Relaxation kinetics and infrared spectra of the complexation of lithium ion by triethylene glycol and by tetraethylene glycol in acetonitrile

Cobranchi, Daryl P.; Garland, Ben A.; Masiker, Marilyn C.; Eyring, Edward M.; Firman, P.; Petrucci, Sergio

doi:10.1021/j100193a040

Cited by 11 publications

(6 citation statements)

References 5 publications

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“…Solutions of LiCF 3 SO 3 in acetonitrile (CH 3 CN) have also been studied. 10,37 Our measurements for this system at room temperature show bands at 1300 cm -1 (33%), 1272 cm -1 (32%), and 1255 cm -1 (27%) which are in agreement with those of Lindgren and co-workers 10 and Cobranchi et al 37 Irish and co-workers [49][50][51] have studied the asymmetric stretch region of the nitrate anion. The ν 3 (E′) degenerate mode for NO 3occurs at ∼1300 cm -1 .…”

Section: Resultssupporting

confidence: 82%

“…The bands at 1299 and 1255 cm -1 have been attributed to contact-ion pairs, ,− , where interactions in the solution have lifted the degeneracy of the doubly degenerate SO 3 asymmetric stretch. Solutions of LiCF 3 SO 3 in acetonitrile (CH 3 CN) have also been studied. , Our measurements for this system at room temperature show bands at 1300 cm -1 (33%), 1272 cm -1 (32%), and 1255 cm -1 (27%) which are in agreement with those of Lindgren and co-workers 10 and Cobranchi et al 8 Infrared spectra of the SO 3 asymmetric stretch region shown for lithium and sodium triflate electrolytes. …”

Section: Resultssupporting

confidence: 82%

“…The model used to fit the PPG C−O−C IR region consists of Gaussian bands at ∼1155, ∼1110, and ∼1060 cm -1 . The band at ∼1110 cm -1 is a mixture of ν(COC) a and ν(COC) s where the subscripts a and s denote respectively asymmetric and symmetric stretching modes. ,, Due to the weakening of the COC bond caused by cation coordination, an additional peak appears at ∼1085 cm -1 . , The degenerate triflate anion SO 3 asymmetric stretch, ν 3 (E‘), consists of three components in the region 1240−1300 cm -1 and the corresponding spectra were fitted using a four component Gaussian model including the ν(CF 3 ) s band at ∼1225 cm -1 . − , For the NaCF 3 SO 3 and LiCF 3 SO 3 samples, the SO 3 symmetric stretch was analyzed by using a three-component model according to previous assignments. , For the lithium complex these three components occur at about 1032, 1042, and 1052 cm -1 , allowing for bands corresponding to respectively “free” anions, contact-ion pairs and higher aggregates; for the sodium complex these frequencies shift to 1032, 1037, and 1046 cm -1 because of the larger ionic radius and, therefore, weaker interaction. The 1042-cm -1 band has also been interpreted to contain the (CF 3 SO - 3 ) 2 Li + triplet .…”

Section: Methodsmentioning

confidence: 99%

“…In these studies the infrared spectrum of the SO 3 asymmetric stretch mode has also been a subject of interest. However, there have been disagreements in the interpretation and assignment of the observed splittings and shifts of this mode in terms of ion−ion interactions. ,,, Ion−polymer interactions are manifested as spectral changes in characteristic regions associated with polar sites of the host polymer, i.e., ether oxygens and OH end groups in the case of PPG. , Therefore, in an attempt to understand the conductivity behavior of the ammonium triflate electrolytes, as reported by Albinsson et al, , FT-IR and FT-Raman spectroscopy have been used to study the polyether C−O−C and the salt vibrations for the PPG4000−NH 4 CF 3 SO 3 /ND 4 CF 3 SO 3 electrolytes. As a basis for comparison and in the interest of understanding the spectroscopic data of Ferry et al, spectra for these vibrations are also given for MCF 3 SO 3 /PPG4000 (M = Li, Na).…”

Section: Introductionmentioning

confidence: 99%

“…However, there have been disagreements in the interpretation and assignment of the observed splittings and shifts of this mode in terms of ion-ion interactions. 8,15,29,37 Ion-polymer interactions are manifested as spectral changes in characteristic regions associated with polar sites of the host polymer, i.e., ether oxygens and OH end groups in the case of PPG. 16,17 Therefore, in an attempt to understand the conductivity behavior of the ammonium triflate electrolytes, as reported by Albinsson et al, 31,32 FT-IR and FT-Raman spectroscopy have been used to study the polyether C-O-C and the salt vibrations for the PPG4000-NH 4 CF 3 SO 3 /ND 4 CF 3 -SO 3 electrolytes.…”

Section: Introductionmentioning

confidence: 99%

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Studies of Ionic Interactions in Poly(propylene glycol)4000 Complexed with Triflate Salts

1996

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In aprotic electrolytes and, in particular, in most polyether-salt systems the molar conductivity increases dramatically with increase in salt concentration from a minimum at low concentrations to an unexpected high maximum. Such increases in conductivity are larger than would be accounted for by Fuoss-Onsager type transport theories in which complete dissociation is assumed. Examples can be found in poly(propylene glycol) (PPG) complexed with triflate salts. The series MCF 3 SO 3 /PPG4000 (M ) Li, Na, NH 4 , ND 4 ) has been studied and illustrates the effect of cation on the value of the maximum molar conductivity and the rate of increase of molar conductivity with increase in concentration. Particular attention has been paid to the previously reported enhancement of the ionic conductivity for ND 4 CF 3 SO 3 /PPG4000 electrolytes over that of NH 4 CF 3 SO 3 /PPG4000. Detailed infrared and Raman studies of the polyether C-O-C vibrations and of the salt vibrations have been carried out as a function of temperature (FT-IR) and salt concentration (FT-IR and FT-Raman). Spectral data are reported which show that the polarizability of the anions is effected differently in chemical coordination processes in these ammonium electrolytes than are the dipole moments. We interpret the results in terms of ionic interactions and attribute the enhanced conductivity for the deuterated electrolyte to an increased ionic mobility due to a looser association of the ND 4 + cations to the CF 3 SO 3anions leading to shorter lifetimes of the various associations of ions. We comment on the ionic interactions that have been previously proposed to explain the observed increase in molar conductivity and propose an additional concept, i.e., that with increase in salt concentration there is an increase in the rate of exchange of cations between ion pairs and higher aggregates and between anion-associated sites and those ether oxygen sites to which the cation is less tightly coordinated.

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