Reductive Formation of a Vanadium(IV/V) Oxide Cluster Complex [V8O19(4,4′-tBubpy)3] Having a C3-Symmetric Propeller-Shaped Nonionic V8O19 Core

Vanadium complexes as potential metal-based antimicrobial drugs

Radical increase of antibiotic resistance among microbes has become a serious problem for clinics all over the world that has led to the need for search of novel types of antimicrobial drugs. Each year, researchers synthesize a multitude of compounds in pursuit of identifying potential chemotherapeutic agents through diverse methodological evaluations. Among the vast array of biologically significant compounds, coordination compounds exhibit a broad range of activities within biological systems. Chelation, in particular, induces significant alterations in the biological properties of ligands and the metal component, contributing to their efficacy. Chelation increases the lipophilicity of metal complexes as a result of which they are easily absorbed by the microorganisms, thus leading to their easy passage across cell membrane. The research and development in the field of metallodrugs can be advantageous to overcome the problem encountered in antibiotic resistance. The multifaceted involvement of vanadium relative to other biometals within biological systems, coupled with its comparatively lower toxicity, underscores its utility in the advancement of novel metal-based therapeutic agents. This review aims to delineate the biological significance of V(V/IV/III) complexes as antimicrobial agents. The amassed data indicate a correlation between the potency of vanadium complexes as antimicrobial agents and the oxidation state of the metal, with III being the least toxic and V representing the most toxic oxidation state of vanadium.

Crystal structure of (μ-hydrogen di-sulfato)-μ-oxido-bis-[(4,4'-di-tert-butyl-2,2'-bi-pyridine)-oxidovanadium(IV/V)] aceto-nitrile monosolvate

The dinuclear oxidovanadium(IV/V) complex, [V2(HS2O8)O3(C18H24N2)2]·CH3CN or [V2O2(μ-O)(μ-H(SO4)2)(4,4'-tBubpy)2]·CH3CN (4,4'-tBubpy = 4,4'-di-tert-butyl-2,2'-bi-pyridine), has crystallographic C 2 symmetry and exhibits a distorted octa-hedral geometry around the vanadium center, where the two 4,4'-tBubpy ligands are nearly orthogonal to each other. The two vanadium ions are linked by an oxo anion and a unique protonated sulfate anion [H(SO4)2 3-]. In the crystal, inter-molecular C-H⋯π and π-π inter-actions between the 4,4'-tBubpy ligands are present, leading to a three-dimensional network.

Supramolecular Chemistry of Windmill-like Al10 Clusters: Adjustable Guests and Hydrogen-Bonding Networks for Enhanced Optical Limiting

The interest in cluster chemistry lies not only in the development of new types of geometric structures but also in the higher-level connectivity and assembly of clusters at the supramolecular level. Here, we report a novel windmill-like Al₁₀ cluster and consider this geometrically unique cluster as an anionic node assembled together with different cationic guests such as imidazolium and guanidinium. These guests with different hydrogen-bond angles can help to obtain a series of diverse hydrogen-bonding networks and then manipulate the stacking mode of hosts and guests. Furthermore, we realized a supramolecular approach to fine-tune the optical limiting properties of the cluster. This work not only enriches the host-guest chemistry of ionic windmill-like clusters but also opens up more possibilities for aluminum oxo cluster-based hydrogen-bonded frameworks.

4,4′-Di-tert-butyl-2,2′-bipyridinium Trifluoromethanesulfonate

4,4′-Di-tert-butyl-2,2′-bipyridinium trifluoromethanesulfonate was synthesized by stirring 4,4′-Di-tert-butyl-2,2′-bipyridine with scandium(III) trifluoromethanesulfonate in acetonitrile, followed by precipitation with diethyl ether. The structure of the new compound was characterized by FT-IR, 1H, 13C{1H} and 19F{1H} NMR spectroscopy and CHN elemental analysis. This is a safe and simple method to obtain mono-protonated bipyridinium trifluoromethanesulfonate without the direct use of trifluoromethanesulfonic acid.

Self-induced synthesis under neutral conditions and novel visible light photocatalytic activity of Ag4V2O7 polyoxometalate

Ag₄V₂O₇ POM with a nanorod-bundle structure was designed under neutral conditions, which showed good visible photodegradation performance against chloramphenicol.

Tris-(4,4'-di-tert-butyl-2,2'-bi-pyridine)(trans-4-tert-butyl-cyclo-hexa-nolato)-deca-μ-oxido-hepta-oxido-hepta-vanadium aceto-nitrile monosolvate including another unknown solvent mol-ecule

The title hepta-nuclear alkoxido(oxido)vanadium(V) oxide cluster complex, [V7(C10H19O)O17(C18H24N2)3]·CH3CN, was obtained by the reaction of [V8O20(C18H24N2)4] with 4-tert-butyl-cyclo-hexa-nol (mixture of cis and trans) in a mixed CHCl3/CH3CN solvent. The complex has a V7O18N6 core with approximately C s symmetry, which is composed of two VO4 tetra-hedra, two VO6 octa-hedra and three VO4N2 octa-hedra. In the crystal, these complexes are linked together by weak inter-molecular C-H⋯O hydrogen bonds between the 4,4'-di-tert-butyl-2,2'-bi-pyridine ligand and the V7O18N6 core, forming a one-dimensional network along the c-axis direction. Besides the complex, the asymmetric unit contains one CH3CN solvent mol-ecule. The contribution of other disordered solvent mol-ecules to the scattering was removed using the SQUEEZE option in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The unknown solvent mol-ecules are not considered in the chemical formula and other crystal data.