|Author||Seth, J. ♦ Palaniappan, V. ♦ Bocian, D. F. ♦ Wagner, R. W. ♦ Johnson, T. E. ♦ Lindsey, J. S.|
|Source||United States Department of Energy Office of Scientific and Technical Information|
|Subject Keyword||CHEMISTRY ♦ PORPHYRINS ♦ SYNTHESIS ♦ ELECTRON SPIN RESONANCE ♦ ABSORPTION SPECTRA ♦ RAMAN SPECTROSCOPY ♦ DIMERS ♦ ZINC COMPOUNDS ♦ ELECTROCHEMISTRY ♦ TEMPERATURE DEPENDENCE ♦ VOLTAMETRY ♦ NUMERICAL DATA|
|Abstract||A comprehensive electrochemical (cyclic and square-wave voltammetry, coulometry) and static spectroscopic (absorption, resonance Raman (RR), electron paramagnetic resonance (EPR)) study is reported for a series of dimeric and trimeric porphyrin-based arrays. All the arrays consist of tetraarylporphyrins linked via ethyne groups at the p-positions of the aryl rings. The complexes investigated include zinc-free base and bis-zinc dimers which contain varying degees of torsional constraint between the porphyrin rings and the aryl group of the linker, and linear and right-angle trimers in which two zinc porphyrins are bridged by either a zinc or free base porphyrin. The spectroscopic studies were performed on singly and multiply oxidized complexes as well as the natural species. The electrochemical and spectral properties of the arrays indicate that the electronic communication between the macrocycles is relatively weak in the ground and excited electronic states. This communication is through-bond, rather than through-space, and is mediated by the diarylethyne linker. The EPR spectra of the oxidized arrays exhibit complex temperature-dependent signatures that reflect hole/electron hopping and/or spin exchange interactions in the ground electronic state. Exchange interactions in the multiply oxidized arrays are significant (probably 1000 MHz pr greater) in both liquid and frozen solutions and, in certain cases, are enhanced upon solvent freezing. 45 refs., 12 figs., 3 tabs.|
|Learning Resource Type||Article|
|Publisher Place||United States|
|Journal||Journal of the American Chemical Society|
Ministry of Human Resource Development (MHRD) under its National Mission on Education through Information and Communication Technology (NMEICT) has initiated the National Digital Library of India (NDLI) project to develop a framework of virtual repository of learning resources with a single-window search facility. Filtered and federated searching is employed to facilitate focused searching so that learners can find out the right resource with least effort and in minimum time. NDLI is designed to hold content of any language and provides interface support for leading vernacular languages, (currently Hindi, Bengali and several other languages are available). It is designed to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is being developed to help students to prepare for entrance and competitive examinations, to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is being developed at Indian Institute of Technology Kharagpur.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Human Resource Development (MHRD), through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
For any issue or feedback, please write to firstname.lastname@example.org