Crown-shaped tetrametallic imidoyl complexes of palladium. X-Ray crystal structure of [{[Pd2{µ-C(C6F5)NMe}2](µ-Cl)(µ-MeCO2)}2]

Abstract

The complexes [{[Pd₂{µ-C(C₆F₅)NR¹}₂](µ-X¹)(µ-X²)}_n](R¹= Me or p-tolyl; X¹= X²= Cl) and their derivatives (X¹= Cl, X²= MeCO₂ or CF₃CO₂; X¹= X²= MeCO₂ or CF₃CO₂), obtained by metathetical reactions with the corresponding silver salts, are shown to be tetrametallic (n= 2) by molecularweight determinations. Their structures are discussed on the basis of ¹H and ¹⁹F n.m.r. data. The crystal structure of the title complex has been solved by X-ray diffraction methods [space group P2₁/n, a= 14.380(4), b= 19.980(4), c= 15.976(4)Å, β= 103.51(3)°, Z= 4, R′= 0.046 for 5 428 unique observed reflections]. The tetrametallic molecule is crown-shaped. The bond lengths at palladium reflect the strong trans influence of the imidoyl-C atom; the Pd–Cl bonds trans to C are amongst the longest known.