Abstract
Oxidative addition of 1-halopenta-2,4-diene to Mo(CO) 3 (CH 3 CN) 3 gives Mo(CO) 2 (CH 3 CN) 2 (η 3 -C 5 H 7 )X (X = Cl (1), Br (2)). Addition of bis(diphenylphosphino)ethane (dppe) and bis(dimethylphosphino)ethane (dmpe) to 1 and 2 gives Mo(dppe)(CO) 2 (η 3 -C 5 H 7 )X (X = Cl (3); Br (4)) and Mo(dmpe)(CO) 2 (η 3 -C 5 H 7 )X (X = Cl (5), Br (6)), respectively, in high yields. The pentadienyl ligands of 3, 5, and 6 exist in syn-η 3 geometries whereas those of 4 exist in the anti-η 3 form exclusively. The vinyl bond length in the anti-η 3 isomer is remarkably long, 1.378 (14) Å. Factors affecting the dienyl ligand structures are discussed on the basis of crystallographic data for 3 and 4. Reaction of 1 and 2 with alkaline-metal salts of cyclopentadienide, indenide, and fluorenide (LiC 5 H 5 , LiC 9 H 7 , and NaC 13 H 9 ) gave compounds of the type Mo(CO) 2 (η 3 -C 5 H 7 )(η 5 -Cp′) (Cp′ = C 5 H 5 (7), C 9 H 7 (8), C 13 H 9 (9)) in good yields. Molecular structures of 2, 3, and 4 were determined. Crystallographic data for 2: space group P2 1 2 1 2 1 , a = 7.0481 (1) Å, b = 12.612 (2) Å, C = 16.028 (2) Å, Z = 4, R F = 2.4%, R w = 2.6%. For 3: space group P1, a = 10.194 (1) Å, b = 11.139 (2) Å, c = 16.176 (2) Å, α = 93.77 (1)°, β = 98.10 (1)°, γ = 106.33 (1)°, Z = 2, R F = 3.0%, R w = 3.0%. For 4: space group C2/c, a = 20.804 (7) Å, b = 9.418 (3) Å, c = 31.035 (6) Å, β = 91.54 (2)°, Z = 8, R F = 3.9%, R w = 4.4%. © 1989 American Chemical Society.