Vanadium complexes phenanthroline

Vanadium complexes with catechols have been of interest to chemists80,98 due to the catalytic properties of such complexes,137,138 and the possible involvement of catecholate complexes in the tunicate accumulation and reduction of vanadium.40,63 139,140 Several new vanadium(V) catecholate complexes have been reported. Of particular interest are the non-oxovanadium(V) complexes with 2,2 -bipyridine and 1,10-phenanthroline (phen) serving as auxiliary ligands.141... 

Scheme 5.8 Insulin-mimetic vanadium complexes. In the peroxovanadate complex, L = bipyridine (bipy), oxalate (ox), phenanthroline (phen) and picolinate (pic). BMOV represents bis(maltolato)oxovanadium(IV).

Highly oxygenated VO(V) complexes can be electrosynthesized. K2[V0(02)2P], K[V0(02)2(X)] (X = H2O, O2, bipyridine, 1,10-phenanthroline), and similar species have been generated by the dissolution of vanadium anodes in the presence of H2O2, HF and various ligands [113, 114[. Such complexes effect unusual oxidations of substrates such as cresols. Vanadium... 

Sergienko, V.S., M.A. Porai-Koshits, V.K. Borzunov, and A.B. Illyukhin. 1993. Crystal structure of three VO(02)+ compounds with pyridine-2-carboxylate ions and o-phenanthroline. Structural features of pseudooctahedral vanadium(V) oxoperoxo complexes. Koord. Khim. 19 767-781. 

Mononuclear Viv complexes of substituted hydroxamates have been characterized with 1,10-phenanthroline or 2,2 -bipyridine as supporting ligands. A seven-coordinate vanadium atom was proposed to exist in these complexes, although a six-coordinate complex may be more likely.652 A range of hydroxamate-containing complexes have been prepared and were subsequently found to facilitate transport of Viv into cells.653... 

DNA cleavage as the mechanism by which tumour growth is inhibited is also been suggested for the action of bis(peroxo)vanadium(V) complexes of the general composition [V0(02)2L] (L = o-phenanthroline or bipyridyl) and traced back to the formation of hydroxyl radicals. 

An early claim 332, 334) to have prepared V(bipy)3+ has been revised 431) the compound V(bipy)3l is considered to be a mixture of V(bipy)3 and V(bipy)3l2. The reaction of V(bipy) + or of Cr(bipy) + with aluminum hydride gives the neutral tris-bipyridyl complexes, but with other dipositive metals Al(bipy)3 is the major product 357). Attempts to prepare bipyridyl and phenanthroline derivatives of hexacarbonylvanadium led to the disproportionation of vanadium(O) 376). 

A similar preparative procedure was used to isolate tetrahedral complexes of bidentate donors (L = bipy or phen) [VL2](SCN)3. However, complexes of vanadium(lll) chloride or bromide with these same bidentate donors have stoichiometries depending on conditions. With excess of bipy or phen, complexes [VXzI zJX were obtained. In EtOH or in MeCN two series of complexes were isolated VCI3LL (L = bipy or phen L = EtOH or MeCN) and [VClzLz] + [VCI4L] . In the reaction of vanadium(III) with phenanthroline ... 

Preliminary results of the reaction between vanadium(iii)-tetrasulpho-phthalocyanine complex with oxygen have been reported these data were compared with those obtained for the corresponding reaction of the hexa-aquo complex ion. The oxidation of methyl ethyl ketone by oxygen in the presence of Mn"-phenanthroline complexes has been studied Mn " complexes were detected as intermediates in the reaction and the enolic form of the ketone hydroperoxide decomposed in a free-radical mechanism. In the oxidation of 1,3,5-trimethylcyclohexane, transition-metal [Cu", Co", Ni", and Fe"] laurates act as catalysts and whereas in the absence of these complexes there is pronounced hydroperoxide formation, this falls to a low stationary concentration in the presence of these species, the assumption being made that a metal-hydroperoxide complex is the initiator in the radical reaction. In the case of nickel, the presence of such hydroperoxides is considered to stabilise the Ni"02 complex. Ruthenium(i) chloride complexes in dimethylacetamide are active hydrogenation catalysts for olefinic substrates but in the presence of oxygen, the metal ion is oxidised to ruthenium(m), the reaction proceeding stoicheiometrically. Rhodium(i) carbonyl halides have also been shown to catalyse the oxidation of carbon monoxide to carbon dioxide under acidic conditions ... 

Three general classes of vanadium-containing compounds are of interest for their utility as insulin-mimetic agents (1) inorganic vanadium salts, both anionic (vanadates [V04] ) and cationic (vanadyl VO +) (2) complexes resulting from combination of vanadium(V) and hydrogen peroxide(s) (mono- and di-peroxovanadates, [V0(02 )(H2O)2(L-0f ( =0,1,2) and [V0(02)2 (L-Oj ( = 1,2, 3, and L = e.g., bipyridil, oxalate, phenanthroline, picoli-nate), and (3) chelated vanadium(IV) complexes (Scheme 5.8) [160], Vanadyl,... 

The mechanism of olefin epoxidation with iodosylbenzene in the presence of Cr(III) Schiff base complexes has been studied.The same reaction is catalysed by V0(acac)2 probably yij free radicals.Trans-stilbene is epoxidised by NalOi, in the presence of RuClg and substituted phenanthroline ligands. Vanadium(V) supported on a functionalised polystyrene resin is a good catalyst for the epoxidation of allylic alcohols by ButQOH a similar Mo(VI) catalyst is more suitable for cyclohexene epoxidation. ... 

---