Early Transition Metal Complexes of Triphosphorus Macrocycles

摘要

The reactions of 1,5,9-triethyl-1,5,9-triphosphacyclodode-cane, [12]aneP_3Et_3, with first-row transition metal halides MCl_3 [M = Ti (1), V (2), and Cr (3)] or their THF adducts are reported. The oxidation of 2 gives the complex ([12]aneP_3Et_3)-V(O)Cl_2 (4). This is the first example of a phosphane ligand that is trans to a vanadyl moiety. Also reported are V~(III) (5) and Cr~(III) (6) complexes of the pendant ether macrocycles [12]aneP_3(C_2H_4OEt)_3 and 12[ane]P_3(C_3H_6OMe)_3 respectively. The complexes 1-6 have been characterised crystallographically and represent a rare class of phosphane complexes of these metals. The paramagnetic d~1 compounds are characterised by EPR and ENDOR spectroscopy, simulation of which gives valuable structural information of these species in frozen solution. With [12]aneP_3Et_3, Nb~(III) and Nb~(IV) chlorides give air-sensitive materials which could not be fully characterised although by comparison with compound 4, EPR and ENDOR spectroscopy indicate the principal oxidation product to be ([12]aneP_3Et_3)Nb(O)Cl_2 (7).