SYNTHESIS AND DYNAMIC BEHAVIOR OF MERCURY-LINKED CLUSTERS CONTAINING METHOXYMETHYLIDYNE LIGANDS - X-RAY STRUCTURES OF HG[FE2M(MU-3-COCH3)(CO)7(ETA-C5H5)]2 (M = CO, RH), HG[RU3(MU-COCH3)(CO)10]2, AND HG[FE(CO)4(MU-HG)FE3(MU-COCH3)(CO)10]2

The reaction of HgPh2 with hydride-containing methoxymethylidyne precursors has led to the high-yield synthesis of Hg[Fe2M(mu(3)-COMe)(CO)7(eta-C5H5)]2 (3, M = Co; 4, M = Rh) and Hg[M3(mu-COMe)(CO)10]2 (5, M = Fe; 6, M = Ru). The trimercury cluster Hg[Fe(CO)4(mu-Hg)Fe3(mu-COMe)(CO)10]2 (9) is formed in low yield in the reaction leading to 5. Crystal data for 3: orthorhombic, space group Pbca, a = 16.572 (4) angstrom, b = 19.846 (3) angstrom, c = 20.224 (5) angstrom, V = 6651 (3) angstrom 3, R (R(w)) = 0.030 (0.035) for 3783 independent absorption-corrected data to theta = 25-degrees. Crystal data for 4: monoclinic, space group C2/c, a = 25.293 (11) angstrom, b = 9.084 (3) angstrom, c = 15.541 (5) angstrom, beta = 100.97 (3)-degrees, V = 3505 (2) angstrom 3, R (R(w)) = 0.041 (0.044) for 1564 independent absorption-corrected data to theta = 25-degrees. Crystal data for 6: monoclinic, space group P2(1)/c, a = 13.894 (3) angstrom, b = 16.828 (6) angstrom, c = 16.620 (4) angstrom, beta = 109.86 (2)-degrees, V = 3655 (2) angstrom 3, R (R(w)) = 0.064 (0.065) for 2209 independent absorption-corrected data to theta = 20-degrees. Crystal data for 9: triclinic, space group P1BAR, a = 8.511 (2) angstrom, b = 8.941 (2) angstrom, c = 17.796 (3) angstrom, alpha = 79.10 (1)-degrees, beta = 75.86 (2)-degrees, gamma = 69.38 (2)-degrees, V = 1221.0 (5) angstrom 3, R (R(w)) = 0.054 (0.064) for 3422 independent absorption-corrected data to theta = 26-degrees. The metal-metal connectivities differ in 3 and 4, the latter having two Hg-Rh and two Hg-Fe bonds, while the former has four Hg-Fe bonds. C-13 and Hg-199 NMR studies show that cluster 4 undergoes a novel metal framework rearrangement in solution involving migration of the Hg atom around the Fe2Rh triangle.