Synthesis and X-ray crystal structure of the chiral trimetal carbonyl clusters (μ3-CPh)FeCoMo(CO)8(RCOCp)H (R = H, CH3 or C2H5O) derived from the clusters (μ3-CPh)CO2Mo(CO)8(RCOCp)

Article abstract of DOI:10.1016/0022-328X(95)05524-S

Three μ₃-phenylmethylidyne trimetal carbonyl clusters (μ₃-CPh)Co2Mo(CO)8(RCOCp) (2, R=H; 3, R=CH3; 4, R=C2H5O) have been obtained from the reaction of the precursor (μ₃-CPh)Co3(CO)9 with the metal exchange reagents NaM(CO)3(RCOCp) in THF under reflux.Reaction of (μ₃-CPh)CO2Mo (CO)8(RCOCp) clusters with Na2 in THF under reflux followed by acidic treatment with 40percent H3PO4 yielded three new chiral clusters (μ-CPh)FeCoMo(CO)8(RCOCp)H (5, R=H; 6, CH3; 7, C2H5O).Experimental results indicate that the electron-withdrawing groups RCO on cyclopentadienyl reduce the activity of the metal exchange reagents NaMo(CO)3(RCOCp) and that the rate of the above reaction increases with increasing temperature.Cobalt carbonyl units Co(CO)3 in the clusters PhCCo3(CO)9 and PhCCo2Mo(CO)8(RCOCp) may be exchanged by organometallic fragments Mo(CO)2(RCOCp) and Fe(CO)3, respectively.Clusters 5-7 were characterized by C/H analysis and IR and 1H NMR spectroscopies and the crystal structures of 4 and 7 were determined.Cluster 4 is monoclinic with space group P2₁/c, a=11.356(2) Angstroem, b=14.030(2) Angstroem, c=16.076(3) Angstroem, β=107.19(1)deg, V=2446.8(7) Angstroem³ and Z=4; final R=0.048 and Rw=0.057 for 4751 reflections.Cluster 7 is monoclinic with space group P2₁/c, a=12.167(5) Angstroem, b=14.032(7) Angstroem, c=15.159(7) Angstroem, β=105.21(3)deg, V=2497(2) Angstroem³ and Z=4; final R=0.0468 and Rw=0.0410 for 3959 reflections.Keywords: Carbonyl; Chirality; Cluster; Cyclopentadienyl; Transition metal; XRD crystal analysis