The phosphatase and anti-cancer activities of three novel acyl hydrazone based zinc(ii) Schiff base complexes have been unveiled.

A novel dinuclear iron complex of a Schiff base ligand has been exploited as a homogeneous water splitting electrocatalyst having possible real life application in renewable energy.

A two-dimensional metal−organic framework, formulated as [Ni 3 (nic) 2 (μ-Cl) 4 (DMF) 4 ]•2DMF (MOF1), was self-assembled from nickel(II) ion and 4-pyridinecarboxylic acid. The MOF1 has a 6c-connected uninoidal net topology and can absorb atmospheric moisture, causing the structural transformation of MOF1 into MOF2. The transformation is reversible, as MOF2 can be returned quickly to its initial structure MOF1 upon heating. The reversible conversion is associated with a color change between green (MOF1) and blue (MOF2), and it can be used as a colorimetric water sensor with a limit of detection (LOD) of 0.246 μM (inorganic solvent) and 0.224 μM (organic solvent). The water-capturing ability also leads to an electrocatalytic oxygen evolution reaction (OER). MOF2 is the first Ni-containing OER electrocatalyst that needs only 180 mV overpotential in 0.001 M KOH to drive 10 mA cm −2 current density. The MOF shows an immense turnover number (TON = 3.8 × 10 5 ) and frequency (TOF = 10.6 S −1 ) and Faradaic efficiency (93.7%) and excellent robustness. The structural change (MOF1 ↔ MOF2) and OER process are additionally supported by a density functional theoretical (DFT) study. The structural transformation in the solid phase further changes the magnetic properties, with both MOF1 and MOF2 showing ferromagnetic interactions. However, the Neél temperature (TN) for MOF1 of <5 K changes to ∼16 K for MOF2.

Three new mononuclear copper Schiff base complexes, namely, ([Cu(L1)Cl].CH3CN (HmC_1), [Cu(L2)Cl].CH3CN (HmC_2) and [Cu(L3)Cl].CH3CN (HmC_3) derived from ONO donor tridentate ligands HL1, HL2 and HL3, respectively, have been synthesized to check their efficacy as target‐specific next‐generation anticancer therapeutics. All the HmCs have been characterized by using various physicochemical techniques (i.e., single‐crystal X‐ray analysis, Fourier transform infrared [FT‐IR] spectroscopy and elemental analysis). Among the synthesized Schiff base complexes, HmC_3 was turned out to be most effective in killing cancer cell carried out on cultured human breast cancer cell line (MDA‐MB‐231) and human lung carcinoma cell line (A549). Finally, in order to improve the cellular permeability, particle size of HmC_3 was scaling down to nano‐regime by immobilizing it onto a suitable matrix MCM‐41@APTES (MCM‐41 = Mobil Composition of Matter No. 41 and APTES = 3‐aminopropyltriethoxysilane) to generate MCM‐41@APTES@HmC_3 (MCM‐41@APTES@HmC_3 = HtC_3). Field‐emission scanning electron microscope (FESEM) and dynamic light scattering (DLS) study revealed the particle size of the synthesized HtC_3 nano‐composite was within nano‐regime and therefore could be further effective for biomedical applications. Furthermore, HtC_3 displayed better cancer cell killing property. To get insight into the mechanism of action of HtC_3, Annexin V‐FITC/PI analysis and TUNEL assay revealed that DNA damage phenomenon is accompanied with changes in cellular morphology leading to cell apoptosis. Cell migration assay on MDA‐MB‐231 cell with HtC_3 exposed the effectiveness of HtC_3 in arresting cancer cell migration. Therefore, all the in‐vitro studies demonstrated that the immobilization of the copper Schiff base complex onto a suitable matrix increased its efficiency and becomes a promising anticancer nano‐therapeutic agent.

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