Pollution that arises from textile industries is a serious environmental issue, and successful purifying has thus far proven to be difficult. In this study, environmentally safe Zr-metal-organic frameworks (Zr-MOF) were used to develop a strategy for removing Methylene Blue (MB) from water contaminants. The elimination of MB in wastewater samples by Zr-MOF showed good adsorption capability. SEM, FT-IR, XRD, XPS, and surface area confirmed that Zr-MOF has a large area of 1498 m2/g besides a microporous material having a pore diameter of 1.2 nanometers. The pH of the starting solution, amount of adsorbent used, contact period, and temperature were investigated. The pHPZC of Zr-MOF was 7.5. The adsorption of MB on Zr-MOF adsorbents was determined as sideways interrelations by a monolayer model based on the real gas law (MMRG) and a monolayer model based on the ideal gas law (MMIG). Zr-MOF has good capability for removing MB (1.58 mmol.g⁻¹) and after numerous cycles, this performance remained; up to the sixth cycle, the adsorbent had recyclability of >91.6%. Adsorption experiments demonstrated that adsorption kinetics matched a pseudo-second-order model and the Langmuir equation. Activation energy was 15.87 kJ/mol. The microporous Zr-MOF adsorbent proved to be simple and effective for water purification. Graphical Abstract

The newly synthesized Schiffs base derivative, N-allyl-2-(2-oxoacenaphthylen-1(2H)-ylidene)hydrazine-1-carbothioamide, has been characterized by different spectral techniques. Its reaction with Co(II), Ni(II), and Zn(II) acetate led to the formation of 1:1 (M:L) complexes. The IR and NMR spectral data revealed keto-thione form for the free ligand. On chelation with Co(II) and Ni(II), it behaved as mononegative and neutral tridentate via O, N¹, and S donors, respectively, while it showed neutral bidentate mode via O and N¹ atoms with Zn(II). The electronic spectra indicated that all the isolated complexes have an octahedral structure. The thermal gravimetric analyses confirmed the suggested formula and the presence of coordinated water molecules. The XRD pattern of the metal complexes showed that both Co(II) and Ni(II) have amorphous nature, while Zn(II) complex has monoclinic crystallinity with an average size of 9.10nm. DFT modeling of the ligand and complexes supported the proposed structures. The calculated HOMO-LUMO energy gap, ΔE_H-L, of the ligand complexes was 1.962.49eV range where HAAT<Zn(II)<Ni(II)<Co(II). The antioxidant activity investigation showed that the ligand and Zn(II) complex have high activity than other complexes, 88.5 and 88.6, respectively. Accordingly, the antitumor activity of isolated compounds was examined against the hepatocellular carcinoma cell line (HepG2), where both HAAT and Zn(II) complex exhibited very strong activity, IC₅₀ 6.45±0.25 and 6.39±0.18μM, respectively.

A series of Ni(II)–hydrazide complexes were prepared using derivatives of hydrazide ligands. The variation of organic ligand elaborates the mode of coordination of the organic compound referring to the addition of coordinating sites besides the NH–NH–CO group. The octahedral configuration is the major form proposed with most isolated complexes. Mass spectra were used to assure the molecular formula proposed based on the elemental analysis data for most investigated compounds. Thermal analysis as well as kinetic data supports the formula of all investigated complexes especially the presence of coordinating water molecules with most of them. Electrochemical measurements assert the stability of Ni(II) oxidation state during the complexation which may be affected during the coordination reaction. pH metric studies as well as the molecular modeling optimization reflect a shadow on the stability of the isolated complexes in solution or in solid state, respectively