Substitution process in phosphine thiopurine palladium complexes

• Published in: Inorganica Chimica Acta 2003-09, Vol.353, p.145-150
• Main Authors: Romerosa, Antonio, López-Magaña, Carlos, Mañas, Sonia, Saoud, Mustapha, Goeta, Andrés E
• Format: Article
• Language: English
• Subjects: Bioinorganic chemistry; Ligand substitution process; Metal–purine–phosphine complexes; Palladium
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/S0020-1693(03)00245-7

The synthesis and characterization of the new palladium phosphane thiopurine complexes [PdCl(Py)(PPh 3)(8-MTT)] ( 1) (8-MTTH=8-methylthiotheophylline) and [PdBr(Py)(PPh 3)(8-BzTT)] ( 2) (8-BzTTH=8-benzylthiotheophylline) are presented. Both complexes have been studied by IR and multinuclear ( 1H, 31P{ 1H}) NMR spectroscopy. In addition, the solid state structure of 2 has been authenticated by X-ray crystallography. In this complex, a square-planar coordination around palladium occurs through a deprotonated N7 8-BzTT − atom trans to a Br − atom, and cis to a PPh 3 and to a pyridine. The substitution process that exchanges one of the two PPh 3 ligands in trans-[PdCl(PPh 3) 2(8-MTT)] by a pyridine to produce 1 has also been studied by multinuclear NMR and GS–MS. The synthesis and the spectroscopic characterization of the novel palladium thiopurine complexes [PdCl(Py)(PPh 3)(8-MTT)] ( 1) (8-methylthiotheophylline) and [PdBr(Py)(PPh 3)(8-BzTT)] ( 2) (8-benzylthiotheophylline) are presented. Additionally, complex 2 has been characterized by X-ray diffraction methods. The substitution process to obtain 1 from [ trans-PdCl(PPh 3) 2(8-MTT)] and pyridine is also presented and discussed.