Synthesis and structural characterization of cyclopentadienyliron- and cyclopentadienylmolybdenum-gallium compounds

Reaction of K[CpFe(CO)(2)] with a large excess of GaCl3 yields [{CpFe(CO)(2 )}Ga(Cl . GaCl3)(mu-Cl)](2) (1), while reactions with 1 and 0.5 equiv yield [{CpFe(CO)(2)}GaCl2](n) (2) and [{CpFe(CO)(2)}(2)Ga(mu-Cl)](infinity), res pectively. The molecular structure of compound 1 can be considered to be a GaCl3 complex of dimeric 2, in which the two GaCl3 moieties coordinate via a near Linear chloride bridge. [{CpFe(CO)(2)}(2)Ga(mu-Cl)](infinity) is pol ymeric in the solid state, involving an infinite Ga-Cl ... Ga-Cl backbone w ith pendent [CpFe(CO)(2)] units; however, the solubility of [{CpFe(CO)(2)}( 2)Ga(mu-Cl)](infinity) in CH2Cl2 and toluene suggests that its polymeric st ructure is cleaved in solution. Compound 2 reacts with MeCN yielding [CpFe( CO)(2)]GaCl2(MeCN) (3). Reduction of [{CpFe(CO)(2)}(2)Ga(mu-Cl)](infinity) with potassium in Et2O yields the previously reported [CpFe(CO)(2)](3)Ga an d gallium metal. Reaction of K[CpFe(CO)(2)] with GaI3 yields [CpFe(CO)(2)]- GaI2 (4), which upon hydrolysis gives the unusual galloxane; [CpFe(CO)(2)]( 6)Gas(6)(mu(3)-O)(4)(mu-OH)(2)I-2 (5). Reaction of CpMo(CO)(3)H with Ga(Bu- t)(3) yields [CpMo(CO)(3)]Ga(Bu-t)(2) (6), which forms a Lewis acid-base co mplex with MeCN: [CpMo(CO)(3)]Ga(Bu-t)(2)(MeCN) (7). The structure of compo und 6 shows evidence of unusual intra- and intermolecular carbonyl ... gall ium interactions. The aluminum analogue of compound 6, [CpMo(CO)(3)]Al(Bu-t )(2) (8); has been prepared, as has the sterically hindered aryloxide deriv ative, [CpMo(CO)(3)]Al(BHT)(2) (9). The structures of compounds 1, 5 . Et2O , 6, and [{CpFe(CO)(2)}(2)Ga(mu-Cl)](infinity) have been determined by X-ra y crystallography.