Polyaromatic amines. Part 3: Synthesis of poly(diarylamino)styrenes and related compounds

The title compounds were synthesised and characterised as part of a study into new aromatic amines for charge transporting materials. Compounds 12-16, 20-24 and 27-34 are alkene linked triarylamines, compounds 35-36 are hydrazone derivatives and compounds 38-41 are pyrrole substituted triarylamines. Each compound was characterised by cyclic voltammetry.     

Spectroscopic characterisation and structural modelling of new hydrogen-bonded charge transfer complex between picric acid and 3-aminoquinoline

New charge transfer hydrogen-bonded (HBCT) complex between the electron donor 3-aminoquinoline with the electron acceptor picric acid has been synthesised and characterised experimentally and theoretically using a variety of physicochemical techniques. The experimental work included the use of UV–vis, IR and ¹H NMR studies to characterise the complex in different hydrogen-bonded solvents. The studied reaction proceeded based on 1:1 stoichiometric ratio and the stability constant recorded high values. The solid complex was prepared and characterised by elemental analysis that confirmed its formation in 1:1. Both IR and NMR studies supported the existence of proton and charge transfers in the formed complex. In complemented with experimental results, molecular modelling using DFT using 31–6G(d,p) basis set was carried out in the gas phase where the existence of both charge and hydrogen transfers was reconfirmed in the obtained complex in full consistency with experimental results.     

Half-subtractor operation in pH responsive N-heterocyclic amines

Intramolecular charge transfer processes in simple molecules can be exploited to implement combinational digital operation.     

Reductive electron injection into duplex DNA by aromatic amines

An assay based on photoinduced reaction and subsequent cleavage of duplex DNA containing a bromodeoxyuridine ((Br)U) residue and an abasic site was developed to screen aromatic amines for their ability to initiate charge transfer by reductive electron donation. Two candidates, N,N,N',N'-tetramethyl-1,5-diaminonaphthalene (TMDN) and 1,5-diaminonaphthalene (DAN), expressed the desired activity, and an oligodeoxynucleotide-TMDN conjugate was subsequently prepared to identify additional variables affecting the efficiency of electron injection and transfer into DNA. This system demonstrated only mild sensitivity to molecular oxygen but was strongly inhibited by high concentrations of 2-mercaptoethanol. The nucleobase counter to the attached TMDN strongly modulated charge transfer as evident by a 60-fold decrease in reduction of the distal (Br)U when the counterbase A was substituted for C. An inverse relationship between this reduction and quenching of TMDN fluorescence by the counterbase was also discovered and is consistent with a competition between radical recombination and electron migration away from the initial site of its injection into DNA.     

Artificial muscle: movement and position control

The movement of an all polymeric triple-layer artificial muscle based on polypyrrole (PPy) that work in aqueous solution was characterised. The magnitude and direction of the experimental current control both rate and direction of the movement. The described angle is a linear function of the consumed charge.     

Fast naked-eye detection of amines with viologen derivatives

Three viologen derivatives with the ability to detect amines were synthesised. Upon interacting with amines, a rapid colour change caused by electron transfer and charge transfer between viologen derivatives and amines can be directly observed by naked eyes. With fluorine substituents, the detection sensitivity of these viologen derivatives for amines is remarkably enhanced to reach the level of ppm.     

Aromatic amines: a comparison of electron-donor strengths

The electron-donor abilities of ten aminophenyl systems and an additional aminothienyl system are compared using density functional theory calculations. The systems studied here include those with amine nitrogen atoms bearing alkyl or aryl groups and those with amine nitrogen atoms as part of a heterocycle. Their abilities to act as donors in electron-transfer processes are assessed from calculated vertical ionization potentials for the aminobenzenes, which are in good agreement with available experimental data. Their abilities to act as intramolecular pi-electron donors in conjugated systems are inferred from the bond lengths and charge densities calculated for the corresponding 4-aminobenzaldehydes and 4-aminobenzonitriles. The computed (13)C NMR chemical shifts for the 4-aminobenzaldehydes and 4-aminobenzonitriles are in good agreement with published and new experimental data. The chemical shifts correlate well with the computed charge densities and can, to some extent, be used as an experimental probe of pi-donor strength. We find that the electron-transfer-donor strengths do not correlate well with pi-donor strengths: these differences can largely be attributed to steric effects.     

Molecular complexes of iron violurate with donor amines

The acceptor character of iron violurate complex was studied by examining the electronic, vibrational and 1H-nmr spectra of the charge transfer molecular complexes formed between the iron violurate as pi-acceptor and some amines as n-donors. Elemental analysis and spectral results establishes 1:2 stoichiometry of the adducts. The study has been conducted at different temperatures. Values of delta G degree, delta H degree and delta S degree have been calculated from the self-consistent values of the formation constants (KCT). Ionization potentials of the donors have been calculated and the solvent effect on the KCT values is discussed. The antibacterial and antifungal effects of the molecular complexes were studied.     

Laser photolysis study of triplet exciplexes of nitronaphthalenes with tertiary aromatic amines

Conclusions Spectrokinetic characteristics were found for the triplet exciplexes of nitronaphthalenes with tertiary aromatic amines. The state with complete charge transfer makes the major contribution to the structure of the triplet exciplexes. Solvation of the triplet exciplexes by methanol molecules is accompanied by a decrease in the rate of reverse charge transfer.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2367–2370, October, 1987.     

Charge transfer complexes between 4,4′-disubstituted diphenyldiacetylenes: experimental and theoretical study

Novel charge transfer (CT) complexes containing donor and acceptor derivatives of diphenyldiacetylene have been synthesised and characterised. The structure of CT complexes was modelled at the B3LYP/6-31G(d)//B3LYP/6-31G(d) level of theory. It was found that the complex formation is mainly due to dipole–dipole interaction between side groups of diacetylene molecules and there was no significant charge transfer between donor and acceptor in the ground state. On the other hand, optical excitation of CT complexes leads to strong charge transfer from donor to acceptor molecule as followed from the modelling using time-dependent density functional theory (DFT) method. Diacetylene molecules adopt strongly bent configuration in CT complexes which is prohibitive for solid-state topochemical polymerisation of diacetylenes     

Fluorescence study of tetracaine–cyclodextrin inclusion complexes

The steady-state fluorescence emission from the local anaesthetic tetracaine (TCA) in water–solvent mixtures and in the presence of α-, β- and γ-cyclodextrin (CD) was investigated at various pH values. Emission was observed from the locally and the intramolecular charge transfer excited states. The TCA–CD system was found to be characterised by 1:1 associate in every case. The association constants of each complex were determined.     

A novel π-donor–π-acceptor system: 1-(4,5-dimethyl-1,3-dithiol-2-ylidene)-1-ferrocenyl-3,3-dicyanopropene

The title compound was prepared by reacting the anion of malononitrile with the corresponding ethanal, and characterised by UV–vis absorption spectroscopy, cyclic voltammetry and X-ray crystallography. Attachment of an additional ferrocenyl donor group to the π-donor–π-acceptor system does not enhance intramolecular charge transfer, because its bulk distorts the planarity of the conjugated chain.     

Nanofiltration of biogenic amines in acidic conditions: Influence of operation variables and modeling

Biogenic amines are present in some fermented and non-fermented beverages and can cause diseases. This study analyzes the feasibility of separating biogenic amines by nanofiltration in acidic medium. Solutions of chloride salts of three biogenic amines: putrescine, histamine and tyramine were filtered through a nanofiltration membrane with a 1000 Da molecular weight cut-off (MWCO) and a positive electrical charge at pH 3. Increasing the transmembrane pressure or cross flow velocity led to an increase in solute rejection and permeate flow. Moreover, a higher electrical charge or lower concentration of amine cations caused a larger rejection indicating that membrane-solutes repulsion governs the filtration process. Finally, the experimental results were analyzed using the classic Donnan–Steric pore model. Values of 0.83 nm and 5.4 μm were estimated for pore radius and membrane effective ratio thickness-porosity from the filtration of neutral solutes. Membrane volumetric charge density and the proton diffusivity inside the pores were estimated from the experimental results.     

Tandem mass spectrometry for the characterisation of sulphated-phosphorylated analogues of the carbohydrate-protein linkage region of proteoglycans

Carbohydrate-protein linkage region of proteoglycans is a key oligosaccharide structure because their sulphated and/or phosphorylated analogues control the biosynthesis of glucosaminoglycans or galactosaminoglycans. Therefore, synthesised sulphated and/or phosphorylated analogues were characterised by tandem mass spectrometry in the negative-ion mode. Results demonstrated that the product ion profile was characterised by glycosidic and cross-ring cleavages depending on the position and the type of the charged group (sulphate, phosphate or carboxylate). When the above compounds were sulphated and phosphorylated, the ion found at m/z 79 was the only one that demonstrated a phosphate group on the structure. The data also suggested that when a sodium cation was present in a sulphated and phosphorylated structure, the phosphate group in most cases was neutralised by the sodium cation, and therefore cleaved off the molecule, while the sulphate group was carrying the negative charge.     

CNDO/2 molecular orbital calculations on the complexes formed between dimethylberyllium and aliphatic amines

A systematic CNDO/2 study has been carried out on the molecular complexes formed between dimethylberyllium and aliphatic amines. It has shown that the calculated molecular properties of these complexes, viz. the interaction energy, amount of charge transferred and the enhancement of the dipole moment are related to the ionization potential of the amine. The results are discussed in terms of the Mulliken's charge transfer theory.     

Design and synthesis of cholesterol-bonded fullerene and porphyrin derivatives for the preparation of a self-assembled donor–acceptor system

The cholesterol-bonded fullerene and porphyrin derivatives were synthesised and characterised. Donor–acceptor thin films were self-assembled through the interaction between cyclodextrin and the cholesterol groups on porphyrin and fullerene derivatives. These uniform films were characterised by ultraviolet–visible and fluorescence spectroscopies. Scanning electron microscopy indicated that the self-assembled film had a chain-like fibre structure with the chains having a diameter of about 50 nm. The intermolecular interaction between chromophores and the formation of complex based on cholesterol and cyclodextrin were proven by the quenching of fluorescence due to the charge transfer from porphyrin moieties to the fullerene units.     

Capillary electrochromatography of hydrophobic amines on continuous beds

The capillary electrochromatographic separation performance of hydrophobic amines and a related quaternary ammonium compound on continuous beds based on polymers of acrylamide has been studied. The chromatographic bed is polymerized in situ and the character of the polymers with regard to hydrophobicity and charge has been systematically changed by regulating its content of isopropyl and sulfonate ligands, respectively. The best performance was obtained for columns with a molar ratio of 1:80 for the sulfonate and isopropyl groups, and resulted in efficiencies up to 200000 plates per meter. The effects on retention, resolution and elution order by ionic strength, pH, and content of acetonitrile in the mobile phase have been investigated. The quaternary ammonium compound was always the least retained irrespective of pH. By increasing the pH, a reversal of the migration order between the tertiary and secondary amine was obtained. The results indicate a complex migration/retention mechanism where ion-exchange, adsorption and electrophoretic mobilities play a role. The concentration limit of detection could be lowered from 1.3 microg/mL to 50 pg/mL by using a high content of 2-propanol (96%) in the sample compared to dissolving the analytes in the mobile phase.     

Enantiotopic interactions in the fluorescence quenching of camphor by chiral amines

A study of the quenching of fluorescence of (+)- and (?) camphor in hexane by a series of chiral primary, secondary, and tertiary amines shows only very small differences in quenching rate constants for the two enantiomers. The collision complex which precedes quenching (probably charge transfer) is thus insufficiently tight for enantiomeric recognition.     

胺、醇和醚类化合物电离能的估算

脂肪族胺、醇、醚、硫醇和硫醚的第一电离能Ip与N、O、S原子的电负性X~Z^O、分子中N、O、S原子的部分电荷q~z以及烷基的极化效应指数PEI的关系可以表示为:Ip(eV)=4.4851+3.0727X~Z~O+7.1702q~z-1.3949∑PEI上式较好地表达了脂肪族胺、醇、醚、硫醇和硫醚的第一电离能变化的共同规律。