Vibrational spectral analysis, XRD-structure, computation, exo⇔endo isomerization and non-linear optical crystal of 5-((5-chloro-1-indol-2-yl)methylene)-1,3-diethyl-2-thioxodihy-dropyrimidine-4,6 (1,5)-dione.

This work deals with the synthesis and characterization of the novel 5-((5-chloro-1-indol-2-yl)methylene)-1,3-diethyl-2-thioxodihydro-pyrimidine-4,6(1,5)-dione π-bridge (D-A-D) donor-acceptor-donor compound. Its exo-isomer structure has been proven by XRD-single-crystal analysis for the first time. The IR, UV-Vis., MS, CHN-, H and C NMR analysis were also carried out. The DFT-optimized structural-parameters were matched with the XRD-crystallographic data. The experimental-XRD-interactions in the lattice were compared to the computed Hirshfeld analysis (HSA), MEP map and Mulliken charge population. The DFT/6-311G(d) calculations like IR/B3LYP, TD-SCF, HOMO-LUMO, GRD and GIAO-NMR have been compared to their corresponding experimental parameters. Non-linear optical (NLO) crystal theoretical-analysis was carried out then compared to urea reference. The compound thermal activity was evaluated in an open-atmosphere by TG/DTG analysis.