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The observation of ready deprotonation of the phenylogous enol of benzodifurantrione (BDT) to give a bright violet conjugate base has led to two follow up explorations. Extension of BDT enol by insertion of a p-phenylene unit into the enol C-O bond gives the known bright red 4-hydroxylated benzodifuranone dyes. Their deprotonation results in previously unreported near infrared-absorbing conjugate bases. These appear to aggregate in solution, the more so in less polar solvents. Ring-opened derivatives of BDT containing alpha-dicarbonyl substituents also give coloured conjugate bases, but alpha-keto-ester and -anilide derivatives differ substantially (ester yellow; anilide intense red). Investigation of this nonintuitive difference leads to the conclusion that while the anilide is essentially planar the ester is nonplanar. The contrast in conformation impacts on the auxochromic effects of the otherwise closely related alpha-dicarbonyl substituents and thus the variation in colour. The latter observation has potential across colour chemistry in general. In contrast to the readily observed BDT enol, no evidence has been adduced for enol tautomers amongst the ring-opened analogues.

We conducted a survey on Zika virus perceptions and behaviors during the 2016 outbreak in Miami-Dade County, Florida, USA. Among women, Zika knowledge was associated with having a bachelor’s degree. Among men, knowledge was associated with knowing someone at risk. Interventions during future outbreaks could be targeted by sex and education level.

The new computer-aided synthesis design tool ICSYNTH has been evaluated by comparing its performance in predicting new ideas for route design to that of historical brainstorm results on a series of commercial pharmaceutical targets, as well as literature data. Examples of its output as an idea generator are described, and the conclusion is that it adds appreciable value to the performance of the professional drug research and development chemist team.

The dyes Nile Blue (C. I. Basic Blue 12, NB) and Thionine (C. I. 52000, TH) were examined in both ionic and neutral forms in different solvents using NMR and UV-visible Spectroscopy to firmly establish the structures of the molecules and to assess the nature and extent of their aggregating characteristics. 1H and 13C NMR assignments and chemical shift data were used along with (for NB) nuclear Overhauser effect information enabling a structure for self-assembly to be proposed. In both cases these data were supplemented with variable temperature, dilution and diffusion-based experimental results using 1H NMR spectroscopy thereby enabling the extended aggregate structures to be assessed in terms of the relative strength of self-association and the extent to which extended aggregates could form. Full and detailed solution phase NMR analysis of such dyes, especially the two studied in this context, have either not been widely reported or have not been studied to the depth presented here. The data and their interpretation form an important addition to the analysis of this class of dye compounds and provide additional insight into the effects of self-assembly on the behaviour of such molecules in various solution-phase environments.

A detailed study of the action of alkali on methylene blue (C.I. Basic Blue 9) and other thiazine dyes was carried out through a combination of UV/visible spectroscopy, thin layer chromatography, mass and NMR spectrometry and computational methods. In 0.1 M aq alkali solution, methylene blue forms a highly coloured, lipophilic species that is mainly Bernthsen's methylene violet i.e. a hydrolysis decomposition product, this being contrary to the report of a red N-hydroxy methylene blue adduct. The nature of the heterocyclic nitrogen atom in C.I. Basic Blue 9 is discussed and it is concluded there is no basis for the proposal of nucleophile addition at this site of the dye. In contrast, other thiazine dyes are deprotonated by alkali to form their neutral, highly coloured, lipophilic conjugate base forms.

The first example of a stable phenylogous enol, resulting from an extended keto-enol tautomerization across a benzene ring, is described. The enol has been isolated, and its structure was proven by X-ray crystallography. The equilibrium between the keto- and enol-tautomers has been extensively studied and quantified in solution by NMR and UV-vis spectroscopy. The position of equilibrium showed a linear correlation to the Kamlet-Taft solvatochromic scale for solvent H-bond acceptor strength (beta(OmicronEta)), and the equilibrium was proven to be fully dynamic, obeying first-order equilibrium kinetics. To attempt to explain why enolization occurs, at what surprisingly appears to be the expense of aromatic resonance stabilization, various structural features have been considered and explored further with the aid of MO calculations. Nucleus independent chemical shift (NICS) index of aromaticity calculations for each of the rings comprising both tautomers showed that while the central benzene ring loses aromaticity on enolization, the alpha-keto-lactone ring showed an unexpected and significant antiaromaticity in the keto-tautomer, which is by no means intuitive. The loss of stabilization energy associated with the central benzene ring is, therefore, to a certain degree compensated by removal of the antiaromatic destabilization of the alpha-keto-lactone ring rendering the two structures much closer in energy than would otherwise be expected.

Pre-formed transition metal-NHC complex is shown to be an effective catalyst for Atom Transfer Radical Cyclisation (ATRC) reactions. © 2007 Elsevier Ltd. All rights reserved.

A sulfonated o-acetylamino arylazo compound unexpectedly cyclised to a cationic benzo-1,2,4-triazinium species under thermal or acid conditions, reversible with base. The same substrate underwent trans to cis-azo photoisomerisation, observable by NMR spectroscopy, under steady state laser irradiation conditions.

Single crystal X-ray diffraction structures of two simple bis(guanidinium) sulfates that have previously been shown to recognise oxoanions in solution are reported. Comparison of these solid state structures with previous data suggests a relationship between increasing ligand planarity (preorganisation) and internal sulfate complexation, the greatest degree of preorganisation resulting in formation of a discrete 1 ∶ 1 host–guest complex.

Background Zika virus transmission dynamics in urban environments follow a complex spatiotemporal pattern that appears unpredictable and barely related to high mosquito density areas. In this context, human activity patterns likely have a major role in Zika transmission dynamics. This paper examines the effect of host variability in the amount of time spent outdoors on Zika epidemiology in an urban environment. Methodology/Principal findings First, we performed a survey on time spent outdoors by residents of Miami-Dade County, Florida. Second, we analyzed both the survey and previously published national data on outdoors time in the U.S. to provide estimates of the distribution of the time spent outdoors. Third, we performed a computational modeling evaluation of Zika transmission dynamics, based on the time spent outdoors by each person. Our analysis reveals a strong heterogeneity of the host population in terms of time spent outdoors–data are well captured by skewed gamma distributions. Our model-based evaluation shows that in a heterogeneous population, Zika would cause a lower number of infections than in a more homogenous host population (up to 4-fold differences), but, at the same time, the epidemic would spread much faster. We estimated that in highly heterogeneous host populations the timing of the implementation of vector control measures is the major factor for limiting the number of Zika infections. Conclusions/Significance Our findings highlight the need of considering host variability in exposure time for managing mosquito-borne infections and call for the revision of the triggers for vector control strategies, which should integrate mosquito density data and human outdoor activity patterns in specific areas., Author summary Zika spread in urban environments is characterized by complicated spatio-temporal patterns, likely linked not only to mosquito density but also to human activity patterns. We conducted a survey on Miami-Dade County residents on time spent outdoors. We then analyzed the Miami-Dade survey data and previously published activity data on the entire U.S. population. Our findings indicate high variability in the amount of time spent outdoors by individual residents. Specifically, we found that the majority of persons spend little time outdoors whereas a few people spend a large amount of time outdoors. This analysis was further elaborated in a modeling framework, showing the effect of the host variability in outdoor time on relevant epidemiological indicators (such as the total number of cases and epidemic timing of spread). Our investigation reveals that when host variability in time spent outdoors is high, Zika will infect fewer people. However, it will spread at a quicker pace than in homogenous host populations (where all people spend nearly the same amount of time outdoors). This information is instrumental for defining new triggers for vector control measures based on both mosquito vector density data and human activity patterns in different areas.

Pronounced solvatochromic shifts are observed in the visible spectra of two series of heteroarylazobenzene derivatives based on m-acetylamino- and m-methyl-N,N-diethylaniline, measured in various solvents. The heteroaryl azo component of these dyes can be viewed as a thiophene ring substituted by cyano, nitro, alkoxycarbonyl, or ring aza (to give thiazole and isothiazole derivatives). Free-Wilson analysis has shown that the influence of each of the substituents is constant across all molecules within the two series for a given solvent. However, the substituent increments vary between different solvents and correlate with the Kamlet-Taft dipolarity/polarisability parameter pi* of the solvents. There appears to be no intuitive explanation for the relative solvent variation of different substituents, but Onsager theory suggests sensitivity to the relative size and shape of the dyes. Visible absorption maxima are predicted for unknown heteroarylazo compounds related to those studied.

Addition of cyanuric chloride 2 (2,4,6-trichlorotriazine) to 4,6-diaminobenzene-1,3-disulfonic acid 1 gives a bis-triazine 3 which may be cyclised with diaminoarenes to yield water-soluble azacalix[4]arenes 5a–d. Alternatively, double substitution of chloride from the bis-triazine 3 yields new bis-triazine derivatives which may likewise be cyclised to functionalised azacalixarenes bearing functionalised side chains.

Azobenzene dyes derived from various anilines and aminothiaheterocycles azo-coupled with commercially important N,N-diethyl-m-toluidine (T series) and N,N-diethyl-m-acetylaminoani-line (A series) are positively solva-tochromic. The visible spectra of 16 pairs of derivatives have been measured in up to 22 solvents, and the transition energies related to Kamlet-Taft solvent polarity parameters. In general, A-series dyes are more bathochromic than their T-series counterparts in nonpolar solvents, consistent with colour chemistry tradition. However, in more dipolar solvents the more bathochromic T-series representatives unexpectedly become more bathochromic than their A-series partners. The relative solvatochromic shifts of the A and T series are related to their respective dipole moments. These in turn are distinguished by the effect of the anilide carbonyl group dipole moment, which is antiparallel to, and thus reduces, the dipole moment of the chromogen.

Telomeres, nucleoprotein complexes at the ends of eukaryotic chromosomes, are 10–12 kbp in length in somatic cells, but as small as 1–2 kbp in rapidly growing cancer cells. Southern blot analysis is currently the standard method for the measurement of telomere length. However, accurate determinations are not possible when DNA is broken or scant. To avoid these problems, a slot blot assay that quantitates the relative content, instead of length, of telomere DNA was developed. The relative contents of telomere DNA determined by this slot blot assay were directly proportional to the relative lengths of telomere DNA determined in parallel by Southern blot analysis. Relative telomere DNA content could be measured in samples containing as little as 15 ng of total DNA. Relative telomere DNA content, but not length, also was unaffected by breakage of DNA into fragments 1 kbp or less in length.

The molecular dipole moment and vector component of the hyperpolarisability of 4-[N,N-bis(2-acetoxyethyl)amino]phenyl-1-azo-2′ -(3′,5′-dinitrothiophene) have been calculated using a semi-empirical approach and the results compared with experimental measurements in solution. The calculated values are found to be highly dependent on the conformation of the bis(2-acetoxyethyl)amino group selected, though experimental results suggest that only certain conformations are preferred under the influence of an applied external electric field. The observed change in the sign of the hyperpolarisability in moving from an applied field to 0.925 to 1.17 eV is well reproduced by the calculations.

Neutron reflection and infrared spectroscopy have been used to investigate molecular ordering in Langmuir−Blodgett films of oligomers for second-order nonlinear optical applications. The results ar...

The paramagnetic complexes [Mo(NO)(Tp ∗ )Cl(NC 5 H 4 -4-{CHCHC 6 H 4 -4OC n H 2 n 2)})] {Tp ∗ = HB(#,5-Me 2 C 3 HN 2 ) 3 ; n = 6, 8, 12} have been synthesized and characterized by spectroscopic methods. Polarizing hot stage microscopy studies provided no evidence of mesogenic phases.

Three different techniques have been used to analyse the relationship between the structure of 62 organic compounds and their sublimation enthalpies. Using a neural network based on molecular structure descriptors (molecular formula, hydrogen bonding and π-characteristics), sublimation enthalpies can be modelled. The best of the neural network models yielded an average error of 2.5 kcal mol–1 in a series of ‘leave-one-out experiments’. The same sublimation enthalpy data have been studied using theoretical techniques based upon crystal packing calculations, and also with a simple three parameter multilinear regression model. The latter two methodss produced results that were superior to the neural network in this particular study (mean errors of 1.4 and 1.8 kcal mol–1, respectively), although in the case of MLRA, this is the result of the model fitting exercise, and not a predictive run. It was surprising to find such a simple linear relationship between characteristics describing the molecular formula and the sublimation enthalpy. Nevertheless, the results here have highlighted the potential of neural networks and MLRA as useful tools for the approximate prediction of physical reperties, as demonstrated for a series of compounds not included in the training set.

A series of thiophenes and bithiophenes containing combinations of dimethylamino and dimethylhydrazono π-donor and nitro and dicyanovinyl π-acceptor groups was synthesized in order to study their non-linear optical properties. Solution molecular hyperpolarizabilities were determined by a combination of experimental dipole moments and results from the electric field induced second harmonic generation experiment. Values obtained correlate well with those calculated by the CNDOVSB molecular orbital method. The main structure-property relationships deduced from the results are: (i) thiophene provides a more efficient electron delocalization pathway than benzene; (ii) this increase is proportionately even greater for bithiophene compared with biphenyl; (iii) dimethylhydrazono results in twice the hyperpolarizability of dimethylamino in a comparable molecule; and (iv) dicyanovinyl is a more effective electron acceptor group than nitro in the thiophenes synthesized and calculated.

PISYSTEM for Windows is a commercial program based on a modified PPP SCF-CI-MO model for the rapid and convenient calculation of excited state properties, especially colour, of π-conjugated systems such as dyes. The use and performance of the program is reviewed.

Capnocytophaga species are part of the normal human oral bacterial flora.They are recognized as opportunistic pathogens leading to various extra-oral infections including septicemia, osteomyelitis, abscesses and keratitis and they have been rarely reported as a cause of chorioamionitis and neonatal infection. We here report the first two cases of chorioamionitis produced by Capnocytophaga sputigena and the recently described C. leadbetteri in Belgium. Both isolates were correctly identified at the genus level, in the first 24 hours of incubation by MALDI-TOF.

The class C tetracycline/H+ antiporter, TetA(C), confers nine distinct phenotypes in Escherichia coli: resistance to tetracycline, reduced culture density at stationary phase (growth yield), increased supercoiling of plasmid DNA, delayed growth in succinate minimal medium, complementation of potassium uptake defects, increased susceptibility to cadmium, increased susceptibility to fusaric acid, increased susceptibility to bleomycin and increased susceptibility to several classes of cationic aminoglycoside antibiotics. These nine phenotypes were resolved into three 'linkage' groups based on their patterns of suppression by mutations of the tetA(C) gene of plasmid pBR322. Group I includes resistance to tetracycline, increased susceptibility to cadmium and reduced growth yield. Group II includes delayed growth in succinate minimal medium and complementation of potassium uptake defects. Group III includes increased supercoiling of plasmid DNA and increased susceptibilities to fusaric acid, bleomycin and cationic aminoglycosides. Phenotypes of Groups II and III, but not Group I, also were conferred by a chimeric gene encoding a fusion between the N-terminal 34 residues of TetA(C) and the C-terminal 429 residues of a structurally-similar protein, the E. coli galactose/H+ symporter, GalP. In contrast, none of these phenotypes was conferred by a chimeric gene encoding a fusion between the N-terminal 34 residues of TetA(C) and a structurally-dissimilar protein, TEM beta-lactamase. These results demonstrate that the three groups of linked phenotypes are dependent on different elements of the TetA(C) amino acid sequence, implying that TetA(C) confers these phenotypes by at least three independent mechanisms.

Gold supported nanoparticles were synthesized by using two colloidal methods. The most active catalysts were generated by calcining the samples at high temperature. In terms of support influence, titania showed better catalytic performance than ceria. Taking into account the particle size and the removal of stabilizer, it is clear the influence of particle size and stabiliser with particles of 10 nm and almost complete removal of stabiliser to demonstrate the highest catalytic performance.

The oxidation of 5-hydroxymethyl-2-furfural was studied under mild conditions using TiO2-supported Au and Au-Cu catalysts synthesized from preformed nanoparticles. Bimetallic gold-copper catalysts display a superior activity compared to monometallic gold supported catalysts. Moreover, after reaction, the bimetallic Au-Cu catalysts can be recovered by filtration and reused without any loss of activity and selectivity. In contrast, the monometallic gold catalysts are not stable under these reaction conditions. The effect of various reaction parameters was studied.

A large series of complexes has been synthesized with two chelating, Schiff base azobenzene derivatives connected linearly by coordination to a central nickel(II) or palladium(II) ion. These compounds have the general formulas M(II)(OC(6)H(3)-2-CHNR-4-N═NC(6)H(4)-4-CO(2)Et)(2) [M = Ni; R = n-Bu (3c), n-C(6)H(13) (3d), n-C(8)H(17) (3e), n-C(12)H(25) (3f), Ph (3g), OH (3h), C(6)H(4)-4-CO(2)Et (3i). M = Pd; R = i-Pr (4a), t-Bu (4b), n-Bu (4c), n-C(6)H(13) (4d), n-C(8)H(17) (4e), n-C(12)H(25) (4f), Ph (4g)], M(II)[OC(6)H(3)-2-CHN(n-C(8)H(17))-4-N═NC(6)H(4)-4-CO(2)(n-C(8)H(17))](2) [M = Ni (9), Pd (10)], M(II)[OC(6)H(3)-2-CHN(n-C(8)H(17))-4-N═NC(6)H(4)-4-C(6)H(4)-4-O(n-C(7)H(15))](2) [M = Ni (14), Pd (15)], and M(II)[OC(6)H(3)-2-CHN(CMe(2))-4-N═NC(6)H(4)-4-CO(2)Et](2) [M = Ni (17), Pd (18); the CMe(2) groups are connected]. These compounds have been characterized by using various physical techniques including (1)H NMR spectroscopy and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. Single-crystal X-ray structures have been obtained for two pro-ligands and five complexes (3e, 4e, 14, 15, and 17). The latter always show a strictly square planar arrangement about the metal center, except for the Ni(II) complex of a salen-like ligand (17). In solution, broadened (1)H NMR signals indicate distortions from square planar geometry for the bis-chelate Ni(II) complexes. Electronic absorption spectroscopy and ZINDO_S (Zerner's intermediate neglect of differential overlap) and TD-DFT (time-dependent density functional theory) calculations show that the lowest energy transition has metal-to-ligand charge-transfer character. The λ(max) of this band lies in the range of 409-434 nm in dichloromethane, and replacing Ni(II) with Pd(II) causes small blue-shifts. Dichroic ratios measured in various liquid crystal hosts show complexation-induced increases with Ni(II), but using Pd(II) has a detrimental effect.

Reaction between aliphatic aldehydes or glyoxals (RCOCHO) and 1,2,4-triazole followed by mesyl chloride gives α-mesylates of 1-alkyl-1,2,4-triazole, regiospecifically. Mesylate ion is readily displaced by alkoxide, aryloxide, alkylthiolate, or arylthiolate nucleophiles to give the corresponding α-functionalised 1-alkyl-1,2,4-triazoles, in good yield.

The molecular dipole moment and vector component of the hyperpolarisability of 4-[N,N-bis(2-acetoxyethyl)amino]phenyl-1-azo-2′ -(3′,5′-dinitrothiophene) have been calculated using a semi-empirical approach and the results compared with experimental measurements in solution. The calculated values are found to be highly dependent on the conformation of the bis(2-acetoxyethyl)amino group selected, though experimental results suggest that only certain conformations are preferred under the influence of an applied external electric field. The observed change in the sign of the hyperpolarisability in moving from an applied field to 0.925 to 1.17 eV is well reproduced by the calculations.

In agreement with theoretical prediction, a squaric acid diamide shows appreciable quadratic non-linear optical (NLO) activity in solution, and because of their transparency such amides may be attractive materials for second harmonic generation of blue light, although all crystalline derivatives measured were essentially NLO inactive.

Successive treatment of cyanuric chloride with two aromatic diamines, at least one of them sulfonated, yields water-soluble sulfonated azacalix[4]arenes which may be isolated by crystallisation. Functionalised azacalixarenes may be made by first displacing two chloro substituents from the cyclisation precursor. Attempted formation of an azacalix[6]arene led to a dimeric species for which two structures may be proposed, one of them an azacalixarene catenane.