Structure of an inclusive compound of bis(piperidinium-4-carboxylate)hydrogen semi-tartrate with water and methanol studied by X-ray diffraction, NMR, FTIR and DFT methods

The formation of the salt and neutral molecule cocrystal from equimolar solution of heliamine and bicyclo[2.2.1]hept-5-ene-endo-2,3-dicarboxylic acid

The possible interaction of 6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (heliamine) with bicyclo[2.2.1]hept-5-ene-endo-2,3-dicarboxylic acid anhydride has been studied. Instead of the reaction with heliamine, the acid anhydride was hydrolyzed into the appropriate dicarboxylic acid. An equimolar mixture of unreacted heliamine and in-situ-generated dicarboxylic acid crystallized in space group P2₁/c. The comprehensive study of the obtained crystals shows that the peculiarities of the crystallization process lead to the formation of the salt-cocrystal structure where the dianion interacts simultaneously with two cations forming a chain as the primary structural motif. The neutral molecules of dicarboxylic acid link the dianions of the neighbouring chains, forming a layer as the secondary structural motif. As a result, the stronger hydrogen bonds formed by the neutral molecules play a secondary role in the crystal structure formation.

Photoluminescence, Third-Order Nonlinear Optical and DFT Studies of Hydrazonium L-Tartrate – Combined Experimental and Theoretical Studies

Isothermal solvent evaporation method was employed to grow Undeuterated Hydrazonium L-tartrate (HLT) single crystals using water:methanol (5:1) solution as a solvent. The proton and carbon positions of HLT have been revealed by 1H and 13C NMR spectrum, respectively. The energy emission behaviour of HLT were analysed by photoluminescence spectrum. The nonlinear refractive index (n2), nonlinear absorption coefficient (β) and third order nonlinear susceptibility (χ 3) of HLT single crystal were determined by adapting Z-scan technique. Quantum chemical calculations on HLT was carried out by DFT using B3LYP/6-311++G(d,p) basis set. The predicted first hyperpolarizability of HLT is found to be 1.09 times greater than that of urea and suggests that HLT could be an attractive material for NLO applications. The predicted HOMO-LUMO energies of HLT confirmed that charge transfers occur within the molecule. The molecular bond strength and stability of the title compound were analysed by employing NBO analysis. The other molecular properties such as Mulliken atomic charge, ESP map, thermodynamic functions and perturbation theory energy have also been investigated. These investigations have been carried out for the first time, to the best our knowledge, in order to study the nonlinear optical properties of HLT and to enhance its usefulness for NLO applications.