COORDINATIVE PROPERTIES OF CIS-TRANS-1,4-DIPHOSPHABUTENE AND 1,4-DIPHOSPHABUTYNE IN CARBONYLVANADIUM COMPOUNDS

[Et4N][V(CO)6] and η5-CpV(CO)4 react photochemically with cis-Ph2,PCHCHPPh2 (c-dppe) to form the mononuclear chelates cis- [ET4N] [V(CO)4c-dppe] and cis-[η5-CpV(CO)2c-dppe]. With trans-Ph2PCHCHPPh2 (t-dppe) and Ph2PCHCPPh2 (dppa), the dinuclear complexes [Et4N]2 [{V(CO)5} 2μ-t-dppe], [Et4N]2 [{V(CO)5}2μ-dppa], {η5-CpV(CO)3}2μ-t-dppe], cis- [ {η5-CpV(CO)2}2 η-tdpp]2], {η5-CpV(CO)3}2μ-dppa and {η5-CpV(CO)2}2(μ-dppa)2 (which probably has a trans-configuration) are obtained. Spectroscopic evidence is given for several other complexes, including η5-CpV(CO)2 η2-dppa with the ligand coordinated via the alkyne system. The complexes are discussed on the basis of their IR (CO-stretching region), 31P and 51V NMR spectra. © 1979.