The influence of metal coordination on ligand geometry: the structure of N-t-butyl-2-(diphenylphosphino)benzylammoniumchloride and (N-t-butyl-2-(diphenylphosphino)benzylamine)diacetatepalladium(II)

The structures of N-t-butyl-2-(diphenylphosphino)benzylammoniumchloride and N-t-butyl-2-(diphenylphosphino)benzylaminediacetatepalladium(II) have been determined by X-ray crystallography. The Pd-complex was prepared by treating palladiumdiacetate with N-t-butyl-2-(diphenylphosphino)benzylamine in CH2Cl2 for 4 h at room temperature. The organic compound crystallises in the monoclinic space group P2(1)/c with cell dimensions a = 13.664(3), b = 15.635(3), c = 10.408(2) Angstrom, beta = 100.14(3)degrees, V = 2188.7(8) Angstrom(3) and Z = 4, synchrotron radiation, lambda = 0.9836 Angstrom. The Pd-compound crystallises in the orthorhombic space group Pna2(1) with cell dimensions a = 15.444(3), b = 13.233(3), c = 12.730(3) Angstrom, V = 2601.6(9) Angstrom(3) and Z = 4, Mo Kalpha radiation. Both structures were solved by direct methods and the refinements resulted in the R-values 0.080 and 0.037, respectively. N-t-butyl-2-(diphenylphosphino)benzylammoniumchloride has an extensive hydrogen bonding with two bridging Cl- between the ammonium groups from two different organic ligands. The bi-dentate ligand binds to palladium(II) via both phosphorus and nitrogen, while two acetate bind via one of their oxygens forming a pseudo square-planar coordination around palladium. The Pd-N distance is 2.075(3) Angstrom, Pd-P = 2.2133(9) Angstrom and the Pd-O distances are 2.041(3) Angstrom (trans to N) and 2.092(2) Angstrom (trans to P). Half-normal probability plot analysis indicates that the s.u,.'s are underestimated in at least one of the investigated structures. Complexation with palladium influences torsion-angles in the amine side-chain in N-t-butyl-2-(diphenylphosphino)benzylamine as well as bond-angles around the N and P atoms, clearly a consequence of the formation of the chelate, while the crystal packing influences the orientation of the phenyl rings.