Chinnappa Arivazhagan

Innovation of sustainable and efficient catalytic systems for controlled aerobic oxidation of alcohols remains a fundamental challenge in green chemistry. Here, we report a phenothiazine‐functionalized covalent organic cage ( P ₂ D ₃ R ) as a robust heterogeneous platform for photocatalytic dehydrogenative oxidation of primary and secondary alcohols. The trigonal‐prismatic cage was synthesized via [2 + 3] imine condensation followed by reduction. Gas‐phase DFT calculations confirmed its shape‐persistent architecture and internal confined cavity. Under ambient aerobic conditions, P ₂ D ₃ R catalyzes the oxidation of various benzyl alcohols to their corresponding benzaldehyde/acetophenone derivatives, under an open atmosphere without any additives or metal‐based oxidants. Optimization studies revealed rapid kinetics, high selectivity, and excellent yields under benign conditions. The catalysis demonstrates broad substrate scope for efficiently oxidizing aryl and heteroaryl alcohols bearing both electron‐donating and electron‐withdrawing substituents with high yields (>90%) and gram‐scale scalability within minutes. Moreover, the catalyst is recoverable and reusable over eight cycles without loss of catalytic activity. Notably, two value‐added natural products, vanillin and camphor, were obtained from this present catalysis, where vanillin is well known for its antibacterial and antioxidant properties. This work highlights organic cages as a promising porous material for next‐generation additive‐free photocatalysts, integrating light harvesting, substrate confinement, and recyclability within discrete multifunctional systems.

The complexes [Ag{κ³‐S,S′,H‐H₂B(mbz)₂}(PR₃)]_x, (1: x = 2, R = Ph; 2: x = 1, R = Cy) (mbz = 2‐mercaptobenzothiazolyl) and amidine based dihydro(2‐mercaptobenzo‐thiazolyl) borates, [HN=C(Ph)–NH(R)–H₂B(mbz)] (3: R = 2,6‐diisopropylphenyl and 4: R = Ph) were synthesized and characterized by various spectroscopic methods and single‐crystal X‐ray crystallography. Complex [Ag{κ³‐S,S′,H‐H₂B(mbz)₂}(PPh₃)]₂ (1) has a dimeric structure in its crystalline state, in which central silver(I) atoms adopt a distorted trigonal bipyramid arrangement. In contrast, complex [Ag{κ³‐S,S′,H‐H₂B(mbz)₂}(PCy₃)] (2) has a monomeric structure in its crystalline state, in which the central silver(I) atoms adopt a distorted trigonal planar arrangement. Infrared spectroscopy was utilized as a tool for investigating the presence of M···H–B interactions. In addition, density functional theory (DFT) calculations were used to analyse the B–H···[M] bonding interaction in the metal borate complexes.

Treatment of [(Dipp)NCMeCHCOMeGeN(SiMe₃)₂] with [Rh₂Cl₂(μ-Cl)₂(η⁵-Cp*)₂] and [Ir₂Cl₂(μ-Cl)₂(η⁵-Cp*)₂] led to cyclometallated complexes of Rh and Ir with deprotonation from the CH₃ group in the germylene ligand.

Designing intramolecular charge‐transfer (ICT)‐based luminogenic ordered assemblies exhibiting significant electrical transport is a challenging task in the field of organic optoelectronics. In this context, a series of novel phenothiazine‐based oligo(p‐phenylenevinylene) (OPV1‐6) derivatives were designed and their structure–property relationship was investigated. Upon examining their photophysical properties, all the OPVs were found to exhibit significant intramolecular charge‐transfer characteristics in organic solvents. While inspecting the self‐assembly behaviour, the OPV with a long alkyl chain on the central phenyl core (OPV4) underwent gelation in organic solvent mixtures through strong hydrophobic interactions of the long hexadecyl chains and π‐interactions from their aromatic counterparts. Computational studies revealed a lamellar packing of molecules in the assembly. Interestingly, the degree of ICT and the gelation abilities of OPVs were significantly influenced by the electronic nature of the substituents appended to the peripheral phenothiazines. Further, the AC impedance results revealed an increase in storage and electronic transport for the fluorescent thin films prepared by an increase in the content of OPV4 in PMMA.

Organic π-conjugated compounds showing polymorphic and mechanofluorochromic (MFC) behaviors are promising candidates for many potential applications in materials chemistry. Herein, we report two distinct molecular designs based on phenothiazine as a donor and triarylborane and cyanostilbene as acceptors, for example, an acceptor–donor–acceptor system (A–D–A; compound 3) and donor–acceptor (D–A; compound 4) moieties, in which 3 exhibits polymorphism with two distinct emissions (yellow and red). The single crystal X-ray diffraction analyses of 3 clearly show two conformational isomers. The color of the emission can be altered by a grinding or fuming process.

Phenothiazines with a dimesityl boron moiety, a new class of aminoboranes with B−N linkage, were synthesized. These aminoboranes exhibited interesting photophysical behavior including aggregation‐induced emission (AIE), mechanochromism (MC), mechanoluminescence (ML), and a mega Stokes shift (up to 312 nm in hexane). The solid‐state emission of the aminoboranes could be switched reversibly by grinding–fuming processes. Furthermore, the phenothiazine derivative with a bromo and an arylborane group at 3‐ and 7‐positions exhibited bright mechanoluminescence.

A facile approach to the design of boron containing poly(aryl ether) dendron based supramolecular gels is reported. The extensive π‐π, as well as H‐bonding interactions between the boronic acid and dendron facilitate the self‐assembly process of the molecular building blocks in suitable solvents. Note that one of the poly(aryl ether) based borogel ( 1 ) [ 1 : first generation poly(aryl ether) dendron attached to boronic acid via acylhydrazone linkage] exhibits almost double viscoelasticity than the best known value for poly(aryl ether) dendron based gels, which signifies that the presence of boronic acid group in the gel significantly enhances the intermolecular interactions through strong hydrogen bonding networks. The gel is successfully utilized as a template for the in situ synthesis of well dispersed silver nanoparticles (AgNPs) in hydrogel networks. In addition, the solvent dependent sensing study of cyanide (CN ⁻ ) and fluoride (F ⁻ ) is also accomplished by these supramolecular materials.

A new ratiometric fluorescent chemodosimeter has been synthesized and characterized that exhibits high selectivity and sensitivity toward CN⁻ ions in aqueous medium.