STRUCTURE OF TETRA-N-BUTYRATODIRUTHENIUM CHLORIDE A COMPOUND WITH A STRONG METAL-METAL BOND

The crystal and molecular structures of tetra-n-butyratodiruthenium chloride, Ru2(O2CC3H7)4Cl, have been determined using the intensities of 708 independent, statistically significant reflections collected with a counter diffract uneter. The compound crystallizes in the tetragonal space group I42d with unit cell dimensions a = 13.265 ± 0.005 Å and c = 24.453 ± 0.008 Å (Pobsd = 1.76 ± 0.03 g cm-3 and poaiod = 1.81 g cm-3 forZ = 8). The structure, excluding hydrogen atoms, was solved using Patterson and Fourier methods and refined by full-matrix least-squares methods to a conventional unweighted residual of 7.3%. The compound contains the dinuclear, carboxylate-bridged species Ru2(O2CC3H7)4+ with a very short Ru-Ru distance of 2.281 Å. This short bond length and the reported presence of three unpaired electrons on the cation may be rationalized in terms of molecular orbital theory. The two ruthenium atoms of a given molecule are equivalent by virtue of a crystallographic twofold axis and therefore, barring disorder, for which we find no evidence, exist in the common, nonintegral oxidation state of +2.5. Chloride ions bridge adjacent dinuclear cations in the crystal to form infinite zigzag chains parallel to the a and b crystallographic axes. © 1969, American Chemical Society. All rights reserved.