Phenanthroline Complexes

Chiral discrimination has also been observed in ci5-[RuCl2(phen)2], where both intercalation and covalent binding are possible, although the binding is weak with a maximum binding ratio of 1/11 base pairs [74]. This series of complexes is of great interest, then, as spectroscopic and conformational probes of helical structure. 

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Crystal stmctures of complexes of copper(II) with aromatic amine ligands and -amino acids " " and dipeptides" have been published. The stmctures of mixed ligand-copper complexes of L-tryptophan in combination with 1,10-phenanthroline and 2,2 -bipyridine and L-tyrosine in combination with 2,2 -bipyridine are shown in Figure 3.2. Note the subtle difference between the orientation of the indole ring in the two 1,10-phenanthroline complexes. The distance between the two... 

This experiment describes the use of FIA for determining the stoichiometry of the Fe +-o-phenanthroline complex using the method of continuous variations and the mole-ratio method. Directions are also provided for determining the stoichiometry of the oxidation of ascorbic acid by dichromate and for determining the rate constant for the reaction at different pH levels and different concentration ratios of the reactants. 

It has been discovered that styrene forms a linear alternating copolymer with carbon monoxide using palladium II—phenanthroline complexes. The polymers are syndiotactic and have a crystalline melting point - 280° C (59). Shell Oil Company is commercializing carbon monoxide a-olefin plastics based on this technology (60). 

Although the number of applications of olefin metathesis to transition metal complexes is small compared to the number of applications in organic synthesis, this field is becoming increasingly important. Spectacular examples are the double RCM reactions of copper phenanthroline complexes as a synthetic route to catenanes [113] or a recently reported approach to steric shielding of rhenium complex terminated sp-carbon chains [114]. 

Further interesting redox modified polypyrrole films were prepared e.g. a polymeric copper phenanthroline complex that can be reversibly de- and re-metallated because it retains the pseudotetrahedral environment after decomple-xation, A very diversified electrochemistry is displayed by polypyrrole films containing electron donor as well as electron acceptor redox centers in the same film... 

Fig. 2. Relationship between the logarithms of the rate coefficients (Atj. 2) and the logarithms of the equilibrium constants (Jfi.i) for the oxidation of various substituted Fe(II)-phenanthroline complexes by Mn(III) in 1 A/ and 3 Af HCIO4 at 25.0 °C. (From Diebler and Sutin, by courtesy of The American Chemical Society.)...

SLOPES AND INTERCEPTS OF PLOTS OF (AGJi 2+LI5 l0g/)W. AG i 2 FOR OXIDATION-REDUCTION REACTIONS INVOLVING SUBSTITUTED Fe(lI)-PHENANTHROLINE COMPLEXES... 

Other linear free-energy relationships are those for the oxidation of a series of Fe(II) phenanthroline complexes by Co(III) and Mn(III). ... 

Konig and others published in the 1970s an impressive series of studies on six-coordinate iron(II)-bis-phenanthroline complexes [160-164] for which they inferred 5=1 from thorough magnetic susceptibility and applied-field Mossbauer measurements. Criteria for the stabilization of the triplet ground state for six-coordinate compounds with tetragonal ( >4 ) and trigonal ( >3 ) symmetry were obtained from LFT analyses [163], The molecular structures, however, were not known because the materials could not be crystallized. 

Pyridyl donors are common and feature in later sections as part of many multidentate ligands, such as macrocycles. Functionalized pyridyl donors will also be discussed and Section 6.8.4.7 provides examples of the bidentate bipyridyl and phenanthroline complexes. 

Mercuric o-carborane-l-carboxylate complexes decarboxylated when heated above their melting points or when refluxed in decane or benzene solution [Eq. (102), L = phen, bpy, or (py)2] (109,110). Asymmetric organomercury carboranes and their 1,10-phenanthroline complexes were also formed by thermal decarboxylation [e.g., Eq. (103), R = Me or Ph] (111). 

Using the tri-iodide/iodide redox couple and the sensitizers (22) and (56), several groups have reported up to 8-10% solar cell efficiency where the potential mismatch between the sensitizer and the redox couple is around 0.5 V vs. SCE. If one develops a suitable redox couple that decreases the potential difference between the sensitizer and the redox couple, then the cell efficiency could increase by 30%, i.e., from the present value of 10% up to 13%. Towards this goal, Oskam et al. have employed pseudohalogens in place of the triiodide/iodide redox couples, where the equilibrium potential is 0.43 V more positive than that of the iodide/iodide redox couple.17 Yamada and co-workers have used cobalt tris-phenanthroline complexes as electron relays (based on the CoII/m couple) in dye-sensitized solar cells.95... 

A few additional Pd-catalyzed schemes have been employed for Ilac type cyclization chemistry. Palladium-phenanthroline complexes were used by the Ragaini group to prepare indoles via the intermolecular cyclization of nitroarenes and alkynes in the presence of carbon monoxide <06JOC3748>. Jia and Zhu employed Pd-catalysis for the annulation of o-haloanilines with aldehydes <06JOC7826>. A one-pot Ugi/Heck reaction was employed in the preparation of polysubstituted indoles from a four-component reaction system of acrylic aldehydes, bromoanilines, acids, and isocyanides <06TL4683>. 

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