Journal of Physical Organic Chemistry

Cover image for Vol. 29 Issue 6

Early View (Online Version of Record published before inclusion in an issue)

Editor-in-Chief: Luis Echegoyen

Impact Factor: 1.38

ISI Journal Citation Reports © Ranking: 2014: 37/58 (Chemistry Organic); 98/139 (Chemistry Physical)

Online ISSN: 1099-1395

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  1. 1 - 50
  1. Research articles

    1. Solvent network at the transition state in the solvolysis of hindered sulfonyl compounds

      Mykyta Iazykov, Ludmila Rublova, Moisés Canle L. and J. Arturo Santaballa

      Version of Record online: 27 MAY 2016 | DOI: 10.1002/poc.3588

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      Mechanistic details of X-ArSO2Cl solvolytic processes at sulphur are discussed. Reaction order increases with the molecular volume of the nucleophile and is not related uniquely to the electronic nature of the X group. Alcoholysis is SN2 with cyclic (unbranched alcohols) or linear (branched alcohols) TSs involving a solvent network that mimics a general base catalysis process.

  2. Special issue articles

    1. Halogen bonding in biological context: a computational study of D2 dopamine receptor

      Adriano M. Luchi, Emilio L. Angelina, Sebastián A. Andujar, Ricardo D. Enriz and Nélida M. Peruchena

      Version of Record online: 25 MAY 2016 | DOI: 10.1002/poc.3586

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      Halogen Bond (X-bond) interactions formed by halogenated ligands (LX) at the Dopamine Receptor D2 binding pocket (DRD2) were studied by Molecular Dynamics (MD) and charge density (QTAIM) analysis. The X-bonds were contrasted with the Hydrogen Bond (H-bond) interactions established by hydroxylated analogs (LOH, where X was replaced by OH). The results suggest a possible role of the X-bond as a protein secondary structure modulator because of the ability of the halogen to interact with the protein backbone.

    2. Lipase catalysed conversion of triglycerides to amides in liquid ammonia

      Joseph M. Griffin, John H. Atherton, Michael I. Page and Nicholas T. Powles

      Version of Record online: 25 MAY 2016 | DOI: 10.1002/poc.3583

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      The image shows the use of enzymes in pure liquid ammonia, exemplifying both catalysis and selectivity.

    3. Theoretical investigation of curved π-conjugated fullerene flakes: open-shell character, aromaticity, and third-order nonlinear optical property

      Kotaro Fukuda, Jun-ya Fujiyoshi, Yuka Minamida, Takanori Nagami, Hiroshi Matsui, Soichi Ito, Ryohei Kishi, Yasutaka Kitagawa, Benoît Champagne and Masayoshi Nakano

      Version of Record online: 25 MAY 2016 | DOI: 10.1002/poc.3581

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      Open-shell singlet nature, aromaticity, and second hyperpolarizabilities of two kinds of curved π-conjugated fragments of C60 fullerene, called C60 flakes, together with their corresponding planar analogues are theoretically investigated. It is found (i) that all C60 flakes present larger average static second hyperpolarizabilities (γs) than C60; and (ii) that the curved A-1 flake, having an intermediate diradical character, exhibits the largest γs value, consistently with the y–γ correlation.

  3. Research articles

    1. Gas-phase Acidities of 2-Aryl-2-chloro-1,1,1-trifluoroethanes and Related Compounds. Experimental and Computational Studies

      Masaaki Mishima, José-Luis M. Abboud, Mizue Fujio, Masahiko Suenaga, Heinz F. Koch and Judith G. Koch

      Version of Record online: 25 MAY 2016 | DOI: 10.1002/poc.3576

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      The β-fluorine negative hyperconjugation of the CF3 and C2F5 groups (ΔG0β-F) and electronic effect of the aryl group (GAel) involved in the gas-phase acidities of 1a,b and 2a,b were evaluated. The substituent effects on the GAel and GA values of various aryl-substituted fluoroalkanes were analyzed.

    2. Design, syntheses and photochromic properties of dithienylcyclopentene optical molecular switches

      Chuanming Yu, Bingcheng Hu, Cheng Liu and Jiting Li

      Version of Record online: 20 MAY 2016 | DOI: 10.1002/poc.3584

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      Two kinds of dithenycyclopentenes based on porphyrins were synthesized, and showed favorable photochromic properties and high fatigue resistance. A nondestructive readout method by luminescence tuning was demonstrated in details.

  4. Special issue articles

    1. Cyclopropenimine as pincer ligand and strong electron donor in proton sponges

      Danijela Barić and Borislav Kovačević

      Version of Record online: 19 MAY 2016 | DOI: 10.1002/poc.3579

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      Cyclopropenimines are more basic than the corresponding phosphazenes in the gas phase. Proton sponges based on cyclopropenimines as pincer ligands also possess higher or at least the same gas-phase proton affinity/basicity as proton sponges based on phosphazenes. Recently, estimated theoretical gas-phase basicity limit of 370 kcal mol−1 could be exceeded utilizing cyclopropenimines as substituents in phosphorus carbenes and phosphorus ylides.

  5. Research articles

    1. Synthesis, crystal structure and dielectric properties of C6H18N2SbCl5

      Houda Kharrat, Nizar Elfaleh and Slaheddine Kamoun

      Version of Record online: 19 MAY 2016 | DOI: 10.1002/poc.3577

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      Preparation and crystal structure of a new C6H18N2SbCl5 compound were reported. Thermal analysis and dielectric measurements of C6H18N2SbCl5 were studied. Dielectric dispersion obeys the well-known Universal Power Law (Jonscher's power law). AC conductivity study shows that the material exhibits two conduction mechanisms.

  6. Special issue articles

    1. Nanoenvironmental effect in AOT reverse micelles on the triplet excited state properties of flavins and quenching by molecular oxygen

      Lorena Valle, Faustino E. Morán Vieyra and Claudio D. Borsarelli

      Version of Record online: 19 MAY 2016 | DOI: 10.1002/poc.3575

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      Quenching of triplet excited states of flavins 3F* and singlet oxygen production is governed by nano-environment of the interior of AOT reverse micelles.

  7. Research articles

    1. Cycloaddition of CS2 to N-benzylaziridine to synthesize N-benzylthiazolidine-2-thione: a novel reaction route proposed by DFT Study

      Amritpal Singh and Neetu Goel

      Version of Record online: 13 MAY 2016 | DOI: 10.1002/poc.3578

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      The step by step reaction pathway presents the details of the proposed novel route to pharmaceutically important N-benzylthiazolidine-2-thione through coupling of CS2 with N-benzylaziridine using DFT formalism. Keeping in view the impediments of the limited synthetic route to N-benzylthiazolidine-2-thione, theoretical prediction of synthesizing N-benzylthiazolidine-2-thione through cycloaddition of CS2 with N-benzylaziridine would encourage synthetic chemists to follow the proposed route to an important intermediate in various reactions of pharmaceutical importance.

  8. Special issue reviews

    1. Electrochemical and computational study of the initiation step in the photoinduced electron transfer reaction between sulphur and selenide nucleophiles toward 1-bromonaphthalene

      Lydia M. Bouchet, Adriana B. Pierini, Verónica Brunetti and Juan E. Argüello

      Version of Record online: 10 MAY 2016 | DOI: 10.1002/poc.3568

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      The initiation step of a number of selenium and sulphur centred anions in the photo-substitution reaction toward 1-bromonaphthalene as an aryl halide generic model was investigated experimentally and by means of quantum chemical calculations. Basicity and Eox were also calculated for all the anions finding a good agreement with the experimental reactivity, pKa and oxidation potential.

  9. Research articles

    1. Conformational flexibility of xanthene-based covalently linked dimers

      Marija R. Zoric, Usha Pandey Kadel, Kirill A. Korvinson, Hoi Ling Luk, Arunpatcha Nimthong-Roldan, Matthias Zeller and Ksenija D. Glusac

      Version of Record online: 6 MAY 2016 | DOI: 10.1002/poc.3572

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      The conformational flexibility of covalently-linked xanthene dimers was investigated using NMR spectroscopy, X-ray crystallography, and DFT calculations. The findings are relevant for the modeling of metal-free water oxidation catalysts

  10. Early excellence profiles

    1. Profile: Early excellence in Physical Organic Chemistry

      Stephen M. Goldup

      Version of Record online: 5 MAY 2016 | DOI: 10.1002/poc.3574

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  11. Special issue articles

    1. Proton transfer reactions of a bridged bis-propyl bis-imidazolium salt

      Richard S. Massey, Peter Quinn, Shengze Zhou, John A. Murphy and AnnMarie C. O'Donoghue

      Version of Record online: 5 MAY 2016 | DOI: 10.1002/poc.3567

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      Reaction of a bis-propyl bis-imidazolium di-iodide salt in buffered D2O solution gave complete deuterium exchange with no competing dimerization. The second-order rate constant for deuteroxide-ion catalyst exchange was used to estimate a carbon acid C(2)-H pKa value of 21.2.

  12. Research articles

    1. Characterizations of B and N heteroatoms as substitutional doping on structure, stability, and aromaticity of novel heterofullerenes evolved from the smallest fullerene cage C20: a density functional theory perspective

      Somayeh Soleimani Amiri, Maryam Koohi and Behrooz Mirza

      Version of Record online: 3 MAY 2016 | DOI: 10.1002/poc.3573

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      In this work, effect of B and N heteroatoms on the proposed six BbNnC20-(b + n) analogs are investigated by using density functional theory method.

    2. A paradigm shift in rate determining step from single electron transfer between phenylsulfinylacetic acids and iron(III) polypyridyl complexes to nucleophilic attack of water to the produced sulfoxide radical cation: a non-linear Hammett

      Perumal Subramaniam, Jebamoney Janet Sylvia Jaba Rose and Rajasingh Jeevi Esther Rathinakumari

      Version of Record online: 2 MAY 2016 | DOI: 10.1002/poc.3571

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      The oxidative decarboxylation of phenylsulfinylacetic acids (PSAA) by iron(III) polypyridyl complexes in aqueous acetonitrile is facilitated by both electron-releasing and electron-withdrawing substituents in PSAA. The observed experimental results are rationalized by change in reaction mechanism involving electron transfer from PSAA to polypyridyl complex for electron releasing groups and nucleophilic attack of water on the sulfoxide cation radical for electron-withdrawing groups in the rate determining step. A fair agreement of the experimental data with Marcus theory is observed.

    3. Solution properties of phenothiazine drug promazine hydrochloride with cationic hydrotropes in aqueous/electrolyte solution at different temperature

      Malik Abdul Rub, Naved Azum, Abdullah M. Asiri, Mohie E. M. Zayed and Abdulrahman O. Al-Youbi

      Version of Record online: 2 MAY 2016 | DOI: 10.1002/poc.3570

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      The current work deals with the mixed micellization phenomena of promazine hydrochloride (PMZ) drug with cationic hydrotropes in absence/presence of 50 mmol kg−1 NaCl at different temperature. PMZ is an amphiphilic phenothiazine drug and employed for the cure of mania and schizophrenia. The experimental data were analyzed according to different mixing models. NaCl further reduces the critical micelle concentration of pure amphiphiles and their mixed systems. Thermodynamic parameters favor the process of micellization, which is found to be entropy driven.

  13. Special issue articles

    1. Recent progress in the synthesis of regio-isomerically pure bis-adducts of empty and endohedral fullerenes

      Maira R. Cerón and Luis Echegoyen

      Version of Record online: 2 MAY 2016 | DOI: 10.1002/poc.3563

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      Tethered bis-additions to empty fullerenes work very well to limit the number of regioisomers but are ineffective with endohedral fullerenes

    2. The solvolysis mechanism of simple secondary tosylates in 50% aqueous TFE

      Dian Li and Nicholas H. Williams

      Version of Record online: 2 MAY 2016 | DOI: 10.1002/poc.3559

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      The solvolysis and isomerisation of simple secondary tosylates can be described by a mechanistic scheme involving a common carbenium ion intermediate, but only if the solvent is preorganised for the solvolysis reaction. 1,2-hydride transfer and isotope exchange compete inefficiently with ion return and solvolysis. Alternatively, a series of parallel concerted reactions (solvolysis, 1,2-hydride transfer and isotope exchange) would also account for these data.

  14. Research articles

    1. Comprehensive investigation on the reactivity of triarylphosphine radical cations by laser flash photolysis time-resolved UV–Vis spectroscopy

      Shinro Yasui, Shinjiro Kobayashi and Masaaki Mishima

      Version of Record online: 2 MAY 2016 | DOI: 10.1002/poc.3557

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      Laser flash photolysis time-resolved UV–Vis spectroscopy was performed at 266 nm on an acetonitrile solution of triarylphosphines, Ar3P, under various atmospheres by varying the concentration of Ar3P. The triarylphosphine radical cation, Ar3P•+, which appeared within 100 ns after the laser flash, decayed on a time scale of microseconds according to the first-order kinetics. Dependence of the first-order rate constant on [O2] and [Ar3P] suggests that Ar3P•+ undergoes either a radical coupling with oxygen or an ionic reaction with Ar3P.

  15. Special issue articles

    1. Computational study of substituent effects on the gas-phase stabilities of N-phenylguanidinium ions

      Kazuhide Nakata, Hans-Ullrich Siehl, Gerhard Maas and Mizue Fujio

      Version of Record online: 26 APR 2016 | DOI: 10.1002/poc.3569

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      Relative gas-phase stabilities of ring-substituted N-phenylguanidinium ions were determined at the B3LYP/6-311 + G(2d,p) level of theory, and the substituent effects were analyzed by the Yukawa–Tsuno equation (1). The substituent-effect analyses revealed a very small through-resonance, which was measured by the r+ value in Eqn (1). Natural bond orbitals analyses were adopted to investigate delocalization mechanisms in detail. The mechanisms of stabilization and delocalization caused by the substituents attached to guanidinium ions, which constitute the guanidinium ionic liquids, are discussed.

  16. Research articles

    1. Rate constant measurements for initial addition reactions of radicals at the propagation step of photo-polymerization as studied by pulsed EPR spectroscopy

      Yusuke Miyake, Yutaka Marushima, Hirona Takahashi, Nobuyuki Akai, Kazuhiko Shibuya and Akio Kawai

      Version of Record online: 26 APR 2016 | DOI: 10.1002/poc.3566

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      Pulsed EPR spectroscopy was employed to determine reaction rate constants at an early stage of addition reactions in radical polymerizations triggered by photodissociation. tert-butylacrylate and tert-butylmethacrylate were examined as reactant. Stern–Volmer analysis of decay time of electron spin echo provides the rate constants for the second step reaction between monomer and adduct radical. The rate constant was evaluated by theoretical calculations with (1) enthalpy difference between product radical and reactants and (2) charge transfer interaction between reacting radical and monomer.

  17. Mini reviews

    1. The intriguing class of altan-molecules

      Riccardo Zanasi, Paolo Della Porta and Guglielmo Monaco

      Version of Record online: 26 APR 2016 | DOI: 10.1002/poc.3558

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      Passion flowers are known for their wonderful 10-petal trait and for their fruits. The 10-petal molecule shown, altan-[10]annulene, has been designed in silico to hold a paratropic perimeter. The latter feature is predicted for the whole class of altan-molecules. No molecule of this class has been synthesized yet; however, their anions are predicted to be stable molecules, and their skeleton can be recognized in experimentally known anionic fullerenes.

  18. Special issue reviews

    1. Extremely reactive carbenes: electrophiles and nucleophiles

      Robert A. Moss, Lei Wang, Hui Cang and Karsten Krogh-Jespersen

      Version of Record online: 26 APR 2016 | DOI: 10.1002/poc.3555

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      We analyze trends in the measured activation parameters for the additions of representative electrophilic and nucleophilic carbenes to alkenes.

  19. Research articles

    1. Relative stability and proton transfer reactions of unsaturated isocyanides and cyanides

      Aiko Adamson, Ivari Kaljurand, Jean-Claude Guillemin and Peeter Burk

      Version of Record online: 13 APR 2016 | DOI: 10.1002/poc.3562

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      Relative stability, gas-phase basicity and acidity of seven unsaturated isocyanides and cyanides were investigated and compared. Experimental gas-phase basicity values for isocyanides are presented. We concluded that the substitutions had greater influence to the basicity of cyanide group than for isocyanide group and deprotonation may lead to isomerization of the substituent in some isocyanide and cyanide species.

    2. A generalized reversal model for the solvatochromism of merocyanines

      Marcos Caroli Rezende

      Version of Record online: 8 APR 2016 | DOI: 10.1002/poc.3565

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      Twenty-one examples validate the described model, which relates the molecular structure with the solvatochromic behaviour of merocyanines.

  20. Special issue articles

    1. Synthesis, structure and properties of nitronyl nitroxide diradicals with fused-thiophene couplers

      Evgeny Tretyakov, Keiji Okada, Shuichi Suzuki, Martin Baumgarten, Galina Romanenko, Artem Bogomyakov and Victor Ovcharenko

      Version of Record online: 8 APR 2016 | DOI: 10.1002/poc.3561

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      Fused-thiophenes form planar structures with the stable nitronyl nitroxide spin carriers and they can be adjusted (isomerized or extended with more thiophene rings) to tune the magnetic interaction through their π-skeleton.Diradicals coupled by the fused-thiophenes demonstrate two one-electron reversible electrochemical oxidation peaks and two-electron quasi-reversible reduction peaks resulting in the formation of the corresponding dication or dianion.

    2. The structure of electronically excited α,β-unsaturated lactones

      Maxime Fréneau, Pascal de Sainte-Claire, Manabu Abe and Norbert Hoffmann

      Version of Record online: 6 APR 2016 | DOI: 10.1002/poc.3560

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      A better knowledge of the structure of the electronically excited state of substrates is indispensable for the understanding and optimization of photochemical reactions. For this study, triplet energies of a variety of α,β-unsaturated γ-lactones (furanones) as well as the structures of the vibrationally relaxed triplet state (T1) have been determined using ab initio coupled-cluster (CCSD) method and/or density functional theory (DFT) calculation. A twist of the original planar structure around C = C bond is found in the relaxed triplet state, π-π*. In the 5-membered ring of furanones the contribution of this mode is limited and the pyramidalization in the C4 position also contributes to the stabilization. The contribution of each stabilization mode is characterized by the dihedral angles and the Mulliken atomic spin densities. The substituent effect on the pyramidalization and the spin density distribution in the C4 and in the C5 position are reported. Depending on the substitution in the C4 position, the orientation of the pyramidalization is either favored syn or anti with respect of the hydroxyl substituent in the C5 position.

  21. Research articles

    1. Role of charge transfer on the nonlinear optical properties of donor-π-acceptor (D-π-a) conjugated schiffbases with DFT approach

      Sivalingaraj Vijayalakshmi and Subramanian Kalyanaraman

      Version of Record online: 31 MAR 2016 | DOI: 10.1002/poc.3556

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      Even though the studied Schiff base molecules possess a large value of first-order hyperpolarizability at the molecular level, owing to a lack of charge transfer across the donor–acceptor conjugated system, they exhibit a lower value of second harmonic generation at the solid state. In the case of the third-order nonlinear optical property, the presence of the strongest donor plays a vital role in determining the large value of second-order hyperpolarizability.

  22. Special issue articles

    1. The effect of the structure of the cation of an ionic liquid on the rate of reaction at a phosphorus centre

      Bradley J. Butler and Jason B. Harper

      Version of Record online: 31 MAR 2016 | DOI: 10.1002/poc.3554

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      Ionic liquids containing different cations were shown to increase the rate constant for the reaction of ethanol-d6 with diethyl chlorophosphate. The effect varies significantly with proportion of the ionic liquid in the reaction mixture. For all the ionic liquids considered, the effects were similar and driven by a decrease in activation enthalpy; the magnitude of the effect depended, to some extent, on the accessibility of the charged centre(s) on the cation; less bulky cations facilitated the greatest increase in rate constant.

  23. Research articles

    1. Investigation of the rheological properties of protic ionic liquids

      Danillo Camargo, Rebecca S. Andrade, Gicelia A. Ferreira, Helen Mazzer, Lúcio Cardozo-Filho and Miguel Iglesias

      Version of Record online: 29 MAR 2016 | DOI: 10.1002/poc.3553

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    2. A new fluorescent sensor for Zn2+ based on diarylethene with a 4-diethylamino-salicylaldehyde Schiff base unit

      Zhaoyan Tian, Shiqiang Cui, Gang Liu, Renjie Wang and Shouzhi Pu

      Version of Record online: 22 MAR 2016 | DOI: 10.1002/poc.3552

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      A new diarylethene with a 4-diethylamino-salicylaldehyde Schiff base unit was synthesized, and its dual-controllable switching properties were investigated by the stimulation of light and chemical species. Moreover, the diarylethene can serve as a fluorescence sensor for highly selective and sensitive recognition of Zn2+ in methanol.

    3. N-Chlorination rate of five-membered heterocyclic nitrogen compounds

      Cristina Pastoriza, Juan Manuel Antelo, Francisco Andrés Amoedo and Mercedes Parajó

      Version of Record online: 18 MAR 2016 | DOI: 10.1002/poc.3545

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      The set of compounds studied in this paper is characterized by having different functional groups and the same cyclic structure, consisting of a fivemember ring with a nitrogen atom in the ring which is suspectible to be chlorinated. The kinetic studies allow us to know like the presence of an ammo, amide or imide group modify the reactivity of nitrogenous compound.

    4. Influence of the side-group at C=N bridging bond of bis-aryl Schiff bases on the wavelength of absorption maximum of ultraviolet absorption spectra

      Qingqing Luo, Chao-Tun Cao, Zhongzhong Cao and Chenzhong Cao

      Version of Record online: 16 MAR 2016 | DOI: 10.1002/poc.3550

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      The influence of the side-group attached to the C=N bridging bond of bis-aryl Schiff bases XArCH=NArY on the νmax of UV is different. The side-group CH3 makes the effect of σ(X) larger than that of σ(Y) on the νmax, whereas the O atom makes the effect of σ(Y) larger than that of σ(X) on the νmax. The cross-interactions of the CH3 versus X/Y and the O versus X/Y have not important effect on the νmax.

  24. Special issue articles

    1. Rapid cleavage of phosphate triesters by the oxime 2-(hydroxyimino)-N-phenyl-acetamide

      Alex M. Manfredi, Willian Demos, Eduardo H. Wanderlind, Bárbara V. Silva, Angelo C. Pinto, Bruno S. Souza and Faruk Nome

      Version of Record online: 4 MAR 2016 | DOI: 10.1002/poc.3549

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      A rapid rate of dephosphorylation of toxic organophosphates promoted by an oxime was observed in aqueous solution, which could lead to the development of applicable antidotes for human poisoning by organophosphorus compounds.

  25. Research articles

    1. Aggregation behavior of amphiphilic drug promazine hydrochloride and sodium dodecylbenzenesulfonate mixtures under the influence of NaCl/urea at various concentration and temperatures

      Dileep Kumar and Malik Abdul Rub

      Version of Record online: 3 MAR 2016 | DOI: 10.1002/poc.3546

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      Aggregation phenomenon of promazine hydrochloride (PMZ) and sodium dodecylbenzenesulfonate (SDBS) mixtures in absence and presence of 50 mmol·kg−1 NaCl/300 mmol·kg−1 urea was investigated conductometrically at different temperatures. The critical micelle concentration values have been evaluated and defined in terms of hydrophobicity and hydrophilicity of PMZ and SDBS in aqueous and non-aqueous solutions. Various physicochemical parameters have been evaluated and discussed in detail. All outcomes obtained herein show attractive interactions in the mixtures of PMZ and SDBS.

  26. Special issue articles

    1. Diketopyrrolopyrrole assembly into J-aggregates

      Yujia Zhou, Carmen X. Guzman, Lance C. Helguero-Kelley, Chuan Liu, Samuel R. Peurifoy, Burjor Captain and Adam B. Braunschweig

      Version of Record online: 2 MAR 2016 | DOI: 10.1002/poc.3548

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      Variable temperature ultraviolet-visible titrations, X-ray crystallography, and computational approaches demonstrate that the organic dye diketopyrrolopyrrole assembles isodesmically into J-aggregates. Mathematics is described to estimate mean stack size at a given concentration and temperature.

  27. Research articles

    1. Understanding the molecular mechanism of the [3 + 2] cycloaddition reaction of benzonitrile oxide toward electron-rich N-vinylpyrrole: a DFT study

      Luis R. Domingo, Saeedreza Emamian, Majid Salami and Mar Ríos-Gutiérrez

      Version of Record online: 23 FEB 2016 | DOI: 10.1002/poc.3544

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      The complete regioselective [3 + 2] cycloaddition reaction of BNO 2 toward NVP 3a in the presence of dichloromethane takes place via a non-concerted two-stage one-step molecular mechanism confirmed by the electron localization function quantum topological analysis.

    2. pH-controlled reaction divergence of decarboxylation versus fragmentation in reactions of dihydroxyfumarate with glyoxylate and formaldehyde: parallels to biological pathways

      Christopher J. Butch, Jing Wang, Jiande Gu, Rebeca Vindas, Jacob Crowe, Pamela Pollet, Leslie Gelbaum, Jerzy Leszczynski, Ramanarayanan Krishnamurthy and Charles L. Liotta

      Version of Record online: 23 FEB 2016 | DOI: 10.1002/poc.3542

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      A simple pH switch causes a strict divergence of decarboxylation or fragmentation reaction of a common intermediate, leading to distinct classes of products. Such a strict control exerted by a change of pH over reaction pathways and the nature of product formation seems to parallel the precise control exhibited by enzymes over analogous metabolic reactions.

    3. Piperidine-appended imidazolium ionic liquids as task-specific catalysts: computational study, synthesis, and multinuclear NMR

      Kenneth K. Laali, Arezu Jamalian and Gabriela L. Borosky

      Version of Record online: 23 FEB 2016 | DOI: 10.1002/poc.3541

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      Imidazolium ionic liquids (IMILs) with a piperidine moiety appended via variable length methylene spacers (with n = 1–4) were studied computationally to assess their potential to act as internal base.

    4. A DFT study of reduction of nitrobenzene to aniline with SnCl2 and hydrochloric acid

      Shinichi Yamabe and Shoko Yamazaki

      Version of Record online: 18 FEB 2016 | DOI: 10.1002/poc.3543

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      A fundamental reduction reaction, nitrobenzene to aniline in the SnCl2 and hydrochloric acid, was investigated by density functional theory calculations. Starting from nitrobenzene, six elementary processes were found to arrive at the protonated aniline. The hydride ion from Cl4SnH– is connected to the cationic nitrogen, and the proton is to oxygens in those processes.

    5. A high-level theoretical study into the atmospheric phase hydration, bond dissociation enthalpies, and acidity of aldehydes

      Sierra Rayne and Kaya Forest

      Version of Record online: 12 FEB 2016 | DOI: 10.1002/poc.3539

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      High-level CBS-Q//B3, G4(MP2), and G4 composite method calculations were used to estimate atmospheric phase hydration equilibrium constants, bond dissociation enthalpies, and enthalpies and free energies of aldehydic proton acid dissociation for various substituted aldehydes with electron withdrawing and electron releasing groups. Correlations with various substituent constants were found, thereby allowing extension of the models towards all possible aldehyde substituents.

    6. Experimental (FT-IR) and theoretical (DFT) studies on prototropy and H-bond formation for pyrazine-2-amidoxime

      Angelika Głębocka, Ewa D. Raczyńska, Agnieszka Chylewska and Mariusz Makowski

      Version of Record online: 4 FEB 2016 | DOI: 10.1002/poc.3538

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      Structural studies with the use of both experimental and theoretical methods on pyrazine-2-amidoxime (PAOX) were shown and discussed. All possible and stable tautomeric forms [(including, for each tautomer, all possible configurations and conformations (isomers-rotamers)] of PAOX were considered. It was found that PAOX formed the intermolecular hydrogen bond with HMPA. The energy barriers of the transitions from the Z(A1) to E(A7) and A1 to A5 conformations, respectively, were computed. These values confirmed that A1 was also found thermodynamically stable.

  28. Special issue articles

    1. Kinetics and mechanism of the reaction between 3-methylbenzenediazonium ions and catechol

      Katarzyna Jaszczuk, Anna Dudzik, Sonia Losada-Barreiro, Marta Szymula, Jolanta Narkiewicz-Michalek and Carlos Bravo-Díaz

      Version of Record online: 28 JAN 2016 | DOI: 10.1002/poc.3536

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      The non-zeron, pH dependent, intercepts of the saturation kinetics suggest a mechanism of the type.

    2. Properties of AOT reverse micelle interfaces with different polar solvents

      M. Alejandra Luna, N. Mariano Correa, Juana J. Silber, R. Dario Falcone and Fernando Moyano

      Version of Record online: 25 JAN 2016 | DOI: 10.1002/poc.3535

  29. Special issue reviews

    1. Chemistry and photochemistry of natural plant pigments: the anthocyanins

      Volnir O. Silva, Adilson A. Freitas, António L. Maçanita and Frank H. Quina

      Version of Record online: 20 JAN 2016 | DOI: 10.1002/poc.3534

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      Anthocyanins, the naturally occurring plant pigments responsible for the red, blue, and purple colors of the majority of fruits, flowers, and leaves, exhibit complex pH-dependent ground-state chemistry and, in the excited state, ultrafast photophysical and photochemical deactivation processes consistent with the proposed biological role of anthocyanins in protecting leaves from excess solar radiation.

  30. Special issue articles

    1. Cyclodextrin-based [2]pseudorotaxane formation studied by probe displacement assay

      Miguel Quiroga, Marcia Pessêgo, Mercedes Parajo, Pedro Rodriguez-Dafonte and Luis Garcia-Rio

      Version of Record online: 23 DEC 2015 | DOI: 10.1002/poc.3518

      Thumbnail image of graphical abstract

      Displacement assays from the CD cavity allow kinetic studies on inclusion of added guests.

    2. Aromatic nucleophilic substitution in aprotic solvents using hydrogen-bonded biological amines. Kinetic studies and quantum chemical calculations

      Cecilia E. Silvana Alvaro, Federico D. Bergero, Federico M. Bolcic, Susana B. Ramos and Norma Sbarbati Nudelman

      Version of Record online: 22 DEC 2015 | DOI: 10.1002/poc.3519

      Thumbnail image of graphical abstract

      Kinetic studies on aromatic nucleophilic substitution where the nucleophiles are amines that can set specific hydrogen bonding in toluene due to their special molecular structures are reported. An additional strong support to the dimer nucleophile mechanism is provided by the quantum chemical calculations on monomers and dimers that show that the calculated order in dimer stability is nicely correlated with kinetic results and strongly indicates that these studies are useful to enlighten the type of mechanism occurring in aprotic solvents.

  31. Mini reviews

    1. Formation and mechanism for reactions of ring-substituted phenonium ions in aqueous solution

      Yutaka Tsuji and John P. Richard

      Version of Record online: 30 NOV 2015 | DOI: 10.1002/poc.3510

      Thumbnail image of graphical abstract

      Ring-substituted phenonium ions are highlighted as early examples of bridging intermediates of solvolysis reactions at aliphatic carbon. Results from recent studies on the lifetime and the mechanism for nucleophilic substitution at these cations are reviewed.

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