Dinuclear and mononuclear platinum(II) and palladium(II) complexes with modified 2,2'-dipyridylamine ligands featuring a cisplatin analogous structure motif

In modern cancer therapy the clinical application of platinum-based drugs is more and more limited by the occurrence of intrinsic or acquired resistances. In this context the potential use of dinuclear platinum complexes in chemotherapy is increasingly relevant. The novel complexes Pd(Bzdpa)Cl-2, Pd-2(C4H8(dpa)(2))Cl-4, and Pt-2(C4H8(dpa)(2))Cl-4 allow a direct comparison of mono- and dinuclear palladium and platinum complexes respectively deriving from a 2,2'-dipyridylamine (Hdpa) ligand system. They were characterized by single crystal X-ray analysis as well as infrared spectroscopy and elemental analysis. The cisplatin analogous mononuclear palladium complex Pd(Bzdpa)Cl-2 (1) (Bzdpa: (2,2'-dipyridylbenzyl)amine) belongs to a range of 2,2'-dipyridylamine-based compounds which were extensively studied in our laboratories. 1 crystallizes in the orthorhombic space group Pna2(1) with a = 13.722(3), b = 13.457(3), c = 9.483(2), V = 1751.1(6) angstrom(3), and Z = 4. The metal binding motif of I was expanded by a flexible butyl-linker to form the tetradentate C4H8(dpa)(2) ligand. The resulting isotypic dinuclear complexes Pd-2(C4H8(dpa)(2))Cl-4.2CH(3)CN (2) and Pt-2(C4H8(dpa)(2))Cl-4.2CH(3)CN (3) crystallize in the triclinic space group Pl with a = 7.8427(2), b = 8.7940(2), c = 11.7645 (3), alpha = 79.219(2)degrees, beta = 84.033(2)degrees, gamma = 87.744(2)degrees, V = 792.58(3) angstrom(3) (2) and a = 7.831(5), b = 8.814(5), c = 11.817(5), alpha = 79.271(5)degrees, beta = 83.571(5)degrees, gamma = 88.063(5)degrees, V = 796.3(8) angstrom(3) (3), both with one centrosymmetrical molecule in the unit cell.