Reactivity studies on a trihydride niobocene complex towards α,β-Unsaturated carboxylic acids

Publication date: Available online 15 June 2019Source: Journal of Organometallic ChemistryAuthor(s): Antonio Antiñolo, Santiago García-Yuste, Isabel López-Solera, Antonio Otero, María Teresa Tercero-Morales, Fernando Carrillo-HermosillaAbstractThe reactions of the trihydride niobocene complex [NbCp’2H3] (Cp’ = η5-C5H4SiMe3) (1) with different α,β-unsaturated carboxylic acids have been studied. The reactions with fumaric and maleic acids (A and B) gave a new dinuclear carboxylato-containing niobocene derivative [(NbCp’2)2(μ-κ2O,O-OOC-CH2-CH2-COO-κ2O,O)] (2), due to the occurrence of two processes, dihydrogen elimination and hydrogenation of the C=C bond of the α,β-unsaturated carboxylic acid. Likewise, the use of an α,β-unsaturated carboxylic acid derivative such as mono-methyl fumarate (ester) (C) gave the mononuclear [NbCp’2(OOC–CH2–CH2–COOMe-κ2O,O)] (3). When other α,β-unsaturated carboxylic acids with less activated alkenes were used, such as trans-cinnamic acid (F), (E)-2-methyl-3-phenylacrylic acid (G), cyclohex-1-ene-1-carboxylic acid (H), 3-methylbut-2-enoic acid (I), (E)-2-methylbut-2-enoic acid (J) or (E)-pent-2-enoic acid (K), only the complexes [NbCp’2(OOCR-κ2O,O)], (R = trans-CH=CHPh (4), trans-CMe = CHPh (5), 1-cyclohexenyl (6), (CH=CMe2) (7), (cis-CMe = CHMe) (8), (trans-C(H) = CH–Et) (9)), were isolated, respectively, resulting from a process with dihydrogen elimination and the hydrogenation of the C=C bon...

Source: Journal of Organometallic Chemistry - June 15, 2019 Category: Chemistry Source Type: research