Directing protonation in [FeFe] hydrogenase active site models by modifications in their second coordination sphere

Abstract

Subtle changes in the second coordination sphere of [Cl(2)bdtFe(2)(CO)(4)(Ph(2)P-CH(2)-X-CH(2)-PPh(2))] (bdt = benzene-1,2-dithiolate, X = NCH(3), NCH(2)CF(3), CH(2)) that do not influence the electronic character of the Fe(2) center can however direct protonation to three different sites: the N in the bis-phosphane, the Fe-Fe bond or the bdt-S.