The reaction of [Fe3(CO)12] with HCCSiR3 (R = Me, Ph) and reactivity of [HFe3(CO)9(CCSiMe3)] with amines. Theoretical studies on NMR 1H and 13C chemical shifts and some advances in the theoretical determinations of pKa in cluster compounds

The reactions of [Fe-3(CO)(12)] with alkynes HC CSiR3 (R = Me, Ph) were carried out under different conditions and the main products of these reactions were characterized spectroscopically and by X-ray diffraction. Products showed oligomerization of alkyne molecules with and without CO insertion. Theoretical calculations were carried out in order to predict the H-1 and C-13 NMR shifts for one of the complexes and use these values to help in the assignment of the signals experimentally observed. The acetylide derivative [(mu-H)Fe-3(CO)(9)(CCSiMe3)] was obtained in higher yield. This allowed us to carry out some studies on the reactivity of this derivative. Reactions with piperidine and morpholine showed the easy loss of the hydride group, as a proton, to form anionic derivatives. Therefore, a theoretical study was undertaken to try to determine the pKa in this complex. (C) 2013 Elsevier B.V. All rights reserved.