Dielectric increments, intercharge distances and conformation of quaternary ammonioalkylsulfonates and alkoxydicyanoethenolates in aqueous and tirfluoroethanol solutions

Abstract

des Hyperfrequences et des Semi-conducteurs US JL -59655 a-(Triethy1ammonio)alkane-a-sulfonates (H,C,),N ' -(CH,),-SO,-( n = 2-4), pyridinio-, 2,6-lutidin ioand Nmet hyl imidazol i n iopropa nesu If onates, and triet hylammon ioa I koxydicya noet henolates (H,C,),N'-(CH,),-0-CO-C-(CN),(n = 2, 3) have been studied by dielectric measurements (1 M Hz-1 GHz) in dilute aqueous or trifluoroethanol solution. Their intercharge distances have been derived from their dipole moments ( p in the range 18-30 D) calculated according to Buckingham's theory, and compared with the maximum and minimum intercharge distances estimated by molecular mechanics for the ideal fully extended and ion-pair conformations respectively. For identical tether length, stronger charge delocalization in the cationic (imidazolinium versus pyridinium) or anionic (dicyanoethenolate versus sulfonate) sites slightly increases the intercharge distance, while better specific solvation of the zwitterions by hydrogen bonding in the less dissociating trifluoroethanol does not result in any significant conformational change with respect t o aqueous solutions. Folding of the intercharge arm, negligible for 2-(triethy1ammonio)ethane-1 -sulfonate, progressively increases with its length, but the ion-pair conformation, where the intercharge distance becomes rapidly insensitive to the tether length, is never reached. This behaviour is in good agreement with the variations of the apparent ApK, values of the zwitterions (normalized to that of n-C,H,SO,H) measured by potentiometry in acetic anhydride-acetic acid (9:1, v/v) solution.4 (R = hexyl). In the present work, we focus our attention mainly on the calculation of the dipole moment from dielectric measurements in polar solvents for two series of low molecular weight zwitterionic species chosen as model compounds for the corresponding polymers of current interest in our laboratory: 8 , ' hydrophilic ammoniosulfobetaines studied in water and in trifluoroethanol (TFE) and hydrophobic ammonio-a1 kox ydicyanoe thenola tes studied in TFE solution. AmmoniosuifobetainesArnmonioal koxydicyanoethenolates n = 2; Et3N-CN3 t~ = 3; EtaN-CN4 O"\CH, n = 3; Py-s3 eN+-(CHJ1-S03-n =3;Lu-s3 \ CH3Critical comparison of the experimental data within these two series may afford useful information on a number of major factors controlling the characteristic zwitterion intercharge distance such as: steric hindrance and polarizability of the * 1 cal = 4.184 J.

Poly(ammonioalkanesulfonate) Blends with Polar Organic Species and Alkali Metal Salts: Structure, Glass Transition and Ionic Conductivity

“…Ethylammonium nitrate (EAN) was prepared according to the literature [17]. Triethylammoniopropanesulfonate and ethane-1, 2-diylbis(dimethylammoniopropanesulfonate) were synthesized as previously described [3].…”

“…(p = 2-4) are of special interest because of their very high dipole moment ( ϳ 18.7-27.6 D as derived from dielectric measurements in aqueous solution [3]), their hydrophilicity and their good stability over a very wide range of pH and temperature. Thus, homopolymers in the (meth)acrylic or vinylheterocyclic series bearing this type of zwitterionic side groups have received much attention in the past ten years, with special emphasis on their acqueous solution properties typified by the now classical "anti polyelectrolyte" behavior (chain expansion with increasing concentration of added low molecular weight electrolytes).…”

“…Most experiments have been performed on poly [3 -N,N-diethyl -N-(5 -methacryloyoxy -3 -oxapentyl) ammonio)propanesulfonate] (R1 = CH 3 , p = 3 in scheme 1) and some punctual measurements have been carried out on the two other polymers in order to test the influence of the backbone flexibility (R 1 = H) and of the length of the zwitterionic intercharge arm (p = 4). The experimental results will be compared with those obtained on analogous systems described in the literature (10)(11)(12)14) where the zwitterionic moiety is disconnected from the chain backbone by a shorter or a longer (polysoap) spacer (see Scheme 2).…”

For Stimul-Responsive Polymers with Enhanced Efficiency in Reservoir Recovery Processes

“…66 ) Also, it should be noted that the reduced viscosity decreases as the incorporation of the sulfobetaine moiety increases, again from the intramolecular aggregation brought about by dipole-dipole interactions. 13 This collapse is also observed in light scattering by a decrease in the polymer-solvent interaction parameter, A2, as the mol % sulfobetaine increases (Table 4).…”

“…[66][67][68][69][70] For a polyampholyte with excess positive or cationic charge, the electrostatic interactions can be characterized by an excluded volume: repulsions is stronger than the screening of the polyampholyte attractions and the excluded volume becomes negative, thus inducing chain collapse. As the ionic strength is increased, the chain swells again because of the screening of the attractive polyampholyte interactions.…”