SYNTHESIS, STRUCTURE AND DFT CALCULATIONS ON COMPLEXES OF PALLADIUM(II) WITH THEOPHYLLINE

Mixed-ligand complexes of Pd(11) containing N(7)-coordinated theophylline (th) and N,N-donor ligands: 2,2'-bipyridine (2,2'-bipy) and 1,10-phenanthroline (1,10-phen) were prepared and characterized by IR, H-1-NMR and C-13-NMR spectroscopy. Single crystal X-ray structure analysis showed that the [Pd(th)(2)(2,2'-bipy)]center dot H2O center dot(C6H14) complex crystallizes in the monoclinic system, space group C2/c. The Pd2+ centre has a distorted square planar configuration with Pd-N bond lengths of 2.018 angstrom (Pd-N(2) and Pd-N(2')) and 2.005 angstrom for Pd-N(7) and Pd-N(7'). The preferred site of coordination of theophylline to palladium was also investigated by DFT/B3LYP calculations.