Thermal, Spectral, and SHG Studies of 4-Piperidinium Carboxylamide Picrate Crystals

Abstract

4-piperidinium carboxylamide picrate crystals were synthesized by slow evaporation method from a methanol solution at room temperature. The stoichiometric ratio of the complex was confirmed by elemental analysis. The ultraviolet-visible transmittance study indicates that the crystal possesses minimum transmittance at 360 nm and no absorption between 480 nm and 900 nm. The thermal analyses were used to analyze the thermal stability of the complex. The thermal anomalies observed in the cooling and heating curves of the differential scanning calorimetry indicate the occurrence of a first-order phase transition. Single crystal X-ray diffraction study reveals that the complex crystallizes in monoclinic system with space group P2₁/c. The various absorption bands observed in Fourier transform infrared spectral analysis were reasonably assigned. The second harmonic generation efficiency of the material was found to be five times greater than that of potassium dihydrogen phosphate.

Keywords:

• Crystallization
• differential thermal analysis
• FTIR spectrum
• growth from solution
• phase transition
• X-ray diffraction

Acknowledgments

The authors gratefully acknowledge the School of Chemistry, University of Hyderabad, Hyderabad for their instrumental facilities. One of the authors, T. Dhanabal thank the UGC-Networking Centre, School of Chemistry, University of Hyderabad, Hyderabad for the measurement of single crystal X-ray diffraction analysis. The authors are thankful to Prof. P.K. Das, IPC, IISc Bangalore for NLO measurements.