New mu-Oxo Octanuclear Complexes of 3d Elements Stabilized by Dialkylcarbamato Ligands. Synthesis, and X-Ray Crystal and Molecular Structures

ABSTRACT The octanuclear aggregates M8(mu4-O)2(O2CNiPr2)12 [M = Mn(II) 1, Co(II) 2, Ni(II) 3] have been prepared in good yields by controlled hydrolysis of the corresponding metal carbamate precursors [M(O2CNiPr2)2]n. X-ray analysis has shown compounds 1-3 to be isostructural. The core of 2 contains two distorted {M4O} tetrahedra related by an inversion center. The hexanuclear carbamates M6(O2CNEt2)12 in toluene undergo a metal redistribution process with formation of the hexanuclear carbamates M'xM' '6-x(O2CNEt2)12, M' = Co, M' ' = Mn, as evidenced by mass-spectrometric data. In the presence of moisture, the mixed octanuclear carbamates CoxMn6-x(MnO)(CoO)(O2CNEt2)12 were promptly formed and detected by DCI/MS measurements. Mass spectral data of Co8(mu4-O)2(O2CNiPr2)12 are also reported