Cd Nenitzescu Of Romanian Academy

Bucharest, Romania

Cd Nenitzescu Of Romanian Academy

Bucharest, Romania
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Dragu E.A.,Cd Nenitzescu Of Romanian Academy | Nica S.,Cd Nenitzescu Of Romanian Academy | Nica S.,Petru Poni Institute of Macromolecular Chemistry | Raicopol M.,Polytechnic University of Bucharest | And 5 more authors.
Tetrahedron Letters | Year: 2012

The novel 1,2-di(azulen-1-yl)cyclopent-1-ene 3 was conveniently synthesized via a two-step procedure involving Vilsmeier-Haack acylation of azulene with N,N,N′,N′-tetraethylglutaramide (TEGA) and POCl 3, followed by an intramolecular McMurry coupling of the resulting diketone. In contrast with the previously reported (E)-1,2-di(azulen-1-yl)ethene that shows negligible fluorescence in the solid state, alkene 3 displays fluorescence emission from the S 2 excited state of the azulene moieties. This compound easily polymerizes upon electrochemical oxidation, leading to the formation of a conducting polymer film at the electrode surface. © 2012 Elsevier Ltd. All rights reserved.

Nica S.,Petru Poni Institute of Macromolecular Chemistry | Nica S.,Cd Nenitzescu Of Romanian Academy | Cristian U.,Cd Nenitzescu Of Romanian Academy | Hanganu A.,Cd Nenitzescu Of Romanian Academy | And 5 more authors.
Revista de Chimie | Year: 2014

Improved synthetic protocol for the syntheses of 4-guaiazulenyl-pyrylium perchlorates substituted with one or two guaiazulen-1-ylvinyl arms via microwave-assisted condensation reaction of the corresponding methyl substituted salt with guaiazulen-l-carbaldehyde is described. Upon replacement of the methyl groups by guaiazulen-1 ylvinyl substituents a strong redshift of the visible absorption band was observed with efficient expansion of the π-electron conjugation within the system. Structural assignment through 1H-NMR spectroscopy revealed an upheld shift of the pyrylium and vinylene protons chemical shifts upon guaiazulenyl substitution.

Inel G.A.,Polytechnic University of Bucharest | Soare M.-L.,Science METAV SA | Bujduveanu M.-R.,Polytechnic University of Bucharest | Varga S.,Polytechnic University of Bucharest | And 2 more authors.
UPB Scientific Bulletin, Series B: Chemistry and Materials Science | Year: 2014

This work is devoted to the electrochemical characterization of two related azulene selenium compounds. The investigations were performed by cyclic voltammetry and differential pulse voltammetry. The redox processes for each compound are established, analyzed and assessed to the particular functional groups at which they take place. This assessment was based on the comparison between the electrochemical behaviour of the compounds and the similarities and differences in their structures, connected to their substituent effects.

Tarko L.,Cd Nenitzescu Of Romanian Academy | Putz M.V.,West University of Timișoara | Ionascu C.,West University of Timișoara | Putz A.-M.,West University of Timișoara | Putz A.-M.,Romanian Academy of Sciences
Current Computer-Aided Drug Design | Year: 2014

The present work employs 152 benzene-carboxylic acid' esters having computed the toxicity within the range [2.251, 10.222] for fathead minnow fish (Pimephales promelas). Calibration set includes many pairs having very similar chemical structure, size, shape and hydrophilicity, but very different value of ECOSAR toxicity or vice versa. The QSTR study, which uses all esters as calibration set, emphasized a large percent (16.2%) of outliers. In this QSTR study most of the estimated values of toxicity for outliers are much lower than ECOSAR toxicity. The LogP and some aromaticity descriptors are predictors. The best QSTR for esters having low value (< 5.5) of ECOSAR toxicity and the best QSTR for esters having high value (> 5.5) of ECOSAR toxicity are obtained when the number of outliers is very small. These QSTRs are different enough and highlight opposite influences of certain descriptors on toxicity. The results emphasize two possibilities: (a) the esters having low value of ECOSAR toxicity and the esters having high value of ECOSAR toxicity are included in two different classes from the point of view of structure-toxicity relationship and/or (b) many high values of ECOSAR toxicity are wrong. By comparison, a QSTR using experimental values of toxicity against rats for 37 benzene-carboxylic esters included in the same database gives good correlation experimental/computed values of toxicity, the number of outliers is null and the result of validation test is good. © 2014 Bentham Science Publishers.

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