Molybdenum Carbonyl Derivatives of Catenated Rings and Chains of CH3As and C6H5As Units. The Synthesis and Structural Characterization of , , and

Article abstract of DOI:10.1021/ja00235a022

Reactions of the molybdenum carbonyls, Mo(CO)6 and (mesitylene)Mo(CO)3, with the homoatomic ring compounds cyclo-(RAs)n(R = CH3, n = 5; R = C6H5, n = 6), in sealed tubes in toluene, have produced mixed main-group, transition-metal clusters containing from eight to ten catenated RAs units coordinated to two Mo(CO)3 groups as fac- complexes.Neither the products nor yields were significantly dependent on which metal precursor was used, but they were strongly dependent on R.From reactions with cyclo-(CH3As)5, in the absence of O2,the only isolable product is (1) containing a ten-membered CH3As ring in a boat-chair-boat conformation; if all 12 heavy atoms are considered, the overall structure is a tetra edge-substituted cubane derivative. 1: orthorhombic, Pnnm, a = 15.689 (3) Angstroem, b = 9.576 (3) Angstroem, c = 11.097 (3) Angstroem, V = 1667.1 (7) Angstroem³, Z = 2, R_F = 4.39 percent .In reactions with cyclo-(PhAs)6, several cluster products are obtained depending on conditions.Two of these products are reported here.At 70 deg C, the major product is (2) which contains a nine-membered ring of PhAs units in one of the stable cyclononane conformations.Overall, the eleven heavy atoms adopt a trishomocubane structure. 2: monoclinic, P2₁/c, a = 13.487 (7) Angstroem, b = 18.784 (7) Angstroem, c = 25.896 (10) Angstroem, β = 94.41 (3)<*>, V = 6489 (3) Angstroem³, Z = 4, R_F = 6.38percent.Neither 1 nor 2 have Mo-Mo bonds.At 120 deg C in toluene, 2 is converted to (3); 3 may also be prepared directly from (mesitylene)Mo(CO)3 and cyclo-(PhAs)6 at the same temperature. 3 contains an eight-membered chain of PhAs units metal bonded in the 1, 4, 5, and 8 positions with its termini bridging both Mo atoms which are bonded, Mo-Mo = 3.094 (2) Angstroem. 3: monoclinic, P2₁/n, a = 13.304 (4) Angstroem, b = 19.654 (4) Angstroem, c = 21.599 (6) Angstroem, β = 100.25 (3)<*>, V = 5558 (3) Angstroem³, Z = 4, R_F = 6.95percent.