes (Tm-tBu) CoX ( X = Cl, Br, I) have been readily prepared and structurally characterized and provide a convenient entry into cobalt(II) tris( mercaptoimidazolyl) borate chemistry. A number of derivatives, including mononuclear triphenylphosphine adducts [(Tm-tBu) Co(PPh3)] X and dinuclear compounds [Co-2(Tm-tBu)(2)X] Y, have been prepared in order to ascertain whether cobalt is a reliable surrogate for zinc in biological systems, particularly in sulfur-rich coordination environments. The structure of the first cobaltaboratrane is also reported.