Syntheses and Crystal Structures of Intramolecularly Stabilized Organo Aluminum,Gallium,and Indium Compounds Containing the C,P-Chelating omicron-Carboranylphosphino Ligand [omicron-C_2B_(10)H_(10)(CH_2PMe_2)-C,P]~-(Cab~(C,P)).X-ray Structure of Pent

摘要

The new phosphino-omicron-carborane ligand HCab~P(1;Cab~P = closo-1-[(dimethylphosphino)-methyl]-1,2-dicarbaborane)with substitution at the carbon and phosphorus atoms was used for the synthesis of the C,P-chelated bis(phosphino-omicron-carborane)group 13 metal complexes(Cab~(C,P))_2MX(4).Reaction of LiCab~(C,P)(2;LiCab~(C,P)= closo-1-[(dimethylphosphino)methyl]-2-lithio-omicron-carborane)with MX_3(M = Al,Ga,In;X = Cl,Br)in a 1:1 molar ratio produced the tetracoordinated metallacyclic compound(Cab~(C,P))MX_2(3),in which the metal atom was stabilized via intramolecular C,P-coordination.The corresponding bis-chelate complexes,(Cab~(C,P))_2MX(4),were synthesized by reacting 3 with an additional C,P-chelate ligand 2.Complexes 4 were also formed upon reaction of 2 with MX_3 in a 2:1 molar ratio.The ~1H and ~(13)C NMR spectra of 4 revealed that intramolecular M-P coordination occurs in solution,resulting in the formation of pentacoordinated complexes(Cab~(C,P))_2MX(4).The trigonal bipyramidal(tbp)coordination of the metal center was confirmed by single-crystal X-ray determination of the complexes(Cab~(C,P))_2GaCl(4b)and(Cab~(C,P))_2InCl(4c).Similar intramo-lecularly base-stabilized gallanes,(Cab~(C,P))GaMe_2(5b)and(Cab~(C,P))_2GaMe(6b),which were tetra-and pentacoordinated,respectively,were synthesized from the reaction of 3b and 4b with LiMe or MeMgBr.The Lewis acid 3b added the base PMe_3 to yield the pentacoordinated adduct(Cab~(C,P))GaCl_2 centre dot PMe_3(7b).The ~1H and ~(13)C NMR spectra revealed that intramolecular Ga-P coordination occurs in solution,resulting in a pentacoordinated structure.