New green fluorescent polyvinylcarbazole copolymer with 1,8‐naphthalimide side chains as chemosensor for iron cations

The synthesis and basic photophysical characteristics of a novel green fluorescent polyvinylcarbazole polymer containing 4‐N,N‐dimethylaminoethyleneamino‐1,8‐naphthalimide side chains has been described. The ability to sense metal cations has been monitored by fluorescence emission spectroscopy. It is shown that the fluorescent intensity is very sensitive to the Fe²⁺ cations and the copolymer can be used as an homogeneous and heterogeneous fluorescent sensor for Fe²⁺ cations. Copyright © 2004 John Wiley & Sons, Ltd.     

Dual reactivity of diphenylphosphinous and phenylphosphonous acid amides in reactions with N-acetoxymethyl-substituted diethylamine,benzamide, and acetamide

Conclusion N-Acetoxymethyldiethylamine reacts with tetraethyldiamidophenylphosphonite and diethylamidodiphenylphosphinite, and N-acetoxymethylbenzamide with tetraethyldiamidophenylphosphonite at the phosphorus atom only to form Arbuzov reaction products. The reaction of N-acetoxymethylacetamide with tetraethyldiamidophenylphosphonite and diethylamidodiphenylphosphinite, and the reaction of N-acetoxymethylbenzamide with diethylamidodiphenylphosphinite proceed at two reaction centers at the phosphorus atom to form the Arbuzov reaction products, and at the nitrogen atom to form acetoxyphosphinites (phosphonites) and N-diethylaminomethylamides.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2765–2769, December, 1986.     

Determination of biologically active low-molecular-mass thiols in human blood. III. Highly sensitive narrow-bore isocratic reversed-phase high-performance liquid chromatography with fluorescence detection

The fast isocratic narrow-bore reversed-phase high-performance liquid chromatographic method employing fluorescence detection is described for the precise reproducible simultaneous measurement of total homocysteine, cysteine and glutathione in human blood. Sample preparation involves conversion of disulfides to free thiols with triphenylphosphine, precipitation of proteins with sulfosalicylic acid, and conjugation of thiols with monobromobimane. Optimized sample preparation conditions as well as chromatographic conditions allowed to obtain reliable quantitative results within the concentration range corresponding to the levels of these thiols in human blood in norm and pathology. The detection limit was approximately 70 amol for all labeled aminothiols. The proposed method for these compounds analysis includes simple sample preparation, high selectivity, good linearity (r2>0.998), high reproducibility (within-run precision for derivatized aminothiol peaks area RSD<1.8% for three times consequently injected sample); high reliability and the small sample volume (1 microl) required for analysis make it suitable for clinical studies.     

Reaction of 2,2-bis(4′-hydroxy-3′-N,N-diethylaminomethylphenyl) propane with triethyl phosphite

Conclusions The reaction of 2,2-bis(4-hydroxy-3-N,N-diethylaminomethylphenyl)propane with triethyl phosphite gave 2,2-bis(4-ethoxy-3-diethylphosphonomethylphenyl)propane via the intermediate formation of a compound with a pentacovalent phosphorus atom. In the presence of acetic acid the reaction leads to 2,2-bis(4-hydroxy-3-diethylphosphonomethylphenyl)propane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1621–1624, July, 1978.     

Measurements and Utilization of Consistent Gibbs Energies of Transfer of Single Ions: Towards a Unified Redox Potential Scale for All Solvents

Utilizing the “ideal” ionic liquid salt bridge to measure Gibbs energies of transfer of silver ions between the solvents water, acetonitrile, propylene carbonate and dimethylformamide results in a consistent data set with a precision of 0.6 kJ mol⁻¹ over 87 measurements in 10 half-cells. This forms the basis for a coherent experimental thermodynamic framework of ion solvation chemistry. In addition, we define the solvent independent - and the values that account for the electronating potential of any redox system similar to the value of a medium that accounts for its protonating potential. This scale is thermodynamically well-defined enabling a straightforward comparison of the redox potentials (reducities) of all media with respect to the aqueous redox potential scale, hence unifying all conventional solvents′ redox potential scales. Thus, using the Gibbs energy of transfer of the silver ion published herein, one can convert and unify all hitherto published redox potentials measured, for example, against ferrocene, to the scale.     

Electronic Structure of Substituted Magnesium Malonates and Malonic Aldehyde Dianion Associates

Ab initio calculations using a molecular pseudopotential and an all-electron approximation have been carried out with various basis sets for Mg complexes and for dianions of malonic aldehyde and its imino and chloro derivatives. The valence levels are reproduced most adequately, whereas the atomic charges and bond characteristics depend heavily on the basis used. Employing a pseudopotential does not change the quality of the electronic characteristics of the system, slightly increasing the existing charge separation. The Cl atom in the -position is involved in -conjugation of the dicarbonyl cycle, causing antibonding in the dianion. Introduction of Mg considerably increases the mesomeric effect of Cl and electron density on the N and O atoms, slightly changing the charges on the carbon atoms. According to the calculations, the Mg–O and Mg–N bonds are slightly covalent. The metal AO is not included in the -system of the ring.     

Nucleophilic substitution reactions in tetranitrodibenzo-18-crown-6

The nature of the reaction of a reagent with tetranitrodibenzo-18-crown-6 was found to depend on its basicity. This behavior was interpreted in the framework of the theory of hard and soft acids and bases.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 605–608, May, 1992.     

N-Heterocyclic Olefins as Electron Donors in Combination with Triarylborane Acceptors: Synthesis,Optical and Electronic Properties of D–π–A Compounds

N-heterocyclic olefins (NHOs), relatives of N-heterocyclic carbenes (NHCs), exhibit high nucleophilicity and soft Lewis basic character. To investigate their π-electron donating ability, NHOs were attached to triarylborane π-acceptors (A) giving donor (D)–π–A compounds 1 – 3 . In addition, an enamine π-donor analogue ( 4 ) was synthesized for comparison. UV–visible absorption studies show a larger red shift for the NHO-containing boranes than for the enamine analogue, a relative of cyclic (alkyl)(amino) carbenes (CAACs). Solvent-dependent emission studies indicate that 1 – 4 have moderate intramolecular charge-transfer (ICT) behavior. Electrochemical investigations reveal that the NHO-containing boranes have extremely low reversible oxidation potentials (e.g., for 3 , =−0.40 V vs. ferrocene/ferrocenium, Fc/Fc⁺, in THF). Time-dependent (TD) DFT calculations show that the HOMOs of 1 – 3 are much more destabilized than that of the enamine-containing 4 , which confirms the stronger donating ability of NHOs.