Synthesis and characterization of dinuclear pyrazolato bridged platinum(IV) complexes

Reactions of [PtMe3(OCMe2)(3)](BF4) and [(PtMe3I)(4)] with pyrazole (pzH) afforded mononuclear pyrazole platinum(IV) complexes [PtMe3(pzH)(3)](BF4) (1) and [PtMe3I(pzH)(2)] (2), respectively. The formation of dinuclear pyrazolato bridged platinum(IV) complexes (PPN)[(PtMe3)(2)(mu-pz)(3)](3), (PPN)[(PtMe3)(2)(mu-I)(mu-pz)(2)] 1/2Et(2)O (4) and [K(18C6)][(PtMe3)(2)(mu-I)(mu-PZ)(2)](5) was achieved by the reaction of each 1 and 2 with [PtMe3(OCMe2)(3)](BF4) in the presence of KOAc followed by reaction with (PPN)CI (PPN+ = bis(triphenylphosphine)iminium cation) and 18C6, respectively. The reaction of complex 4 with AgO2CCF3 followed by addition of RSR ' (R/R ' = Me/Me, Me/Ph) resulted in the formation of complexes [(PtMe3)(2)(mu-pz)(2)(mu-RSR ')] (R/R ' = Me/Me, 6; Me/Ph, 7). All complexes were characterized unambiguously by microanalysis and NMR (H-1, C-13) spectroscopic investigations. Additionally, crystal structures of complexes 3 and 4 as well as DFT calculation are presented. Furthermore, in vitro studies on the anti-proliferative activity of complexes 2 and 5 were carried out. (c) 2007 Elsevier Ltd. All rights reserved.