Crystal Structure of the V^V Dimer [V₂O₂(μ‐O)(dmpp)₂(OCH₃)₂] and Its Equilibrium with the V^V Trimer [V₃O₃(μ‐O)₃(dmpp)₃(H₂O)](H₂O)₂ in Methanol/Water Solutions

Abstract

The behaviour of the cyclic trimeric V V complex [V 3 O 3 (µ-O) 3 (dmpp) 3 (H 2 O)](H 2 O) 2 , V 3 L 3 , (L = Hdmpp = 3-hydroxy-1,2-dimethyl-4-pyridinone) was studied in methanol and methanol/water solutions by using 51 V and 1D-and 2D 1 H NMR spectroscopy. Red crystals, isolated from a highly concentrated methanol solution of the trimeric complex, were analysed by X-ray crystallography. The solid-state structure of the compound showed the presence of a new dinuclear V

Vanadate complexes of 3-hydroxy-1,2-dimethyl-pyridinone: Speciation, structure and redox properties

“…Several articles were published about the speciation of the vanadate-dhp system [13][14][15][16], although the conclusions are sometimes contradictory in the different publications and the final picture is still not complete.…”

“…Addition of methanol to the system makes the speciation even more complicated because the alcohol is able to react with the V-OH part of the complexes forming "esters", and this process is not advantageous for understanding the feature of the basic V(V)-dhp system. Temperature dependence of 51 V-NMR spectra and 2D 1 H homonuclear NMR spectra was also measured and isomers of the dinuclear ([V(V)O(OMe)(dhp)] 2 O) and the bis complex [V(V)O(OMe)(dhp) 2 ) were detected [16].…”

Vanadium compounds as therapeutic agents: Some chemical and biochemical studies

“…1B shows 51 V NMR spectra obtained in different media at physiological pH. The broad single signal at %À512 ppm assigned to V V -sal-DPA species, [27] is also observed in the DMEM-HG medium, indicating that these V V -species are stable and their structures are maintained regardless the medium involved.…”

“…The compounds bis(1,2-dimethyl-3-hydroxy-4-pyridinonate)oxovanadium(IV), V IV O(dmpp) 2 , and (N,N 0 -diaminopropionate)bis(salicylaldehyate)-oxovanadium(IV), V IV O(salDPA), were synthesized following previously published procedures [17,27]. The pyrimidinone compound MHCPE was recently synthesized in our laboratory [40].…”

“…In this work we report a screening for the cytotoxic activity of three different vanadium(V) systems in two cellular models following previous studies on similar systems [17,18,[27][28][29][30][31]. For two of these systems, the V Vdmpp (Hdmpp = 1,2-dimethyl-3-hydroxy-4-pyridinone) and V VsalDPA (H 3 salDPA = 2,3-bis[(2-hydroxybenzyl)amino] propanoic acid) (Scheme 1), the starting materials are the solid V IV -compounds, namely V IV O(dmpp) 2 1 [17] and V IV O(salDPA) 2 [32] that have been fully characterized previously from a chemical point of view.…”