title: 2-Pyridinium propanol hydrogen squarate: experimental and computational study of a nonlinear optical material.
abstract: The experimental and theoretical investigation of a novel organic nonlinear optical (NLO) squarate salt of 2-pyridinium propanol hydrogen squarate (1), C8H12ON(+)·C4HO4(-), were reported in this study. The crystal structure of the title compound was found to crystallize in the triclinic P-1 space group. In the asymmetric unit each squaric acid molecules have donated one H atom to the pyridines N1 and N2 atoms of a 2-pyridine propanol molecule, forming the salt (1). The X-ray analysis clearly indicated that the crystal packing has shown the hydrogen bonding ring pattern of D2(2)(10) (α-dimer) through N-H⋯O interactions. The structural and vibrational properties of the compound were also studied by computational methods of ab initio performed on the compound at DFT/B3LYP/6-31++G(d,p) (2) and HF/6-31++G(d,p) (3) level of theory. The calculation results on the basis of two models for both the optimized molecular structure and vibrational properties for the 1 are presented and compared with the X-ray analysis result. The molecular electrostatic potential (MEP), electronic absorption spectra, frontier molecular orbitals (FMOs), conformational flexibility and non-linear optical properties (NLO) of the title compound were also studied at the 2 level and the results are reported. In order to evaluate the suitability for NLO applications thermal analysis (TG, DTA and DTG) data of 1 were also obtained.
authors.affiliation: Department of Physics, Faculty of Arts and Sciences, Ondokuzmayıs University, Kurupelit, 55139 Samsun, Turkey.
authors.forename: Ufuk
authors.initials: U
authors.lastname: Korkmaz
authors.affiliation: Department of Physics, Faculty of Arts and Sciences, Ondokuzmayıs University, Kurupelit, 55139 Samsun, Turkey.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Bulut
mesh_terms: D018360:Crystallography, X-Ray; D003503:Cyclobutanes / Q000737:chemistry*; D004055:Differential Thermal Analysis; D004583:Electrons; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D017711:Nonlinear Dynamics; D055620:Optical Phenomena; D020005:Propanols / Q000737:chemistry*; D011726:Pyridinium Compounds / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity; D013818:Thermogravimetry; D014732:Vibration
chemical_list: D003503:Cyclobutanes; D020005:Propanols; D011726:Pyridinium Compounds; C030042:squaric acid
keywords: Non-linear optical materials; Quantum chemical calculations; Squaric acid; Strong hydrogen bonding; Vibrational spectra; X-ray diffraction