A Tripodal Trisilanol Ligand and Its Complexation Behavior towards CuI, CuII, and ZnII

A three‐step synthetic route for a new tripodal branched trisilanol ligand PhSi(OSiPh2OH)3 (LH3) was developed. X‐ray diffraction analysis revealed that the trisilanol crystallizes as a dimer with a cyclic hydrogen‐bonding network. The reaction of LH3 with three equivalents of CunMesn (Mes = mesityl) led to a hexanuclear compound [L2Cu6] (1), which was characterized by single‐crystal X‐ray diffraction analysis as well as by solution NMR spectroscopy. The crystal structure of 1 revealed that the compound features a hexagonal planar CuI6 ring, which is the first of its kind in an oxygen environment. Deprotonation of the ligand with n‐butyllithium and subsequent reaction with CuBr2 resulted in the dinuclear CuII complex [L′2Cu2][Li(THF2)]2 (2, THF = tetrahydrofuran), which contains a new siloxide ligand formed from L3– by the elimination of a SiOPh2 unit, as evidenced by X‐ray diffraction analysis. To check if the “Ph2SiO” elimination is a general behavior of this trisilanol, the reaction with ZnBr2 was investigated under analogous conditions. However, this led to the isolation of [L2Zn2][Li(OEt)]2 (3) without any rearrangement of the siloxide ligand. A tripodal branched trisilanol ligand PhSi(OSiPh2OH)3 (LH3) was synthesized. Its reaction with three equivalents of CunMesn (Mes = mesityl) led to a hexanuclear compound [L2Cu6] with a planar CuI6 ring. Deprotonation of LH3 with n‐butyllithium and subsequent reaction with either CuBr2 or ZnBr2 resulted in dinuclear complexes. In the case of CuBr2, the original ligand eliminates a “Ph2SiO” unit.