http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/691 Mon, 20 May 2013 01:25:11 GMT 2013-05-20T01:25:11Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1993 Photophysical and Electrochemical Investigations on Photoconducting Poly(6-tert-butyl-3,4-dihydro-2H- 1,3-benzoxazine) Sreekumar, K; Dhanya, R; Kishore, V C; Sudha Kartha, C; Rani, Joseph Poly(6-tert-butyl-3,4-dihydro-2H-1,3-benzoxazine) was synthesized by thermally activated cationic ring opening polymerization. The structure of the polymer was confirmed by spectral and thermal studies. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were estimated using cyclic voltammetry and optical absorption. Modulated photocurrent measurement technique was employed to study the spectral and field dependence of photocurrent. Photocurrent of the order of 1.5 micro A/m2 was obtained for polymer at a biasing electric field of 40 V/mico m. Thu, 01 Jan 2009 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1993 2009-01-01T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1968 Three Component Mannich Reaction and 1,5-Benzodiazepine Synthesis Catalyzed by a Tetranitrile-Silver Complex Sreekumar, Krishnapillai; Rajesh Krishnan, Gopalakrishnapanicker; Sreerekha, Radhakrishnan This manuscript describes the first example of silver ion complex of a dendritic tetranitrile ligand catalyzed one-pot three component Mannich reaction and 1,5-benzodiazepine synthesis. The catalyst can be separated from the products by a change in the solvent. The catalyst is reusable. Fri, 22 Aug 2008 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1968 2008-08-22T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1967 Organocatalysis by poly(amidoamine) dendrimers; Knoevenagel and Mannich reactions catalyzed in water Sreekumar, Krishnapillai; Rajesh Krishnan, G; Jinimol, Thomas Knoevenagel condensation between carbonyl compounds and active methylene compounds as well as three component Mannich reaction between aldehydes, ketones and amines proceeded smoothly in water with good to excellent yield and high selectivity in the presence of zero and first generation poly(amidoamine) (PAMAM) dendrimers. The products and the catalyst were separated by simple biphasic extraction. The catalyst was found to be reusable. Thu, 01 Jan 2009 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1967 2009-01-01T00:00:00Z http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1966 First Example of Organocatalysis by Polystyrene-Supported PAMAM Dendrimers: Highly Efficient and Reusable Catalyst for Knoevenagel Condensations Sreekumar, Krishnapillai; Rajesh Krishnan, G This paper describes the first use of polystyrene-supported poly(amidoamine) (PAMAM) dendrimers as heterogeneous basic organocatalysts for carbon–carbon bond formation. Polystyrene-supported PAMAM dendrimers of first, second and third generations have been used as reusable base catalysts in Knoevenagel condensations of carbonyl compounds with active methylene compounds. The reactions proceed in short periods of time and with 100% selectivity. This novel catalyst eliminates the use of aromatic and halogenated solvents, as well as complex purification processes. The catalysts can be recycled ten times. Fri, 01 Aug 2008 00:00:00 GMT http://dyuthi.cusat.ac.in:80/xmlui/handle/purl/1966 2008-08-01T00:00:00Z