Synthesis, spectroscopic characterization, second and third-order nonlinear optical properties, and DFT calculations of a novel Mn(II) complex

•A novel Mn(II)− 1,3−Thiazolidin−2,4−dicarboxylate complex was synthesized.•FT-IR, FT-Raman and UV–vis spectra were recorded.•DFT calculations were performed to support experimental results.•Small HOMO-LUMO energy gap is an indicator of intramolecular charge transfer.•Mn(II) complex is an excellent candidate for NLO materials.

A novel Mn(II) complex with 1,3-Thiazolidine-2,4-dicarboxylic acid and 1,10 phenanthroline has been synthesized, and its FT-IR, FT-Raman and UV–vis spectra have been recorded. Density functional theory calculations with the HSEH1PBE/6–311++G(d,p) level have been used to determine optimized molecular geometry, harmonic vibrational frequencies, electronic transitions, infrared and Raman intensities and bonding features of [Mn(tda)(phen)] complex (tda = 1,3-Thiazolidine-2,4-dicarboxylic acid; Mn = Manganese (II); phen = 1,10 phenanthroline). The assignments of vibrational modes have been performed on the basis of the weightiness of internal coordinates contributing to the vibrational frequencies calculated by HSEH1PBE method. The calculated small energy gap between HOMO and LUMO energies shows that the charge transfer occurs within Mn(II) complex. Molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength have been investigated by the applying of natural bond orbital (NBO) analysis. DFT calculations have been also performed to investigate total static dipole moment (μ), the mean polarizability (<α>), the anisotropy of the polarizability (Δα), the mean first-order hyperpolarizability (<β>), and the mean second-order hyperpolarizability (<γ>) for Mn(II) complex. The obtained values show that Mn(II) complex is an excellent candidate to NLO materials.

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