Synthesis and characterization of tantalum-based early-late heterobimetallic complexes supported by 2-(diphenylphosphino)pyrrolide ligands.

The synthesis of the metalloligand Ta(κ2-NP) 3 Cl 2 (NP = 2-diphenylphosphinopyrrolide) and its coordination chemistry with group 9 and 10 metals is reported. Treatment of Ta(κ2-NP) 3 Cl 2 with group 9 and 10 metals resulted in clean formation of the heterobimetallic complexes Cl 2 Ta(μ 2 -NP) 3 M (M = Ni (2), Pd (3)) or Cl 2 Ta(μ 2 -NP) 3 MCl (M = Rh (4), Ir (5)). The synthesis of the metalloligand Ta(κ2-NP) 3 Cl 2 (NP = 2-diphenylphosphinopyrrolide) and its coordination chemistry with group 9 and 10 metals is reported. Treatment of Ta(κ2-NP) 3 Cl 2 with group 9 and 10 metals resulted in clean formation of the heterobimetallic complexes Cl 2 Ta(μ 2 -NP) 3 M (M = Ni (2), Pd (3)) or Cl 2 Ta(μ 2 -NP) 3 MCl (M = Rh (4), Ir (5)). Each pair of complexes is isostructural and contains three phosphinopyrrolide ligands that bridge the metal centers. The d10 or d8 complexes are all diamagnetic and X-ray crystallographic analysis reveals similarly short metal - metal distances, ranging from 2.2979(5) Å to 2.4366(2) Å. Despite the similar bonding metrics in 2 – 5, treatment with an L type donor (2,6-dimethylphenylisocyanide (CNXylyl)) reveals 3 different coordination geometries in TaNi(CNXylyl) (6), TaPd(CNXylyl) (7), and TaIr(CNXylyl) (8). While complexes 6, 7, and 8 all bind the isocyanide at the late metal, ligand rearrangements are observed in the first row complex 6. Complex 7 binds the isocyanide in the axial position while equatorial binding is observed in 8. All isocyanide adducts maintain close metal - metal contacts in the solid state. [ABSTRACT FROM AUTHOR]