NEW MIXED-METAL CARBONYL TELLURIDO CLUSTERS FROM SOLVOTHERMAL SYNTHESIS

Mixed-metal carbonyl telluride clusters (Ph(4)P)(2)[Fe(2)MTe(3)(CO)(11)] (M = Mo, (1), W, (2)) and Na(Et(4)N)(2)[Fe3W2Te8(TeMe)(CO)(12)]. 2H(2)O (3) have been synthesized methanothermally at 80 degrees C using mixtures of Fe-3(CO)(12), M(CO)(6) (M = Mo, W), and Na2Te2 with Ph(4)PBr, or Et(4)NCl . H2O, in a sealed Pyrex tube. Compound 1 crystallizes in the monoclinic space group C2/c with a = 20.379(4) Angstrom, b = 14.724(3) Angstrom, c = 39.298(6) Angstrom, beta = 95.22(1)degrees, V = 11742(7) Angstrom(3), and Z = 8. In the anionic [Fe2Mo(Te-2)(Te)(CO)(11)](2-) cluster of 1, a [Fe-2(Te-2)(Te)(CO)(6)](2-) unit is joined to an Mo(CO)(5) moiety by its Te-2(2-) ligand. Compound 3 crystallizes in the triclinic space group P (1) over bar with a = 12.636(3) Angstrom, b = 13.385(4) Angstrom, c = 20.804(7) Angstrom, alpha = 73.30(3)degrees, beta = 87.24(3)degrees, gamma = 65.40(2)degrees, V = 3054(4) Angstrom(3), and Z = 2. In the [Fe3W2(Te-2)(3)(Te)(2)(TeMe)(CO)(12)](3-) anion of 3, a W-W unit is connected to the rest of the cluster through telluride ligands to form an unsymmetrical cagelike structure. Te-125 NMR spectral data for 1-3 and (Ph(4)P)(2)[Fe-2(Te-2)(Te)(CO)(6)] have been obtained in DMSO-d(6). Clusters 1, 2, and (Ph(4)P)(2)[Fe-2(Te-2)(Te)(CO)(6)] display three-line spectra, while seven singlets are observed for 3, corresponding to seven different environments for the tellurium atoms in 3.