Oxidovanadium(IV) Complexes of 3-Hydroxy-4-pyrone and 3-Hydroxy-4-pyridinone Ligands: A New Generation of Homogeneous Catalysts for the Epoxidation of Geraniol

Systematic Development of Vanadium Catalysts for Sustainable Epoxidation of Small Alkenes and Allylic Alcohols

The catalytic epoxidation of small alkenes and allylic alcohols includes a wide range of valuable chemical applications, with many works describing vanadium complexes as suitable catalysts towards sustainable process chemistry. But, given the complexity of these mechanisms, it is not always easy to sort out efficient examples for streamlining sustainable processes and tuning product optimization. In this review, we provide an update on major works of tunable vanadium-catalyzed epoxidations, with a focus on sustainable optimization routes. After presenting the current mechanistic view on vanadium catalysts for small alkenes and allylic alcohols' epoxidation, we argue the key challenges in green process development by highlighting the value of updated kinetic and mechanistic studies, along with essential computational studies.

Catalytic Applications of Vanadium: A Mechanistic Perspective

The chemistry of vanadium has seen remarkable activity in the past 50 years. In the present review, reactions catalyzed by homogeneous and supported vanadium complexes from 2008 to 2018 are summarized and discussed. Particular attention is given to mechanistic and kinetics studies of vanadium-catalyzed reactions including oxidations of alkanes, alkenes, arenes, alcohols, aldehydes, ketones, and sulfur species, as well as oxidative C-C and C-O bond cleavage, carbon-carbon bond formation, deoxydehydration, haloperoxidase, cyanation, hydrogenation, dehydrogenation, ring-opening metathesis polymerization, and oxo/imido heterometathesis. Additionally, insights into heterogeneous vanadium catalysis are provided when parallels can be drawn from the homogeneous literature.

A new chiral dimanganese(iii) complex: synthesis, crystal structure, spectroscopic, magnetic, and catalytic properties

The two enantiomeric dimanganese(iii) complexes are efficient catalysts, with a total enantioselectivity, in the epoxidation of methyl trans-cinnamate.

Uncovering novel 3-hydroxy-4-pyridinone metal ion complexes with potential anti-inflammatory properties

Ligands of the 3-hydroxy-4-pyridinone (3,4-HPO) type, with one (Hmpp) or two methyl groups (Hdmpp), have been reported to possess biomedical, chemical and analytical applications. In this first screening study aiming to uncover new promising agents to mitigate the oxidative damage highly present in several metabolic disorders, such as diabetes mellitus, we assessed the potential of twelve 3,4-HPO metal ion complexes to modulate oxidative burst in human neutrophils. Metal ion 3,4-HPO complexes of Ni, Fe, V, Co, Cu and Zn were synthesized and tested up to 15μM. Among all the compounds, [Cu(mpp)2] and [Cu(dmpp)2] exhibited the highest scavenging capacity against superoxide radical (O2(-)) (IC50=0.36±0.07 and 0.30±0.06μM, respectively) and against hypochlorous acid (HOCl) (IC50=0.6±0.3 and 0.4±0.1μM, respectively). In the particular case of O2(-), [Fe(mpp)3] and [Fe(dmpp)3] (both at 15μM) presented 35% and 22% of inhibition, respectively, while all the other compounds were neither able to scavenge O2(-) nor stimulate its production. Regarding the scavenging capacity against hydrogen peroxide (H2O2), all the compounds showed low efficiency (from 6-39%). Finally, with exception of [VO(mpp)2] and [VO(dmpp)2], all compounds exhibited scavenging activity against HOCl (39-81%) and the most efficient compounds were Cu(II) and Zn(II) complexes. Thus, these preliminary results uncover promising new metal ion complexes, inhibitors of neutrophil's oxidative burst, with potential anti-inflammatory properties, which may be seen as an useful strategy for further studies in the treatment of a number of diseases where oxidative damage is a serious issue.