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

•Reactivity studies of [Fe3(CO)12] with HCCSiR3 (R = Me, Ph).•Products included complexes with coupling of alkyne and CO molecules.•The acetylide derivative [HFe3(CO)9(CCSiMe3)] was obtained in higher yields tan previously.•Reactions of the acetylides with amines showed an acidic behavior of the hydride.•A theoretical pKa was calculated for the acetylide.

The reactions of [Fe3(CO)12] with alkynes HCCSiR3 (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 1H and 13C NMR shifts for one of the complexes and use these values to help in the assignment of the signals experimentally observed. The acetylide derivative [(μ-H)Fe3(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.

Graphical abstractThe synthesis in higher yield of [(μ-H)Fe3(CO)9(CCSiMe3)] allowed us to carry out the study of its reactivity with piperidine and morpholine which leads to deprotonation of the cluster and formation of the corresponding anion. A theoretical study was carried out to determine the pKa of the hydride cluster.Figure optionsDownload full-size imageDownload as PowerPoint slide