Four-Coordinate, Trigonal Pyramidal Pt(Ⅱ) and Pd(Ⅱ) Complexes

摘要

We report herein the characterization of electrophilic, trigonal bipyramidal {[SiP_3~R]Pt(L)}~+ cations ([SiP_3~R] = [(2-R_2PC_6H_4)_3Si]; R= Ph, ~iPr) that feature weakly coordinated ligands including CH_2CI_2, Et_2O, toluene, and H_2. A cationic toluene adduct that shows a close platinum aryl C-H σ-contact is perhaps most noteworthy in this context. For the isopropyl-substituted ligand, [SiP_3~(Pr)], it has proven possible to exclude the fifth axial donor to afford the rigorously four-coordinate, trigonal pyramidal (TP) complex {[SiP_3~(Pr)]Pt}~+. An isostructural TP palladium complex {[SiP_3~(Pr)]Pd}~+ is also accessible. Prototypical four-coordinate d~8 platinum and palladium complexes are square planar. The TP d~8 cations described herein are hence geometrically distinct.