Organometall‐Oxide — Höhervalente Derivate der d‐Metall‐Säuren, 6. Tris(3,5‐dimethyl‐1‐pyrazolyl)boranato‐substituierte Alkyl(dioxo)1‐, Methylenphosphoranyl(dioxo)1‐ und s̀1‐Allyl(dioxo)1‐Komplexe des Molybdäns und Wolframs

Abstract

Organometallic Oxo Complexes — Highervalent Derivatives of the d‐Metal Acids, 6. — Hydrotris(3,5‐dimethyl‐1‐pyrazolyl)borato‐Substituted Alkyl(dioxo)1‐, Methylenephosphoranyl(dioxo)1‐, and s̀1‐Allyl(dioxo) Complexes of Molybdenum and TungstenTp*MoO2Cl (1) and Tp*WO2Cl (2) [Tp* = κ31‐HB(3,5‐Me2pz)3] react with trimethyl aluminium to form the corresponding dioxo(methyl) complexes Tp*MO2(CH3), MMo (3), W (4). An X‐ray crystal structure analysis of 3 is performed. The less oxidizing tungsten complex 2 is alkylated by Grignard reagents to yield alkyl complexes of the type Tp*WO2R 5–7 [RCH2SiMe3, CH2tBu and CH2C(Me)Ph2] and the s̀1‐2‐methallyl complex Tp*WO2(CH2CMeCH2) 8. Reactions of 2 with methylenephorphoranes R3PCH2 (RiPr, Ph) give transylidation products Tp*WO2(CHPiPr3) (9) and Tp*WO2(CH‐PPh3) (10). Hydrolysis of 10 leads to a trioxotungstate [Tp*WO3]– (11), stabilized by a hydroxyphosphonium cation.