112680-37-2Relevant academic research and scientific papers
Protonation and bonding in heterometallic butterfly carbide clusters
Hriljac, Joseph A.,Harris, Suzanne,Shriver, Duward F.
, p. 816 - 821 (2008/10/08)
The protonation of the heterometallic butterfly carbide clusters [CrFe3(CO)13C]2-, [WFe3(CO)13C]2-, [MnFe3(CO)13C]-, and [RhFe3(CO)12C]- was studied by multinuclear NMR spectroscopy, and the protonation products were characterized. With 1 equiv of acid all of the clusters protonate at the carbide ligand to produce an agostic C-H-Fe linkage with a wingtip iron atom. This contrasts with the behavior of the isoelectronic homometallic cluster [Fe4(CO)12C]2-, for which the first proton adds across the Fe-Fe hinge of the cluster. Fenske-Hall molecular orbital calculations were carried out for [RhFe3(CO)12C]- and [MnFe3(C-O)13C]-, and the electronic structures of these heterometallic clusters were compared with that of [Fe4(CO)12C]2-. The introduction of a heterometal perturbs the metal framework bonding orbitals, and the relative energies of the resulting orbitals depend on the nature of the heterometal. In both heterometallic clusters the nature of the HOMO correlates with the site of proton attack.
