Phenanthrolin-7-ones

Here, MV " is methylviologen and the reaction rate of each process is denoted above. The MFEs on the formation of free radicals (Te) was measured by photostationary illumination in a continuous flow system. The observed relative MFEs (AR B)=[Ye(B)- Ye(PTY]/ Ye OTY) on the yield of photoinduced MV" radical with the four complexes (la-ld) is depicted in Fig. 12-13. This figure shows that the Te value of each complex decreases with increasing B from 0 T to 15 T and that it is almost saturated above 15 T. It is noteworthy that the AR(E) value decreases regularly for every replacement of a bipyridine ligand by a phenanthroline one. 

The rotaxane 13 + [the nomenclature of the rotaxanes described here is 13W n+, where N refers to the coordination number of the metal (4 or 5) and n to its charge] synthesized herein is composed of two subunits a macrocycle and a molecular thread (Fig. 11). The 33-membered macrocycle Mt33 [18, 19] contains two different coordinating sites a terpyridine moiety and a 1, 10-phenanthroline one. 

Charge-transfer absorption is important because it produces very large absorbances, providing for a much more sensitive analytical method. One important example of a charge-transfer complex is that of o-phenanthroline with Fe +, the UV/Vis spectrum for which is shown in Figure 10.17. Charge-transfer absorption in which the electron moves from the ligand to the metal also is possible. 

One of the best oxidation-reduction indicators is the 1,10-phenanthroline-iron(II) complex. The base 1,10-phenanthroline combines readily in solution with iron(II) salts in the molecular ratio 3 base l iron(II) ion forming the intensely red l,10-phenanthroline-iron(II) complex ion with strong oxidising agents the iron(III) complex ion is formed, which has a pale blue colour. The colour change is a very striking one ... 

The standard redox potential is 1.14 volts the formal potential is 1.06 volts in 1M hydrochloric acid solution. The colour change, however, occurs at about 1.12 volts, because the colour of the reduced form (deep red) is so much more intense than that of the oxidised form (pale blue). The indicator is of great value in the titration of iron(II) salts and other substances with cerium(IV) sulphate solutions. It is prepared by dissolving 1,10-phenanthroline hydrate (relative molecular mass= 198.1) in the calculated quantity of 0.02M acid-free iron(II) sulphate, and is therefore l,10-phenanthroline-iron(II) complex sulphate (known as ferroin). One drop is usually sufficient in a titration this is equivalent to less than 0.01 mL of 0.05 M oxidising agent, and hence the indicator blank is negligible at this or higher concentrations. 

The synthesis of [3]- (figuratively shown as 7) and a [5]rotaxane (8) with one central and two terminal porphyrins in the open configuration has been reported <96AG(E)906> also a rotaxane with two Ru(terpy>2 stoppers has appeared <96CC1915>. A pseudorotaxane comprised of a macroring of 2,9-diphenyl-1,10-phenanthroline unit and a molecular string... 

Ligand 92 was readily prepared by reaction of (+)-pinocarvone with 1-phenacylpyridinium iodide. The authors similarly prepared corresponding 5,6-dihydro-1,10-phenanthrolines derived from (+)-pinocarvone and a tetrahydroquinolone (structure 93, [127]) and obtained up to 81% in the palladium-catalyzed test reaction. Chelucci et al. [ 128] reported the synthesis of chiral Ci-symmetric 1,10-phenanthrolines incorporated in asteroid backbone. Structure 94 derived from 5o -cholestan-4-one in Scheme 51, allowed very high yield and up to 96% ee using BSA and tetrabutylammonium fluoride to generate the malonate anion. 

Hydrazine reduction of ferric ethylenediaminetetraacetate (denoted FeY ) gives nitrogen in high yield" In the absence of added phenanthroline the reaction, initially rapid, slows down and becomes second order in FeY . When ferrous ethylenediaminetetraacetate (FeY ) is initially present, the reaction is second-order in FeY throughout. In the presence of phenanthroline the order in FeY is one throughout. Under both sets of conditions the reaction is first-order in hydrazine. 

Hydrosilylation of dienes accompanied by cyclization is emerging as a potential route to the synthesis of functionalized carbocycles. However, the utility of cycliza-tion/hydrosilylation has been Umited because of the absence of an asymmetric protocol. One example of asymmetric cycUzation/hydrosilylation has been reported very recently using a chiral pyridine-oxazoUne ligand instead of 1,10-phenanthroline of the cationic palladium complex (53) [60]. As shown in Scheme 3-21, the pyridine-oxazoUne Ugand is more effective than the bisoxazoUne ligand in this asymmetric cyclization/hydrosilylation of a 1,6-diene. 

The treatment of gold(III) complexes with the rigid bidentate ligand phen allows the synthesis of pseudo-pentacoordinate gold(III) derivatives. This is the case of [Au(dmp)(phen)PPh3](BF4)2 (288) (dmp = 2-(dimethylaminomethyl)phenyl)1699 or [AuCl(C4Ph4)(phen)].16 2 The donor atoms of the phenanthroline ligand occupy one equatorial and the axial position of a square pyramid with distances 2.154(8)A and 2.627(10)A in (288). 

The presence of zinc with bidentate nitrogen donor ligands in the formation of novel composite materials by hydrothermal reactions has been studied. A zinc-containing one-dimensional material, [Zn(phenanthroline)Mo04] was isolated from molybdate, and from vanadium oxide in the presence of zinc 2,2 -bipyridine [Zn(2,2,-bipyridine)2V40i2] was obtained.212,213... 

The first attempt to construct a dendrimer with an electroactive Ru-polypyridi-ne core was based on the reaction of Ru(bpy)2Cl2 with a branched polyether-substituted phenanthroline ligand (11) [27]. In the potential window +2/-2V, this compound shows a one-electron oxidation process and three distinct one-electron reduction processes that, by comparison with the behavior of the... 

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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