New VIVO2+ complexes containing biologically relevant ligands as synthetic models for the vanadium(IV) transferrins

Solution studies of copper(II) complexes as a contribution to the study of the active site of galactose oxidase

“…IR ν max /cm H 3 bpeten, (L2). 11,12 This compound was obtained according to Scheme 2. The first step was a condensation reaction of N-(2-hydroxyethyl) ethylenediamine (2.60 g; 25 mmol) with 2-pyridinecarboxyaldehyde (2.68 g; 25 mmol), followed by reduction with NaBH 4 (1.90 g; 50 mmol) in methanol, producing N-(2-pyridylmethyl)-N'-(2-hydroxyethyl)ethane-1,2-diamine (Hpeten).…”

“…We describe here solution studies of four copper(II) complexes derived from four unsymmetrical N,O-donor polyfunctional ligands, two of which bear no substituent at the phenol moieties (L1 and L2) [10][11][12] and two which bear the electron-withdrawing -NO 2 group at one or two of the phenol moieties (L3 and L4). These four compounds have been designed with the aim of studying the effect of -NO 2 group on the physicochemical properties of the copper complexes.…”

Model studies related to vanadium biochemistry: recent advances and perspectives

“…37 Vanadium(III), as V 3+ , and vanadium(V) as VO 2 + , can also be accommodated in a similar environment. 37 Recently, Neves et al 38,39 have prepared some interesting model systems for the VO 2+ -transferrin complex, using N,O-donor ligands. With some of these models they were able to reproduce UV-Vis and EPR properties of oxovanadium(IV) complexes of human serum transferrin and ovotransferrin and they advanced some new proposals about the coordination sphere of vanadium in these systems.…”

“…It has also been shown that some of these complexes can be oxidized chemically or electrochemically to the respective vanadium(V) complexes without changing the coordination sphere of the vanadium. 39 Some aspects of the vanadium/albumin interactions are now understood. 13,34 In one of the first EPR studies of the VO 2+ /bovine serum albumin system, it was found that the cation binds tightly probably at the specific sites for Cu II , located at the N terminus of the polypeptide chain.…”

Síntese e caracterização de novos compostos de coordenação de cobre (II) com ligantes não-simétricos N,O-doadores: contribuições para o sítio ativo da galactose oxidase

“…As A 30 mL de uma solução metanólica dos ligantes H 2 BBPETEN (0,410 g; 1 mmol), H 3 BPETEN (0,528 g; 1mmol), HTPETEN (0,414 g; 1 mmol) e H 3 BIMETEN (0,411 g; 1 mmol), sintetizados previamente como descrito na literatura [22][23][24][25] , adicionou-se 0,371 g (1 mmol) de Cu(ClO 4 ) 2 .6H 2 O. Ao meio reacional foram adicionados ainda 0,5 mL de Et 3 N. A reação foi feita sob agitação a 40 o C por 30 minutos (Esquema 1). Na síntese com o ligante HTPETEN, trocou-se o contra-íon adicionando-se ao meio, sob agitação e aquecimento brando, 2 mmol (0,336 g) de NaPF 6 .…”