Perylene-iodine

Comparatively little work on copper batteries has been reported. The substitution of silver by copper in RbAg I does not exceed 0.34 wt % and cells of/this electrolyte with copper anodes behaved in an unstable fashion. Preliminary cell measurements have also been reported using NN dimethyl triethylene-d gj ne dibromide - cuprous bromide in conjunction with copper anodes. With charge transfer complex cathodes (Br -perylene, iodine-perylene) the cells were unstable as the halogen oxidised the CuBr (or Cul) reaction product to the Cu state. With a stable behaviour was observed. 

The first report of a perylene-iodine complex with metallic conductivity was Per(l2)4 by Kao et al. [10], with values as high as 51.9 S/cm at 300 K. A broad maximum of conductivity exists at ca. 235 K (Figure 2.3). In a few samples that did not crack at lower temperatures, a gap of 0.1 eV was measured. The EPR linewidth at room temperature is 10.9 G, clearly distinguishable from the Per2(l2)3 complex. The authors indicate that spin density from EPR exhibits an activated behaviour with = 0.02 eV in the range 100-300 K, consistent with a model of a narrow band-gap semiconductor. The determination of the crystalline structure was not accomplished, but from X-ray oscillation photographs, an incommensurate structure was proposed. 

The use of the tetrachalcogenoperylene molecules such as TTP to obtain molecular conductors has been greatly limited by the low solubility of these compounds, which is much smaller than perylene in the usual solvents. Hilti et al. [120] obtained, by cosublimation of this donor and iodine, a highly conducting compound, TTP-I. 28- In this case, as opposed to the perylene—iodine complexes, the iodine composition was found to be much more stable in a... 

Synthesis of Radical Cation Perchlorates and Subsequent Coupling with NucleophilesT Syntheses of the radical cation perchlorates of BP and 6-methylBP (12) were accomplished by the method reported earlier for the preparation of the perylene radical cation (13,14). More recently we have also synthesized the radical cation perchlorate of 6-fluoroBP (15). Oxidation of the PAH with iodine in benzene in the presence of AgClO. instantaneously produces a black precipitate containing the radical cation perchlorate adsorbed on Agl with... 

In a different study, anthracene, phenanthrene, perylene 93 (Fig. 31), and 2,7-di-tert-butylpyrene underwent regioselective oxidative-substitution reactions with iodine(III) sulfonate reagents in dichloromethane to give the corresponding aryl sulfonate esters. The use of [hydroxy(tosyloxy)iodo]benzene, in conjunction with trimethylsilyl isothiocyanate, led to thiocyanation of the PAH nucleus. 

In this context it is important to keep in mind, however, that di(2-naphthyl)ethylene (2 + 2) and 3-styrylphenanthrene (3 +1) form pentahelicene on irradiation, but in the presence of iodine it cyclizes into benzo[g,h,i]-perylene 17). The second cyclization... 

No photoreactions, except incidental photodestruction are known for hexa- and higher helicenes. As already mentioned in 2.1.1. pentahelicene forms benzo[g,h,i]perylene on irradiation in the presence of iodine as an oxidizing agent. Remarkably, the symmetrical benzoderivative (111) does not yield a similar cyclization product. This is ascribed to the antibonding character of the ji-orbitals at C-(l) and C-(14) involved in the expected photoreaction as appeared from EHMO calculation 17b). 

A curious case is that of perylene, 23, which takes up 1.512 per molecule50. The spectrum requires five subspectra for a satisfactory fit, three of which are similar to I3. The remaining two subspectra are similar to those of singly bound I2. A structure is proposed in which two I2 molecules are charge-transfer bound to one end of a linear I3 ion, 24. Phenothiazine shows similar behaviour6 the iodine-doped sample appears to contain two I2 molecules and three I3 ions for every five molecules of phenothiazine. 

In the above radical-cation salts, the crystal contains partially oxidized donors, while the electroneutrality is achieved by the presence of closed shell anions. The structural requirements necessary for electrical conductivity in solid salts can also be met upon mixing of donors and acceptors in the resulting charge-transfer (CT) complexes both the donor and acceptor exist in a partially oxidized and reduced state, respectively. Famous examples are the conducting CT complexes formed upon mixing of perylene (112) [323. 324] and iodine or of tetrathiafulvalene (TTF, 119) as donor and 7,7,8,8-tetracyanoquinodimethane (TCNQ, 120) as acceptor [325-327] the crucial structural finding for the... 

The systems that were used by this writer and colleagues contained one of some four or five different donor molecules—phthalocyanine, violan-threne, perylene, etc.—we found that almost any highly aromatic system could serve as a conducting matrix and phthalocyanine was only one of these. The electron acceptor systems that we used were o-chloranil (the most commonly used), iodine and tetracyanoethylene. These donor and acceptor systems were used in various combinations. A pattern of results based on a conductivity cell is shown in Figs. 3a, b, and c. It is made of aquadag electrodes on which is coated the matrix (phthalocyanine or violanthrene, as the case may be) usually the samples are sublimed onto the electrode system. On top of the matrix is placed one of the doping agents, one of the donors or acceptors. 

Use of iodine-silver perchlorate may accomplish cation-radical formation before the oxidizing pair can themselves react. In modern usage, silver ion (as the perchlorate usually) is added to a solution of the substrate and iodine, and the complexity of the iodine-silver perchlorate system is avoided, provided that the substrate undergoes reasonably fast oxidation. Such is the case with perylene (Sato et al., 1969 Ristagno and Shine, 1971) and pheno-thiazine, but not the case with diphenylanthracene and thianthrene (Shine et al., 1972). 

We have already referred to oxidations by iodine-silver perchlorate (p. 168). This is an easy way of making the perchlorates of some cation radicals such as of perylene (Sato et al., 1969 Ristagno and Shine, 1971b). In appropriate circumstances, silver ion itself should be able to oxidize some compounds to their cation radicals, and this has been achieved with some 2-phenyl-3-arylaminoindoles and silver perchlorate in acetone or acetonitrile a silver mirror is formed (Bruni et al., 1971). 

To our knowledge no reaction of iodide ion as a nucleophile with a cation radical is known. Iodide ion reduces cation radicals very well and is frequently used for the iodimetric assay of cation-radical salts. Since the reduction is reversible and some compounds can be oxidized to the cation radical stage by iodine, an excess of iodide is used. Some cation radicals are also reduced by other halide ions for example, that of 9,10-diphcnylanthracene is reduced by bromide ion (Sioda, 1968), that of perylene by bromide and chloride ions (Ristagno and Shine, 1971b), and thianthrene radical cation to some extent by chloride ion (Murata and Shine, 1969). These reductions, particularly those by iodide ion, reflect again the competition between nucleophilicity and oxidizability of a nucleophile in reactions with cation radicals. 

Single crystals of Perx[M(mnt)2] (M = Cu, Ni, Pt, Au, Co, Fe) can be prepared either by electrocrystallization from dichloromethane solutions containing perylene and the corresponding tetraalkylammonium salt of [M(mnt)2] , or by perylene oxidation with iodine. The first method usually gives better results, and has been more extensively used, but, for M = Pd, crystals could only be obtained by iodine oxidation. 

Although far from presenting the lowest oxidation potential among many other known 7t-donors, the perylene molecule can be oxidised in several organic solvents, either by the direct action of chemical oxidants such as iodine or bromine, or electrochemi-cally. In dichloromethane solutions, at a potential of 0.9 V versus SCE (saturated calomel electrode), it... 

The Per M(mnt)2 compounds are prepared by perylene oxidation in solutions containing the M(mnt)J anion. This oxidation can be carried out chemically by the addition of iodine, or electrochemically. The perylene cation once generated, promptly associates with neutral perylene as Per which reacts with the anions present in the solution [3] to precipitate on the electrodes the low-solubility Per M(mnt)2 compounds, usually with n = 2. 

In the chemical oxidation process, typically a small excess of iodine is added to a solution of perylene and M(mnt)f, usually as a TEA salt in stoichiometric proportions, and the crystals are collected after cooling and partial evaporation. The best samples are obtained by a slow diffusion-controlled process lasting a few days. 

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