Hydrazone Groups Research Articles

Is indium tin oxide a suitable electrode in organic solar cells? Photovoltaic properties of interfaces in organic p∕n junction photodiodes

The charge generation properties at all interfaces of a p∕n junction, bilayer photodiode have been investigated by means of the photoaction spectrum (PAS) as a function of applied bias. The organic photodiode was fabricated with a low-glass transition temperature (Tg) polysiloxane with pendant hydrazone groups as the p-type material and a perylene diimide derivative as the n-type material. The PAS under short circuit and reverse bias showed an antibatic response at the high-energy region (3.0–3.5eV), and a symbatic response at the low-energy region (2.0–3.0eV). However, under forward bias, the PAS showed the opposite behavior. These results are interpreted in terms of the band structure of tin-doped indium oxide (ITO) that prevents effective photoinjection of electrons at the polymer/ITO interface and the relative energy levels of the constituent materials.

Investigation of solid hybrid solar cells based on molecular glasses

We have synthesized new carbazole and ethylenedioxythiophene based molecular glasses with hydrazone and imine goups. Thermal analysis confirms the metastable amorphous properties of these molecules with glass temperature in the range of 62 to 76 °C. Electrochemical properties have been studied and show the effect of the conjugated imine or hydrazone groups on the electronic delocalization of the structures. A decrease of the oxidation potential, compared to the parent unsubstituted molecules, is observed, which decreases the HOMO energetic level and improves the donor properties of the molecules. Amorphous materials of low molecular weight should allow the regeneration of the oxidized sensitizer in agreemen t with their respective energetic levels. Moreover, all the molecules absorb light in the range of th e wavelength, blue-shifted in comparison with the ruthenium dye, which limits the shield effect for a good photogeneration of charge carrier in the dye. Results suggest that such molecular glasses could find applications in photovoltaic devices.

Use of Carbonyl Group Addition—Elimination Reactions for Synthesis of Nucleic Acid Conjugates

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Use of Carbonyl Group Addition−Elimination Reactions for Synthesis of Nucleic Acid Conjugates

This review outlines the synthesis of covalent conjugates of oligonucleotides and their analogues that are obtained by reactions of carbonyl compounds with various nucleophiles such as primary amines, N-alkoxyamines, hydrazines, and hydrazides. The products linked by imino, oxime, hydrazone, or thiazolidine groups are shown to be useful intermediates for a wide range of chemical biology applications. Methods for their preparation, isolation, purification, and analysis are highlighted, and the comparative stabilities of the respective linkages are evaluated. The relative merits of incorporation of a carbonyl group, particularly an aldehyde group, into either the oligonucleotide or the ligand parts are considered. Examples of harnessing of aldehyde-nucleophile coupling for the labeling of nucleic acids are given, as well as their conjugation to various biomolecules (e.g. peptides and small molecule ligands), site-specific cross-linking of oligonucleotides to nucleic acid-binding proteins, assembly of multibranched supramolecular structures, and immobilization on functionalized surfaces. Future perspectives of bioconjugation and complex molecular engineering via carbonyl group addition-elimination reactions in nucleic acids chemistry are discussed.

Semiempirical and Ab Initio Studies of the Structure and Spectroscopy of the Azo Dye Direct Blue 1: Comparison with Experiment

The structure and spectroscopy of the bis-azo dye Direct Blue 1 have been studied using semiempirical, Hartree−Fock, and density functional theory (DFT) calculations, and the results have been compared with those from experiment. The calculated dye structure comprises two essentially identical near-planar halves with a twist about the central biphenyl bond; the structures produced by the semiempirical AM1 method and the ab initio Hartree−Fock and DFT methods were found to be similar to each other. Excited-state calculations describe the transition to the lowest excited state of Direct Blue 1 as a charge transfer from the central biphenyl group onto both naphthyl rings, along with charge redistribution within the region of the hydrazone groups. Infrared and Raman spectra calculated by ab initio methods match the experimental spectra well; by contrast, IR spectra were modeled poorly by the semiempirical AM1 method. NMR resonances calculated with the DFT methods give good correlation with the experimental NMR resonances of Direct Blue 1 in solution. Overall, the match between the calculated and experimental properties is good for this large (88-atom) molecule, demonstrating that such calculations can assist greatly in analyzing the structure and spectroscopy of azo dyes, provided that a suitable level of theory is used.

Phtodeceomposition of Pigment Yellow 74, a Pigment Used in Tattoo Inks¶

ABSTRACTTattooing has become a popular recreational practice among younger adults over the past decade. Although some of the pigments used in tattooing have been described, very little is known concerning the toxicology, phototoxicology or photochemistry of these pigments. Seven yellow tattoo inks were obtained from commercial sources and their pigments extracted, identified and quantitatively analyzed. The monoazo compound Pigment Yellow 74 (PY74; CI 11741) was found to be the major pigment in several of the tattoo inks. Solutions of commercial PY74 in tetrahydrofuran (THF) were deoxygenated using argon gas, and the photochemical reaction products were determined after exposure to simulated solar light generated by a filtered 6.5 kW xenon arc lamp. Spectrophotometric and high‐pressure liquid chromatography (HPLC) analyses indicated that PY74 photodecomposed to multiple products that were isolated using a combination of silica chromatography and reversed‐phase HPLC. Three of the major photodecomposition products were identified by nuclear magnetic resonance and mass spectrometry as N(2‐methoxyphenyl)‐3‐oxobutanamide (o‐acetoacetanisidide), 2‐(hydroxyimine)‐N‐(2‐methoxyphenyl)‐3‐oxobutanamide and N,N″‐bis(2‐methoxyphenyl)urea. These results demonstrate that PY74 is not photostable in THF and that photochemical lysis occurs at several sites in PY74 including the hydrazone and amide groups. The data also suggest that the use of PY74 in tattoo inks could potentially result in the formation of photolysis products, resulting in toxicity at the tattoo site after irradiation with sunlight or more intense light sources.

3-[(2,4-Dinitrophenyl)hydrazono]butan-2-one oxime

The title compound, C10H11N5O5, contains of di­nitro­phenyl, monooxime and hydrazone groups. The mol­ecules are linked through O—H⋯N and C—H⋯O hydrogen bonds. There are also π–π interactions and intramolecular hydrogen bonds. All these hydrogen bonds are highly effective in forming dimeric chains, thereby stabilizing the crystal structure. The monooxime and hydrazone groups both have an E configuration.

Photodecomposition of Pigment Yellow 74, a pigment used in tattoo inks.

Tattooing has become a popular recreational practice among younger adults over the past decade. Although some of the pigments used in tattooing have been described, very little is known concerning the toxicology, phototoxicology or photochemistry of these pigments. Seven yellow tattoo inks were obtained from commercial sources and their pigments extracted, identified and quantitatively analyzed. The monoazo compound Pigment Yellow 74 (PY74; CI 11741) was found to be the major pigment in several of the tattoo inks. Solutions of commercial PY74 in tetrahydrofuran (THF) were deoxygenated using argon gas, and the photochemical reaction products were determined after exposure to simulated solar light generated by a filtered 6.5 kW xenon arc lamp. Spectrophotometric and high-pressure liquid chromatography (HPLC) analyses indicated that PY74 photodecomposed to multiple products that were isolated using a combination of silica chromatography and reversed-phase HPLC. Three of the major photodecomposition products were identified by nuclear magnetic resonance and mass spectrometry as N-(2-methoxyphenyl)-3-oxobutanamide (o-acetoacetanisidide), 2-(hydroxyimine)-N-(2-methoxyphenyl)-3-oxobutanamide and N,N''-bis(2-methoxyphenyl)urea. These results demonstrate that PY74 is not photostable in THF and that photochemical lysis occurs at several sites in PY74 including the hydrazone and amide groups. The data also suggest that the use of PY74 in tattoo inks could potentially result in the formation of photolysis products, resulting in toxicity at the tattoo site after irradiation with sunlight or more intense light sources.

Surface-enhanced resonance Raman scattering of black inkjet dyes in solution and in situ printed onto paper.

Understanding the changes that occur when dyes are absorbed onto paper is crucial for the design of new inkjet dyes. This problem is particularly difficult for black dyes that have complex chromophores, and as a result, spectroscopic information on electronic and structural changes can be of importance. Surface-enhanced resonance Raman scattering (SERRS) and electronic structure calculations were used to probe in situ changes in the chromophore in black di-azo dyes printed onto paper. The data indicate that the low-energy chromophore is due mainly to the hydrazone group and the high-energy chromophore to both the azo and hydrazone groups. A comparison of SERRS from the dyes adsorbed onto silver particles in suspension and from the dyes on paper demonstrated a broadening of the chromophore into the red for both dyes and evidence of a structural change in one dye.

Anthracene-9-carbaldehyde hydrazone

In the title compound, C15H12N2, the geometric parameters are normal, within experimental error. The mol­ecules are arranged in pairs, with their hydrazone groups oriented towards one another.

Novel ferrocene-containing helical triangular macrocycle achieved via an exchange reaction.

A novel ferrocene-containing helical triangular macrocyclic compound has been constructed through an exchange reaction of hydrazone groups which templated and catalyzed by Co(II) ions.

Synthesis and photoconductivity study of new bisazos containing hydrazone groups

Based on molecular design, three high photosensitive bisazos containing hydrazone groups were synthesized by reacting bis(2″-hydroxy-3″-chlorocarbonyl) -4,4′-biphenyl bisazo with various amines containing hydrazone groups. Characterization was made by elementary analysis, melting point, IR spectra and Raman spectra. The xerographic properties have been investigated in bilayer photoreceptor devices and all bisazos exhibit high photosensitivity. Study of spectral responses of the three bisazos containing hydrazone groups showed that the best photoconductivity was observed at about 690 nm and the maximum of absorption spectra was recorded at ∼570 nm.

4-Nitrophenylhydrazones of partially formylated polystyrene, their properties and crosslinking

The title polymers were prepared as potential non-linear optical materials with a degree of substitution 3–13 mole %. During UV-irradiation and/or heating near the glass transition temperature these polymers crosslink through the hydrazone groups and their UV-vis absorption band diminishes. Degrees of crosslinking of swollen samples were estimated. A possibility of simultaneous crosslinking and poling of these polymers is discussed.

Effect of a methyl substituent on the molecular and crystal structure of (2-acetyl-5-nitrofuran)-N-benzoylhydrazone

An x-ray diffraction study of (2-acetyl-5-nitrofuran)-N-benzoylhydrazone has shown that the molecules of this compound have a nonplanar structure with syn arrangement of the oxygen and nitrogen atoms of the keto and hydrazone groups and an anti arrangement of the oxygen atom of the furan fragment. With such a conformation, the molecules do not form crystal hydrates; in the crystal, they are connected with one another into chains by intermolecular hydrogen bonds N-H...O 2.26 A. However, intermolecular N → O proton phototransfer does not occur between them.

The analogy between CF 2- and co-groups. The reaction of polyfluoromethylenketones and perfluorocycloolefins with hydrazins

Few examples are known, when in the compounds of the same structure CF 2-group reacts as CO-group, e.g.: ▪ Unexpectedly the same analogy in the reactions of polydifluoromethylenketones with hydrazins is discovered. In this case the polyhydrazones of polyketones are formed by initial conversion of carbonyl group and further transformation of all difluoromethylen groups into hydrazone groups ▪ The mechanism of the reaction taking its course via steps of monohydrazone (I), azaolefin (II), bishydrazone (III), trishydrazone (IV) and tetrahydrazone (V) formation is revealed by isolation of the all intermediate products. Thus, the monocarbonyl compounds, having the chain of CF 2-groups, are (concerning the reaction with hydrazins) the formal analogous of polyketones: CF 3CF 2CF 2CF 2COCF 3 is the analog of the hypothetic polyketone CF 3COCOCOCOCF 3. Applying the analogy of CF 2- and CO-groups in cyclic perfluoroolefins in the reaction with hydrazins tetra (VI)- and pentahydrazones (VII) of the cyclic perketones are obtained in the quantitative yields: ▪