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Ultrasonic Investigations of Inclusion Complexation of α-Cyclodextrin by DMSO in Pseudo-Binary Aqueous System

100%

Kaczmarek-Klinowska M. , Hornowski T. , Skumiel A. , Jażdżewska M.

tom Vol. 40, No. 4

569--574

The paper reports the study of the complexation processes in aqueous solution of α-CD and DMSO. Cyclodextrins (CDs) (sometimes called cycloamyloses) are cyclic oligosaccharides formed by glucose units interconnected by α-(1,4) linkages; α-CD is one of three the most common CDs. It consists of six glucopyranose units. The speed of ultrasonic waves has been measured by the resonance method on ResoscanTM System apparatus. Some collateral data, such as density and heat capacity of the system, have also been measured. On the basis of the experimental data the excess adiabatic compressibility was determined. The extremes of the excess adiabatic compressibility function for different mixture compositions allowed us to establish the composition of molecular complexes formed in the solution. The obtained results suggest the formation of the α-CD with DMSO inclusion complexes with chemical stoichiometric ratio value of 1:1.

Ultrasonic speed, density, viscosity and associated acoustical parameters of chloroform solutions of symmetric double Schiff bases at 308.15K

88%

Gangan B. J. , Parsania P. H.

International Letters of Chemistry, Physics and Astronomy

2015

tom Vol. 45

16--23

The density, viscosity and ultrasonic speed (2MHz) of chloroform and symmetric double Schiff bases have been investigated at 308.15K. Various acoustical parameters such as specific acoustical impedance(Z), adiabatic compressibility(Кa), Rao’s molarsound function(Rm), Vander Waals constant(b), internal pressure(π), free volume(Vf), intermolecular free path length(Lf), classical absorption coefficient(α/f2)Cl) and viscous relaxation time(τ) were determined using ultrasonic speed(U), viscosity(ƞ) and density(ƿ) data of Schiff bases solutions and correlated with concentration. Increasing linear or nonlinear trends of ( Z, Rm, b, τ and (α/f2)Cl) and decreasing trend of Кa, Lf, π and Vf with increasing concentration of Schiff bases suggested presence of strong molecular interactions in the solutions and solvophilic nature of the Schiff bases, which is further supported by the positive values of solvation number. The nature and position of substituent also affected the strength of molecular interactions.