The alarming global warming due to rising carbon dioxide levels in the atmosphere triggered the quest for efficient catalysts for the carbon dioxide reduction. Molecular catalysts based on Mn, and Re metals incorporating bipyridyl (bpy) ligands in the first coordination sphere garnered much attention in the field of electrochemical carbon dioxide reduction.1 We have synthesized Re, and Mn tricarbonyl complexes, [M(CO)3(dmapbpy)X] (M = Re (1a), Mn (1b); dmapbpy = {6-(2-dimethylaminophenyl)-2,2′-bipyridyl}; X = Br) with the aim of investigating the role of pendant amines in the secondary coordination sphere as a intramolecular proton relays. We have characterized the complexes with the help of NMR, FTIR, mass spectrometry, and single crystal X-ray diffraction techniques. Electrochemical CO2 reduction capabilities of the compounds 1a, 1b will be presented. Current investigations are also underway with these catalysts for CO2 reduction in the presence of a Brønsted acids. We have also synthesized new series of metal complexes [M(CO)3(Hzbpy)X] (M = Re (2a), Mn (2b); Hzbpy = {6-(hydrazyl)-2,2′-bipyridyl}; X = Br or Cl) with a slightly modified bipyridyl ligand framework for comparative studies (see fig 1). Based on cyclic voltammetry results, the effect of altering the pKa of pendant amines in the secondary coordination sphere on the reduction of CO2 to CO will be presented.

Rhenium and manganese complexes with proton relays in the secondary coordination sphere for the electrocatalytic reduction of carbon dioxide

254th National Meeting (2017)

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