209547-82-0Relevant academic research and scientific papers
Pyridine, isocyanide, carbodiimide and allene adducts of hexakis(trifluoromethyl t-botoxy)ditungsten. A comparison of ligand binding to W2(OtBu)6 and W2(OCMe2CF3)6
Budzichowski, Theodore A.,Chisholm,Folting, Kristen,Huffman, John C.,Streib, William E.,Tiedtke, Darin B.
, p. 857 - 867 (1998)
W2(OR)6 compounds, where R = tBu and CMe2CF3, both reversibly bind pyridine in hydrocarbon solvents to form adducts W2(OR)6L2. Pyridine binds more strongly to the fluoroalkoxide but the structural parameters of the compounds W2(OCMe2CF3)6(C6H 5N)2 and W2(OtBu)6(4-CH3C6H 4N)2 reveal an essentially identical W2O6N2 core with W-W = 2.39(1) A, W-O = 1.92-1.95 A and W-N = 2.26(1) A. Both compounds were crystallographically characterized in the space group C2/c and each molecule has rigorous C2 symmetry. Allene and 1,3-di-p-tolylcarbodiimide form 1 : 1 adducts with W2(OCMe2CF3)6 in which the substrate is bound parallel to the M-M axis, i.e. μ-η2,η2-C3H4 and μ-η2,η2-ArNCNAr-W2(OCMe 2CF3)6. Also W2 (OCMe2CF3)6 and W2(OSitBuMe2)6 bind two equivalents of xylylisocyanide to afford W2(OR)6(η1-CNAr)2. For W2(OCMe2CF3)6(η 1-CNAr)2, the molecular structure has been determined by X-ray crystallography and shows a nearly eclipsed central W2O6C2 skeleton with W-W = 2.44(1) A, W-O = 1.94(1) A (av.) and W-C = 2.14(1) A, whereas the W-W-O angles span the range 105-114°, the W-W-C angles are 83(1)°. Similarly, W2(OCMe(CF3)2)4(NMe 2)2 forms a bis adduct upon reaction with the isocyanide. However, the molecular structure of W2(OCMe(CF3)2)4(NMe 2)2(η1-CNAr)2 shows a staggered arrangement of the two ligands about the ditungsten center where W-W = 2.382(1) A, W-O = 2.00(1) A (av.), W-N = 1.93(1) A (av.) and W-C = 2.14(1) A (av.) with a C-W-W-C dihedral angle of 41.9°. These reactions and their products are compared for W2(OR)6 compounds where R = tBu, tBuMe2Si and CMe2CF3.
