Crystal Structure Determination of 4-[(Di-p-tolyl-amino)-benzylidene]-(5-pyridin-4-yl-[1,3,4]thiadiazol-2-yl)-imine along with Selected Properties of Imine in Neutral and Protonated Form with Camforosulphonic Acid: Theoretical and Experimental Studies

• Published in: Materials Vol. 14; no. 8; p. 1952
• Main Authors: Dylong, Agnieszka, Dysz, Karolina, Bogdanowicz, Krzysztof A, Przybył, Wojciech, Konieczny, Krzysztof A, Turowska-Tyrk, Ilona, Kaim, Andrzej, Iwan, Agnieszka
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 13.04.2021; MDPI
• Subjects: Absorption spectra; azomethines; Bonding strength; camforosulphonic acid; Crystal defects; Crystal structure; Crystallization; Density functional theory; Hydrogen bonds; imines; Molecular structure; Nitrogen; NMR spectroscopy; non-covalent interactions; Optimization; Optoelectronics; Overheating; Protonation; Research methodology; Single crystals; Solvents; Thermal stability; thermographic camera; Thermography; Time dependence; protonation; azomethines; non-covalent interactions; crystal structure; imines; camforosulphonic acid; thermographic camera
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14081952

The crystal structure was determined for the first time for 4-[(di-p-tolyl-amino)benzylidene]-(5-pyridin-4-yl-[1,3,4]thiadiazol-2-yl)-imine ( -PPL9) by X-ray diffraction. The imine crystallized in the monoclinic P2 /n space group with a = 18.9567(7) Å, b = 6.18597(17) Å, c = 22.5897(7) Å, and β = 114.009(4)°. Intermolecular interactions in the PPL9 crystal were only weak C-H⋯N hydrogen bonds investigated using the Hirshfeld surface. The electronic and geometric structure of the imine were investigated by the density functional theory and the time-dependent density-functional theory. The properties of the imine in neutral and protonated form with camforosulphonic acid (CSA) were investigated using cyclic voltammetry, UV-vis and H NMR spectroscopy. Theoretical and experimental studies showed that for the 1:1 molar ratio the protonation occured on nitrogen in pyridine in the PPL9 structure, as an effect of Brönsted acid-base interactions. Thermographic camera was used to defined defects in constructed simple devices with ITO/PPL9 (or PPL9:CSA)/Ag/ITO architecture. In conclusion, a thermally stable imine was synthesized in crystalline form and by CSA doping, a modification of absorption spectra together with reduction of overheating process was observed, suggesting its potential application in optoelectronics.