Multiway data analysis approach toward understanding of photoluminescence and energy transfer in carbon nanodots.

In this study, dilution analysis and anion exchange chromatography (AEC) were employed to provide insights into the photoluminescence (PL) of carbon nanodots (CNDs). A stepwise dilution process revealed that some of the fluorophores with higher energy emission were quenched in the high concentration solution and appeared in the dilute solutions. AEC fractionation led to seven sorts of CND fractions with similar surface charges. The fractionation for this CND mixture showed that excitation wavelength dependence was lower for separated CND particles. The wavelength dependence of excitation spectra could be due to energy exchange between particles that was reduced in diluted solutions and separated fractions. Multivariate analysis of AEC's data demonstrated that there were five distinct fluorophores, which formed the total CND emission. It is interesting that none of these fluorophores had a clear contribution to the surface charge of the CND particles. Further characterization through FTIR spectroscopy and 1 H NMR revealed that optical properties of CNDs did not follow the surface functional groups in CNDs. This situation means that the optical behaviour of particles and their fluorophores differed depending on the surface functional groups.

Synthesis and theoretical study of a mixed-ligand indium(III) complex for fabrication of ß-In2S3 thin films via chemical vapor deposition.

Two new heteroleptic indium aminothiolate compounds [InClSC2H4N(Me)SC2H4]3[1] and [InSC2H4N(Me)SC2H4(C8H5F3NO)] [2] were synthesized by in situ salt metathesis reaction involving indium trichloride, aminothiol, and N,O-ß-heteroarylalkenol ligands. The complexes were subsequently purified and thoroughly characterized by nuclear magnetic resonance (NMR) analysis, elemental studies, mass spectroscopy, and X-ray diffraction single crystal analysis that showed a trigonal bipyramidal coordination of In(III) in both complexes. Thermogravimetric analysis of [1] revealed a multistep decomposition pathway and the formation of In2S3 at 350 °C, which differed from the pattern of [2] due to the lower thermal stability of [1]. Compound [2] exhibited a three-step decomposition process, resulting in the formation of In2S3 at 300 °C. The Chemical Vapor Deposition (CVD) experiment involving compound [2] was conducted on the FTO substrate, resulting in the production of singular-phase In2S3 deposits. A comprehensive characterization of these deposits, including crystal structure analysis via X-ray diffraction (XRD), and surface topography examination through scanning electron microscopy (SEM) has been completed. The presence of In-S units was also supported by the Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDS) of the as-deposited films. Moreover, the electronic structure and thermal properties of compound [2] were investigated through DFT calculations. Electron density localization analysis revealed that the highest occupied molecular orbital (HOMO) exhibited dense concentration at the aminothiolate moiety of the complex, while the lowest unoccupied molecular orbital (LUMO) predominantly resided at the N,O-ß-heteroarylalkenolate ligand. Furthermore, our computational investigation has validated the formation of indium sulfide by elucidating an intermediate state, effectively identified through EI-MS analysis, as one of the plausible pathways for obtaining In2S3. This intermediate state comprises the aminothiolate ligand (LNS) coordinated with indium metal.

A supported manganese complex with amine-bis(phenol) ligand for catalytic benzylic C(sp3)-H bond oxidation.

With regards to the importance of direct and selective activation of C-H bonds in oxidation processes, we develop a supported manganese amine bis(phenol) ligand complex as a novel catalyst with the aim of obtaining valuable products such as carboxylic acids and ketones that have an important role in life, industry and academic laboratories. We further analyzed and characterized the catalyst using the HRTEM, SEM, FTIR, TGA, VSM, XPS, XRD, AAS, and elemental analysis (CHN) techniques. Also, the catalytic evaluation of our system for direct oxidation of benzylic C-H bonds under solvent-free condition demonstrated that the heterogeneous form of our catalyst has high efficiency in comparison with homogeneous ones due to more stability of the supported complex. Furthermore, the structural and morphological stability of our efficient recyclable catalytic system has been investigated and all of the data proved that the complex was firmly anchored to the magnetite nanoparticles.