Synthesis and characterization of a new isoxazolone-based nonlinear optical crystal: MPMOI

Abstract

A new 3-(4-methoxy)phenyl-5-isoxazolone-based crystal MPMOI (C₁₈H₁₅NO₄) was designed and synthesized by the substitution of –OCH₃ groups on two sides of the molecular framework. Striped yellow MPMOI crystals were successfully grown by slow evaporation from chloroform solution. Due to the introduction of the –OCH₃ group, MPMOI crystallizes in the noncentrosymmetric space group of P2₁2₁2₁ and exhibits a second harmonic generation (SHG) response about 3.7 times larger than that of KDP under a 1064 nm fundamental laser. Thermal analysis, UV-visible absorption, infrared spectroscopy, and Raman spectroscopy were also performed to characterize the physical and chemical properties of MPMOI. This work not only presents a new NLO crystal, but also provides a feasible design strategy for group substitution.