Synthesis, characterization and catalytic oxidation of tetrahydrofuran with 16-membered pentaazabis(macrocyclic) copper(II) complexes; {[Cu([16]aneN5)]2R}~(4+) (R = aromatic nitrogen-nitrogen linkers)

摘要

New square-planar bis(macrocyclic)dicop-per(II) complexes containing phenylene bridges between 16-membered pentaaza macrocyclic subunits have been synthesized via in-situ one pot template condensation reaction (IOPTCR) of aromatic nitrogen-nitrogen linker (R = 1,4-phenylenediamine; benzidine; 4,4'-diaminodiphenyl methane; 4,4'-diaminodiphenylether; 4,4'-diaminodiphe-nylsulfone), formaldehyde, bis(1,3-diaminopropane)cop-per(II) perchlorate and 1,3-dibromopropane in a 1:4: 2:2 molar ratio results in the formation of new series of binuclear copper(II) complexes; 1-phenyl- (1); 1,1'-phenyl- (2); 1,1'-diphenylmethan- (3); 1,1'-diphenylether- (4); 1,1'-diphenylsulfone- (5) bis(1,3,7,11,15-pentaazacyclohexade-cane)copper(II)), {[Cu([16]aneN5)]2R}(ClO4)_4". The formation of the macrocyclic framework and the mode of bonding of the complexes have been confirmed by data obtained from elemental analyses, UV-visible, FT-IR, ~1H-NMR, electronic spectral studies, conductivity and magnetic susceptibility measurements. These bis(macro-cyclic) complexes catalyzed efficiently the selective oxidation of tetrahydrofuran into tetrahydrofuran-2-one and a small amount of tetrahydrofuran-2-ol and 4-hydroxybu-tyraldehyde using dil. H2O2 as the oxidant.