TY - JOUR
T1 - Aerobic oxidation of benzylic alcohols catalysed by new (aryl-BIAN)copper(I) complexes
T2 - Their synthesis and structural characterization
AU - Rosa, Vítor
AU - Laronha, Helena
AU - Gomes, Clara S. B.
AU - Cordas, Cristina M.
AU - Brinco, João
AU - Freitas, Flávia
AU - Gomes da Silva, Marco D. R.
AU - Avilés, Teresa
N1 - Funding Information:
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F50006%2F2020/PT#
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDP%2F50006%2F2020/PT#
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/LA%2FP%2F0008%2F2020/PT#
info:eu-repo/grantAgreement/FCT/9444 - RNIIIE/PINFRA%2F22161%2F2016/PT#
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDB%2F04378%2F2020/PT#
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/UIDP%2F04378%2F2020/PT#
info:eu-repo/grantAgreement/FCT/6817 - DCRRNI ID/LA%2FP%2F0140%2F2020/PT#
info:eu-repo/grantAgreement/FCT/OE/UI%2FBD%2F150867%2F2021/PT#
info:eu-repo/grantAgreement/FCT/OE/2020.08089.BD/PT#
info:eu-repo/grantAgreement/FCT/POR_CENTRO/2022.13262.BD/PT#
The authors acknowledge LabRMN at FCT‐UNL and Rede Nacional de RMN (RNRMN) for access to the facilities. The NMR spectrometers are part of The National NMR Facility, supported by FCT (ROTEIRO/0031/2013 ‐ PINFRA/22161/2016) (co‐financed by FEDER through COMPETE 2020, POCI, and PORL and FCT through PIDDAC).
X‐ray infrastructure financed by FCT‐MCTES through project RECI/BBB‐BEP/0124/2012.
V.R. and C.M.C. thanks FCT (Fundação para a Ciência e Tecnologia) for funding through program DL 57/2016 – Norma transitória.
Publisher Copyright:
© 2023 John Wiley & Sons, Ltd.
PY - 2023/9
Y1 - 2023/9
N2 - A new neutral dimeric Ar-BIAN Cu(I) complex (where Ar-BIAN = bis(aryl-imino)acenaphthene) of formulation [CuBr(4-iPrC6H4-BIAN)]2 (2) was obtained by reacting CuBr and ligand 4-iPrC6H4-BIAN (L2) in refluxing acetonitrile under an argon atmosphere. When the ligand used was 2,4,6-Me3C6H2-BIAN (L1), we obtained 1 in which the expected dimer (1a) is present, but we could also observe, in solution, the presence of the bis-chelate dimer [Cu(2,4,6-Me3C6H2-BIAN)2][CuBr2] (1b) bearing CuBr2− as counter-ion; attempts to separate them failed. When the ligand used was 2-iPrC6H4-BIAN (L3), we obtained 3 in which the expected dimer (3a) is in equilibrium, in solution, with its bis-chelate isomer [Cu(2-iPrC6H4-BIAN)2][CuBr2] (3b). The solid-state molecular structures of compounds 2 and 3b were determined by single crystal X-ray diffraction. The electrochemical behaviour of complexes: 1 (1a, and 1b), 2, and 3 (3a and 3b) and the known compound [Cu(2-iPrC6H4-BIAN)2][BF4] (7) were investigated by cyclic voltammetry. The new complexes 1 (1a, 1b), 2, and 3 (3a, 3b) were tested as catalysts for the aerobic oxidation of benzylic alcohols into aldehydes; they all catalyse the reaction, with good results; the catalytic studies were extended to the similar known complexes [CuBr(2,6-iPr2C6H3-BIAN)]2 (4), [CuI(2,6-iPr2C6H3-BIAN)]2 (5), [CuCl(2,6-iPr2C6H3-BIAN)]2 (6) and (7), in order to study the effect of different bridging halides or counter ions in the catalytic activity. We found that compound 4 exhibited a high catalytic activity comparable to the best results published so far. The oxidation products, benzaldehydes, were detected and further confirmed by NMR spectroscopy, and the conversion rate was determined after GC-FID analysis.
AB - A new neutral dimeric Ar-BIAN Cu(I) complex (where Ar-BIAN = bis(aryl-imino)acenaphthene) of formulation [CuBr(4-iPrC6H4-BIAN)]2 (2) was obtained by reacting CuBr and ligand 4-iPrC6H4-BIAN (L2) in refluxing acetonitrile under an argon atmosphere. When the ligand used was 2,4,6-Me3C6H2-BIAN (L1), we obtained 1 in which the expected dimer (1a) is present, but we could also observe, in solution, the presence of the bis-chelate dimer [Cu(2,4,6-Me3C6H2-BIAN)2][CuBr2] (1b) bearing CuBr2− as counter-ion; attempts to separate them failed. When the ligand used was 2-iPrC6H4-BIAN (L3), we obtained 3 in which the expected dimer (3a) is in equilibrium, in solution, with its bis-chelate isomer [Cu(2-iPrC6H4-BIAN)2][CuBr2] (3b). The solid-state molecular structures of compounds 2 and 3b were determined by single crystal X-ray diffraction. The electrochemical behaviour of complexes: 1 (1a, and 1b), 2, and 3 (3a and 3b) and the known compound [Cu(2-iPrC6H4-BIAN)2][BF4] (7) were investigated by cyclic voltammetry. The new complexes 1 (1a, 1b), 2, and 3 (3a, 3b) were tested as catalysts for the aerobic oxidation of benzylic alcohols into aldehydes; they all catalyse the reaction, with good results; the catalytic studies were extended to the similar known complexes [CuBr(2,6-iPr2C6H3-BIAN)]2 (4), [CuI(2,6-iPr2C6H3-BIAN)]2 (5), [CuCl(2,6-iPr2C6H3-BIAN)]2 (6) and (7), in order to study the effect of different bridging halides or counter ions in the catalytic activity. We found that compound 4 exhibited a high catalytic activity comparable to the best results published so far. The oxidation products, benzaldehydes, were detected and further confirmed by NMR spectroscopy, and the conversion rate was determined after GC-FID analysis.
KW - alcohol oxidation
KW - Ar-BIAN ligands
KW - Cu(I)
KW - homogeneous catalysis
UR - http://www.scopus.com/inward/record.url?scp=85165480748&partnerID=8YFLogxK
U2 - 10.1002/aoc.7193
DO - 10.1002/aoc.7193
M3 - Article
AN - SCOPUS:85165480748
SN - 0268-2605
VL - 37
JO - Applied Organometallic Chemistry
JF - Applied Organometallic Chemistry
IS - 9
M1 - e7193
ER -