II phenanthroline complexes

The iron(II) complexes of 1,10-phenanthroline and to a lesser extent a,a -bipyridine form an ideal series to study because they span the 

Compound T/K 3/mms- A/mm s Effective magnetic moment/) T/K Spin state 

In contrast, if the divalent ion is smaller than iron(II), as is the case for cobalt(Il) and nickel(II), which have ionic radii of 0.072 and 0.070 nm respectively, then substitution will place iron in a smaller than expected lattice site. In this case the positive lattice pressure will produce shorter iron-ligand bonds, and a stronger effective crystal field potential which will favour the low spin configuration and/or a higher spin crossover temperature. This is exactly what is observed in a series of 

FexCO x(phenanthroline)2(NCS)2 complexes (Ganguli, Giitlich Muller, 1982). 

3 Light-induced excited state spin trapping 

---

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). 

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.)...

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

A variety of mixed ligand complexes of copper(II) are known which contain bipyridine and phenanthroline. Examples of the other ligands are 8-diketones (479), salicylaldehyde and salicylaldimines (552), and nitrate (721). The use of some mixed ligand copper(II) phenanthroline complexes as absorbents for gas chromatography has been considered (14). 

Table 15-1 RATE CONSTANTS FOR THE OXIDATION OF IRON(II)-PHENANTHROLINE COMPLEXES BY CERIUM(IV) IN 0.5 M SULFURIC ACID AT 25°C...

Coupling of an amine-functionalized Ru(II) phenanthroline complex to a poly(thionyl phosphazene) backbone has been reported to yield polymer (219) with excellent oxygen-sensing properties. ... 

Into a series of 100-mL volumetric flasks, add with pipets 1.00, 2.00, 5.00, 10.00, and 25.00 mL of the standard iron solution. Into another 100-mL volumetric flask, place 50 mL distilled water for a blank. The unknown sample will be furnished in another 100-mL volumetric flask. To each of the flasks (including the unknown) add 1.0 mL of the hydroxylammonium chloride solution and 5.0 mL of the 1,10-phenanthroline solution. Buffer each solution by the addition of 8.0 mL of the sodium acetate solution to produce the red color of ferrous 1,10-phenanthroline. P he iron(II)-phenanthroline complex forms at pH 2 to 9. The sodium acetate neutralizes the acid present and adjusts the pH to a value at which the complex forms.] Allow at least 15 min after adding the reagents before making absorbance measurements so that the color of the complex can fully develop. Once developed, the color is stable for hours. Dilute each solution to exactly 100 mL. The standards will correspond to 0.1, 0.2, 0.5, 1, and 2.5 ppm iron, respectively. 

Rhodamine-labeled hydroquinone substrates 11 were also prepared with the aim of monitoring redox catalysis. H2O2 oxidation to the corresponding benzo-quinones by Cu ions or Cu(II) phenanthroline complexes results in a strong reduction of rhodamine fluorescence [93]. Compound 11 is not suitable as a substrate for SMFS studies with immobilized individual Cu complexes because affinity for... 

M sulfuric acid to bring to the 1 dm mark on the flask. This solution absorbs more than 99% of the incident light with X > 390 nm in a 1 cm cell. Irradiate 3 cm of this solution in a 1 cm cuvette at 405 nm in the colorimeter or spectrometer for 30 minutes. At the end of this time, take the cell out of the colorimeter and add 0.5 cm of a solution of sodium acetate (1.8 M) and sulfuric acid (2.16 M) containing 0.1% (m/v) of 1,10-phenanthroline. After 30 min measure the absorbance at 510 nm. Repeat with a reference solution that has been kept in the dark. Convert the difference in absorbance between the irradiated sample and the reference into concentration of Fe " produced in the irradiated solution, knowing that the iron(II)-phenanthroline complex in a 0.1 mM solution in a 1 cm cell has an absorbance of 1.11. Repeat the experiment, irradiating for 45 and 60 min. 

---