93110-45-3Relevant academic research and scientific papers
Mechanistic Insight into the Reaction of Phenyl Isocyanate with Ditungsten Hexa-tert-butoxide: Isolation and Characterization of Early Intermediates
Cotton, F. Albert,Shamshoum, Edwar S.
, p. 4662 - 4667 (2007/10/02)
By working at low temperature (-80 to -45 deg C) the purple crystalline compound W2(OCMe3)6*(μ-PhNCO) (1), which is known to be a precursor in the preparation of W2(OCMe3)4*2 (2) from W2(OCMe3)6 and PhNCO, has been isolated and its structure determined.The molecule consists of a (RO)3W=W(OR)3 (R = tert-butyl) moiety (W-W = 2.488(1) Angstroem) bridged by the PhNCO molecule and the structure is quite similar to that of W2(OR)6*(μ-tolylNCNtolyl) recently reported by us.Compound 1 will react with additional PhNCO at temperatures above -15 deg C to give 2.It has also been found that 1 reacts with PMe3 to give W2(OR)5(PMe3) (3), which has also been structurally characterized.The molecule contains a (RO)3WW(OR)2PMe3 moiety bridged by the bidentate PhNC(OR)O(-) ligand.Crystallographic data for the two compounds are as follows. 1: P21/c; a=11.054(6) Angstroem, b=17.821(7) Angstroem, c=19.401(8) Angstroem, β=100.52(2) deg; V=3758(2) Angstroem3, Z=4. 3: P1; a=10.2916(6) Angstroem; b=21.1376(7) Angstroem, c=22.0929 Angstroem, α=117.04(1) deg, β=90.33(4) deg, γ=93.73(4) deg; V=4268.2(3) Angtroem3; Z=4.Mechanistic pathways for the formation of 2 are discussed critically in the light of the new structural information.
Insertion reactions of hexaalkoxydimolybdenum and -ditungsten compounds with organic isocyanates. Syntheses and structures of W2(OCMe3)4[N(C6H 5)C(O)OCMe3]2 and Mo2(O-i-Pr)4[N(C6H5)C(O)O-i-Pr]
Chisholm, Malcolm H.,Cotton, F. Albert,Folting, Kirsten,Huffman, John C.,Ratermann,Shamshoum, Edwar S.
, p. 4423 - 4427 (2008/10/08)
Dimolybdenum and ditungsten hexaalkoxides react with phenyl isocyanates (2 equiv) in nonpolar solvents to form products involving insertion of the isocyanate into the metal alkoxide bond. The new products Mo2(O-i-Pr)4[N(C6H5)C(O)O-i-Pr] 2 (1) and W2(OCMe3)4[N(C6H 5)C(O)OCMe3]2 (2) have both been characterized by X-ray crystallography. Compound 1 crystallizes in space group Pnab with a = 18.652 (22) ?, b = 10.808 (11) ?, c = 18.912 (24) ?, and Z = 4 (at -55 °C). The molecule has a twofold axis of symmetry perpendicularly bisecting the Mo-Mo bond, and it consists of two cis bridging bidentate ligands and four isopropoxy groups. Each molybdenum atom is in the +3 oxidation state, and the Mo-Mo bond length is 2.221 (5) ?. Compound 2 crystallizes in space group P1 with a = 10.48 (1) ?, b = 11.38 (1) ?, c = 11.80 (1) A, α = 96.96 (3)°, β = 110.02(3)°, γ = 106.93(3)°, V = 1226 (2) ?3, and Z = 1. The molecule is centrosymmetric and consists of two trans bridging bidentate ligands and four tert-butoxy ligands. Each tungsten atom is in the +3 oxidation state, and the W-W bond length is 2.290 (1) ?. The bond distance in each compound is consistent with a bond order of 3, and the magnitude of the difference, 0.069 (5) ?, is as expected.
