Cobalt-Centered Supramolecular Nanoensemble for Regulated Aerobic Oxidation of Alcohols and “One-Pot” Synthesis of Quinazolin-4(3H)-ones

Abstract

The supramolecular assemblies of the donor–acceptor (D–A) system Im-Tpy, having phenanthro­[9,10-d]­imidazole as the donor and terpyridyl group as the acceptor unit, have been developed, which serve as supramolecular host to stabilize Co­(II) in its nanoform. The as-prepared supramolecular nanoensemble Im-Tpy@Co in DMSO:water (7:3) shows high thermal stability and photostability. Even in the case of solvent mismatch, i.e., on dilution with cosolvent THF/DMSO, insignificant changes were observed in the size/morphology of the nanoensemble. The as-prepared Im-Tpy@Co nanoensemble in low catalytic loading (0.1 mol % of Co) catalyzes the oxidation of a wide variety of alcohols to aromatic aldehydes/ketones using visible light radiations as the source of energy without the need of any additive at room temperature. In comparison to already reported systems, the Im-Tpy@Co nanoensemble exhibits high turnover numbers (TONs) and turnover frequencies (TOFs). The practical application of the catalytic system has also been demonstrated in the gram-scale synthesis of 4-chlorobenzaldehyde. The Im-Tpy@Co nanoensemble exhibits recyclability up to four catalytic cycles with insignificant leaching and morphological changes. The present study also demonstrates the catalytic activity of the Im-Tpy@Co nanoensemble in “one-pot” synthesis of quinazolin-4­(3H)-ones from 2-aminobenzamide and primary alcohols with better efficiency in comparison to other transition-metal-based catalytic systems.

Strategic Insertion of Heavy Atom to Tailor TADF OLED Material for the Development of Type I Photosensitizing Catalytic Red Emissive Assemblies

“…[32][33] The powder X-ray diffraction (XRD) studies also support the existence of intermolecular π-π stacking in DPZ-PHZ molecules (Figure S11). [34][35] To have an idea about morphology, we carried out scanning electron microscopy (SEM) studies. The SEM image of DPZ-PHZ in DMSO shows the presence of nanorods whereas in H 2 O: DMSO (8 : 2) solvent mixture formation of dispersed squareshaped aggregates were observed (Figures 2a-c).…”