Axial ligand effect on the reaction mechanism of head-to-head pivalamidato-bridged Pt(III) binuclear complex containing an equatorial bromide ligand with acetone

作者：Kishi Masatoshi; Terada Takaaki; Kuraishi Yu; Sugaya Tomoaki; Iwatsuki Satoshi; Ishihara Koji^*; Matsumoto Kazuko

来源：Inorganica Chimica Acta, 2015, 433: 45-51.

DOI：10.1016/j.ica.2015.04.020

• Platinum
• Reaction mechanism
• Pivalamidate
• Acetone

The axial ligand substitution reactions of head-to-head (HH) pivalamidato-bridged platinum(III) binuclear complexes containing equatorial Br- ligands, ([(H2O)(NH3)(2)Pt(mu-pivalamidato)(2)Pt(Br)(2)(OH2)](2+) (complex 1) and [(Br)(NH3)(2)Pt(mu-pivalamidato)(2)Pt(Br)(2)(Br)] (complex 2)) with acetone were kinetically investigated in acidic aqueous solutions. Both the complexes reacted with acetone slowly and acetonyl Pt-III binuclear complexes were formed in two steps (1 and 2). The observed pseudo first-order rate constants (k(obs1)) for step 1 of the reactions of complexes 1 and 2 were linearly and quadratically dependent on the excess ligand concentration (C-L) at a given [H+], respectively. The rate constants for step 2 in both the reactions were independent of both C-L and [H+]. A reaction mechanism involving an intermediate with one p-coordinated acetone molecule was proposed for complex 1, which is similar to those proposed previously for the reactions of HH tetraammine amidato-bridged diplatinum(III) complexes with acetone. In contrast, a reaction mechanism involving an intermediate with two p-coordinated acetone molecules on the axial sites was proposed for complex 2.

• 出版日期2015-7-1