New Organic Polymers for Solar Cells

From the moment of conductive polyacetylene discovery, semiconducting polymers and other organic thin films and multilayers are important for a wide range of applications, including electronics, photovoltaics and sensors. The main idea of this chapter is the synthesis of new conjugated donor and acceptor polymers and development of organic solar cells on their basis. As donor polymers were used modified polyanilines (PANIs) and its dopants, as acceptor compounds - the fullerene C60 derivatives. Experimental prototypes of organic solar cells were obtained on the basis of binary donor-acceptor layers and bulk heterojunctions, consisting of novel polyaniline derivatives and fullerene-contained polymers. The current-voltage characteristics of solar cells were measured and the values of such parameters, such as open-circuit voltage, short-circuit current, fill factor and power conversion efficiency, were calculated. Comparison of parameters of the various types of organic solar cells was held

Theoretical Models for Quantitative Description of the Acid–Base Equilibria of the 5,6-Substituted Uracils

The acidities of 18 5,6-substituted uracils have been numerically estimated as p<i>K</i>_a values in terms of three theoretical models. The first scheme includes the calculation of the gas-phase acidity of uracil with the G3MP2B3 method and taking into account the solvent effect using the polarizable continuum approximation PCM­(SMD)-TPSS/aug-cc-pVTZ. The second model is one step and implies calculation of the free Gibbs energies of the hydrate complex of uracil (and its anion) with 5 water molecules by the TPSS/aug-cc-pVTZ method. This model accounts for the solvent effect corresponding to both specific and nonspecific solvation. The third scheme required high time and computational resources and includes the strong features of the two previous schemes. Here, the theoretical estimation of p<i>K</i>_a is performed by the CBS-QB3 composite method. As in the second approach, both specific (as pentahydrate) and nonspecific solvent effects are determined. We have analyzed the advantages and model restrictions of the considered schemes for the p<i>K</i>_a calculations. All models have systematic errors, which have been corrected with the linear empirical regression relations. In the presented model, the absolute mean deviations of the p<i>K</i>_a values of uracils dissociating via the N1–H bonds diminish to 0.25, 0.28, and 0.23 p<i>K</i>_a units (respectively, for I, II, and III models), which corresponds to ∼0.3 kcal/mol on the energy scale. The applicability of our computational schemes to uracils dissociating via N3–H, O–H (orotic acids) and C–H bonds is discussed

Evaluation of Cytotoxicity and α-Glucosidase Inhibitory Activity of Amide and Polyamino-Derivatives of Lupane Triterpenoids

A series of two new and twenty earlier synthesized branched extra-amino-triterpenoids obtained by the direct coupling of betulinic/betulonic acids with polymethylenpolyamines, or by the cyanoethylation of lupane type alcohols, oximes, amines, and amides with the following reduction were evaluated for cytotoxicity toward the NCI-60 cancer cell line panel, &alpha;-glucosidase inhibitory, and antimicrobial activities. Lupane carboxamides, conjugates with diaminopropane, triethylenetetramine, and branched C3-cyanoethylated polyamine methyl betulonate showed high cytotoxic activity against most of the tested cancer cell lines with GI50 that ranged from 1.09 to 54.40 &micro;M. Betulonic acid C28-conjugate with triethylenetetramine and C3,C28-bis-aminopropoxy-betulin were found to be potent micromolar inhibitors of yeast &alpha;-glucosidase and to simultaneously inhibit the endosomal reticulum &alpha;-glucosidase, rendering them as potentially capable to suppress tumor invasiveness and neovascularization, in addition to the direct cytotoxicity. Plausible mechanisms of cytotoxic action and underlying disrupted molecular pathways were elucidated with CellMinner pattern analysis and Gene Ontology enrichment analysis, according to which the lead compounds exert multi-target antiproliferative activity associated with oxidative stress induction and chromatin structure alteration. The betulonic acid diethylentriamine conjugate showed partial activity against methicillin-resistant S. aureus and the fungi C. neoformans. These results show that triterpenic polyamines, being analogs of steroidal squalamine and trodusquemine, are important substances for the search of new drugs with anticancer, antidiabetic, and antimicrobial activities

Photoconductivity of Thin Films Obtained from a New Type of Polyindole

The optoelectronic properties of a new poly(2-ethyl-3-methylindole) (MPIn) are discussed in this paper. The absorption and photoluminescence spectra were studied. The electronic spectrum of MPIn showed a single absorption maximum at 269 nm that is characteristic of the entire series of polyindoles. The fluorescence spectra show that the emission peaks of the test sample are centered around 520 nm. The photoconductivity of thin film samples of MPIn polyindole was studied by measuring the current-voltage characteristics under ultraviolet radiation with a wavelength of 350 nm. Samples of phototransistors were obtained, where thin films of MPIn polyindole were used as a transport layer, and their characteristics were measured and analyzed. The value of the quantum efficiency and the values of the mobility of charge carriers in thin polyindole films were estimated