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

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.