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Mangalore, India

Rajamohan R.,SKP Institute of Technology | Kothai Nayaki S.,Annamalai University | Swaminathan M.,Annamalai University
Journal of Solution Chemistry | Year: 2011

Spectral characteristics of 5-amino-2-mercaptobenzimidazole (AMBZ) have been investigated in aqueous β-cyclodextrin (β-CDx) solutions. The absorbance and fluorescence intensity of the neutral and monocationic forms of AMBZ are enhanced due to the formation of an inclusion complex with β-CDx. The stoichiometry and binding constants of the complex were calculated using the Benesi-Hildebrand equation. Formation of an inclusion complex between AMBZ and β-CDx was also confirmed by steady state and time-resolved fluorescence spectroscopy. FT-IR spectral data and SEM images of the solid complex provide supporting evidence for complex formation. The effect of acidity on the ground and excited state equilibrium between neutral and monocationic forms of AMBZ was analyzed in aqueous and β-CDx environments. The ground and excited state acidity constants in β-CDx solutions were found to be different from those in aqueous solution. Based on these results, the structure of the 1:1 complex is proposed. © 2011 Springer Science+Business Media, LLC. Source


Rajamohan R.,SKP Institute of Technology | Kothai Nayaki S.,Annamalai University | Swaminathan M.,Annamalai University
Journal of Inclusion Phenomena and Macrocyclic Chemistry | Year: 2012

The effects of the addition of β-cyclodextrin (β-CDx) on the absorption and emission properties of the 5-aminoisoquinoline (5AIQ) have been investigated in aqueous media. The formation of host-guest inclusion complex with 1:1 stoichiometry was revealed by absorption, steady state and time-resolved emission spectroscopy. The complex formation has also been confirmed by FT-IR spectra and SEM image analysis of the solid inclusion complex between 5AIQ and β-CDx. No significant change was observed in the ground and excited state pKa values in β-CDx medium. Based on photophysical and prototropic characteristics of 5AIQ in β-CDx, the structure of the 1:1 inclusion complex is proposed. © 2011 Springer Science+Business Media B.V. Source


Rajaram R.,SKP Institute of Technology | Sundararajalu K.N.,Annamalai University | Meenakshisundaram S.,Annamalai University
Journal of Fluorescence | Year: 2011

The interaction between 6-aminobenzothiazole (6ABT) and β-cyclodextrin (β-CDx) has been investigated in solution and solid state. The stoichiometry and binding constants of the complex between 6ABT and β-CDx in solution have been determined by steady state and timeresolved fluorescence spectroscopy. Fluorescence intensity of neutral form decreases during complexation which is contrary to the usual observation. This is explained by hydrogen bonding interaction between lone pair of nitrogen with OH groups of β-CDx. The FT-IR spectral study and SEM images of solid complex confirmed the formation of inclusion complex. Excited state acidity constants for 6ABT have been determined in aqueous and β-CDx medium and discussed. © 2010 Springer Science+Business Media, LLC. Source


Rajamohan R.,SKP Institute of Technology | Swaminathan M.,Annamalai University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

Spectral characteristics of diphenylamine (DPA) have been investigated in β-cyclodextrin (β-CDx) solution. The formation of the complex was revealed by UV, steady state and time-resolved fluorescence spectroscopy. The stoichiometry of DPA:β-CDx complex, determined using Benesi-Hildebrand equation and Job's continuous variation method is 1:1. The binding constants calculated from various methods are reported. This inclusion complex formation from DPA and β-CDx was also confirmed by the FT-IR spectral study and SEM image analysis of solid complex prepared by co-precipitation method. © 2011 Elsevier B.V. Source


Kumar R.,SKP Institute of Technology | Balasubramanian M.,Alagappa Chettiar College of Engineering And Technology
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2015

A method to decide near optimal settings of the process parameters in friction welding was proposed. The success of the friction welding process is based on various input parameters like friction pressure, friction time, upset pressure and upset time and output parameters like tensile strength, hardness and material loss. Ti-6Al-4V and SS304L(SS) materials were joined by friction welding process using interlayer techniques. The Box-Behnken design and response surface methodology (RSM) were applied to deciding the number of experiments to be performed and identify the optimum process parameters for obtaining better joint strength. The results were highly encouraging. Join strength of 523 MPa was obtained at a friction pressure of 12 N/mm2, upset pressure of 40 N/mm2, friction time of 1.2 s and upset time of 7 s. © 2015 The Nonferrous Metals Society of China. Source

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