resumo
The reactivity of ruthenium hydride complexes supported by 2-((di-tert-butylphosphaneyl)methyl)pyridine, L1 and 2-(di-tert-butylphosphaneyl)pyridine, L2, was explored. The reaction of {Ru(COD)Cl2} x with L1 in the presence of base and 10 bar of H2 gave the expected complex [Ru(L1)2(H)Cl], 1, while the same reaction with L2 gave [Ru(L2)(P(H) t Bu2)(H)Cl], 2, that results from the cleavage of a C-P bond. We were able to establish that under the reaction conditions the first species formed is [Ru(L2)2(H)Cl], 3, and that this species decomposes to give complex 2 and is in equilibrium with [Ru(L2)2Cl2], 4. The proposed mechanism obtained by DFT has the protonation of the carbon as the highest energy step (38.9 kcal/mol), consistent with a slow reaction. Preliminary studies reveal that complex 2 is a very active catalyst in the hydrogenation of benzaldehyde (TONs up to 44,000).
palavras-chave
CATALYSTS; ALDEHYDES; CO2; RU; FUNCTIONALIZATION; HYDROFORMYLATION; ACTIVATION; DIHYDROGEN; CHEMISTRY; ALCOHOLS
categoria
Chemistry
autores
Cacho, VRG; Veiros, LF; Gomes, CSB; Sardo, M; Figueira, CA; Martins, AM; Ferreira, MJ
nossos autores
Mariana Coutinho Sardo
Investigador AuxiliarProjectos
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
agradecimentos
The authors acknowledge Fundacao para a Ciencia e Tecnologia (FCT) for funding projects UIDB/00100/2020 and UIDP/00100/2020 awarded to CQE, LA/P/0056/2020 awarded to IMS, UIDB/50006/2020, UIDP/50006/2020 and LA/P/0008/2020 awarded to LAQV-REQUIMTE Research Unit and Associated Laboratory, respectively, UIDB/04378/2020 and UIDP/04378/2020 awarded to UCIBIO, LA/P/0140/2020 awarded to i4HB and UIDB/50011/2020, UIDP/50011/2020 and LA/P/0006/2020 awarded to CICECO-Aveiro Institute of Materials. V.R.G.C. acknowledges FCT for the doctoral fellowship PD/BD/147841/2019 integrated in the PhD Program in NMR applied to chemistry, materials and biosciences (PD/00065/2013). The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project No 022161 (cofinanced by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC). The authors also acknowledge Vania Andre for X-ray data acquisition, Goncalo Justino for Mass Spectrometry data and Marina Kirillova for the use of the GC.