90245-18-4Relevant academic research and scientific papers
Reactions of metal-metal multiple bonds. 13. Reactions of diazoalkanes with hexaalkoxides of dimolybdenum and ditungsten (M≡M). Preparation and characterization of Mo2(O-i-Pr)6(N2CPh2) 2(py), W2(O-t-Bu)6(N2C(p-tol)2) 2, and Mo(O-t-Bu)4(N2CPh2)
Chisholm, Malcolm H.,Folting, Kirsten,Huffman, John C.,Ratermann
, p. 2303 - 2311 (2008/10/08)
Various aryl-substituted diazomethanes have been found to react with M2(OR)6 (M≡M) compounds in hydrocarbon solvents at room temperature. A variety of products are formed, depending on M (Mo or W) and the alkoxy ligand, but in no instance is there evidence of alkylidene formation. The dinuclear center serves as a source of electrons for the reduction of the diazoalkane to a 2- ligand, i.e. to a hydrazone-type NNCRR′ ligand. In the reaction between Mo2(O-t-Bu)6 and Ph2CN2 the M≡M bond is cleaved, and the mononuclear compound Mo(O-t-Bu)4(NNCPh2) has been isolated as a crystalline compound. The molecule has a trigonal-bipyramidal central MoO4N moiety with short Mo-N (1.797 (3) ?) and long Mo-O (1.944 (3) ?) bonds in the axial positions. The equatorial Mo-O bond distances are 1.889 (3) ? (averaged). Related reactions involving W2(O-t-Bu)6 and Ar2CN2 yield W2(O-t-Bu)6(μ-NNCAr2)2 compounds where Ar = Ph and p-tolyl (p-tol). The molecular structure of the p-tolyl derivative reveals a central [O3W-μ-N]2 moiety based on the fusing of two trigonal-bipyramidal units sharing a common equatorial-axial edge formed by the agency of a pair of NNCAr22- ligands. The W-W and N-N distances are respectively 2.675 (1) and 1.410 (16) ?, indicative of single bonds. In the presence of donor ligands (pyridine or HNMe2) the less sterically demanding isopropoxy and neopentoxy Mo2 compounds form adducts of formula Mo2(OR)6(N2CAr2)2(L). The molecular structure of the compound Mo2(O-i-Pr)6(NNCPh2)2(py) has three O-i-Pr ligands bridging a Mo-Mo single bond (2.662 (1) ?), with one terminal NNCPh22- ligand coordinated to each molybdenum atom. NMR and IR data are reported and the present results are compared and contrasted to related work involving mono-and dinuclear transition-metal complexes. Crystal data: for Mo(O-t-Bu)4(NNCPh2), a = 17.652 (10) ?, b = 12.366 (6) ?, c = 9.060 (3) ?, α = 76.95 (3)°, β = 87.92 (3)°, γ = 124.92 (2)°, V = 1545 (1) ?3, dcalcd = 1.252 g cm-3, and space group P1; for W2(O-t-Bu)6(NNC(p-tol)2)2(hexane), a = 23.672 (5) ?, b = 12.214 (2) ?, c = 21.221 (6) ?, β = 97.24 (1)°, V = 6086 (1) ?3, dcalcd = 1.459 g cm-3, and space group C2/c; for Mo2(O-i-Pr)6(NNCPh2)2(py), a = 12.512 (8) ?, b = 14.795 (9) ?, c = 14.099 (8) ?, β = 109.51 (2)°, V = 2460 (1) ?3, dcalcd = 1.369 g cm-3, and space group P21.
