Metal vapour synthesis of phospha-organometallic compounds via reaction ofcobalt atoms with the phospha-alkyne (BuC)-Bu-t P: synthesis and structural characterisation of the sandwich compounds [Co(eta(5)-(P3C2Bu2)-Bu-t)(eta(4)-(P2C2Bu2)-Bu-t)], [Co(eta(5)-(P2C3Bu3)-Bu-t)(eta(4)-(P2C2Bu2)-Bu-t)] and the protonated tetraphospha-barrelene complex [Co(eta(4)-(P4C4Bu4H)-Bu-t)(eta(4)-(P2C2Bu2)-Bu-t)], the latter as its [W(CO)(5)] adduct

The reaction of cobalt atoms with ' BuC dropP gives the sandwich compounds [Co(eta (5)-P3C2' Bu-2)(eta (4)-P2C2' Bu-2)] and [Co(eta (5)-P2C3' Bu-3)], which have both been structurally characterised by single crystal X-ray dif fraction studies. The novel P2C3' Bu-3)(eta (4)-P2C2' Bu-2)] protonated tet raphospha-barrelene complex [Co(eta (P4C4)-P-4' Bu4H)(eta (4)-(P2C2Bu2)-Bu- ')] is also formed in the reaction and has been structurally characterised as its [W(CO)(5)] adduct. Variable temperature NMR spectra of these complex es are reported and discussed. (C) 2001 Elsevier Science B.V. All rights re served.