Synthesis and characterization of nido-[1,1,2,2-(CO)(4)-1,2-(PPh(3))(2)-1,2-FeIrB2H5]: A heterobimetallaborane analogue of nido-[B4H7](-)

The synthesis and characterization of nido-[1,1,2,2-(CO)(4)-1,2-(PPh(3))(2)-1,2-FeIrB2H5] (1) is reported. 1 is formed in low yield as a degradation product from the reaction between [{mu-Fe(CO)(4)}B6H9](-) and trans-Ir(CO)Cl(PPh(3))(2) in THF and is characterized from NMR, IR, and analytical data and by a single-crystal X-ray diffraction study. 1 crystallizes in the monoclinic space group P2(1)/n with a = 12.8622(12), b = 14.3313(12), c = 23.579(3) Angstrom, beta = 97.12(2)degrees, Z = 4, V = 4257.0(8) Angstrom(3), R(1) = 4.83%, and wR(2)(F-2) = 12.43%. The heterobimetallaborane structure may be viewed as a derivative of the binary boron hydride nido-[B4H7](-) and is related to the known homobimetallatetraborane analogues [Fe-2(CO)(6)B2H6] and [Co-2(CO)(6)B2H4] 1 exhibits proton fluxionality in its H-1 NMR spectrum, which is related to that found in the latter two compounds.