Patrick Brant

Ion implantation studies of (SN)x and (CH)x

Abstract We report the results of the initial investigation of the application of ion implantation for the “doping” of the electroactive polymers, (SN) x and (CH) x . Increases in conductivity have been measured for some (CH) x samples after being implanted. Evidence for the formation of a discrete chemical species has been observed in the case of (CH) x implanted with Br + ions. Advantages and drawbacks associated with this technique are discussed.

X-Ray photoelectron spectra of iron complexes: correlation of iron 2p satellite intensity with complex spin state

Abstract Metal and ligand core-level spectra have been obtained for 36 iron complexes which possess a variety of ligands including carbonyl, nitrosyl, triphenylphosphine,o-phenylenebis(dimethylarsine), halides and pseudohalides. Formal metal oxidation states range from − 1 to + 3, and complex spin states represented in the series include 0, 1 2 , 3 2 , 2 and 5 2 . A clear correlation between complex spin state and satellite intensity in the Fe 2p spectra is found. The satellite intensities observed experimentally are in approximate quantitative accord with those predicted by a “spin flipping” model. Although the present analysis does not provide a definitive choice between the “sudden approximation” and “spin flipping” models, the agreement between experimental satellite intensities and the intensities predicted by the “spin flipping” model suggests that such a mechanism can be important in the satellite process.

Gas phase and solid state X-ray photoelectron spectra of the substituted acetylenes (SF5)n C2 (CF3)2−n (n = 0, 1, 2): A comparison of the pentafluorosulfur and trifluoromethyl groups

Abstract The core level X-ray photoelectron spectra (XPS) of CF 3 CCCF 3 , CF 3 CCSF 5 and SF 5 CCSF 5 have been measured in the solid state. Gas phase spectra of CF 3 CCCF 3 and CF 3 CCSF 5 have also been obtained. The XPS data, interpreted with the point charge potential model and semiempirical MNDO (minimum neglect of differential overlap) molecular orbital calculations, indicate that the electron withdrawing effect of the −CF 3 group is greater than that of the −SF 5 group. Results further suggest that sulfur 3 d orbitals do not play a detectable role in the bonding or charge distribution in these molecules. Carbon 1 s linewidths of −CF 3 carbon atoms are found to be much narrower than those arising from the acetylenic carbon atoms. The narrower lines correlate with the much higher binding energy of the −CF 3 carbon atoms. Large shifts (nearly 1 eV) in heteroatom core level binding energy differences (for example, F 1 s — C 1 s ) between the gas phase and solid state data are observed. These shifts are attributed to solid state effects (Madelung potential, intermolecular bonding interactions, and/or extramolecular relaxation contributions). From these comparisons it is clear that solid state effects are not uniform in their influence on the photoionized sites in these molecules.

Identification of intercalated species in AsF5NO2SbF6 intercalated graphite using 19F N.m.r.; fluorine exchange between the various species

Abstract An intercalated graphite was prepared by reaction of polycrystalline graphite with AsF 5 followed by reaction with NO 2 SbF 6 . At −73%, four narrow lines are found in the 19 F n.m.r. spectrum at +124.1, +112.7, +66.7, and +46.8 ppm (relative to CFCl 3 ). These lines are attributed to SbF 6 − , SbF 5 , AsF 6 − in rapid chemical exchange with AsF 5 , and AsF 3 , respectively. This demonstrates the use of n.m.r. for the qualitative analysis of the chemical species present in the interlamellar space. As the temperature is increased, the lines broaden (except for that of AsF 3 ) and subsequently narrow, indicating, further, that chemical exchange of fluorine is occurring among SbF 6 − , SbF 5 , AsF 6 − and AsF 5 . At 22 °C the exchange rate is ∼ 10 3 s −1 for SbF 6 − and >3 × 10 3 s −1 for the other species. The data are interpreted in terms of a model in which fluorine exchange between SbF 6 − and the fluoro-arsenic species occurs via SbF 5 .

Mass-spectral investigation of AsF5-doped (CH)x

Abstract Polyacetylene, (CH)x, doped with arsenic pentafluoride has been the subject of considerable study since the discovery of its high electrical conductivity, but controversy has surrounded the form of the dopant in the polymer. We report the results of a mass-spectral study aimed at identifying the arsenic fluoride species present after doping. The results demonstrate that AsF6− is present, and models are proposed to explain the possible source of the controversy concerning previous anlytical results. A method of synthesis is suggested for reproducible production of a pure AsF6−-doped material.

X-Ray photoelectron spectra of dopant molecules for conducting polymers. Vapor phase core level binding energies for arsenic and antimony pentafluorides

Abstract The core level binding energies of AsF 3 and AsF 5 gas have been measured and the ΔBE(F 1s-As 3d) shift between the two molecules has been found to be over twice as large as the value previosly reported. Core data lavel has also been recorded for antimony pentafluoride gas. It is anticipated that these data will be useful in evaluating the nature of polymerdopant interactions.

The application of gas phase and solid state X-ray photoelectron spectroscopy to the investigation of derivatives containing the repeating SN unit☆

Abstract Solid state X-ray photoelectron spectra of S 2 N 2 , S 4 N 4 , (SNBr 0.04 ) x , and (SNBr 0.25 ) x have been obtained and the gas phase spectrum of S 2 N 2 is also reported. Both the solid state and gas phase core level spectra, as well as MNDO and CHELEQ calculations, show that there is greater S → N charge transfer in S 4 N 4 than in S 2 N 2 . The solid state data indicate that the charge distributions in S 2 N 2 and (SN) x are the same. All of the data can be satisfactorily explained without recourse to N p π → S d π bonding. Bromination of an (SN) x film and single crystals results in complicated, broad N 1s and S 2p envelopes. Changes in the relative core level intensities on bromination suggest that the bromine resides largely between and/or on the (SN) x fibrils, rather than penetrating into the fibrils.

NMR observations of fluorine ion-implanted into polyacetylene and graphite

Abstract 19 FNMR spectroscopy has been used to characterize fluorine implanted into polyacetylene and highly orientated pyrolytic graphite. The intensities of the 19 F NMR spectra at 4.5 K show that essentially all the fluorine is retained in these materials after the implantation process is over. The Une width of the spectrum of the graphite sample indicates that the fluorine remains where it was deposited. For the polyacetylene sample the ratio of the NMR solid echo height to the spin echo height, as calibrated herein, shows that the predominant nuclear diploar interaction of the implanted fluorine is heteronuclear.

Doping of poly(acetylene) to the metallic state using thionyl chloride

Abstract SOCl 2 has been found to be an effective oxidant for poly(acetylene), increasing the electrical conductivity by several orders of magnitude. The oxidized (CH) x sites are thought to be compensated with chloride ion liberated by reduction of SOCl 2 . The use of poly(acetylene) as a current collector in lithium/oxyhalide cells is reported elsewhere [14].

19F NMR Spectroscopic and Relaxation Studies of SbF5 and AsF5 Intercalated in Graphite, Graphite Fibers, and Polyacetylene

19F NMR spectra are presented for graphite powder reacted with SbF5, NOSbF6, NO2SbF6, graphite fibers reacted with AsF5, and polyacetylene reacted with NOSbF6 and with AsF5. For polyacetylene the linewidths imply rapid rotation and slow diffusion. For the other specimens linewidths imply that both rotation and diffusion are rapid. For SbF5 in graphite an activation enthalpy of 5±1 kcal/mol is deduced from the observed T1 behavior.