Chromium carbonyl complexes with aryl mono- and oligogermanes: Ability for haptotropic rearrangement

Publication date: Available online 12 July 2019Source: Journal of Organometallic ChemistryAuthor(s): Kirill V. Zaitsev, Igor P. Gloriozov, Yuri F. Oprunenko, Elmira Kh Lermontova, Andrei V. ChurakovAbstractThe intra- and intermolecular inter-ring η6 ⇌ η6-haptotropic rearrangements (IRHR), occurring by involving interactions to Ge atoms in arylgermanes, were investigated theoretically and experimentally. The new methods for the synthesis of non-symmetrical polyaromatic Ge compounds were elaborated. Digermane Ph3GeGeMe2Cl (2) was obtained from Ph3GeGeMe2NMe2 (1) under action of Me3SiCl. Aryl digermane Ph3GeGeMe2(η6-C6H5)Cr(CO)3 (4) was obtained after lithiation of (η6-C6H6)Cr(CO)3 (3) with subsequent interaction with 2. It was established that thermally induced intramolecular IRHR in 4 is not observed experimentally; at similar reaction conditions in the presence of tetralin C10H12 (7) the bimolecular intermolecular IRHR occurs giving (η6-C10H12)Cr(CO)3 (8). DFT analysis of the intramolecular IRHRs for model germane (p-Tol)2Ge(H)(η6-Tol-p)Cr(CO)3 (MC1) and digermane Ph3GeGeH2(η6-Ph)Cr(CO)3 (MC2) indicates a plausible effect of 3c-2e (agostic) Ge–H···Cr interaction on success of such rearrangement. The theoretical activation barrier is determined to be in the range of 35–37 kcal/mol. The model compound (η6-C6H3(GeHPh2)Me2-p)Cr(CO)3 (12) was obtained from (η6-C6H4Me2-p)Cr(CO)3 (11). The decomposition of 12 was observed under conditions of thermally induced IRH...

Source: Journal of Organometallic Chemistry - July 12, 2019 Category: Chemistry Source Type: research