First-Row Transition Metal Complexes of a Phosphine-Silylene-Based Hybrid Ligand.

We have prepared two new silylene-phosphine-based hybrid ligands Si{N(R)CH(PPh)}{PhC(NBu)} [R = TMS {trimethylsilyl} () and TBDMS {-butyldimethylsilyl} ()], which possess two donor sites. Furthermore, the treatment of the bidentate ligand with base metal halides {FeBr, CoBr, NiCl·dme [nickel chloride(II) ethylene glycol dimethyl ether]} and with NiBr·dme [nickel bromide(II) ethylene glycol dimethyl ether] afforded four-coordinate six-membered metal complexes , respectively, which feature coordination from both Si(II) and P(III) sites. Subsequently, complexes [(FeBr)Si{N(SiMe)CH(PPh)}{PhC(NBu)}], [(CoBr)Si{N(SiMe)CH(PPh)}{PhC(NBu)}], [(NiCl)Si{N(SiMe)CH(PPh)}{PhC(NBu)}], and [(NiBr)Si{N(SiBuMe)CH(PPh)}{PhC(NBu)}] are studied for their redox and magnetic properties with the help of UV-vis spectroscopy, cyclic voltammetry, SQUID magnetometry, and theoretical calculations. Complexes were found to display a paramagnetic behavior. All the compounds are well established by single-crystal X-ray diffraction studies.