Giant {Mo} polyoxometalate isolated with diverse organic cations: a systematic proton conductivity study.

The development of efficient and stable proton conductors is a pivotal area of research due to their transformative potential in alternative energy technologies. Recently, there has been a surge of interest in synthesizing proton conductors based on polyoxometalate (POM) materials, attributed to their highly negatively charged and oxygen-rich surfaces. In this study, we report on a highly water-soluble giant POM, (NH)[MoO(CHCOO)(HO)]·300HO·10CHCOONH (designated as {Mo}), which was rendered insoluble in water by exchanging its ammonium cations with larger organic cations, specifically histidinium, pyridinium, bipyridinium, and methyl viologen, resulting in His-Mo132, Py-Mo132, Bpy-Mo132 and MV-Mo132, respectively.

Stimuli-responsive and self-healing supramolecular Zn(II)-guanosine metal-organic gel for Schottky barrier diode application.

Spontaneous formation of a supramolecular metal-organic hydrogel using unsubstituted guanosine as a ligand and Zn ions is reported. Guanosine, in the presence of NaOH, self-assembled into a stable G-quadruplex structure, which underwent crosslinking through Zn ions to afford a stable hydrogel. The gel has been characterized using several spectroscopic as well as microscopic studies.

Barrel-Shaped-Polyoxometalates Exhibiting Electrocatalytic Water Reduction at Neutral pH: A Synergy Effect.

Two copper-based barrel-shaped polyoxometalates (POMs), namely, [{HO}{Na(HO)}][{Cu (HO)}{Cu (HO)}{B-α-BiWO}]·7HO () and Li[{NH}{HO}{Li(HO)}][{Cu(SH)}{(CuCu)(B-α-BiWO)}]·9HO () have been synthesized and structurally characterized. The single-crystal X-ray diffraction analyses of and reveal the presence of penta- and hexa-nuclear copper wheels per formula units, respectively; these copper wheels are sandwiched between two lacunary Keggin anions {B-α-BiWO} (BiW) to form the barrel-shaped title POM compounds. In both the compounds and , the mixed-valent copper centers are present in their respective penta- and hexa-nuclear copper wheels, established by X-ray photoelectron spectroscopy (XPS) as well as by bond valence sum (BVS) calculations.

Evolution of metal organic frameworks as electrocatalysts for water oxidation.

In the last two decades, metal organic frameworks (MOFs) have been extensively investigated to develop heterogeneous electrocatalysts for water oxidation (WO). The scope of reticular synthesis, enormous surface area and accessible internal volume of MOFs make them promising candidates for catalysis. However, low electrical conductivity, slow mass transport and lack of stability restrict the scope of MOF-based WO.

Probing through-space and through-bond magnetic exchange couplings in a new benzotriazinyl radical and its metal complexes.

The synthesis and characterization of a new chelating benzotriazinyl radical (Rad) are described. Crystallographic studies coupled with SQUID magnetometry on Rad reveal the presence of discrete radical pairs which are antiferromagnetically coupled. The reaction of Rad with the 3d transition metal complexes M(hfac)·xHO (hfac = hexafluoroacetylacetonate) led to mononuclear metal complexes of general formula M(hfac)(Rad) [M = Zn(ii) (1); Ni(ii) (2) and Co(ii) (3)] whose structures have been determined by single crystal X-ray diffraction.

Targeted water soluble copper-tetrazolate complexes: interactions with biomolecules and catecholase like activities.

Two new mononuclear water soluble copper(II) complexes, [Cu{(5-pyrazinyl)tetrazolate}2(1,10-phenanthroline)] 1 and [Cu{(5-pyrazinyl)tetrazolate}(1,10-phenanthroline)2](NO3)0.5(N3)0.5 2, have been synthesized using the metal mediated [2 + 3] cycloaddition reaction between copper bound azide and pyrazinecarbonitrile.

Greener Selective Cycloalkane Oxidations with Hydrogen Peroxide Catalyzed by Copper-5-(4-pyridyl)tetrazolate Metal-Organic Frameworks.

Microwave assisted synthesis of the Cu(I) compound [Cu(µ₄-4-ptz)]n [1, 4-ptz=5-(4-pyridyl)tetrazolate] has been performed by employing a relatively easy method and within a shorter period of time compared to its sister compounds. The syntheses of the Cu(II) compounds [Cu₃(µ₃-4-ptz)₄(µ₂-N₃)₂(DMF)₂]n∙(DMF)2n (2) and [Cu(µ₂-4-ptz)₂(H₂O)₂]n (3) using a similar method were reported previously by us. MOFs 1-3 revealed high catalytic activity toward oxidation of cyclic alkanes (cyclopentane, -hexane and -octane) with aqueous hydrogen peroxide, under very mild conditions (at room temperature), without any added solvent or additive.

Nickel(II) complexes with a flexible piperazinyl moiety: studies on DNA and protein binding and catecholase like properties.

Four new mononuclear Ni(ii) complexes [Ni(L(1))]ClO4 (), [Ni(L(2))]ClO4(), [Ni(SCN)3(CH3OH)(aminoethylpiperazineH)] (), and [Ni(DMSO)4(aminoethylpiperazineH)](ClO4)3()have been synthesized from two Schiff base ligands [L(1) = 1-phenyl-3-((2-(piperidin-4-yl)ethyl)imino)but-1-en-1-ol and L(2) = 4-((2-(piperazin-1-yl)ethyl)imino)pent-2-en-2-ol] by exploiting the flexibility of the piperazinyl moiety. Structural analysis reveals that and are square planar complexes with piperazine rings in boat conformations whereas hydrolysis of Schiff bases (L(1) and L(2)) occurs during formation of octahedral complexes ( and ) with piperazine rings in chair conformations. Screening tests were conducted to quantify the binding ability of complexes (, and ) towards DNA, BSA and HSA and it was found that square planar complexes ( and ) showed more effective binding properties over octahedral complex ().

Copper-organic frameworks assembled from in situ generated 5-(4-pyridyl)tetrazole building blocks: synthesis, structural features, topological analysis and catalytic oxidation of alcohols.

Two new metal-organic compounds {[Cu3(μ3-4-ptz)4(μ2-N3)2(DMF)2](DMF)2}n (1) and {[Cu(4-ptz)2(H2O)2]}n (2) {4-ptz = 5-(4-pyridyl)tetrazolate} with 3D and 2D coordination networks, respectively, have been synthesized while studying the effect of reaction conditions on the coordination modes of 4-pytz by employing the [2 + 3] cycloaddition as a tool for generating in situ the 5-substituted tetrazole ligands from 4-pyridinecarbonitrile and NaN3 in the presence of a copper(ii) salt. The obtained compounds have been structurally characterized and the topological analysis of 1 discloses a topologically unique trinodal 3,5,6-connected 3D network which, upon further simplification, results in a uninodal 8-connected underlying net with the bcu (body centred cubic) topology driven by the [Cu3(μ2-N3)2] cluster nodes and μ3-4-ptz linkers. In contrast, the 2D metal-organic network in 2 has been classified as a uninodal 4-connected underlying net with the sql [Shubnikov tetragonal plane net] topology assembled from the Cu nodes and μ2-4-ptz linkers.

Limiting nuclearity in formation of polynuclear metal complexes through [2 + 3] cycloaddition: synthesis and magnetic properties of tri- and pentanuclear metal complexes.

A tridentate ligand p-chloro-2-{(2-(dimethylamino)ethylimino)methyl}phenol (HL) was used to generate an octahedral nickel complex [Ni(L)Cl(H2O)2] 1 which was further converted into a square-planar nickel complex [Ni(L)(N3)] 2. The [2 + 3] cycloaddition reaction between metal coordinated azide 2 and different organonitriles under microwave irradiation afforded tri- and pentanuclear nickel(II) complexes 4a-4c. Reaction with benzonitrile and 3-cyano pyridine furnished the trinuclear species [Ni3L2(5-phenyltetrazolato)4(DMF)2] 4a and [Ni3L2{5-(3-pyridyl)-tetrazolato}4(DMF)2]·2H2O 4b, respectively.