8 research outputs found
Hydrogen Bonding in Ionic Liquids Probed by Linear and Nonlinear Vibrational Spectroscopy
Three imidazolium-based ionic liquids of the type [Cnmim][NTf2] with varying
alkyl chain lengths (n = 1, 2 and 8) at the 1 position of the imidazolium ring
were studied applying IR, linear Raman, and multiplex CARS spectroscopy. The
focus has been on the CH-stretching region of the imidazolium ring, which is
supposed to carry information about a possible hydrogen bonding network in the
ionic liquid. The measurements are compared to calculations of the
corresponding anharmonic vibrational spectra for a cluster of [C2mim][NTf2]
consisting of four ion pairs. The results support the hypothesis of weak
hydrogen bonding involving the C(4)-H and C(5)-H groups and somewhat stronger
hydrogen bonds of the C(2)-H groups.Comment: revised manuscript, accepted for publication in New J. Phy
Ultrafast CARS with Improved Spectral Resolution
Molecular vibrations are investigated by time and frequency resolved CARS applying ultrafast excitation and picosecond probing for high spectral resolution. Enhanced spectral structure and beating phenomena are demonstrated for coalescing Raman bands
Flexible Application of Object Oriented Technologies to Distributed Intelligent Networks
this paper that the true potential of the IN concept can be more easily exploited by these technologies than it can by legacy, "static" softwar
Evaluation study of mobile agent technology: standardization, implementation and evolution
A novel tele-medical environment appropriate for use in tele-advisory and tele-surgery cases
Zinc thiolate complexes ZnLn(SR)(+) with azamacrocyclic ligands, part II: Mechanism of the reaction with CS2
The thiolate complexes Zn(15]aneN(4))(S-CH2-C6H5)]ClO4 (1) (15aneN(4) = 1,4,8,12-tetraazacyclopentadecane) and Zn(i-14]aneN(4))(S-CH2-C6H5)ICIO4 (2) (i-14aneN(4) = 1, 4,7, 11 -tetraazacyclotetradecane) have been reacted with carbon disulfide. The trithiocarbonate complexes Zn(15]aneN(4))S-C(S)-S-CH2-C6H5]CIO4 1a, monoclinic, space group P2(1)/n, Z = 8, a = 13,2338(1) angstrom, b = 12.9251(2) angstrom, c = 30.1669(4) angstrom, beta = 101.463(1)degrees, V = 5057.1(1) angstrom(3) and Zn(i14]aneN(4))S-C(S)-S-CH2-C6H5]CIO4 2a, orthorhombic, space group P2(1)2(1)2(1), Z = 8, a = 9.9936(1) angstrom, b 22.1261(4) angstrom, c = 22.3192(4) angstrom, V = 4935.2(l) angstrom(3) were obtained. The reaction of 1 with CS2 is second order with a rate constant of k = (57.6 +/- 2.4) x 10(-3) m(-1.)s(-1) at 25 degrees C. The experimentally determined Eyring activation barrier is Delta H-exp(double dagger) = 65.3 +/- 0.7 kJ(.)mol(-1) (Delta S-exp(double dagger) = -49.9 +/- 2.5 J(.)mol(-1.)K(-1)) and a free energy of activation of Delta G* = 80.2 +/- 1.5 kJ(.)mol(-1) at 25 degrees C. To discriminate between an associative and a dissociative mechanism the barriers for both processes were calculated using density functional theory at the C-PCM(B98/G3MP2Large)//B3LYP/ 6-311+G(d) level. The associative mechanism is clearly favored with a difference in free energies of activation of delta Delta G(double dagger) approximate to 80kJ(.)mol(-1). Its calculated barrier Delta G(theor)(double dagger) = 114.3 kJ(.)mol(-1) is in reasonable agreement with the experimental value. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)