86260-96-0Relevant academic research and scientific papers
Reactions of hexa-tert-butoxyditungsten( W≡W) with diphenylacetylene. Syntheses and structures of W2(OCMe3)4(μ-C6H 5C)2 and W2(OCMe3)4(C6H5CCC 6H5)2
Albert Cotton,Schwotzer, Willi,Shamshoum, Edwar S.
, p. 1167 - 1171 (2008/10/08)
Reaction of W2(OCMe3)6 with tolan, PhCCPh, at about 70°C in nonpolar solvents produces W2(OCMe3)4(μ-PhC)2 (1) and W2(OCMe3)4(PhCCPh)2 (2). Both of these new compounds have been characterized by X-ray crystallography. Compound 1 crystallizes in space group P21/c with a = 9.029 (3) A?, b = 19.769 (11) A?, c = 9.813 (5) A?, β = 107.67 (2)°, V = 1669 (2) A?3, and Z = 2. The molecule consists of two tetrahedra joined centrosymmetrically on a common edge formed by the μ-PhC groups. The tolan has been separated into two PhC units (C?C = 2.82 (2) A?), and the W-W distance is 2.665 (1) A?. There is structural evidence that the W-O bonds have appreciable O→W π character, and it is proposed that this is responsible for the rather long W-W bond. Compound 2 crystallizes in space group P1 with a = 10.206 (6) A?, b = 11.028 (3) A?, c = 20.763 (9) A?, a = 92.16 (3)°, β = 90.91 (5)°, γ = 104.40 (3)°, V = 2261 (2) A?3, and Z = 2. The molecules are dinuclear with two terminal Me3CO groups on each metal atom and two μ-η2-tolan molecules. The O2WWO2 group is planar and the four alkyne carbon atoms define approximately a plane that is perpendicular to it; however, this second plane is not perpendicular to the W-W axis. Each alkyne carbon atom forms a short W-C bond, 1.99 ± 0.03 A?, and a long one, 2.34 ± 0.10 A?, and the W-W distance, 2.677 (1) A?, is consistent with a bond order between 1 and 2. A resonance description that accounts for the structure is presented.
