PdII–PdII bonding interaction in dinuclear PdII complex with non-macrocyclic (O&N) chelates: Characterization, kinetics and DFT study. (29th March 2015) - Mitra, Ishani
Graphical abstract: A unique Pd II complex with metal–metal (d 8 –d 8 ) bonding interaction, [Pd(pic)(cbdca)]2 ·H2 O (pic = 2-aminomethylpyridine and cbdca 2− = cyclobutane-1, 1-dicarboxylate) has been synthesised and characterized by spectroscopic methods. Density Functional Theory (DFT) study shows Pd II –Pd II bond distance of 3.18 Å in the complex which is close to the observed distance of 3.1790(1) Å found from X-ray crystal structure. Abstract: A unique Pd II complex with metal–metal (d 8 –d 8 ) bonding interaction, [Pd(pic)(cbdca)]2 ·H2 O4 (where, pic = 2-aminomethylpyridine and cbdca 2− = cyclobutane-1, 1-dicarboxylate) has been synthesised and characterized by X-ray structure, FT-IR, ESI Mass, Raman and NMR spectroscopy. Density Functional Theory (DFT) study shows Pd II –Pd II bond distance of 3.18 Å in complex4 which is close to the observed distance of 3.1790(1) Å found from X-ray crystal structure. Powder X-ray structure of [Pd(pic)Cl2 ]1 has been solved and polymeric chain structure is found without any supporting ligand. At pH 5.5, complex [Pd(pic)(OH2 )2 ](ClO4 )2 2, the hydrolyzed product of1 exists as dimeric complex [Pd(pic)(OH)]2 (ClO4 )2 3 . Third order kinetics is followed for the reaction of cbdca with the di-μ-hydroxo bridged dimer3 . The substitution process is a ligand-dependent second order reaction, found to take place in two consecutive steps in accordance with the rate law k obs = k 1 [cbdca] 2 . The reaction follows an associative mechanistic path and the activation parameters (Δ H ‡ and Δ S ‡ ) for both the steps were evaluated using Eyring equation.