Abstract
The reaction of NaCo(CO) 4 with trans-1-bromppenta-2,4-diene in tetrahydrofuran at -78°C affords (syn-η 3 -2,4-pentadienyl)Co(CO) 3 (1) in moderate yield. Addition of triphenylphosphine to 1 in ether at 0°C gives (syn-η 3 -2,4-pentadienyl)Co(CO) 2 [P(C 6 H 5 ) 3 ] (2a). In solution, 2a equilibrates with its anti isomer (2b) at room temperature. The crystal structure of 2a has been determined by X-ray diffraction analysis. Compound 2a crystallizes in the triclinic space group P1 with lattice parameters: a 10.326(2), b 10.763(4), c 11.452(2) Å, α 105.99(2), β 100.10(1), γ 108.05(2)°; V 1114.98 Å 3 , Mol. wt. 539.69, D (calcd.) 1.324 g/cm 3 and Z = 2. The structure was solved and refined to R and R w values of 0.0357 and 0.0408, respectively for 4046 reflections. © 1986.