1,2-Addition of Formic or Oxalic Acid to -N{CH2CH2(PiPr2)}2-Supported Mn(I) Dicarbonyl Complexes and the Manganese-Mediated Decomposition of Formic Acid

Article abstract of DOI:10.1021/acs.organomet.6b00274

(PN^HP)Mn(CO)₂ (I) carboxylate complexes (PN^HP = HN{CH₂CH₂(PiPr₂)}₂) were prepared via 1,2-addition of either formic or oxalic acid to (PNP)Mn(CO)₂ (PNP = the deprotonated, amide form of the ligand ^-N{CH₂CH₂(PiPr₂)}₂). The structural and spectral properties of these complexes were compared. The manganese formate complex was found to be dimeric in the solid state and monomeric in solution. Half an equivalent of oxalic acid was employed to form the bridging oxalate dimanganese complex. The catalytic competencies of the carboxylate complexes were assessed, and the formate complex was found to decompose formic acid catalytically. Both dehydrogenation and dehydration pathways were active as assessed by the presence of H₂, CO₂, and H₂O. The addition of LiBF₄ exhibited a strong inhibitory effect on the catalysis.