Reactions of the terminal [Ni.sup.III]-OH group in substitution and electrophilic reactions with carbon dioxide and other substrates: structural definition of binding modes in an intramolecular [Ni.sup.II]-[Fe.sup.II] bridged site

A structure similar to the singular feature of the catalytic C-cluster of carbon monoxide dehydrogenase, a sulfide-bridged Ni-Fe locus where substrate is bound and transformed in the reversible reaction, is described. The synthesis and reactivity of [Ni.sup.II][Fe.sup.II] complexes have shown that molecular [Ni.sup.II]-[Fe.sup.II] sites and bridges are attained, which is a necessity in the biomimetic chemistry of C-clusters.