Arsenic pentafluoride conductivity

When heated, polyvinyl chloride (PVC) and polyvinyl alcohol (PVA) lose HC1 and H20, respectively, to produce dark-colored conductive polyacetylene. Superior polymers of acetylene can be made by the polymerization of acetylene with Ziegler-Natta catalysts. The conductivity of polyacetylene is increased by the addition of dopants, such as arsenic pentafluoride or sodium naphthenide. 

Excess arsenic pentafluoride was condensed at — 196° onto bis[trifluoromethyl] tellurium. The reaction mixture was slowly warmed to — 78° and stirred for 1.5 h. The volatile components were removed by distillation and the residue was washed at — 78° with fluorotrichloromethane. The reaction with antimony pentafluoride was conducted similarly with fluorotrichloromethane as the reaction medium1. 

The reaction between bis[trifluoromethyl] tellurium difluoride and arsenic pentafluoride or antimony pentafluoride was conducted at — 78° for two days. The excess pentafluoride was removed by distillation at low temperature1. 

Solutions of arsenic pentafluoride have conductivities and freezing point depressions (Dean et al., 1970) that are only approximately one-half those of SbF5 at the same concentration and it has been shown that even in dilute solutions there is essentially complete formation of the As2Ff1 ion according to equation (14). 

The report of the doping of polyacetylene (PAc) films to produce metallic levels of conductivity by Shirakawa et al. (1977) sparked the interest in electrically conductive polymers that has continued until today. While it was not the first example of a conductive polymer, the increase in conductivity, by a factor greater than 107, observed on exposing films of trans-PAc to arsenic pentafluoride and iodine, was dramatic, see Fig. 9.1. The impact of this result was immediate, and created an upsurge of interest in conjugated polymers and the possibility of rendering them conductive. 

Intercalation of graphite by arsenic pentafluoride had been reported in 1975, by Lin Chun-Hsu et al. In 1977, E. R. Falardeau et al. reported that graphite fully intercalated by AsFs, had a basal-plane specific conductivity akin to copper metal. I had already pondered on the reasons for the easy intercalation of graphite by AsFs and had wondered if removal of electrons from the 7r-electron band of graphite was involved. 

The recent facts on new conducting polymers [13] should be used to examine its action against the accumulation of static electricity, provided they are not harmful to the stability of the powder. Particularly interesting seem to be poly-acetylene or poly-p-phenylene arsenic pentafluoride. 

When trans (CH)y film is partially oxidized (i.e. p-doped) by bromine, iodine, arsenic pentafluoride, etc. its conductivity increases by eight orders of magnitude and it is converted to an "organic metal having all the electronic properties of a conventional metal (1-3). Until recently it had been believed that all p-doped material was very unstable in the presence of water. When the present study was undertaken there were only two apparent exceptions to this water instability. 

Poly( 1,2-oxy propylene )dioI (PPG) 604 Poly-p-phenyiene arsenic pentafluoride. as conducting agent 622 Polyurethane binders 602.603.6IJ5... 

G. Kossmehl and G. Chatzitheodorou, Electrical conductivity of poly(2,5-thiophenediyl)-arsenic pentafluoride-complexes, Makromol. Chem., Rapid Commun., 2, 551-555 (1981). 

Arsenic pentafluoride effects a Friedel-Crafts chain extension and cross-linking in PPV. The electrical conductivity takes place by a variable-range hopping mechanism. 

K. D. Gourley, C. P. Lillya, J. R. Reynolds, and J. C. W. Chien. Electrically conducting polymers arsenic pentafluoride-doped poly(phenylene-vinylene) and its analogs. MflcroOTo/ecM/es, 17(5) 1025-1033, 1984. 

As an example of RBS applied to a polymer system, figure 3.22 shows the spectrum obtained from a sample of the conjugated polymer poly(phenylene, vinylene) after exposure to arsenic pentafluoride vapour (Masse et al. 1990). This dopant diffuses into the polymer and reacts with it to form an electrically conducting complex and RBS is well suited to following the kinetics of the doping process by providing concentration-depth profiles of the elemental components of the dopant as a function of time. The peaks in the spectrum... 

Horhold and Rathe [248] reported that they have prepared poly(9-methylcarbazole-3,6-diyl-l,2dipenylvinylene). The polymer (M = 10,000) was formed by dehalogenating polycondensation of 3,6-bis(a,oc-dichlorobenzyl)-10,9-methylcarbazole with chromitm(II) acetate. This polymer was found to be also highly photoconductive. Its dark conductivity increases by doping it with arsenic pentafluoride [248]. 

While many applications for PPS involve its inherent electrical insulating behavior, it is a member of the family of organic polymers which can be rendered electrically conductive by "doping" with appropriate compounds such as arsenic pentafluoride. PPS is the only commercially available polymer which can be made conductive in this manner. Furthermore, it is the only melt processable resin in the group of such polymers. This behavior was initially described jointly by Chance, et al, at Allied and by Street, et al, at IBM at the 1980 Spring Meeting of the American Chemical Society31,32,33. More recently workers at GTE Laboratories have... 

In 1981, the first conducting silicon polymer, arsenic pentafluoride-doped polysilane, was reported by West and co-workers [5]. In 1983, Marks et al. reported that... 

West and co-workers reported that when poly-(dimethyl-co-methylphenylsilane) (3) prepared from cocondensation of dichlorodimethylsilane and di-chloromethylphenylsilane with sodium metal was treated with strong electron acceptors such as SbFs and AsFs, the polymer became semiconducting [5]. Since this initial report, much attention has been focused on the preparation of conducting silicon polymers. To date, many types of polysilanes that have various substituents have been used for the preparation of the conducting polymers. Iodine, ferric chloride, arsenic pentafluoride, and antimony pentafluoride are usually used as dopants. 

Polysilane copolymers also become conducting when they are doped with oxidizing agents. Treatment of copolymer 3 with arsenic pentafluoride affords a conducting polymer as shown in Table 15.2 [5,7]. Interestingly, when the crosslinked copolymer prepared from irradiation of a linear polysilane 3 with x = 0.5 and y = 1.0 is doped with arsenic pentafluoride, the conductivity of the polymer increases slowly, but eventually reaches a level of 2 x 10 S cm [5]. 

Table 15.5 Conductivity of polymers 15-18, after doping with arsenic pentafluoride [23]...

Herold A., Conductivity anisotropy in arsenic pentafluoride-intercalated graphite. In Chemical Physics of Intercalation, Legrand A. P. (ed.), NATO ASI Series, Vol. 172 (1987), p. 3B. 

Caution. All reactions should be conducted In a well-ventilated fume hood with appropriate precautions. Arsenic and antimony pentafluoride and arsenic trifluoride are very poisonous and hydrolyze readily to form Bromine is corrosive and is harmful to the skin and mucous membranes. Sulfur dioxide is poisonous and can generate 3 to 4 atmospheres pressure at room temperature. Well-constructed glass vessels or metal systems must be employed to prevent pressure bursts. The use of rubber gloves, safety glasses, and face shields is recommended. 

Selenium and tellurium and their compounds produce very unpleasant and dangerous physiological reactions. They are hazardous both through inhalation as dusts and through skin absorption from solution. Because of these properties and because of the toxicity of the sulfur dioxide used as a solvent, the reactions should be conducted in an efficient fume hood. Rubber gloves and apron are recommended to prevent contact with solutions containing selenium and tellurium compounds as well as the dangerous pentafluorides of antimony and arsenic. 

The pentafluorides of arsenic and antimony are probably molecular in all the states of aggregation. There are, however, indications that polar forms are produced in CH3CN, since the compounds AsF.-CH3CN and SbF.-CH3CN crystallize from this solvent and the solutions exhibit conductivities comparable with values for phosphorus (V) chloride (Table II). 

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