SYNTHESIS AND CRYSTAL-STRUCTURE OF DINUCLEAR PALLADIUM(I) DPPM COMPLEX WITH 4-MERCAPTOPYRIDINE IN THE THIONE MODE - D-2(MU-DPPM)(2)(HPYS)(2)](CLO4)(2)CENTER-DOT-CH3OH

The reaction of [Pd-2(mu-dppm) (2)](2+) With 4-mercaptopyridine (pySH) in methanol produced the dipalladium(I) dppm complex [Pd-2( mu-dppm)( 2)(HpyS)(2)] (ClO4)(2). CH3OH (1), and its structure and properties we re characterized by a single crystal X-ray structure analysis, UV-Vis, IR and NMR spectra. The two Pd atoms are doubly-bridged by two dppm l igands to form an eight-membered Pd2P4C2 framework, in a twist-chair c onformation. The HpyS ligand in the thione mode is also coordinated to each Pd atom, forming the Pd2P4C2 framework in a side-by-side conform ation. The average Pd-S and Pd-P distance is 2.403(2) and 2.299(2) Ang strom, respectively. The Pd-Pd distance of 2.6645(6) Angstrom is short er than that (2.75 Angstrom) in Pd metal, which is indicative of a dir ect Pd-Pd bond. The results of IR, NMR and W-Vis spectra supported tha t the dinuclear structure of 1 is kept in solid and solution. (C) 1998 Elsevier Science S.A. All rights reserved.