Bakir, Mohammed Lawrence, Mark W. Nelson, Peter Yamin, M. Bohari Catalytic C–C cross-coupling and hydrogen evolution by two Pd(II)-complexes of di-2-pyridyl ketone benzoyl hydrazones <p>The reactions between [PdCl<sub>2</sub>(CH<sub>3</sub>CN)<sub>2</sub>] and dpk-h [dpk-h = di-2-pyridyl ketone benzoyl hydrazone (dpkbh) or di-2-pyridyl ketone 4-aminobenzoyl hydrazone (dpk-4-abh)] at room temperature in air produced [PdCl<sub>2</sub>(κ<sup>3</sup>-N<sub>py</sub>,N<sub>im</sub>,O-dpkbh)] (<b>1</b>) and PdCl<sub>2</sub>(κ<sup>3</sup>-N<sub>py</sub>,N<sub>im</sub>,O-dpk-4-abh)] (<b>2</b>). X-ray structural analysis on a single crystal of PdCl(κ<sup>3</sup>-N,N,O-dpk-4-abh-H)]·H<sub>2</sub>O·dmf (<b>3</b>) established its authenticity, points to keto-enol tautomerization due to solvent-compound interactions and revealed pseudo-coordination of the carbonyl group to the Pd ion. Solid-state infrared measurements confirmed the pseudo coordination of the carbonyl group of dpk-h as evident from the appearance of the ν(C=O) of coordinated dpk-h in close proximity to the ν(C=O) of uncoordinated dpk-h. <sup>1</sup>H NMR measurements on protophilic solutions of <b>1</b> and <b>2</b> disclosed solvent dependence and keto-enol tautomerization while variable temperature studies established the predominance of the keto form. The electronic absorption spectra of <b>1</b> and <b>2</b> measured in protophilic solvents confirmed the coordination of the Pd ion to dpk-h as evident from the appearance of d-d and ligand based electronic transitions. The catalytic C–C cross-coupling reactions and electro-catalytic behavior of <b>1</b> and <b>2</b> toward a proton reduction were investigated and revealed good catalytic properties. Overall rate constants (<i>k</i><sub>app</sub>) for the electrocatalytic H<sub>2</sub> evolution of (3.39 ± 0.3) × 10<sup>3</sup> and (4.04 ± 0.2) × 10<sup>3</sup> M<sup>−1</sup> s<sup>−1</sup> were estimated and overpotentials of 157 and 67 mV, and turnover numbers (TON) of 2.0 and 3.2 for <b>1</b> and <b>2</b>, respectively, were determined.</p> Palladium;catalysis;C-C cross-coupling;di-2-pyridyl ketone benzoyl hydrazones;spectroscopy;electrochemistry 2019-07-31
    https://tandf.figshare.com/articles/journal_contribution/Catalytic_C_C_cross-coupling_and_hydrogen_evolution_by_two_Pd_II_-complexes_of_di-2-pyridyl_ketone_benzoyl_hydrazones/9198857
10.6084/m9.figshare.9198857.v1