Icosahedral carboranes. XVII. Carboranyl sulfoxides and sulfones

Scott, Robert N.; Hooks, H.; Sieckhaus, John F.

doi:10.1021/ic50104a064

Cited by 43 publications

(5 citation statements)

References 5 publications

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“…This result can be interpreted in terms of past results for the PPO/LiClO 4 complex. In this complex, the ClO 4 - anions are weakly solvated and located among the polymer chains, which causes chain expansion as the polymer chains are pushed apart by the large anions. ,, According to X-ray and neutron diffraction studies, it has been suggested that the Li + in the PPO/LiClO 4 complex has a pulling-together effect because Li + forms cross-links between the polymer chains, whereas ClO 4 - pushes the polymer chains apart. The increase of the interchain distance at concentrations above [CO]:[Ag] = 3:1 seen in our work (Figure ) may be attributed to the expansion of the POZ chains as more anions accumulate among the polymer chains.…”

Section: Resultsmentioning

confidence: 99%

Wide-Angle X-ray Scattering Studies on the Structural Properties of Polymer Electrolytes Containing Silver Ions

2001

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Wide-angle X-ray scattering (WAXS) has been used to study the structural properties of polymer electrolytes containing silver ions. The WAXS spectra of pure poly(2-ethyl-2-oxazoline) (POZ) and poly(vinylpyrrolidone) (PVP) showed two broad amorphous peaks. The first of these peaks was assigned to the interchain distance, and the second peak was assigned to the distance between the pendant groups of the polymer chains. When silver salts such as AgBF4, AgCF3SO3, or AgClO4 were introduced into the polymer matrices, their silver ions coordinated with the carbonyl oxygens on the pendant groups to form polymer/silver salt complexes. In the case of the PVP/silver salt complexes, the first peak shifted to lower angle and became narrower with increasing silver concentration, indicative of an increase in the interchain distance and ordering. In contrast, the position of the second peak remained almost constant. For the POZ/silver salt complexes, however, the positions of both peaks shifted to higher scattering angle with increasing silver concentration until the mole ratio of carbonyl oxygen to silver reached about 3:1. Further increase of the concentration caused the first peak to shift to lower angle while the second peak remained almost constant, which is similar to the behavior of the PVP/Ag salt complexes. The difference in the behavior of the PVP/Ag and POZ/Ag salt complexes may arise from different strengths of the transient cross-links formed by silver cations with the pendant groups of POZ and PVP. The Bragg d spacing results calculated from the second peak indicate that the silver ions coordinate more strongly with the pendant groups in the POZ/AgClO4 complex than in the POZ/AgCF3SO3 and POZ/AgBF4 complexes. It is worth noting that the Bragg d spacings for the POZ/silver and PVP/silver salt complexes were very different at low silver concentrations but approach almost the same value at high silver concentrations (e.g., at a mole ratio of [CO]:[Ag] = 1:1). These findings are consistent with our previous results on facilitated olefin transport and glass transition temperature behavior in silver polymer electrolyte membranes. We therefore conclude that the facilitated olefin transport and glass transition temperature behavior in polymer electrolytes are strongly related to the structural change that occurs upon coordination of silver cations with the carbonyl oxygens of the polymeric chains.

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Section: Resultsmentioning

confidence: 99%

Wide-Angle X-ray Scattering Studies on the Structural Properties of Polymer Electrolytes Containing Silver Ions

2001

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“…The sulfur atom already possesses its highest formal oxidation state and the sulfur−carbon bond is known to be very stable . Although previous studies of the oxidation of the SH-groups of 1,7- and 1,12-bis(thiol)-substituted m - and p -carborane have been reported, − 1,12-sulfinic and sulfonic acid derivatives of p -carborane had not yet been prepared. The synthesis of closo -1,7-(HO 3 S) 2 -1,7-C 2 B 10 H 10 ( 8 ), also the subject of a patent, has been accomplished by a stepwise oxidative conversion of the parent 1,7-bis(thiol) to the corresponding closo -1,7-bis(chlorosulfenyl)- and closo -1,7-bis(chlorosulfonyl)- m -carborane, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The reaction of 10 with SO 2 Cl 2 furnished closo -1,12-bis(chlorosulfonyl)- p -carborane ( 11 ) in quantitative yield. Use of the AlCl 3 -mediated hydrolysis of 11 , analogous to the procedure employed in the synthesis of 8 , afforded the bis(sulfonic acid) closo -1,12-(HO 3 S) 2 -1,12-C 2 B 10 H 10 ( 12 ) in 95% yield. In parallel, the corresponding bis(sulfinic acid) closo -1,12-(HO 2 S) 2 -1,12-C 2 B 10 H 10 ( 13 ) was obtained as an air-stable compound after H + -cation exchange of 10 (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Synthesis, Structure, and Reactivity of closo-2,3,4,5,6,7,8,9,10,11-Decahydroxy-1,12-bis(sulfonic acid)-1,12-dicarbadodecaborane(12)

Herzog

2001

J. Am. Chem. Soc.

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The reaction of closo-1,12-bis(lithio)-1,12-dicarbadodecaborane(12) (1,12-bis(lithio)-p-carborane) with SO(2) formed closo-1,12-bis(lithiosulfinato)-p-carborane (10) in nearly quantitative yield. The latter was converted to closo-1,12-bis(sulfinic acid)-p-carborane (13) via H(+)-exchange. The corresponding 1,12-bis(sulfonic acid) derivative of p-carborane (12) was obtained in high yield by treating 10 with SO(2)Cl(2) and subsequent AlCl(3) mediated hydrolysis of the closo-1,12-bis(chlorosulfonyl)-p-carborane intermediate. The exhaustive oxidation of 12 in hot aqueous H(2)O(2) (30%) afforded B-decahydroxy-1,12-bis(sulfonic acid)-p-carborane (15) in 40% yield. As a byproduct, closo-B-decahydroxy-1-sulfonic acid-p-carborane (14) was formed. Both 14 and 15 were also obtained from the hydroxylation of 10 and 13. Compound 14 was obtained directly in 88% yield by heating 1-sulfinic acid-p-carborane (17) in H(2)O(2) (30%). Compound 17 was synthesized from diphenylmethylsilyl-protected p-carborane by using the method employed in the synthesis of 13. The X-ray structures of 15, its disodium salt, and its dipotassium salt are presented and discussed. Exhaustive methylation of 15 with methyl triflate furnishes closo-B-decamethoxy-1,12-bis(methyl sulfonate)-p-carborane (20). The characterization of closomer 20 also includes its crystal structure determination.

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“…Stringently drying the PPG clears ether oxygen sites so that it is easier for the extremely dry salt to dissociate and effect a solvation of the NH 4 + cation. The anion does not in general solvate except possibly through hydrogen bonding with the OH terminal groups on the polyether chains. ,,,,− The MCF 3 SO 3 /PPG4000 (M = Li, Na) electrolytes were prepared in a similar manner.…”

Section: Methodsmentioning

confidence: 99%

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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Icosahedral carboranes. XVII. Carboranyl sulfoxides and sulfones

Cited by 43 publications

References 5 publications

Wide-Angle X-ray Scattering Studies on the Structural Properties of Polymer Electrolytes Containing Silver Ions

Wide-Angle X-ray Scattering Studies on the Structural Properties of Polymer Electrolytes Containing Silver Ions

Synthesis, Structure, and Reactivity of closo-2,3,4,5,6,7,8,9,10,11-Decahydroxy-1,12-bis(sulfonic acid)-1,12-dicarbadodecaborane(12)

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

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