1.10- phenanthroline spectra

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. 

Photoinduced oxidation of 1,4-dimethoxybenzene (DMB) and tetrahydrofuran (THF) by [Au(C N N-dpp)Cl]+ in acetonitrile upon UV/Vis irradiation have been observed. The time-resolved absorption spectrum recorded 12 (xs after excitation of [Au(C N N-dpp)Cl] with a laser pulse at 35 5 nm showed the absorption band of the DMB radical cation at 460nm, whereas upon excitation at 406 nm in the presence of THF, a broad emission characteristic of the protonated salt of 2,9-diphenyl-l,10-phenanthroline (Hdpp ) developed at 500 nm. 

In search of new sensitizers that absorb strongly in the visible region of the spectrum, Arakawa and co-workers have developed several sensitizers based on 1,10-phenanthroline ligands. Among these new compounds, (29) and (30) are noteworthy they show an intense and broad MLCT absorption band at 525 nm in ethanol. The energy levels of the LUMO and HOMO for (29) were estimated to be —1.02 and 0.89 eV vs. SCE, respectively, which are slightly more positive than those of the sensitizer (22). These sensitizers, when anchored onto a Ti02 surface, yield more than 85% photon to electron injection efficiencies.8,52,53... 

The AOM has recently been used in the analysis of the polarized crystal spectrum of aquobis(l,10-phenanthroline)coppei(II) nitrate (127), where the coordination geometry is trigonal bipyramidal. The water molecule occupies an equatorial position, so that the appropriate point group is C2 although C2v is a reasonable approximation. However, it was found impossible to fit the spectrum with AOM parameters which could be regarded as chemically meaningful. 

Using one of your standards and the Spectronic 20, or other single-beam visible spectrophotometer, obtain an absorption (or transmittance) spectrum of the Fe-o-phenanthroline complex ion (instructor will demonstrate use of instrument). Determine the wavelength of maximum absorbance from the spectrum and use this wavelength to obtain absorbance readings of all the solutions. (Use the blank for the 100% transmittance setting.)... 

In this study, the complex where L = 4,7-diphenyl-l,10-phenanthroline was used. A solution in which the mass fraction Re-complex in methyl methacrylate was 0.12 % gave two absorption bands at 350 and 475 nm. Both absorption bands produced an emission feature at 612 nm. No other emission features were observed in the visible part of the spectrum. 

Figure 6 shows spectra of other manganese compounds. The spectrum of manganese 1,10-phenanthroline dichloride matches those of the divalent... 

Complexes containing the 3,5-dinitrosalicylate ion, e.g. [Ln2(C2H202N2)3],- H20 (u = 7 -> 15), and methylsalicylate (MesaP ), e.g. [Ln(Mesal)2(OH)-(H2O)] (Ln = La, Pr, Nd, Sm, Gd, Dy, Er, Yb and have been reported. Tris-salicylaldehydato (said ) complexes, Ln(sald)3 (La, Pr, Nd, Sm, Eu, or Tb) form 1 1 adducts with o-phenanthroline (o-phen), aa -bipyridyl, quinoline, and pyridine. The luminescence spectrum of the Eu " complexes showed that, in the solid state, the symmetrically forbidden electric dipole transition intensity was much enhanced for the o-phen adduct when compared to its salicylate analogue. The simple said" complexes were very poor emitters. 

Arthur Wahl Martin Dietrich, David Larsen and I have studied tris(l,10-phenanthroline)iron(II) and iron(III) systems and have looked at the proton NMR spectrum of the two oxidation states and mixtures of the two oxidation states (2,11). 

The infrared (IR) spectra of 1,10-phenanthroline, its hydrate and perchlorate in the region 600-2000 cm-1 have been obtained, and the principal features of the spectra interpreted.66 Further studies on the IR spectra of 1,10-phenanthroline,67-69 substituted 1,10-phenanthrolines,70,71 and 1,7-phenanthroline67 have also been reported. The IR spectrum of 4,7-phenanthroline in the region 650-900 cm-1 has been analyzed, and the C—H out-of-plane deformation frequencies were compared with those of phenanthrene and benzo[/]quinoline.72 The IR spectra of salts of 1,10-phenanthroline have been taken, and the NH vibrations determined.28,73 Infrared spectroscopy has been used to detect water associated with 1,10-phenanthroline and some of its derivatives on extraction into nitromethane from aqueous solution.74 The Raman spectrum of 1,10-phenanthroline has been compared with its IR spectrum.75 Recently, the Raman and IR spectra of all ten isomeric phenanthrolines were measured in solution and solid states, and the spectra were fully discussed.76... 

The spectrum of 1,10-phenanthroline in polarized light102 has also been compared with that of phenanthrene.103... 

The proton NMR spectrum of 1,10-phenanthroline has been obtained and analyzed by several authors in nonaqueous solvents 04-109 and in water at various pH values.28,110 Examples of studies of the NMR spectra of substituted 1,10-phenanthrolines that have been investigated in some detail are also worthy of mention.47,104,106,11° The NMR spectra of all ten phenanthrolines have been determined in deuterochloroform, and the spectra were interpreted12 (Table IV). The spectra of the 1,7-, 1,10-, and 4,7-isomers have also been compared with that of phenanthrene.111 Shifts in the NMR spectrum of 1,10-phenanthroline induced by a europium shift reagent have been discussed,112 and 13C chemical shifts of free and protonated 1,10-phenanthroline were measured.113... 

The electron spin resonance (ESR) spectrum of the radical anion of 1,10-phenanthroline obtained by reduction of 1,10-phenanthroline with sodium has been measured, and hyperfine splitting constants were assigned.116... 

The radical anion of 4,7-phenanthroline-5,6-dione has been prepared electrolytically, and its ESR spectrum was recorded.274... 

Phenanthroline inhibits proline incorporation into proteins.391,392 Benzo-substituted-l,8-phenanthrolines and 1,10-phenanthrolines are amoebicides.180 l,8-Phenanthroline-8-oxide has a wide spectrum of antibacterial activity.393... 

Bis( 1,10-phenanthroline)copper(I) has an absorption spectrum which is a function of concentration. This has been attributed to oligomerization, possibly via n—K intermolecular stacking interactions. The tendency to oligomerize has a marked effect on the electrochemistry of the complex. For example, the complex exhibits extensive adsorption on the surface of a graphite electrode. The multilayers exhibit good electron mobility and the layers probably grow by reduction of surface copper(II). Rotating disc voltammetric measurements of the reduction of... 

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