Iron bipyridine

Long-range electron transfer is postulated to occur from ferrocene to tris(bipyridine)iron(lll) constructed within the pores of a NaY zeoUte. The iron bipyridine complex is too large to move throughout the faujasite pores to the surface, thus requiring the long-range transfer. The asyimnetric catalyst, titanium tartrate, has been prepared inside NaY and used as an immobilized catalyst for the epoxidation of cinnamyl alcohol. ... 

Nakamura observed the a-arylation of THE by an diorganozinc reagent in the presence of an iron/bipyridine-type ligand and 4-iodotoluene that presumably acted... 

The earliest example of cycloisomerization in conjugated dienes was reported by Takacs et al. in 1980 [68]. In their study a low-valent iron bipyridine complex was prepared by reducing Fe(acac>3 with EtjAl and used for the cycloisomerization of trienes (Schane 7.49). 

The pale blue tris(2,2 -bipyridine)iron(3+) ion [18661-69-3] [Fe(bipy)2], can be obtained by oxidation of [Fe(bipy)2]. It cannot be prepared directiy from iron(III) salts. Addition of 2,2 -bipyridine to aqueous iron(III) chloride solutions precipitates the doubly hydroxy-bridged species [(bipy)2Fe(. t-OH)2Fe(bipy)2]Cl4 [74930-87-3]. [Fe(bipy)2] has an absorption maximum at 610 nm, an absorptivity of 330 (Mem), and a formation constant of 10. In mildly acidic to alkaline aqueous solutions the ion is reduced to the iron(II) complex. [Fe(bipy)2] is frequentiy used in studies of electron-transfer mechanisms. The triperchlorate salt [15388-50-8] is isolated most commonly. 

In analogy to the situation for bipyridine, the blue tris(l,10-phenanthroline)iron(3+) ion [1347949-7], [Fe(phen)2], must be obtained by oxidation of the corresponding iron(II) ion. [Fe(phen)2] has an absorption maximum at 590 nm, an absorptivity of 600 (Mem), and a formation constant of 10 . In solutions of pH > 4, this species is reduced to the iron(II) complex. The reduction is instantaneous in alkaline solution. At pH < 2, protons compete with iron(III) for the phenanthroline nitrogens and coordination is incomplete. [Fe(phen)2] is used most often in solution as an oxidant, but the trichloride [40273-22-1] and the triperchlorate monohydrate [20774-81-6] salts have been prepared. 

Ascorbic acid, for example, is oxidized to dehydroascorbic acid with reduction of the iron(III) ions. The Fe(II) ions so produced react with 2,2 -bipyridine with formation of a colored complex. 

Bipyridine — Iron(III) Chloride Reagent (Emmerie-Engel Reagent) 217... 

Note The dipping reagent, which can also be applied as a spray reagent, can be employed on cellulose and silica gel layers. A 3% solution of 2,2 -bipyridine in 40% thioglycolic acid can be employed as a specific spray reagent for the detection of iron (red coloration) [7],... 

In addition to the Raney nickel catalysts, Raney catalysts derived from iron, cobalt, and copper have been examined for their action on pyridine. At the boiling point of pyridine, degassed Raney iron gave only a very small yield of 2,2 -bipyridine but the activity of iron in this reaction is doubtful as the catalyst was subsequently found to contain 1.44% of nickel. Traces of 2,2 -bipyridine (detected spectroscopically) were formed from pyridine and a degassed, Raney cobalt catalyst but several Raney copper catalysts failed to produce detectable quantities of 2,2 -bipyridine following heating with pyridine. 

Vinyl substituted bipyridine complexes of ruthenium 9 and osmium 10 can be electropolymerized directly onto electrode surfaces The polymerization is initiated and controlled by stepping or cycling the electrode potential between positive and negative values and it is more successful when the number of vinyl groups in the complexes is increased, as in 77 A series of new vinyl substituted terpyridinyl ligands have recently been synthesized whose iron, cobalt and ruthenium complexes 72 are also susceptible to electropolymerization... 

The reduction of [Pt(bipy)2]2+ in water by metallic iron or at a platinum electrode gives monomeric [Pt(bipy)2]N03-2I I20 that forms as black-green needles. 25The needles have a relatively high electrical conductivity and a Pt - Pt separation of 3.563(1) A.125 In contrast, reduction in aprotic solvents such as DMF or DMSO results in the formation of dimeric [Pt2(bipy)2(/x-bipy)]21 (bipy = 2,2 -bipyridine) with a Pt- -Pt separation of 2.527,2(5) A.126... 

A more dramatic color change can be observed by substitution of two iron-bound cyanides by a suitable bidentate ligand.144 Thus, 2,2 -bipyridine can be indirectly attached to the nickel... 

The iron(III) complexes FeL33+, where L = 2,21-bipyridine and various substituted 1,10-phenanthrolines, cleave a variety of or-ganometals in acetonitrile according to the general reaction mechanism in Scheme I (6). The activation process for oxidative clea-... 

---