Protonation of electron-rich diphosphazane-bridged derivatives of dicobalt octacarbonyl: crystal structure of [Co2(µ-H)(CO)4{µ-(MeO)2PN(Et)P(OMe)2}2]BPh4·CH2Cl2

Abstract

Protonation of [Co₂(CO)₄{µ-(RO)₂PN(Et)P(OR)₂}₂](R = Me or Prⁱ) proceeds without CO loss to give [Co₂(µ-H)(CO)₄{µ-(RO)₂PN(Et)P(OR)₂}₂]⁺. Proton n.m.r. spectroscopic data, as well as an X-ray structure determination of [Co₂(µ-H)(CO)₄{µ-(MeO)₂PN(Et)P(OMe)₂}₂]BPh₄, confirm the presence of a bridging hydride ligand. Both cobalt atoms are trigonal bipyramidal but the overall conformation is staggered as evidenced by P–Co–Co–P torsion angles of 34.7(1) and 35.7(1)°. Attempts to form a dihydrido species by addition of H^– merely served to deprotonate the cation with formation of the starting complex and H₂.