The transition metal-gallium complexes [Ga(MLJ3] [where ML, = Fe(C0)2(q-C5H5), M o ( C O )~(~-C~H~) , Co(C0)3(PPh3), and Mn(CO),] have been synthesised by salt elimination between GaC13 and M'(ML,) (MI = Na/K). The iron complex [Ga{Fe(C0)2(q-C5H5)]31 (1) has been characterised by X-ray crystallography and shown to contain a planar, three-coordinate gallium centre bound to three Fe(C0)2(q-C5H5) fragments by unsupported Ga-Fe bonds [av. 2.444(1) A]. A partial struc-(5) is consistent with a trigonal-planar GaMo3 core. Brief mention is also made of two chloro complexes (GaCl(ML,),] [ML, = Fe(CO)2(q-C5-H5) and Co(CO), (PPh,)].Compounds containing both gallium and a transition metal are currently of interest as potential single-source precursors to binary intermetallic phases. Such interest stems from the fact that certain phases are useful as Schottky barriers and Ohmic contacts to 13 -15 semiconductors and, in this regard, we note a recent paper by Chen et al."] concerning the chemical vapour deposition of CoGa and PtGa, from precursor molecules containing these respective elements. Nevertheless, such applications are likely to be limited at present by the relative paucity of known compounds containing gallium and a transition metal.The most extensive studies on transition metal-gallium complexes have been carried out by Haupt and coworkers over a number of years. The compounds which have been
[R~Z(C~)~(PP~~)Z(C~-~)Z{~-G~R~(CO)~(PP~~)}I['~, Na[CL,-Ga{Mn(CO)s},] (n = 1-3) [61, and [Re3(C0) Herein we report details on some of our own studies on transition metal-gallium complexes.
Results and DiscussionThe reaction between GaC13 and three equivalents of Na[Fe(C0)2(q-C5HS)] afforded, after workup and recrystallisation from THF/hexane mixtures, dark red crystals of the triiron-gallium complex 1, and it was evident from a solution infrared spectrum [ Table 1, Figure l(a)] that this complex was very similar to the indium analogue 2[l8]. The molecular structure of 1, as determined by X-ray crystallography, is
