STRUCTURE OF A TE-METHYLENE-TE BRIDGED DOUBLE-BUTTERFLY COMPLEX

Te,Te'-Methylenebis[hexacarbonyl-,mu-me-thyltellurio-mu-tellurio-diiron(Fe-Fe)], [Fe2(mu-CH3-Te)(CO)6}2(mu-4-CH2Te2)], M(r) = 1090.01, monoclinic, C2/c, a = 28.865 (10), b = 13.787 (7), c = 14.733 (4) angstrom, beta = 104.67 (2)-degrees, V = 5671.86 angstrom3, Z = 8, D(x) = 2.637 Mgm-3, lambda(Mo K-alpha) = 0.7107 angstrom, mu = 5.83 mm-1, F(000) = 4096, T = 296 K. Final R and wR are 0.0632 and 0.0598, respectively, for 2591 observed reflections. The crystal is stacked with two isomers occupying alternative lattice points. Each lattice point is associated with two identical structures with occupation probabilities of 80 and 20%. One Fe atom [Fe(l)/Fe(3)], and a CO group attached to it, are common in both. For the remaining atoms, a symmetry relationship 1 - x, y, 1/2 - z exists between the positions with unequal probabilities. Each molecule contains two butterfly shaped [(CO)6Fe2Te(CH3)Te] units bridged through a CH2 group.