Facile metalation of silicon and germanium analogues of thiocarboxylic acids with a manganese(II) hydride precursor

Abstract

Synthesis and characterization of the first manganese(II)-containing heavier thiocarboxylate analogues, [LDipSi(=S)OMnLDep] (4; LDip=CH[C(Me)N(2,6-iPr2C6H3)] 2, LDep=CH[C(Me)N(2,6-Et2C6H 3)]2) and [LDipGe(=S)OMnLDep] (5) are described. They are accessible through reaction of the silicon and germanium analogues of the respective thiocarboxylic acids [LDipE(=S)OH] (E=Si, Ge) with the β-diketiminato (nacnac) manganese(II) hydride precursor [(LDepMn)2(μ-H)2] (3) in high yield. The first Mn nacnac hydride 3 has been prepared by the reaction of manganese bromide [(LDepMn)2(μ-Br)2] (2) with KBEt 3H. Compounds 4 and 5 represent the first transition-metal heavier thiocarboxylates with the Si=S and Ge=S functionalities. All new compounds are paramagnetic and were characterized by elemental analysis, IR spectroscopy, MS (EI), and single-crystal X-ray diffraction analyses. Due to the N→E (E=Si, Ge) and E=S→Mn donor-acceptor interaction as well as the carboxylate-like π-electron delocalization within the E(S)O moieties, the E=S double bonds in these compounds are resonance stabilized. Active guys: The first transition-metal sila- and germathiocarboxylates were obtained by facile metalation of the corresponding heavier thiocarboxylic acids with currently unknown β-diketiminato manganese hydride. Preliminary investigations revealed that these complexes are capable of activating dioxygen and oxygenating triphenylphosphane at ambient temperature (see scheme). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.