Synthesis and characterization of tris(η 5 ‐cyclopentadienyl‐μ‐carbonyliron)‐μ 3 ‐nitrosyl cluster: X‐ray structure of [(η 5 ‐C 5 H 5 )(μ‐CO)Fe] 3 (μ 3 ‐NO)·C 4 H 8 O

Tris)(η 5 ‐cyclopentadienyl‐μ‐carbonyl‐iron)‐μ 3 ‐nitrosyl cluster was obtained from the reaction of cyclopentadienyl dicarbonyliron dimer with nitrogen monoxide in xylane. The cluster was characterised by elemental analyses, IR, MS and 1 H NMR. The crystal structure of [(η 5 ‐C 5 H 5 )(μ‐CO)Fe] 3 (μ 3 ‐NO)·C 4 H 8 O was determined by X‐ray diffraction analysis. It crystallises in the orthorhombic space group Pnma, a =9.063(2), b =10.546(2), c =22.525(4) Å, V =2150.3(7) Å 3 , Z =4, D c =1.68 g·cm −3 ; structure solution and refinement based on 1141 reflections with I ≥ 3.0σ ( I ) (MoK α , λ=0.71073 Å) converged at R =0.0540. The infrared absorption band at 1325 cm −1 of the μ 3 ‐NO in the cluster, which is red shifted, shows that μ 3 ‐NO is activated.