Dirhenium complexes containing linked diphenylacetylene molecules from the photoreaction of H 3Re 3(CO) 12 with PhCCPh. Crystal and molecular structures of Re 2CO) 5(C 4Ph 4)(C 4Ph 4) and Re 2(CO) 4(C 6Ph 6)(C 2Ph 2· [formula omitted] hexane

Abstract

Photolysis of H 3Re 3(CO) 12 in presence of diphenylacetylene (DPA) yields Re 2(CO) 10, HRe(CO) 5, and the three alkyne complexes Re 2(CO) 7(DPA) 2, Re 2(CO) 5(C 4Ph 4)(DPA) ( 4) and Re 2(CO) 4(C 6Ph 6)(DPA) ( 3), the latter two which were shown by X-ray crystallography to possess linked DPA ligands. The complex Re 2(CO) 5(C 4Ph 4)(DPA) crystallizes in the triclinic space group P 1 (No. 2) with a 11.277(3), b 12.301(3), c 14.851(3) Å, α 97.37(2), β 104.68(2), γ 104.49(2)°, V 1889(2) Å 3, and Z = 2. The structure was refined using the 4548 reflections with I ⩾ 2σ( I) to give final residuals of R = 0.031 and R w = 0.041. Complex 4 possesses a rhenacyclopentadiene group bonded to the second rhenium atom and an η 2-DPA ligand bound to the rhenium atom of the metallacycle. The complex Re 2(CO) 4(C 6Ph 6)(DPA) crystallizes in the monoclinic space group P2 1/ c (No. 14) with a 17.048(4), b 16.676(2), c 18.569(4) Å, β 106.70(2)°, V 5056(3) Å 3, and Z = 4. For the 3568 reflections with I ⩾ 2σ( I), the structure refined to R = 0.078 and R w = 0.074. Three of the DPA molecules in Re 2(CO) 4(C 6Ph 6)(DPA) are linked together to form a “fly-over bridge” between the two rhenium atoms. The fourth DPA molecule is η 2-bound to one rhenium center.