Study on the reaction of the (μ 3-CPh)Co 3(CO) 9 cluster with NaM(CO) 3(η 5-RCOCp): synthesis, characterization and crystal structures of the hetero-nuclear trimetal carbonyl clusters (μ 3-CPh)Co 2M(CO) 8(η 5-RCOCp) (M=Mo, W; R=H, CH 3, C 2H 5O)

Abstract

Six μ 3-benzylidyne trimetal carbonyl clusters (μ 3-CPh)Co 2M(CO) 8(η 5-RCOCp) ( 2a: M=Mo, R=H; 3a: M=Mo, R=CH 3; 4a: M=Mo, R=C 2H 5O; 2b: M=W, R=H; 3b: M=W, R=CH 3; 4b: M=W, R=C 2H 5O) were obtained by refluxing a solution of the precursor (μ 3-CPh)Co 3(CO) 9 with the metal exchange reagents NaM(CO) 3(η 5-RCOCp) in THF. The results show that the electron-withdrawing groups RCO on cyclopentadienyl affected the activity of the metal exchange reagents NaM(CO) 3(η 5-RCOCp) and the above reactions were accelerated thermally. The results further show that the metal carbonyl unit Co(CO) 3 in the precursor PhCCo 3(CO) 9 could be exchanged by organometallic groups M(CO) 2(RCOCp). The clusters were characterized by C/H analysis, IR and 1H NMR, and crystal structure determinations of clusters 3a and 4a. The crystals of 3a are triclinic with space group P 1 ̄ , a=13.631(4), b=14.563(4), c=14.684(6) Å, α=116.36(2), β=106.82(2), γ=100.58(2)°, V=2328 Å 3 and Z=4; final R and R w=0.052 and 0.061 for 8552 reflections. The crystals of 4a are monoclinic with space group P2 1/ c, a=11.356(2), b=14.030(2), c=16.076(3) Å, γ=107.19(1)°, V=2446.8(7) Å 3 and Z=4; final R and R w=0.048 and 0.057 for 4751 reflections.