A cationic fluorescent probe for highly selective detection of sodium dodecyl sulfate (SDS) by electrostatic and hydrophobic self-assembly

Sodium dodecyl sulfate (SDS) has a wide range of applications in the chemical industry due to its excellent characteristics including good emulsification, foaming, water solubility and stability, easy synthesis and low price. However, it is a kind of anionic surfactant which is slightly toxic to the human body, and use of a large amount will cause potential pollution of the environment. Therefore, the development of a simple method to realize the monitoring of SDS in the environment is of great significance. Herein, a cationic fluorescent probe was prepared by the condensation reaction between 4-di-p-tolylamino-benzaldehyde and 3-ethylbenzothiazolium iodide. It can be used for the quantitative determination of SDS in the range of 5-50 μM showing red fluorescence and high selectivity by forming banded assemblies. This work provides an effective tool based on a new strategy for the detection of SDS.

Photoluminescent biocomposite films of chitosan based on styrylbenzothiazolium-g-cellulose nanocrystal for anti-counterfeiting applications

In the present investigation, novel photoluminescent and transparent biocomposite films based on chitosan reinforced with styrylbenzothiazolium-g-cellulose nanocrystal for anti-counterfeiting applications were successfully prepared by casting solvent. Three novel styrylbenzothiazolium derivatives were synthesized by Knoevenagel condensation and characterized by FTIR, ¹H, ¹³C NMR and photoluminescence analysis. These photochromic compounds have been used to functionalize cellulose nanocrystal and the resulting fluorescent photonic materials were characterized by FTIR, ¹³C-CP/MAS NMR as well as photoluminescent analysis to confirm the successful grafting. It can be concluded that the addition of 5 wt% of fluorescent modified CNC to chitosan matrix increase the photoluminescent properties as well as improved the mechanical properties of the Cs/CNC-dye biocomposite films. These photoluminescent biocomposite film hold promising applicative value in anti-counterfeiting material in large-scale.

Effect of chitosan/modified montmorillonite coating on the antibacterial and mechanical properties of date palm fiber trays

In this study, the coated date palm fiber (Dpf) trays were developed using new non-toxic, and eco-friendly materials which are date palm fibers coated with a bio-composite of modified clay (Mt-Tbz). The thiabendazolium was intercalated in the interlayer space of montmorillonite and used in order to enhance the biological properties of final materials. This material was prepared as bilayer material, the first layer contains the treated palm fibers and the second one composes of bio-composite films through coating process. The elaborated coated Dpf trays were characterized using several techniques. The morphological characterization of the Dpf trays and coated Dpf trays (Dpf@Cs/Mt-Tbz), show a better dispersion/distribution of chitosan/montmorillonite modified thiabendazolium salt based coating bio-composite on the fibers surface, these results can improve the mechanical properties of the new coated Dpf trays in term of Young's modulus from 330 MPa to 1035 MPa and tensile strength from 0.5 MPa to 4 MPa. In addition, their inhibitory effect against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa has been investigated. Furthermore, the coating layer increase also the surface hydrophobicity compared to uncoated trays. The present study suggests that the elaborated coated Dpf trays can be used as potential bilayer material in the smart packaging industry.

Crystal structure, Hirshfeld surface analysis and inter-action energy and DFT studies of 1-(1,3-benzo-thia-zol-2-yl)-3-(2-hy-droxy-eth-yl)imidazolidin-2-one

In the title mol-ecule, C12H13N3O2S, the benzo-thia-zine moiety is slightly non-planar, with the imidazolidine portion twisted only a few degrees out of the mean plane of the former. In the crystal, a layer structure parallel to the bc plane is formed by a combination of O-HHydethy⋯NThz hydrogen bonds and weak C-HImdz⋯OImdz and C-HBnz⋯OImdz (Hydethy = hy-droxy-ethyl, Thz = thia-zole, Imdz = imidazolidine and Bnz = benzene) inter-actions, together with C-HImdz⋯π(ring) and head-to-tail slipped π-stacking [centroid-to-centroid distances = 3.6507 (7) and 3.6866 (7) Å] inter-actions between thia-zole rings. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (47.0%), H⋯O/O⋯H (16.9%), H⋯C/C⋯H (8.0%) and H⋯S/S⋯H (7.6%) inter-actions. Hydrogen bonding and van der Waals inter-actions are the dominant inter-actions in the crystal packing. Computational chemistry indicates that in the crystal, C-H⋯N and C-H⋯O hydrogen-bond energies are 68.5 (for O-HHydethy⋯NThz), 60.1 (for C-HBnz⋯OImdz) and 41.8 kJ mol-1 (for C-HImdz⋯OImdz). Density functional theory (DFT) optimized structures at the B3LYP/6-311 G(d,p) level are compared with the experimentally determined mol-ecular structure in the solid state.