Reaction studies on some functionalized alkyl transition metal compounds and the crystal structure of [Cp(CO)3W{(CH2)3NO2}]

The reactions of the halogenoalkyl compounds [Cp(CO)3W{(CH2)nX}] (Cp = η5-C5H5; n = 3–5; X = Br, I) and [Cp(CO)2(PPhMe2)Mo{(CH2)3Br}] with the nucleophiles Z = CN− and N3- gave compounds of the type [Cp(CO)3W{(CH2)nZ}] for the tungsten compounds, whilst cyclic carbene compounds were obtained from the reactions of the molybdenum compound. The reactions of [Cp(CO)3W{(CH2)nBr}] (n = 3, 4) and [Cp(CO)2(PPhMe2)Mo{(CH2)3Br}] with NO3- gave [Cp(CO)3W{(CH2)nONO2}] and [Cp(CO)2(PPhMe2)Mo{(CH2)3ONO2}], respectively. The reaction of [Cp(CO)3W{(CH2)nBr}] with AgNO2 gave [Cp(CO)3W{(CH2)nNO2}]. In the solid state the complex [Cp(CO)3W{(CH2)3NO2}] crystallizes in a distorted square pyramidal geometry. In this molecule the nitropropyl chain deviates from the ideal, all-trans geometry as a result of short, non-hydrogen intermolecular N–O⋯O–N contacts. The reactions of the heterobimetallic compounds [Cp(CO)3W{(CH2)3}MLy] {MLy = Mo(CO)3Cp, Mo(CO)3Cp∗ and Mo(CO)2(PMe3)Cp; Cp∗ = η5-C5(CH3)5} with PPh3 and CO were found to be totally metalloselective, with the ligand always attacking the metal site predicted by the reactions of the corresponding monometallic analogues above with nucleophiles. Thus the compounds [Cp(CO)3W{(CH2)3}C(O)MLz] {MLz = Mo(CO)2YCp, Mo(CO)2YCp∗ and Mo(CO)Y(PMe3)Cp; Y = PPh3 or CO} were obtained. Similarly, the reaction of [Cp(CO)2Fe{(CH2)3}Mo(CO)2(PMe3)Cp] with CO gave only [Cp(CO)2Fe{(CH2)3C(O)}Mo(CO)2(PMe3)Cp]. Hydrolysis of the bimetallic compound, [Cp(CO)3W(CH2)3C(O)Mo(CO)(PPh3)(PMe3)Cp], gave the carboxypropyl compound [Cp(CO)3W{(CH2)3COOH}]. Thermolysis of the compound [Cp(CO)2Fe(CH2)3Mo(CO)3(PMe3)Cp] gave cyclopropane and propene, indicating that β-elimination and reductive processes had taken place.

Reactions of [Cp(CO)3W{(CH2)nX}] (n = 3–5; X = Br, I) with nucleophiles Z− gave [Cp(CO)3W{(CH2)nZ}], whilst those of [Cp(CO)2(PPhMe2)Mo{(CH2)nBr}] gave substitution or cyclic carbene compounds. Reactions of the heterobimetallic compounds, [Cp(CO)3W{(CH2)3}Mo(CO)Ly] {Ly = (CO)2Cp, (CO)2Cp∗ and (CO)(PMe3)Cp}, with PPh3 and CO were found to be totally metalloselective. Hydrolysis of [Cp(CO)3W(CH2)3C(O)Mo(CO)(PPh3)(PMe3)Cp] gave [Cp(CO)3W{(CH2)3COOH}], whilst thermolysis of [Cp(CO)2Fe(CH2)3Mo(CO)2(PMe3)Cp] gave cyclopropane and propene.Figure optionsDownload as PowerPoint slide