Organometallics of diphosphazanes. Part 10. Dinuclear group 6 metal carbonyl complexes bridged by a cyclodiphosphazane in its cis or trans form
摘要:
Mononuclear Group 6 metal tetracarbonyl complexes containing a cyclodiphosphazane ligand, [PhNP(OC(6)H(4)Me-p)](2) (L), have been used as synthons to prepare homo- and hetero-bimetallic complexes in which the cyclodiphosphazane bridges the two metal centres in its cis or trans isomeric forms. The dimolybdenum complex [Mo-2(eta(5)-C5H5)(2)(CO)(4)(mu-L)] has also been synthesized. The trends in P-31 NMR chemical shifts and the structural features as revealed by X-ray crystallography are discussed.
The reactions of cyclodiphosphazanes [PhNP(OR)]2 (R = CH2CF3 (1) and C6H4Me-p (2)) with Group 6 metal carbonyl derivatives have been investigated. The stereochemistry of the ligand appears to play a significant role in determining its coordination behaviour. The cyclodiphosphazane 1 (isolated as the trans-isomer) affords the dinuclear complexes 9-11 in which the two metal centres are bridged by the diphosphazane ligand. In contrast the cyclodiphosphazane 2 (isolated as a 3/1 mixture of cis- and trans-isomers) yields the mononuclear complexes 3-7 in which the cyclodiphosphazane is coordinated in the eta1-fashion. The structures of [W(CO4(NHC5H10)(PhNP(OC6H4Me-p))2}] (6) and [Mo(CO)4(NHC5H10)}2mu-[PhNP(OCH2CF3)]2}] (9a) have been determined by X-ray crystallography.
Krishnamurthy, S. S.; Reddy, V. Sreenivasa; Chandrasekaran, A., Phosphorus, Sulfur and Silicon and the Related Elements, 1992, vol. 64, # 1-4, p. 99 - 106
作者:Krishnamurthy, S. S.、Reddy, V. Sreenivasa、Chandrasekaran, A.、Nethaji, M.