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Intramolecular charge transfer (ICT)-based chromophores are highly sought after for designing near-infrared (NIR) absorbing and emitting dyes as well as for designing materials for nonlinear optical (NLO) applications. The properties of these 'push-pull' molecules can easily be modified by varying the electronic donor (D) and acceptor (A) groups as well as the π-conjugation linker. This study presents a methodical approach and employs quantum chemical analysis to explore the relationship between the structural features, electro-optical properties, and the NLO characteristics of molecules with D-π-A framework. The one- and two-photon absorption (2PA), linear polarizability ( α ), and first hyperpolarizability ( β ) of some novel chromophores, consisting of a dimeric aza-Boron Dipyrromethene (aza-BODIPY) analogue, called, pyrrolopyrrole aza-BODIPY (PPAB), serving as the acceptor, have been investigated. The electronic donors used in this study are triphenylamine (TPA) and diphenylamine (DPA), and they are conjugated to the acceptor via thienyl or phenylene π-linkers. Additionally, the Hyper-Rayleigh Scattering ( β HRS ), which enables direct estimation of the second-order NLO properties, is calculated for the studied chromophores with 1064 nm excitation in acetonitrile. The β value shows a significant increase with increasing solvent polarity, indicating that the ICT plays a crucial role in shaping the NLO response of the studied molecules. The enhancement of the 2PA cross-section of the investigated molecules can also be achieved by modulating the combinations of donors and linkers. The results of our study indicate that the novel D-π-A molecules designed in this work demonstrate considerably higher hyperpolarizability values than the standard p -nitroaniline, making them promising candidates for future NLO applications., Competing Interests: The authors declare no competing financial interest., (This journal is © The Royal Society of Chemistry.)

Herein, the efficacy of WO x -promoted CeO 2 -SiO 2 and CeO 2 -ZrO 2 mixed oxide catalysts in the solvent-free selective oxidation of benzyl alcohol to benzaldehyde using molecular oxygen as an oxidant is reported. We evaluated the effects of the oxidant and catalyst concentration, reaction duration, and temperature on the reaction with an aim to optimize the reaction conditions. The as-prepared CeO 2 , CeO 2 -ZrO 2 , CeO 2 -SiO 2 , WO x /CeO 2 , WO x /CeO 2 -ZrO 2 , and WO x /CeO 2 -SiO 2 catalysts were characterized by X-ray diffraction (XRD), N 2 adsorption-desorption, Raman spectroscopy, temperature-programmed desorption of ammonia (TPD-NH 3 ), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). These characterisation results indicated that the WO x /CeO 2 -SiO 2 catalyst possessed improved physicochemical ( i.e. , structural, textural, and acidic) properties owing to the strong interactivity between WO x and CeO 2 -SiO 2 . A higher number of Ce 3+ ions ( I u''' / I Total ) were created with the WO x /CeO 2 -SiO 2 catalyst than those with the other catalysts in this work, indicating the generation of a high number of oxygen vacancies. The WO x /CeO 2 -SiO 2 catalyst exhibited a high conversion of benzyl alcohol (>99%) and a high selectivity (100%) toward benzaldehyde compared to the other promoted catalysts ( i.e. , WO x /CeO 2 and WO x /CeO 2 -ZrO 2 ), which is attributed to the smaller particle size of the WO x and CeO 2 and their high specific surface area, more significant number of acidic sites, and superior number of oxygen vacancies. The WO x /CeO 2 -SiO 2 catalyst could be quickly recovered and utilized at least five times without suffering any appreciable activity loss., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)