Synthesis, molecular structural, optical, thermal and third harmonic nonlinear optical analysis of Piperazine-1,4-diium bis(2-carboxy-6-nitrobenzoate) tetrahydrate single crystal

• Published in: Optical materials Vol. 129; p. 112503
• Main Authors: Srividya, J., Sivamadhavi, V., Anbalagan, G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2022
• Subjects: Fluorescence lifetime measurements: z-scan optical characterization; Hirshfeld surface analysis; Single crystal X-ray diffraction; UV–Visible analysis; Vibrational spectra; Single crystal X-ray diffraction; Hirshfeld surface analysis; Vibrational spectra; UV–Visible analysis; Fluorescence lifetime measurements: z-scan optical characterization
• ISSN: 0925-3467; 1873-1252
• DOI: 10.1016/j.optmat.2022.112503

Structure and molecular interactions of the title molecular salt (NPP) were established by X-ray diffraction. The elucidated structure model assigns centrosymmetric triclinic arrangement for the molecules. Molecular packing was established through robust O–H⋯O, N–H⋯O and C–H⋯O hydrogen bond network revealing infinite chains, sheets and spiral ladder patterns. The molecular patterns were abridged through C–H … π and π – π linkages expressing several S and R graph set motifs. Single crystals of NPP with defined morphology were grown by the method of slow evaporation from solution from 1: 1 mixed solvent of methanol and water. FT- IR, FT - Raman spectra reinforced the functional groups and with NMR spectra, the protonated-deprotonated nature of the title molecule. UV–visible, Urbach plot, photoluminescence and fluorescence spectral profiles endorsed the electronic transitions and photophysical properties of NPP. Z-scan profile in the closed and open aperture modes was deployed to estimate the magnitude of the third-order nonlinear optical constants. Thermogravimetry coupled with Differential Scanning Calorimetry (DSC) declare the optimal thermal stability of the material till 71.8 °C. [Display omitted] •Crystal structure of a novel proton-transfer molecular salt, piperazine-1,4-diium bis(2-carboxy-6-nitrobenzoate) tetrahydrate.•Illustration of hydrogen bond, C–H … π, π … π and nitro and carboxylate interactions.•The long fluorescence lifetime of 33.1 ns with greater amplitude confirmed the presence of intermediate triplet states in the material.•The material can be a promising optical imaging fluorophore and good scintillating material for detector applications.•Induced charge transfer in the structure through the shallow defects, inferred through blue emission.