Tantalum complexes butadiene

Green et al. observed that the tantalum complex 101 is converted into the bicyclic complex 109 after prolonged exposure to sodium and trimethyl-phosphine.930 Two phosphine ligands of 101 are easily displaced by butadiene, affording the complex 110, while treatment of 109 with dihydrogen leads to the reduction of the metallic center. In both cases, the metallacycle remains intact.930... 

Bis(butadiene) complexes, with tantalum, 5, 173 Bis(z-butanethiolato) complexes, with bis-Cp Ti(IV), 4, 601 Bis(calixarene) complexes, as organic molecule hosts, 12, 799 Bis(carbene) complexes with gold(I), 2, 287-288 with manganese, 5, 780, 5, 826 with mercury, 2, 429 with palladium, 8, 230 with silver , 2, 206... 

Mashima, K. Kaidzu, M. Tanaka, Y. Nakayama, Y Nakamura, A. Hamilton, J. G Rooney, J. J. Control of stereoselectivity in the ring-opening metathesis polymerization of norbornene by the auxiliary ligands butadiene and o-xylylene in well-defined pentamethylcyclopentadiene tantalum carbene complexes. Organometallics 1998,17,4183 195. 

Mashima K, Matsuo Y, Tani K. Unique complexation of 1,4-diaza-l,3-butadiene ligand on half-metallocene fragments of niobium and tantalum. OrganometaUics 1999 18 1471-1481. 

---