Integration of Open Metal Sites in an Amino-Functionalized\nSm(III)–Organic Framework toward Enhanced Third-Order Nonlinear\nOptical Property

A variety\nof new inorganic and organic materials have\nemerged to advance laser technologies and optical engineering. A rational\ndesign approach can contribute significantly to fabricating nonlinear\noptically active metal–organic frameworks (MOFs) by considering\nthe underlying structure–property linkage. Here, it has been\nembarked on a study of novel samarium(III) MOF, ([Sm<sub>2</sub>(ata)<sub>3</sub>(DMF)<sub>4</sub>]·DMF (ata<sup>2–</sup>: 2-aminoterephthalate),\nabbreviated as NH<sub>2</sub>-Sm-MUM-4) with enhanced nonlinear optical\n(NLO) properties. The crystal structure of this MOF represents a 6-connected\nframework with a <b>pcu</b> topology and distinctive characteristics,\nincluding open metal sites, free amine groups, and great stability,\nmaking it suitable for third-order NLO activity. The nonlinear index\nof refraction (<i>n</i><sub>2</sub>) revealed the self-focusing\nimpacts of NH<sub>2</sub>-Sm-MUM-4 at different incident intensities.\nThe highest value of <i>n</i><sub>2</sub> and β related\nto 10 mw power of incident intensity are 5.15 cm<sup>2</sup>/W and\n2.65 cm/W, respectively. As far as the authors know, this is the first\nstudy examining the potential systematic structural–property\nassociations in Sm-MOFs considering improved third-order NLO properties.