Journal of the Chemical Society Perkin Transactions 2 (Perkin Trans 2 )

Publisher: Royal Society of Chemistry (Great Britain)

Description

Perkin Transactions 2 is a major international journal containing important high quality work in the field of physical organic chemistry. It covers physicochemical aspects of organic, organometallic, bioorganic and supramolecular chemistry, including kinetic, mechanistic, structural, spectroscopic, and theoretical studies. Such topics include structure-activity relationships and physical aspects of biological processes and of the study of polymers and biological macromolecules. Times to publication, for full papers, are typically 150 days from receipt of manuscript. Perkin Transactions 2 contains a Communications section for chemists requiring urgent publication of preliminary results in all areas of physical organic chemistry. Publication times are ca. 60-80 days from receipt. In 2001 Perkin Transactions 2 will introduce reviews. These reviews will be critical overviews of recent advances in a particular area and are aimed to define the scope of the journal. Contributions will normally be commissioned by an appointed member of the Editorial Board, but the Board welcomes proposals for reviews. In such cases we request that authors submit a synopsis of the review to the Editorial Office for consideration by the Board. Alternate ISSN: 1472-779X.

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  • Website
    Perkin Transactions 2 website
  • Other titles
    Journal of the Chemical Society. Perkin transactions. 2, Perkin transactions two, Perkin transactions 2, Perkin 2, Journal of the Chemical Society
  • ISSN
    1364-5471
  • OCLC
    37104095
  • Material type
    Document, Periodical, Internet resource
  • Document type
    Internet Resource, Computer File, Journal / Magazine / Newspaper

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: The novel N-aryl-2,5-dimethylpyrrole-3-carbaldehydes (1)–(7) have been synthesized by condensation of hexane-2,5-dione with the appropriate aniline and subsequent Vilsmeier–Haack formylation of the pyrrole ring. Diastereoisomeric association complexes of these racemic pyrroles were studied by 1H n.m.r. spectroscopy chemical shifts and the splittings induced by the optically active auxiliary compound (+)-Eu(hfbc)3. Separation of the enantiomers of (6) was achieved by liquid chromatography on triacetylcellulose. The barrier to partial rotation about the C–N bond in (6) was determined and their lower limits in (2) and (4) were estimated by variable temperature 1H n.m.r. spectroscopy.
    Journal of the Chemical Society Perkin Transactions 2 05/2013; 1:713-717.
  • Journal of the Chemical Society Perkin Transactions 2 05/2013; 1:2059-2062.
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    ABSTRACT: Tertiary (2-propyl)cyclopentyl and (2-propyl)cyclohexyl carbocations were investigated by 13C NMR spectroscopy in superacid solution. Both ions undergo fast nondegenerate 1,2-hydride shifts to the corresponding 2-cycloalkyl-2-propyl cations. The direction of these equilibria depends on the size of the ring. The more stable isomer of the (2-propyl)cyclopentyl cation has the formal positive charge at the endocyclic carbon atom, while the more stable isomer of the (2-propyl)cyclohexyl cation has the formal charge at the exocyclic carbon atom. The dynamic NMR results were confirmed by NMR spectroscopic measurement of the equilibrium isotope effects and rationalized by quantum chemical calculations.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: Condensation of triformylmethane (TFM) with adenosine has been studied in pyridine and aqueous dioxane. One 1 ∶ 1 (2) and two 2 ∶ 1 (6 and 7) TFM–adenosine adducts were isolated. The structural assignment of these products by 1H and 13C NMR and UV spectroscopy and MS spectrometry suggested that the appearance of the 2 ∶ 1 adducts is connected to a competitive self-condensation of TFM, the stable end product of which is benzene-1,3,5-tricarbaldehyde. The intermediates on the reaction pathway can be reacted with adenosine affording a new procedure for nucleic acid base modification. The mechanisms of formation and the role of intramolecular hydrogen bonding in stabilization of cyclic adenosine adducts are discussed.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: Despite the great number of 4,5-dihydro-1H-1,2,3-triazoles synthesized, 15N NMR data of these heterocycles are extremely rare. The aim of this paper is to present such data and examples of their application. The compounds investigated have been synthesized according to the given references or procedures. Their 15N NMR spectra were measured at natural abundance. For some compounds, the chemical shift assignments were confirmed with the help of 15N labelled material. The influences on 15N chemical shifts of substitution pattern, solvent and concentration were investigated. Additionally, some lanthanide induced shift (LIS) investigations were performed. 13C labelled compounds were employed as tools to provide the assignment of tautomeric structures.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: 1H NMR measurements of a series of ortho-phenyl substituted 3-aryl-2-cyano-5,5-bis(alkylthio)- (3h), 3-aryl-2-cyano-5-alkylthio-5-dialkylamino- (4h, 5) and 3-aryl-2-cyano-5,5-bis(dialkylamino)penta-2,4-dienenitriles (6) with prochiral groups showed the rotation about the C-3–C-aryl bond to be hindered within the NMR timescale. The activation parameters of this atropisomerization process are discussed with respect to steric effects of substituents. The rotation barriers correlate with bond lengths and angles as determined by X-ray structure analyses.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: A series of seven alkyl-substituted benzonitriles was investigated as a model for small steric effects (van der Waals tension) excluding any steric inhibition due to resonance. The energies were calculated at a B3LYP/6-311+G(d,p) level and the gas-phase basicities of some compounds were measured by Fourier-transform ion cyclotron resonance. Substituent effects were evaluated separately for neutral molecules and protonated forms by means of isodesmic reactions, and dissected into polar and steric effects by comparing ortho and para derivatives. One or two ortho methyl groups have a relatively small steric effect operating almost exclusively in the protonated form which leads to weakened basicity. An ortho tert-butyl group exerts a strong steric effect both in the protonated and nonprotonated forms, manifested also in a rather strong distortion of geometry. The effect on basicity is then a small difference of two large values and is base strengthening. Acid–base properties are in such cases a poor measure of substituent effects and cannot be interpreted in simple terms.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: Photolysis of p-toluidides of methacrylic (1a) and cyclohex-2-enecarboxylic (1b) acids in nitrogen-saturated cyclopentane solution yields the corresponding 2-quinolones with over 90% chemoselectivity at almost complete conversion. In the presence of substoichiometric amounts (0.1 equivalents) of chiral inductor, low to moderate enantiomeric excesses (ee) are observed in the photo-product. Ephedrine gave the highest ee (37% ee for the photocyclization of 1a) in a series of 11 chiral inductors including alcohols, amines, aminoalcohols, α-amino and α-hydroxy acids. In the case of the irradiation of 1b in the presence of chiral inductors, both diastereo- and enantioselectivity were observed. A weakly absorbing transient species (λmax 400 nm) was detected following 308 nm laser excitation and was assigned to the zwitterionic enolate intermediate resulting immediately after the concerted electrocyclic ring closure. The lifetime of this intermediate is unaffected by oxygen but is quenched by trifluoroacetic acid (kq = 3.76 × 107 M−1 s−1) and ephedrine (kq = 1.19 × 107 M−1 s−1).
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: Rate constants and activation parameters for the reactions of the 2-nitrobenzoate and 2,6-dichlorobenzoate ions with ethyl iodide have been determined in acetonitrile–methanol mixtures. The activation parameters for the two reactions indicated different responses to solvent compositions. Single-ion enthalpies of transfer for the two anions have also been determined in the same solvent mixtures and on the basis of the results single-ion enthalpies of transfer for the transition-state anion for the two reactions have also been calculated and separated into their components. By empirical analysis of the transfer enthalpies due to the “more physical” interaction for the transition-state anion, ΔtHPHYSAN→MeOH (TS−), the approach of solvent molecules to the α-carbon atom and the central carbon atom in carboxylate group in the carboxylate ion, together with the number of partial dipoles in the anion, have been suggested to account for the various transfer enthalpies.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: The rate constants of the oxidation of N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPPD) are measured in water by means of stopped-flow techniques using different inorganic ions, like Fe(CN)63−, MnO4−, Co(NH3)63+, Ru(OH)3+6. The rates do not depend on the different oxidation potentials, but can be correlated well with calculated rate constants from the Marcus cross-relation.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: The syntheses of three cyclic dithiatetraynes 4–6 with the sulfur atoms in propargylic positions are reported. Their structural features have been studied by means of X-ray analysis on single crystals. Additionally, six cyclic octathiatetraynes 15–20 with sulfur atoms in α,α′-positions to the triple bond have been prepared. The structures of 15 and 17 have been elucidated by means of X-ray analysis. These macrocycles exhibit an ellipsoidal geometry dominated by the stiff triple bond moieties. In the case of 4 a three-dimensional columnar structure is found, demonstrating the unique features of the potential cavities.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: The conformations and vibrational spectra of bis(2-hydroxyphenyl)methane have been analysed within the framework of density functional theory. The calculated force fields (B3LYP/6-31G*) of seven possible energy minima were transformed to internal coordinates, and a set of ten different scaling factors was applied. The scaled quantum mechanical (SQM) method reproduces the experimental IR and Raman spectra with high accuracy. The dependence of the CH2 stretching vibrations on the conformation and the possibility of its use as a probe for larger systems, e.g., calixarenes or polyphenols, are discussed.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: Structural models for self-assembled dimers composed of two urea calix[4]arenes which entrap benzene or cyclohexane are developed using Fourier transform infrared (FTIR) spectroscopy. Based on the host–guest ratio determined by 1H NMR spectroscopy in solution, and confirmed for the solid state by a thermogravimetric analysis, it is possible to prove by a comparison of the FTIR data of host, guest, complex and model compounds, that the capsule is held together by a cyclic array of weak and strong hydrogen bonds between the urea units attached at the wide rim of the calixarenes. The dimerization of the two urea units leads to a loss of symmetry, and an averaged C4 symmetrical arrangement is probable. Guest molecules, such as benzene or cyclohexane, are enclosed inside the container rotating fast on the IR timescale around a longitudinal axis of the guest. From the observed splitting of absorption bands upon dimerization and inclusion it follows that either two crystallographically independent types of capsules exist in the crystal lattice or that the guests are occupying two major orientations in the capsule. As indicated by a higher complexation induced shift for cyclohexane, this guest exhibits a tighter interaction with the host molecules compared to benzene.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: The ion transport ability in a planar phospholipid bilayer, of two p-tert-butylcalix[4]arene-crown-5 derivatives (1, 2), a p-tert-butylcalix[5]arene ester 3, dibenzo-18-crown-6, and valinomycin have been investigated using a voltage clamp method. Membrane current measurements showed that the synthetic calixarene ionophores except for dibenzo-18-crown-6, show ion transport activities for K+ in the bilayer membranes. The order of K+ transport activities of the compounds was valinomycin >1 > 3 > 2. From the measurements of reversal potentials, the relative ion permeability across the bilayer was determined for 1, 3 and valinomycin. Both 1 and 3 showed ion transport selectivity for K+, while valinomycin showed ion transport selectivity for Rb+. Among the calixarene ionophores, compound 1 showed the highest K+ conductivity and K+/Na+ selectivity. Although the K+/Na+ selectivity of 1 is less than that of valinomycin by a factor of ca. 2, calix[4]arene-based ionophore 1 has the potential for use as a synthetic K+ carrier in phospholipid bilayer membranes.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: Covering: 1996–2001
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: A range of axially substituted silicon phthalocyanines has been synthesised using various carboxylates as the ligands. 4-tert-Butylbenzoic acid gives rigid, orthogonal axial substituents, whilst a thiophene-containing bis-acetate was conformationally more flexible. Varying the aromatic substituents of phenylacetic acids gave phthalocyanines with altered spectroscopic properties, and changes in the alkyl chain length between the phthalocyanine and the aromatic nucleus of the ligand induced variations in the fluorescence lifetime and quantum yield. Three X-ray crystal structures of axially substituted silicon phthalocyanine bis-esters have been determined.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: In this paper absorption and fluorescence spectra and emission quantum yields and lifetimes of the red colorants, carminic acid and its metal complex, carminic lake, were studied in solution and on painted surfaces. Accelerated photo-aging of carminic acid and lake was investigated in solution, in the presence and absence of a binder (arabic gum) commonly used in water-colour painting, while natural ageing was followed for several months on water-colour painted paper.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: The equilibrium constants for the association of a fluorinated alcohol, 1,1,1,3,3,3-hexafluoropropanol with amino acid and peptide derivatives dissolved in methylene chloride were calculated. The mathematical approach for the determination of the equilibrium constant KOH is based on the decrease of the integral intensity of the OH stretching signal in the infrared spectrum. Alternatively, the decrease of the intensities of the acceptor signals can be used for the calculation of individual equilibrium constants KZ, KPeptide and KEster, for the association of the alcohol on the urethane, peptide and ester function, respectively. The equilibrium constants obtained with both approaches for a number of amino acid, di- and tripeptide derivatives will be discussed. Generally, in no case was the ester function involved in a complex formation with the fluorinated alcohol. For most examples the association constant for the peptide function was larger than for the urethane group. The investigation of the effect of the variation of the concentration on the equilibrium constant shows that up to a ratio cA0/cB0 of the initial concentrations of the alcohol, cA0, and the acceptor compound, cB0, equal to 10, no formation of 1 ∶ 2 or 1 ∶ 3 associates need to be considered.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: Reaction of freshly prepared C60Cl6 (from chlorination of [60]fullerene by ICl in benzene) with methyllithium followed by hydrolysis and work-up including HPLC separation yields Cs symmetry C60Me6 (isostructural with C60Br6 and C60Cl6), together with unsymmetrical C60Me12 which is comprised of two of the motifs present in C60Me6 and must arise from the presence of a small amount of C60Cl12 in the C60Cl6. From the same reaction mixture we have also obtained C60Me5Cl [isostructural with C60Ar5Cl and C60(OR)5Cl], hydroxyepoxides [C60Me5O2OH (symmetrical), C60Me5OOH and C60Me4PhO2OH (both unsymmetrical)] and unsymmetrical C60Me5O3H (a cage-opened ketone). The results provide further information concerning the addition patterns and mechanistic features of fullerene chemistry, show that methylated, arylated, alkoxylated and halogenated [60]fullerenes are isostructural, and that C60Cl6 also contains traces of C60PhCl5. Some of the compounds give exceptionally high intensities of the C58+ fragmentation ion during EI mass spectrometry.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;
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    ABSTRACT: The anthracene based fluorescent PET chemosensor 1 and the azo-dye based chemosensor 2 show high selectivity for Na+ over other alkali and alkaline-earth metal cations in the 12–300 mM concentration range in 50 ∶ 50 MeOH–H2O at pH 7.4. Chemosensor 1 shows fluorescence ‘off-on’ switching upon Na+ complexation with λFmax of 440 nm and a log βNa of 2.5 (±0.05) and a pKa of 5.3 with no concomitant changes in the absorption spectra. Conversely, 2 displays only a weak fluorescent emission at around 520–640 nm, and large changes in its absorption spectra upon addition of Na+, with a log βNa of 1.25 (±0.05) and a pKa of 3.9. In 100% water the sensitivity of 2 for Na+ was somewhat lower with a log βNa of 0.8 (±0.05). The crystal structure of 2, and its corresponding protonated form (2·H+) were obtained, showing 2 in its trans conformation with the crown ether moiety at a 75° angle to the plane of the chromophore. These results, in conjunction with 1H NMR measurements of 2, and UV–VIS measurements of the ion receptor 3, suggest that upon complexation of Na+, the 2′-methoxy group of the crown receptor participates in the Na+ complexation through chelation to the Na+ ion. We propose that this interaction forces the amine moiety of the crown ether to twist out of the plane of the chromophore, inducing loss of conjugation which gives rise to large Na+-induced spectral changes in the absorption spectra, which are most noticeable for 2.
    Journal of the Chemical Society Perkin Transactions 2 12/2002;

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