3-and 3,4-substituted pyrroles and thiophenes and their corresponding polymers: a review

In the field of conducting polymers, both poly(pyrrole) and poly(thiophene) have been investigated extensively and are used currently in a wide variety of applications including microelectronics, electrode materials, sensors and optoelectronics. Amongst these polymers, 3- and 3,4- substituted poly(pyrroles) and poly(thiophenes) have received significant attention in recent years as demonstrated by the increase in the number of patents and publications that describe their use. This review covers the development in the synthesis of 3- and 3,4- Substituted poly(pyrroles) and poly(thiophenes) over the last 30 years, their polymerisation in addition to describing the material properties and applications of the resulting polymers. In particular, this review focuses upon the variety of methodologies employed for the synthesis of 3- and 3,4-substituted pyrroles and thiophenes as well as upon the broad range of functional groups that can be attached to the heterocyclic ring system in order to tailor the properties of the resulting polymers.

2,2-Dialkyl-2H-benzimidazoles, the high energy tautomers of the corresponding 1,2-dialkyl-1H-benzimidazoles. Syntheses and their complexes with Cu(I) and Ag(I)

Reaction of Cu(1,2-phenylenediamine)(2)(ClO4)(2) with neat RR'=O (R = methyl and/or ethyl) (lives Cu(2,2-dialkyl-2H-benzimidazole)ClO4. demetallation of which by the action of aqueous ammonia yields Pure 2,2-dialkyl-2H-benzimidazoles. These are characterised by NMR. hi the X-ray crystal Structure, Ag(2,2-methyl-2H-benzimi-dazolc)NO3 is Found to be a spiral 1D coordination polymer where the 2H-benzimidazole acts as an N,N bridge between two Ag(I) centus. Although 2H-benzimidazoles are very unstable in the free state, they are quite stable in their Cu(I)(1) and Ag(I) complexes. The 1,2-tautomerisation in imidazole and benzimidazole have been Studied by means of transition state calculations at B3LYP/6-3 11 +G(2d,p)* level.

Antioxidant and cellular activities of anthocyanins and their corresponding vitisins A - studies in platelets, monocytes, and human endothelial cells

During red wine aging, there is a loss of anthocyanins and the formation of various other pigments, so-called vitisins A, which are formed through the chemical interaction of the original anthocyanins with pyruvic acid. The objective of this study was to investigate the antioxidant activities of the most abundant anthocyanins present in red wine (glycosides of delphinidin, petunidin, and malvidin) and their corresponding vitisins A. Anthocyanins exhibited a higher iron reducing as well as 2,2'-azinobis (3-ethyl-benzothiazoline-6-sulfonate) and peroxyl radical scavenging activity than their corresponding vitisins A. Delphinidin showed the highest antioxidant effect of the tested compounds in all of the assays used. Furthermore, we studied the effect of anthocyanins and vitisins A on platelet aggregation and monocyte and endothelial function. Anthocyanins and vitisins did not affect nitric oxide production and tumor necrosis factor-alpha (TNF-alpha) secretion in lipopolysaccharide plus interferon-gamma-activated macrophages. Furthermore, anthocyanins and vitisins did not change collagen-induced platelet aggregation in vitro. However, anthocyanins and to a lesser extent vitisins exhibited protective effects against TNF-alpha-induced monocyte chemoattractant protein production in primary human endothelial cells.

Synthesis of a mononuclear oxidovanadium(V) complex by bridge-splitting of the corresponding binuclear precursor

The mononuclear oxidovanadium(V) complex VO(OEt)L (2), where L2- is the dianion of a diprotic tridentate ONO donor ligand, 2-hydroxyacetophenone-2-aminobenzoylhydrazone (H2L), has been synthesized by oxido-bridge splitting of the corresponding binuclear complex V2O3L2 (1) and structurally characterized by single crystal X-ray diffraction analysis, together with electrochemical and spectral studies. Splitting of the oxido-bridge was effected by refluxing 1 with excess triphenylphosphine in ethanol medium. The crystal structure of 2 is compared with that of the precursor binuclear complex 1.

Ozone database in support of CMIP5 simulations: results and corresponding radiative forcing

A continuous tropospheric and stratospheric vertically resolved ozone time series, from 1850 to 2099, has been generated to be used as forcing in global climate models that do not include interactive chemistry. A multiple linear regression analysis of SAGE I+II satellite observations and polar ozonesonde measurements is used for the stratospheric zonal mean dataset during the well-observed period from 1979 to 2009. In addition to terms describing the mean annual cycle, the regression includes terms representing equivalent effective stratospheric chlorine (EESC) and the 11-yr solar cycle variability. The EESC regression fit coefficients, together with pre-1979 EESC values, are used to extrapolate the stratospheric ozone time series backward to 1850. While a similar procedure could be used to extrapolate into the future, coupled chemistry climate model (CCM) simulations indicate that future stratospheric ozone abundances are likely to be significantly affected by climate change, and capturing such effects through a regression model approach is not feasible. Therefore, the stratospheric ozone dataset is extended into the future (merged in 2009) with multimodel mean projections from 13 CCMs that performed a simulation until 2099 under the SRES (Special Report on Emission Scenarios) A1B greenhouse gas scenario and the A1 adjusted halogen scenario in the second round of the Chemistry-Climate Model Validation (CCMVal-2) Activity. The stratospheric zonal mean ozone time series is merged with a three-dimensional tropospheric data set extracted from simulations of the past by two CCMs (CAM3.5 and GISSPUCCINI)and of the future by one CCM (CAM3.5). The future tropospheric ozone time series continues the historical CAM3.5 simulation until 2099 following the four different Representative Concentration Pathways (RCPs). Generally good agreement is found between the historical segment of the ozone database and satellite observations, although it should be noted that total column ozone is overestimated in the southern polar latitudes during spring and tropospheric column ozone is slightly underestimated. Vertical profiles of tropospheric ozone are broadly consistent with ozonesondes and in-situ measurements, with some deviations in regions of biomass burning. The tropospheric ozone radiative forcing (RF) from the 1850s to the 2000s is 0.23Wm−2, lower than previous results. The lower value is mainly due to (i) a smaller increase in biomass burning emissions; (ii) a larger influence of stratospheric ozone depletion on upper tropospheric ozone at high southern latitudes; and possibly (iii) a larger influence of clouds (which act to reduce the net forcing) compared to previous radiative forcing calculations. Over the same period, decreases in stratospheric ozone, mainly at high latitudes, produce a RF of −0.08Wm−2, which is more negative than the central Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) value of −0.05Wm−2, but which is within the stated range of −0.15 to +0.05Wm−2. The more negative value is explained by the fact that the regression model simulates significant ozone depletion prior to 1979, in line with the increase in EESC and as confirmed by CCMs, while the AR4 assumed no change in stratospheric RF prior to 1979. A negative RF of similar magnitude persists into the future, although its location shifts from high latitudes to the tropics. This shift is due to increases in polar stratospheric ozone, but decreases in tropical lower stratospheric ozone, related to a strengthening of the Brewer-Dobson circulation, particularly through the latter half of the 21st century. Differences in trends in tropospheric ozone among the four RCPs are mainly driven by different methane concentrations, resulting in a range of tropospheric ozone RFs between 0.4 and 0.1Wm−2 by 2100. The ozone dataset described here has been released for the Coupled Model Intercomparison Project (CMIP5) model simulations in netCDF Climate and Forecast (CF) Metadata Convention at the PCMDI website (http://cmip-pcmdi.llnl.gov/).

An efficient and rapid microwave-assisted synthesis of 1-acetyl-1H-indol-3-YL acetates

An efficient and rapid synthesis of 1-acetyl-1H-indol-3-yl acetate 1 and its derivatives 7 via the microwave-assisted cyclisation and decarboxylation of 2-[(carboxymethyl)amino]benzoic acids 5 is described. The latter were left to react with acetic anhydride using triethylamine as the base and were subjected to microwave irradiation for 1 minute, at 80 °C with initial power of 300 W. The target 1-acetyl-1H-indol-3-yl acetate 1 and derivatives 7 were isolated in 34-71% yield. In particular, synthesis of 1-acetyl-6-(trifluoromethyl)-1H-indol-3-yl acetate 7f and 1-acetyl-3-methyl-1H-indol-3-yl acetate 7h is reported for the first time.