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Catalytic Assessment of Copper(I) Complexes and a Polymer Analog towards the One‐Pot Synthesis of Imines and Quinoxalines
Author(s) -
Sindhuja Dharmalingam,
Vasanthakumar Punitharaj,
Bhuvanesh Nattamai,
Karvembu Ramasamy
Publication year - 2019
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201900555
Subject(s) - chemistry , copper , catalysis , polystyrene , carbon 13 nmr , proton nmr , benzene , polymer chemistry , medicinal chemistry , nuclear chemistry , polymer , organic chemistry
Three copper(I) complexes, [CuCl(L)(PPh 3 ) 2 ] [L = FL ( 1 ), BL ( 2 ) or TL ( 3 )] were prepared from [(PPh 3 ) 2 Cu(µ‐Cl) 2 Cu(PPh 3 )] and N ‐carbamothioylfuran‐2‐carboxamide (FL), N‐ carbamothioylbenzamide (BL) or N ‐carbamothioylthiophene‐2‐carboxamide (TL) ligands in benzene and four‐coordinated tetrahedral copper complexes were well characterized by various spectroscopic techniques (UV/Vis, FT‐IR, 1 H NMR, 13 C NMR and 31 P NMR). The molecular structure of the ligands (FL and BL) and complexes was established from single‐crystal X‐ray diffraction studies. Copper complexes have been shown to catalyse the one‐pot synthesis of imines and quinoxalines. Heterogenized catalyst ( 4 ) was prepared by reacting more active complex 3 with polystyrene supported triphenylphosphane, and characterized by elemental analyses, and DRS‐UV, FT‐IR, ICP‐OES, and solid‐state NMR techniques. Catalytic activity of the complexes ( 3 and 4 ) was tested in the formation of imines from alcohols and amines, and quinoxalines from hydroxy ketones and diamines. Heterogeneity and reusability of catalyst 4 were evaluated, and the catalyst can be reused for four runs without any loss in activity.