Structural, vibrational and thermal studies of a new nonlinear optical material: l-Asparagine-l-tartaric acid

Crystals of a new nonlinear optical (NLO) material, viz., l-asparagine-l-tartaric acid (LALT) (1) were grown by slow evaporation of an aqueous solution containing equimolar concentrations of l-asparagine and l-tartaric acid. The structure of the title compound which crystallizes in the non-centrosymmetric monoclinic space group P21 consists of a molecule of l-asparagine and a molecule of free l-tartaric acid both of which are interlinked by three varieties of H-bonding interactions namely OH⋯O, NH⋯O and CH⋯O. The UV–Vis–NIR spectrum of 1 reveals its transparent nature while the vibrational spectra confirm the presence of the functional groups in 1. The thermal stability and second harmonic generation (SHG) conversion efficiency of 1 were investigated.

Graphical abstractThe material reported, viz., l-asparagine-l-tartaric acid (LALT) is a new nonlinear optical (NLO) material. Second harmonic generation (SHG) conversion efficiency is about 31% of that of the standard KDP crystals. The compound is stable up to 195 °C and transparent for the fundamental and second harmonic of Nd:YAG (λ = 1064 nm) laser. The compound may have possible applications in non-linear optics.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The material reported, viz., l-asparagine-l-tartaric acid (LALT) is a new nonlinear optical (NLO) material. ► This is a new amino acid compound reported for the first time and its structure is elucidated. ► Second harmonic generation (SHG) conversion efficiency is about 31% of that of the standard KDP crystals. ► The compound is stable up to 195 °C and transparent for the fundamental and second harmonic of Nd:YAG (λ = 1064 nm) laser. ► The compound may have possible applications in non-linear optics.