Third-Order Nonlinear Optical Behavior of an Amide-Tricarboxylate Zinc(II) Metal–Organic Framework with Two-Fold 3D+3D Interpenetration

A new metal–organic framework (MOF), [Zn4(μ4-O)­(μ6-L)2(H2O)2] n ·nDMF (ZSTU-10), was assembled from zinc­(II) nitrate and N,N′,N″-bis­(4-carboxylate)­trimesicamide linkers and fully characterized. Its crystal structure discloses an intricate two-fold 3D+3D interpenetrated MOF driven by the [Zn4(μ4-O)]-based tetragonal secondary building units and the C3-symmetric tris-amide-tricarboxylate linkers (μ6-L3–). Topological analysis of ZSTU-10 reveals two interpenetrated 3,6-connected nets with an rtl (rutile) topology. Z-Scan analysis at 532 nm was conducted to study a nonlinear optical (NLO) behavior of ZSTU-10. The nonlinear responses of ZSTU-10 were explored under various laser intensities, revealing notable third-order NLO properties in the visible region. A large two-photon absorption at lower incident intensities highlights the fact that ZSTU-10 can be applied in optical limiting devices as well as optical modulators. Moreover, a nonlinear refractive index (n 2) is indicative of a self-defocusing behavior. This work thus expands a family of novel MOF materials with remarkable optical properties.