The sequencing and mapping of DNA and the technologies to accomplish these tasks are rapidly evolving. Sequence information can give insite into the location and function of genes, provide an understanding of the relationship between variations in sequence and different genetic diseases, and serve as a basis for the prediction, treatment and cure of those disease conditions. In pursuit of these capabilities the Human Genome Program has proposed sequencing the entire human genome over the next 15 years. The work presented here represents our efforts to advance the technology for faster and more automated sequencing procedures. Focusing on metal-centered organic compounds and a variety of detection methods, several strategies for labeling and detecting DNA sequencing reaction products are presented. The synthesis and testing of a variety of compounds and approaches are discussed including mass labels using tin, iron and lanthanide elements, electrochemically detectable ferrocene derivatives, and luminescent complexes of given lanthanides. The results of this work are discussed and future directions presented.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

A new, general synthetic method for the title compound has been developed, based on the nitration of 2-benzyl-1,4-7,10-tetraazacyclododecane (64 % yield), which provides higher yields and easier purification for scale-up than previously reported methods.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The spectroscopic properties, photodimerization, and cross-cycloaddition reactions of 2-quinolone and three of its methylated derivatives have been investigated in the absence and presence of the strong Lewis acid BF3. Comparison of quinolone, which forms a hydrogen-bonded dimer, and its N-methylated derivatives establishes that hydrogen bonding has little effect on these properties. Methylation at C-4 also has little effect on spectroscopic properties, but does retard photodimerization and result in the formation of photoene products in competition with cycloadduct formation with alkenes. All of the quinolones form strong complexes with BF3. Complex formation results in changes in the NMR, absorption, and fluorescence spectra of the quinolones and in their photochemical behavior. Complexation is proposed to occur on oxygen for all of the quinolones resulting in changes in electron populations that have been probed using GAUSSIAN 86 calculations. A decrease in the energy of the oxygen nonbonding orbitals upon complexation results in a change in the configuration of the lowest singlet state from n,pi* to pi,pi* upon complexation. This change results in an increase in singlet lifetime and a change in cycloaddition mechanism from triplet (stepwise) to singlet (concerted) upon complexation.

A novel photoresponsive polymer containing organic chromophores which possess thermal stability as well as substantial and reversible responsiveness upon external photostimulus has been developed. trans-2{4-[2-(Dimethylcarbamoyl)vinyl]phenoxy}ethyl methacrylate (1) was synthesized and copolymerized by free-radical methods with methyl methacrylate giving a copolymer poly[(methyl metharcrylate)-co-1] (poly(MMA-co-1) (2) with cinnamamide moiety chromophores randomly attached as side groups. Photoisomerization and ultraviolet absorbance were used to examine the photostationary states and solubility changes upon photoirradiation. Poly[(methyl methacrylate)-co-1] (90,7:9,3 mol %) with 9,3 mol-% cinnamamide content has better solubility in a polar solvent such as acetonitrile (theta temperature THETA-PMMA = 30-degrees-C) than in a nonpolar solvent such as carbon tetrachloride THETA-PMMA = 27-degrees-C). Photoisomerization of the transcinnamamide to cis-cinnamamide units significantly shifts the cloud point of poly[(methyl methacrylate)-co-1] (90,7:9,3 mol-%) in carbon tetrachloride; this cloud point shift is reversible by photoisomerization back to the trans state. However, in a hydrogen-bonding solvent such as tert-butyl alcohol, while photoirradiation of poly[(methyl methacrylate)-co-1] (90,7:9,3 mol %) yields a significant shift in cloud point, this is not reversible by photoirradiation as hydrogen-bond formation between the tertiary amide and the hydroxylic solvent reduces the isomerization efficiency. Fatigue of the photoreversibility of the copolymer, which is not present in dilute solutions of the cinnamamide chromophore, is noted.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

The fluorescence lifetimes of methyl cinnamate and methyl indenoate have been investigated by means of picosecond laser spectroscopy. Values of <3 ps and 15 ± 2 ps for these esters are significantly shorter than those previously reported for ethyl cinnamate. The short lifetimes are tentatively attributed to the competition between fluorescence from the originally populated π,π* singlet state and its internal conversion to a lowest n,π* singlet state. The efficiency of isomerization is independent of solvent, but dependent upon temperature and excitation wavelength. Comparison of the quantum yields for direct and triplet-sensitized dimerization indicates that intersystem crossing is highly inefficient. Thus the isomerization which occurs upon direct irradiation occurs predominantly from the singlet manifold.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTConfiguration-dependent photoisomerization of (E)-cinnamamidesFrederick D. Lewis, Jeffrey E. Elbert, Alana L. Upthagrove, and Paul D. HaleCite this: J. Am. Chem. Soc. 1988, 110, 15, 5191–5192Publication Date (Print):July 1, 1988Publication History Published online1 May 2002Published inissue 1 July 1988https://pubs.acs.org/doi/10.1021/ja00223a048https://doi.org/10.1021/ja00223a048research-articleACS PublicationsRequest reuse permissionsArticle Views155Altmetric-Citations11LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts