Syntheses and characterization of monobasic tridentate Cu(ii) Schiff-base complexes for efficient oxidation of 3,5-di-tert-butylcatechol and oxidative bromination of organic substrates

Abstract

Enhanced bifunctional catalytic activities are shown by monobasic tridentate Cu(ii) Schiff-base complexes.

Intermolecular Hydrogen Bonding Modulates O‐H Photodissociation in Molecular Aggregates of a Catechol Derivative

“…In both the 5 and 75 m m samples, new red‐shifted absorption bands appear over time. These bands are assigned to o ‐quinones, the fully oxidized form of catechol . This assignment is supported by mass spectrometry measurements made with the 5 m m sample (Figure in Appendix ).…”

Polymer‐anchored mononuclear and binuclear CuII Schiff‐base complexes: Impact of heterogenization on liquid phase catalytic oxidation of a series of alkenes

“…This structural difference is evident in EPR spectral patterns and g ‐values. Hyperfine splitting in the neat complexes 1–4 in DMSO solution could not be resolved at room temperature due to the rapid intermolecular copper–copper interaction in solution . The absence of half field transition (~16 000 G ) signifies the presence of a monomeric form of neat complexes in solution.…”

“…The X‐band EPR spectra of Cu II complexes 1–4 were recorded in DMSO at room temperature and presented in Figure (a), whereas room temperature EPR spectra of polymer‐anchored Cu II complexes 5–8 are shown in Figure (b). All the complexes show typical axial spectra with gǁ g(z)> g⊥ g(x) ≈ g(y) > g e , which is characteristic of a distorted square planar or square pyramidal Cu II center with the d x 2 ‐ y 2 ground state . Computer‐simulated spectra [shown by colored lines in Figure (a) and (b)] and Hamiltonian parameters are listed in Table S3.…”

“…During this period, a small but progressive mass loss of 1.6%, 2.51%, 2.50% and 3.90% was recorded in the DTA plot by complexes 5–8 , respectively. This is because of the elimination of adsorbed gases and water molecules from the polymeric matrix . In its second step, an exothermic thermal decomposition is observed in the range of 353–373°C by complexes 5–8 with an average mass loss of 27–47%, due to the melting of polymeric backbone along with the expulsion of Cl and a small fraction of ligand moiety.…”

“…Surface morphology of the pure polymer, catalyst grafted polymers 5–8 and recycled ones were also examined by SEM and are shown in Figure . SEM image of pure chloromethylated polystyrene is reproduced from our previous work . During the covalent anchoring of Cu II complexes 1–4 into polymer matrix, morphological changes were monitored by scrutinizing the SEM image of a single bead of pure and metal complex grafted polymer.…”