Microdetermination of iron in plant tissue with 4,7-diphenyl-1,10-phenanthroline

A method is described for the wet digestion and colorimetric determination of small amounts of iron in plant tissues. The wet digestion uses a mixture of sulphuric and nitric acids instead of perchloric acid; a volumetric flask is used for weighing, digestion, and dilution. The iron complex with 4,7-diphenyl-1,10-phenanthroline is extracted into hexanol.     

Iron(II) and nickel(II) mixed-ligand complexes containing 1,10-phenanthroline and 4,7-diphenyl-1,10-phenanthroline

Two types of mixed-ligand complexes, i.e. [M(phen)2 (dip)]2+ and [M(phen)(dip)2]2+ (M = iron(II) and nickel(II); phen = 1,10-phenanthroline and dip = 4,7-diphenyl-1,10-phenanthroline) have been prepared from their related tris-complexes, [M(phen)3]2+ by ligand substitution, and isolated by semi-preparative HPLC. Elemental and chromatographic analyses confirm the purity of the isolated complexes while u.v./vis and i.r. spectra were used to identify and characterize them. 1H-n.m.r. and room temperature Mössbauer spectra of the iron(III) complexes were also measured and the results are discussed. In addition, our preliminary results on hypochromicity in the MLCT band and circular dihroism (CD) emerging in the u.v./vis region upon addition of CT(calf thymus)-DNA to the racemic complexes indicated that the iron(II) mixed-ligand complexes interact with CT-DNA.     

Mono- and di-nuclear oxorhenium(V) complexes of 4,7-diphenyl-1,10-phenanthroline

The reactions of [ReOX₃(AsPh₃)₂] (X = Cl, Br) with 4,7-diphenyl-1,10-phenanthroline (dpphen) have been examined and the complexes [ReO(OMe)X₂(dpphen)] and [Re₂O₃X₄(dpphen)₂]·2/3CH₂Cl₂ (X = Cl, Br) have been obtained. They were characterized by IR, UV–Vis spectroscopy, and single crystal X-ray analysis has been performed for [ReO(OMe)Cl₂(dpphen)] and [Re₂O₃Br₄(dpphen)₂]·2/3CH₂Cl₂. The nature of the frontier orbitals of [ReO(OMe)Cl₂(dpphen)] and [Re₂O₃Br₄(dpphen)₂] and the electronic transitions involved in the absorption spectra have been studied by means of the density functional and time-dependent density functional methods.     

4,7-二苯基-1,10-菲啰啉的合成研究

以4-苯基-8-硝基喹啉为起始原料,经还原得到4-苯基-8-氨基喹啉,再以I2/KI为氧化剂,在乙酸和盐酸的存在下,用Skraup法合成了4,7-二苯基-1,10-菲啰啉.化合物结构经IR和1H NMR得到了证实.实验研究得到了最佳的合成条件为:n(3-氯苯丙酮)∶n(4-苯基-8-氨基喹啉)=1.5∶1,I2/KI用量为8%,反应温度120℃,反应时间2.5 h.产品收率可达82%.     

Fluorimetric determinations of nucleic acids using iron, osmium and samarium complexes of 4,7-diphenyl-1,10-phenanthroline

New sensitive, reliable and reproducible fluorimetric methods for determining microgram amounts of nucleic acids based on their reactions with Fe(II), Os(III) or Sm(III) complexes of 4,7-diphenyl-1,10-phenanthroline are proposed. Two complementary single stranded synthetic DNA sequences based on calf thymus as well as their hybridized double stranded were used. Nucleic acids were found to react instantaneously at room temperature in Tris-Cl buffer pH 7, with the investigated complexes resulting in decreasing their fluorescence emission. Two fluorescence peaks around 388 and 567 nm were obtained for the three complexes using excitation lambda(max) of 280 nm and were used for this investigation. Linear calibration graphs in the range 1-6 microg/ml were obtained. Detection limits of 0.35-0.98 microg/ml were obtained. Using the calibration graphs for the synthetic dsDNA, relative standard deviations of 2.0-5.0% were obtained for analyzing DNA in the extraction products from calf thymus and human blood. Corresponding Recovery% of 80-114 were obtained. Student's t-values at 95% confidence level showed insignificant difference between the real and measured values. Results obtained by these methods were compared with the ethidium bromide method using the F-test and satisfactory results were obtained. The association constants and number of binding sites of synthetic ssDNA and dsDNA with the three complexes were estimated using Rosenthanl graphic method. The interaction mechanism was discussed and an intercalation mechanism was suggested for the binding reaction between nucleic acids and the three complexes.     

Molecular distortion effect on ff-emission in a Pr(III) complex with 4,7-diphenyl-1,10-phenanthroline.

The electronic and structural behaviour of a Pr(III) complex with 4,7-diphenyl-1,10-phenanthroline, [Pr(bathophen)(2)(NO(3))(3)], is investigated with respect to the effect of configuration changes on the Pr(III) centre. [Pr(bathophen)(2)(NO(3))(3)] luminesces from the excited states of the ligand and the metal ion. The fluorescence, ff-emission ((1)D(2)-->(3)H(4)), and phosphorescence bands appear at 394, 608.2 and 482 nm, respectively, in the solid state. In acetonitrile, the complex also shows multiple emissions. From the time-resolved emission and the lifetime measurements, the excitation energy-transfer in [Pr(bathophen)(2)(NO(3))(3)] is clarified, that is, the upper excited triplet level of the ligand acts as an energy donor, while the (1)D(2) levels of Pr(III) is the acceptor. Additionally, the emission phenomena of the complex can be modified by molecular distortion, particularly by rotation of the phenyl groups in the ligand.     

Detection of hydrophobic microdomains in anionic polyelectrolytes with tris-(4,7-diphenyl-1,10-phenanthroline)3Cr(III)

This paper describes the changes in the luminescent properties of the tris-(4,7-diphenyl-1,10-phenanthroline)(3)Cr(III), [Cr(dip)(3)](3+) complex in an aqueous solution of three polyelectrolytes containing cyclohexyl, phenyl or 1-naphthyl groups in the side chain. When the polyelectrolytes form hydrophobic microdomains the luminescence of [Cr(dip)(3)](3+) is affected. The luminescence increases in the presence of cyclohexyl groups in the side chains, but decreases in the presence of phenyl and naphthyl groups (in that order). This fact can be explained in terms of a reductive quenching mechanism between the complex and the aromatic groups. Indeed, experiments performed with the complex and the alcohols corresponding to the functional groups, i.e., cyclohexanol, phenol, and naphthol, also show the same behavior, confirming the interaction with the functional groups and not other components of the polyelectrolyte. The luminescent properties of the [Cr(dip)(3)](3+) complex allow the detection of hydrophobic microdomains arising from the host-guest interaction. Moreover, the complex is able to distinguish between a nonaromatic hydrophobic microdomain and an aromatic one.     

Iron (III) derivatives of 4,7-dihydroxy-1,10-phenanthroline

The chemistry of the iron (III) derivatives of 4,7-dihydroxy-l,10-phenanthroline has been studied in detail. Oxidation of the intensely red tris(4,7-dihydroxy-l,10-phenanthroline) iron (II) ion results in a grey compound, tris(4,7-dihydroxy-l,10-phenanthroline)iron(III), which is stable below pH 10. Above pH 10 the grey compound is partially converted into an amber compound in which the ratio of phenanthroline to iron is 2:1. The amber compound is the conjugate base of a purple 2:1 compound with pK(a) = 9.77. The visible absorption spectra of the three species at various pH values are reported. For 4,7-dihydroxy-1,10-phenanthroline pK(3), as determined by ultraviolet absorptometry, is 12.62 +/- 0.2.     

Application of the thermal lens effect for determination of iron(II) with 4,7-diphenyl-1,10-phenanthroline disulfonic acid

A heat-induced refractive index change is used to increase the sensitivity of the spectrophotometric determination of iron(II) in a dual-beam system. An argon ion laser (514.5 nm) is used as the heating source and the intensity variation of a helium—neon laser (632.8 nm) is measured. The sensitivity is increased 7.3 times compared with spectrophotometry; the detection limit is 3 × 10^-7 M.     

Luminescence of bound forms of Schiff bases in a perfluorosulfonic membrane

Perfluorosulfonic membranes were modified by Schiff bases by sorption of molecules on sulfonic groups of the membranes and by coordination attachment to preliminarily implanted La³⁺ cations. The fixation of the molecules in nanosized cavities of membranes is responsible for their luminescence at room temperature in a violet-blue spectral range. The choice of guest molecules of bases and the mode of their immobilization in a membrane provides certain possibilities of regulating the position of the de-excitation band of film luminophores.     

Efficient and stable solid-state light-emitting electrochemical cell using tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II) hexafluorophosphate

The complex tris(4,7-diphenyl-1,10-phenanthroline)ruthenium(II), prepared via a simple microwave-assisted synthesis, was used to prepare a single-layer light-emitting electrochemical cell. This device reaches a high power efficiency of 1.9 Lum/W at a brightness of 390 cd/m2. Moreover, its lifetime is an order of magnitude longer than that of a similar cell making use of tris(bipyridine)ruthenium(II) as the emitting complex.     

Indirect extraction—spectrophotometric method for the determination of traces of tin(II) by means of 4,7-diphenyl-1,10-phenanthroline

An indirect extraction-spectrophotometric determination of tin(II) is based on reduction of iron(III) and determination of the iron(II) formed with bathophenanthroline. Analysis is possible in strongly acidic samples even with large excesses of iron(III). The apparent molar absorptivity is 39,080 dm³ mol^-1 cm^-1 ; the limit of determination is 32 ng cm^-3 and the sensitivity is 64 ng cm^-3. Interferences are reported. The method is applicable to the determination of tin in samples soluble in non-oxidizing acids, and to the determination of tin in lead.     

4,7-Dimethoxy-1,10-phenanthroline: an excellent ligand for the Cu-catalyzed N-arylation of imidazoles

[reaction: see text] 4,7-Dimethoxy-1,10-phenanthroline (L) was found to be an efficient ligand for the copper-catalyzed N-arylation of imidazole with aryl iodides and bromides under mild conditions. A variety of hindered and functionalized imidazoles and aryl halides were transformed in good to excellent yields.