Syntheses, crystal structures, DFT calculation and solid-state spectroscopic properties of new zincate(II) complexes with N-(4-substituted phenyl)-N'-(4-nitrophenyl)-oxamate

• Published in: Arabian journal of chemistry Vol. 15; no. 12; p. 104349
• Main Authors: Ishtaiwi, Zakariyya, Taher, Deeb, Korb, Marcus, Helal, Wissam, Al-Hunaiti, Afnan, Juwhari, Hassan K., Amarne, Hazem, Amer, Mohammad W., YouSef, Yaser A., Klaib, Sami, Abu-Orabi, Sultan T
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-12-2022; Elsevier
• Subjects: DFT calculations; Electrochemistry; Optical Analyses; Oxamide; Solid State Structure; Zinc; Electrochemistry; Optical Analyses; Zinc; Oxamide; DFT calculations; Solid State Structure
• ISSN: 1878-5352; 1878-5379
• DOI: 10.1016/j.arabjc.2022.104349

Straightforward synthetic methodologies for the preparation of N-(4-R-phenyl)-N'-(4-nitrophenyl)-oxamate Zincate(II)complexes are discussed. The molecular solid state structures of three compounds are reported. Photoluminescence properties of the Zn(II) complexes in solid state were studied by varying electron-donating substituents at the 4′-position of the phenyl ring.
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•Synthesis of N-(4-nitrophenyl)-N'-(4- substituted phenyl)- oxamate Zincate(II) complexes.•Compounds 3a − e were crystallographically characterized.•The optical analyses of zinc complexes (3a–e) show strong emission band in the visible region.
The electronic effects electron donating and withdrawing groups R on the properties of N-(4-R-phenyl)-N'-(4-nitrophenyl)oxamito zincate(II) complexes was investigated featuring R = Me (a), H (b), F (c), Cl (d) and Br (e). The N-(4-R-phenyl)-N'-(4-nitrophenyl)oxamide ligands 2 were synthesized by reacting ethyl 4-nitrooxanilate with the respective 4-substituted anilines. Subsequent treatment with [nBu4N]OH and [Zn(OAc)2(H2O)2] gave the respective zincate complexes [nBu4N]2[Zn(N-(4-nitrophenyl)-N'-(4-substituted phenyl)oxamides)2] (3). Spectroscopic methods were used to describe compounds 2a–e and 3a–e. Single crystal X-ray diffraction analysis confirmed the formation of 3a–c in the solid state. The tetrahedral coordination sphere of the zinc (II) ion features four amide nitrogen donor atoms based on two ethanediamide ligands. The UV–Vis spectra of Complexes 3a–e display a characteristic LLCT (π → π *) band, which was confirmed by TD-DFT calculations. DFT calculations show that the Zn(II) orbitals do not contribute to the HOMO or LUMO, with the latter being primarily found on the two 4-nitrophenyl rings for compounds 3a − e, while the HOMO-1 and HOMO are located on the 4-substituted phenyl rings. Notably, HOMO and LUMO energies and gabs do not differ significantly. Transitions from HOMO to LUMO + 1 are the most important for all ligands. The luminescence properties of solid compounds 3a − e were also investigated at 298 K. Solid state photoluminescence studies reveal that these complexes emit strong yellow-orange luminescence at 450–600 nm with a maximum at about ∼ 500 nm in the cyan region. Furthermore, the thermal stabilities of compounds 3a − e have been investigated.