Reply to the ‘Comment on “Trimorphs of 4-bromophenyl 4-bromobenzoate. Elastic, brittle, plastic”’ by J. J. Whittaker, A. J. Brock, A. Grosjean, M. C. Pfrunder, J. C. McMurtrie and J. K. Clegg, Chem. Commun., 2021, 57, DOI: 10.1039/D0CC07668F

Different molecular structures and still the same crystal property.

NEW MACROMOLECULAR STRUCTURES SYNTHESIS AND CHARACTERIZATION

Liquid crystals are unique in their properties and use and has an essential role in the area of technological applications such as electrical, optical, displayers, temperature maps, and switching materials. This study aimed to synthesize hexaethynylbenzene derivatives starting from 1,3,5-trichlorobenzene benzene as a central core substituted with three aromatic ring and three armed of 2-chloro-4,6-bis((3,7-dimethyloct-6-en-1-yl) oxy)-1,3,5-triazine. These molecules are formed by the covalent linking of three arms symmetrically to a central core which may be attached to the central core through flexible, semi-flexible or rigid linkers. The substitution occured at the acetylenic periphery on the central benzene ring and was achieved efficiently by Sonogashira coupling. The six-armed compounds based on the benzene core was mixed with the complementary 4-dodecyloxybenzoic acid 1:1 ratio, which already possessed liquid crystal property to increase the formation of these resulting in an organic salt. The obtained organic salts were investigated for their liquid crystal behaviour by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). All the intermediate and final compounds were confirmed by spectroscopic techniques (1H NMR, 13C NMR, and mass spectrometry).

Six-armed Structures Based on Benzene Ring, Synthesis and Characterization Via Sonogashira Coupling

A new six-armed compounds consist of benzene ring as a central core substituted with aromatic ring and three rod-like armed of 2-chloro-4,6-bis(dodecyloxy)-1,3,5-triazine as the peripheral arms unit which obtained by sequential nucleophilic substitution of chlorine atoms in cyanuric chloride. The substitution took place at the acetylenic periphery on the central benzene ring by Sonogashira coupling. Equimolar mixtures of the six-armed compounds based on the benzene core with the complementary 4-dodecyloxybenzoic acid, which already possessed liquid crystal property, resulted in an organic salt. The organic salts and structures were investigated by differential scanning calorimetry (DSC), and confirmed by spectroscopic methods (1H-NMR, 13C-NMR and Mass spectroscopy)

Preparation of Nano-ZnO by Paralled Flaw Precipitation Method under Ultrasonic and their Photocatalytic Performance

Nano-ZnO with high photocatalytic performance was prepared by paralled flaw precipitation method under ultrasonic radiation with Zn(NO3)2·6H2O and NH3·H2O as raw materials. The prepared samples were characterized by XRD, SEM and TG/DTA. The decolorization of methylene blue solution as model reaction, the effect of calcining temperature on the structure and photocatalytic performance of the samples were investigated. The results show that nano-ZnO with well crystal property and uniform size distribution, prepared by calcining the precursor at 300 °C for 2 h, had the average diameter of about 38 nm. When 100 mL methylene blue solution with 10 mg/L of mass concentration is treated with the nano-ZnO photocatalyst for 60 min, the decolorizing efficiency of the methylene blue solution reached 62.5 %.