Role Of Electronic Factors Research Articles

Stereoselective synthesis of 2-(2,4-dinitrophenyl)hydrazono- and (2-tosylhydrazono)-4-oxo-thiazolidine derivatives and screening of their anticancer activity

Stereoselective synthesis of (Z)-methyl 2-[(Z)-3-substituted 2-[2-(2,4-dinitrophenyl)hydrazono]-4-oxothiazolidine-5-ylidene]acetates and (Z)-methyl 2-[(Z)-3-substituted 2-[2-(tosylhydrazono)-4-oxothiazolidine-5-ylidene]acetates via the cyclization of N-substituted 2-arylhydrazino-carbothioamides with dialkyl acetylenedicarboxylates in absolute ethanol is reported. The structures were confirmed by spectroscopic data as well as single-crystal X-ray analyses. The mechanism of nucleophilic addition and the role of electronic factors were discussed. The anticancer activity of the newly synthesized compounds was evaluated against a panel of 60 cell lines derived from 9 different types of cancers including, leukemia, melanoma, lung, colon, CNS, ovarian, renal, prostate, and breast cancers and the results revealed that the cyclohexyl derivative has a significant broad anticancer activity, especially against different leukemia and colon cancer cell lines.

Role of Electronic Factor in Soot Oxidation Process Over Tunnelled and Layered Potassium Iron Oxide Catalysts

This paper describes the investigations of the catalytic activity in soot oxidation over well-defined iron oxide based materials. The nanostructuration of iron oxide by potassium into tunnelled (KFeO2) and layered (K2Fe22O34) ferrites and the surface promotion with CeO2 results in the marked increase in the catalytic activity (decrease of the ignition temperature down to 210 °C and T 10 % to 310 °C). The measurements of the catalysts work function showed that both nanostructuration and surface promotion with ceria of the best KFeO2 phase led to increase of the electron availability (decrease of the work function). Strong correlation of the catalytic activity in soot combustion of the Ce–K–Fe–O systems with the work function value was revealed for the first time in the model studies, and can be used as a guideline for optimisation of the real catalytic filters.

Development of squaraine dyes for photodynamic therapeutical applications: synthesis and study of electronic factors in the dye formation reaction

With a view to developing sensitizers for applications in photodynamic therapy (PDT), a series of quinaldine based squaraine dyes have been synthesized and the role of electronic factors in the dye formation have been investigated through absorption spectroscopy, product analysis and theoretical calculations. It has been observed that semisquaraine intermediates were formed as the sole products in the reaction of quinaldinium salts containing electron-donating substituents with squaric acid. However, with salts possessing electronegative and electron-withdrawing groups, the squaraine dyes were isolated in quantitative yields. The semisquaraine intermediates that have been isolated as the butyl adducts, could be converted to the squaraine dyes by reacting with the quinaldinium salts having electronegative and / or electron-withdrawing groups. These dyes exhibit absorption in the range 700-800 nm with significant molar extinction coefficients (e = 1-3 x 10 5 M -1 cm -1 ) and hence can have potential PDT applications.

Role of electronic factors in the formation of anionic complexes of tellurium(IV): Crystal structure of bis(4-methylbenzoylmethyltriphenylphosphonium) hexabromotellurate(IV)

Reactions of [(4-MeOC 6H 4COCH 2)Ph 3P]Br ( 1c) with (4-XC 6H 4COCH 2) 2TeBr 2 (X = H, 2a; Me, 2b; OMe, 2c) lead to Te–C bond cleavage to afford [(4-MeOC 6H 4COCH 2)Ph 3P] 2[TeBr 6] ( 3c). The analogous complexes [(4-MeC 6H 4COCH 2)Ph 3P] 2[TeBr 6] ( 3b) and [(C 6H 5COCH 2)Ph 3P] 2[TeBr 6] ( 3a) are obtained from the reaction of the corresponding phosphonium bromide with 2c. The 1:1 adducts [(4-XC 6H 4COCH 2)Ph 3P] +[(4-XC 6H 4COCH 2) 2TeBr 3] −, formed as intermediates, could be isolated only in case of X = H or Me. The crystal structure of 3b, which crystallizes with one molecule of dichloromethane, shows the presence of close C–H⋯Br/Cl contacts among the ions and solvated molecules. These weak interactions distort, though marginally, the otherwise ideal octahedral shape of the [TeBr 6] − anion adopted as a consequence of stereochemical inertness of the lone pair on the central tellurium atom. The supramolecular extended arrays of ionic molecular units formed by means of solvated head-to-tail linkers are identified.

Synthesis of Novel Quinaldine‐Based Squaraine Dyes: Effect of Substituents and Role of Electronic Factors.

ChemInformVolume 36, Issue 5 Organic Dyes Synthesis of Novel Quinaldine-Based Squaraine Dyes: Effect of Substituents and Role of Electronic Factors. Kuthanapillil Jyothish, Kuthanapillil Jyothish Photosci. Photonics Div., Reg. Res. Lab., CSIR, Trivandrum 695 019, Kerala, IndiaSearch for more papers by this authorKalliat T. Arun, Kalliat T. Arun Photosci. Photonics Div., Reg. Res. Lab., CSIR, Trivandrum 695 019, Kerala, IndiaSearch for more papers by this authorDanaboyina Ramaiah, Danaboyina Ramaiah Photosci. Photonics Div., Reg. Res. Lab., CSIR, Trivandrum 695 019, Kerala, IndiaSearch for more papers by this author Kuthanapillil Jyothish, Kuthanapillil Jyothish Photosci. Photonics Div., Reg. Res. Lab., CSIR, Trivandrum 695 019, Kerala, IndiaSearch for more papers by this authorKalliat T. Arun, Kalliat T. Arun Photosci. Photonics Div., Reg. Res. Lab., CSIR, Trivandrum 695 019, Kerala, IndiaSearch for more papers by this authorDanaboyina Ramaiah, Danaboyina Ramaiah Photosci. Photonics Div., Reg. Res. Lab., CSIR, Trivandrum 695 019, Kerala, IndiaSearch for more papers by this author First published: 11 January 2005 https://doi.org/10.1002/chin.200505171Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume36, Issue5February 1, 2005 RelatedInformation

Density functional study on the role of electronic factors in variation of polymerization activity for Ziegler–Natta catalyst

The role of electronic factors in the variation of activity of Ziegler–Natta (ZN) catalysts having chloride, alkoxy and other ligands for ethylene and propylene polymerization has been investigated using density functional calculations at B3LYP/LANL2DZ level. The barriers for olefin insertion into [TiCl 2CH 3] + for ethylene and propylene are comparable whereas for catalysts with alkoxy and non-alkoxy ligands having varying heteroatoms, the insertion barriers for propylene are about 3–6 kcal/mol higher than the corresponding ethylene insertion barriers. This supports the experimental observation that the propylene polymerization with ZN catalyst having alkoxy and non-alkoxy ligands has very low catalytic activity as compared to that for ethylene polymerization whereas [TiCl 2CH 3] + polymerizes both ethylene and propylene.

Role of electronic factors in the formation of a standard quasi-stable mixture of toxic polychlorinated dibenzo- para-dioxins and polychlorinated dibenzofurans

Only electronic factors are responsible for the kinetics and mechanism of consecutive chlorination of 2,3,7,8-tetrachlorodibenzo- para -dioxin and 2,3,7,8-tetrachlorodibenzofuran; this results in the formation of a standard quasi-stable mixture of chlorination products (congeners), polychlorinated dibenzo- p -dioxins and dibenzofurans, whose composition was independent of the sample type and the place of sampling.

The role of electronic factors in reagents in controlling thestereochemistry of arylsulfenyl chlorides addition

For a series of substituted arylsulfenyl chlorides the stereochemistry of Ad E-reactions with a series of substituted Z- and E-β-deuterostyrenes has been elucidated. Non-stereospecific reaction was observed only for the pair 2,4-dinitrobenzenesulfenyl chloride-p-methoxystyrene; for all the other reactants the reaction proceeded in a strictly stereospecific manner.

Steric and electronic contributions to barriers of internal rotation in 1,8-dibenzoylnaphthalenes

Restricted rotation about the naphthalenylcarbonyl bonds in the title compounds resulted in mixtures of cis and trans rotamers, the equilibrium and the rotational barriers depending on the substituents. For 2,7-dimethyl-1,8-di-(p-toluoyl)-naphthalene ( 1) ΔH° = 3.66 ± 0.14 kJ mol −1, ΔS° = 1.67 ± 0.63 J mol −1 K −1, ΔH ≠ ct = 55.5 ± 1.3 kJ mol −1, ΔH ≠ ct = 51.9 ± 1.3 kJ mol −1, ΔS ≠ ct = −41.3±4.1 J mol −1 K −1 and ΔS ≠ ct = −42.9±4.1 J mol −1 K −1. The rotation about the phenylcarbonyl bond requires ΔH ≠ = −56.9±4.4 kJ mol −1 and ΔS ≠ = −20.5±15.3 J mol −1 K −1 for the cis rotamer, and ΔH ≠ = 43.5Δ0.4 kJ mol −1 and ΔS ≠ =± −22.4Δ1.3 J mol −1 K −1 for the trans rotamer. The role of electronic factors is likely to be virtually the same for both these rotamers but steric interaction between the two phenyl rings occurs in the cis rotamer only. Hence, the difference of the activation enthalpies obtained for the cis and trans rotamers, ΔΔH −1 = 13.4 kJ mol −1, provides a basis for the estimation of the role of steric factors in this rotation. For the tetracarboxylic acid 2 and its tetramethyl ester 3 the equilibrium is even more shifted towards the trans form because of enhanced steric and electrostatic interactions between the substituents in the cis form. The barriers for the rotation around the phenylcarbonyl bond and the cis-trans isomerization are lowered; an explanation for this result is presented.