Synthesis, an experimental and quantum chemical computational study of a new nonlinear optical material: 2-Picolinium hydrogensquarate

Korkmaz U., Bulut A.

SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, vol.130, pp.376-385, 2014 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 130
  • Publication Date: 2014
  • Doi Number: 10.1016/j.saa.2014.04.038
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.376-385
  • Keywords: Squaric acid, X-ray diffraction, Strong hydrogen bonding, Vibrational spectra, Quantum chemical calculations, Non-linear optical materials, DENSITY-FUNCTIONAL THEORY, X-RAY-DIFFRACTION, SQUARIC ACID, VIBRATIONAL-SPECTRA, MOLECULAR-STRUCTURE, CRYSTAL-STRUCTURE, PROTON-TRANSFER, ANIONS, BOND, ELUCIDATION
  • Ondokuz Mayıs University Affiliated: Yes


The experimental and theoretical investigation results of a novel organic non-linear optical (NLO) organic squat-ate salt of 2-Picolinium hydrogensquarate (1), C6H8N+ C4HO4-, were reported in this study. The space group of the title compound was found in the monoclinic C2/c space group. It was found that the asymmetric unit consists of one monohydrogen squarate anion together with mono protonated 2-Picolinium, forming the (1) salt. The X-ray analysis clearly indicated that the crystal packing has shown the hydrogen bonding ring pattern of D-2(2)(10) (alpha-dimer) through N-H...O interactions. The hydrogensquarate anions form alpha-dimer, while 2-Picolinium molecule interacts through N-H...O and C-H...O with the hydrogensquarate anion. 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 obtained are presented and compared with the X-ray analysis result. On the other 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. (C) 2014 Elsevier B.V. All rights reserved.