Palladium phosphine complexes from 8-(thio)-theophylline, 8-(methylthio)-theophylline and 8-(benzylthio)-theophylline

A series of palladium(II) complexes have been synthesized and characterized to examine the coordination chemistry of several 8-thio-purine derivatives : 8-(thio)-theophylline (8-TTH2), 8-(benzylthio)-theophylline (8-BzTTH) and 8-(methylthio)-theophylline (8-MTTH). All of the complexes have been studi ed by IR and multinuclear (H-1, P-31, C-13 NMR) spectroscopy A representati ve example of a Pd complex, [cis-Pd(8-BzTT)(2)(PPh3)(2)], has been authenti cated by X-ray crystallography. In this complex square-planar coordination about palladium occurs through two deprotonated N7 purine atoms cis to each other, and two triphenylphosphine phosphorus atoms. In this paper, we pres ent and discuss details of the synthesis, characterization and structural p roperties of the novel complexes. The synthesis and the characterization of 8-(benzylthio)-theophylline (8-BzTTH), a new organic ligands based on the molecular skeleton of X-thio-purine, and a new procedure to obtain 8-(methy lthio)-theophylline (8-MTTH) are also presented. (C) 2000 Elsevier Science S.A. All rights reserved.