Dielectric Relaxation Study of Aqueous Amides in Non-Polar Solute Using Picoseconds Time Domain Technique

Abstract

Abstract-The dielectric permittivity of amide -1, 4-dioxane (DX) for various concentrations has been studied in the frequency range from 10 MHz to 30 GHz using the time domain reflectometry (TDR) method. A hydrogen bonded theory suggested by Luzar is applied to compute correlation terms for the mixtures. Static permittivity for the mixtures can be explained using the Luzar model by assuming the formation of two types of hydrogen bonded dimmers, one between amide-amide (pair 1) and other between amide-1, 4-dioxane (pair 2). The numbers of these pairs are also estimated as a function of concentration. Index Terms-Dielectric permittivity, relaxation time, time domain reflectometry (TDR), bruggeman factor I. INTRODUCTIONAmide represents an important class of bio-organic solvent. The hydrogen bond formation ability of these solvents is useful in understanding the peptide linkage in complex bio-systems [1]- [3]. The study of hydrogen bonding molecular interactions of binary mixtures is currently a significant challenge in the research field of science and technology. Hydrogen bond constitutes a very interesting class of intermolecular interactions, which are of extreme importance in many fields of chemistry and molecular biology. "Hydrogen Bonding in Biological Structures" can be used in many ways by biophysicists [4]. The study of the H-bonds of the type O=H ---O=C occupies a position of considerable importance as it relates to the study of biopolymers [5]. In the case of amides, N, N-dimethylformamide (DMF) is able to form the H-bonded network structures with dipolar aprotic and protic solvents [6]. Malathi M. et al. have studied mutual interaction of amides with non polar solvents to understand the conformational stability of protein molecules [7]. Thenappan and Sankar were studied hydrogen-bonded complexes of alcohol with N, N-dimethylformamide (DMF) [8]. DMF is a widely used solvent for many recently developed synthetic procedures because of its powerful solvating properties [9]. N-methylacetamide (NMA) is the most frequently used analog compound for the peptide unit in Manuscript received February 4, 2012; revised March 25, 2012 proteins. Paul Firman and S. Sahoo were studied the mixture of N-methylacetamaide (NMA) with non-polar solvent [10], [11]. The non polar solvent 1, 4-dioxane (DX) is used as a laboratory reagent and as a solvent for the production of cellulose acetate, ethyl cellulose, benzyl cellulose, dyes, oils, fats and polyvinyl polymers. The intermolecular interaction plays an important part in intermolecular recognition processes essential to most of biological systems. It also found that Physical and chemical phenomenon of binary systems are closely related to the intermolecular interactions.In the present work, we report a comparative dielectric relaxation study of amide (DMF and NMA) with non polar solute (DX) at various concentrations at 25 o C employing Time Domain Reflectometry (TDR) in the frequency range of 10 MHz-30 GHz. The complex permittivity spectra of DMF-DX and NMA-DX have been fitt...

Hydrogen bond analysis in alcohol (1-Propanol, 2-Propanol and Glycerol)-DMF mixtures based on dielectric spectroscopy

“…Thought Time domain reflectometry [20], Microwave cavity techniques [26], Infrared, Far-infrared and Raman spectra [27] have been used to estimate the contribution of molecules interaction, DRS is especially helpful for researching the HBs cooperative nature. DRS can monitor the collective motion of a molecular ensemble through the total dipole moment of the sample to a time dependent electric field [28].…”

“…The dielectric constant, Kirkwood correlation factors and relaxation time for the alcohol-DMF mixtures have been determined in TDR by G.R. Mahajan et al [20]. R. J. Sengwa [18] has described structure and hydrogen bonding in binary mixtures of DMF with some dipolar aprotic and protic solvents by dielectric characterization.…”