Electrical conduction in organic polyiodide chain complexes

Oza, A. T.

doi:10.1002/crat.2170190522

“…[11] Depending on the forces exerted by the organic counterions (chemical pressure), PIs exhibit useful electrochemical properties,s uch as charge-carrier transportation, high electrolyte energy densities,high redox reaction reversibility, [12,13] and aw ide range of electrical conductivity properties,f rom insulating to metallic behavior. [14,15] Hence,P Is have found technical applications in electronic and electrochemical devices such as flow batteries,f uel cells,d ye-sensitized solar cells,a nd optical devices. [12,16,17] Compared with chemical pressure,anexternal mechanical pressure more substantially affects the crystal inter-a nd intramolecular landscape.I nf act, al arge lattice strain may induce phase transformations and even chemical reactions.…”

mentioning

confidence: 99%

Pressure‐Induced Polymerization and Electrical Conductivity of a Polyiodide

Poręba

¹

,

Ernst

²

,

Zimmer³

et al. 2019

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We report the high-pressure structural characterization of an organic polyiodide salt in which ap rogressive addition of iodine to triiodide groups occurs.C ompression leads to the initial formation of discrete heptaiodide units, followed by polymerization to a3Danionic network. Although the structural changes appear to be continuous,t he insulating salt becomes as emiconducting polymer above1 0GPa.T he features of the pre-reactive state and the polymerized state are revealed by analysis of the computed electron and energy densities.T he unusually high electrical conductivity can be explained with the formation of new bonds.Polyiodides (PIs) in crystal form were discovered about 200 years ago. [1] Their structural diversity,which is due to the bonding flexibility of iodine,r emains the subject of continuous interest. [2][3][4] Nowadays,v arious PIs are known, ranging from I 3 À to I 29 3À ,with the general formula I nÀ 2 m+n and n up to 4. Their building blocks consist of I 3 À as adonor and I 2 as an acceptor forming ac harge transfer (CT) complex. CT complexes can interact further to form extended structures with various topologies,u pt oc ubic networks.A st he aggregation of iodine units is somewhat unpredictable,t he design of PIs is not easy.Moreover,the classification of higher units is,thus far,pragmatically based on the distance between iodine atoms,but universal criteria are still lacking.Different theoretical approaches to study bonds in PIs exist, for example,calculations of the potential energy surface and bond order, [5] energy decomposition analysis (EDA), [6] analysis of the electron density and its Laplacian at bond critical points (BCP), [7] theelectron localization function, and the one-electron potential. [8] Furthermore,t he energy den-

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“…Dithionaphthalene (DTN) was prepared by a direct reaction between sulphur and naphthalene in dimethylformamide medium as described in details elsewhere (Oza 1980). The chocolate-brown coloured dithionaphthalene and iodine were sublimated in a cosublimation growth tube to interact with each other in the vapour phase and the crystalline complex was collected on a glass rod as substrate.…”

Section: Methodsmentioning

confidence: 99%

“…Recently an increase in the electrical resistivities of some inclusion compounds of iodine at high pressures has been reported (Oza 1980(Oza , 1982(Oza , 1983(Oza , 1984. The increase in the electrical resistances of the samples was attributed to either the localization near the band edges (Oza 1982(Oza , 1984 or localization associated with the traps (Oza 1983).…”

Section: Introductionmentioning

confidence: 99%

“…Recently an increase in the electrical resistivities of some inclusion compounds of iodine at high pressures has been reported (Oza 1980(Oza , 1982(Oza , 1983(Oza , 1984. The increase in the electrical resistances of the samples was attributed to either the localization near the band edges (Oza 1982(Oza , 1984 or localization associated with the traps (Oza 1983). In the present work the pressure dependence of the electrical resistivities of four charge transfer complexes called dithionaphthalene-iodine (1 : 1), anthracene-trinitrobenzene (1 : 1), pyrene-212 and benzidine-TCNQ (dichloromethane), where TCNQ = 7, 7, 8, 8tetracyano-p-quinodimethane, has been reported to have similar nature which shows that the suggested conduction mechanism is not limited only to the inclusion compounds of iodine.…”

Section: Introductionmentioning

confidence: 99%

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Pressure dependence of electrical resistivities of some charge transfer complexes

Oza

¹

1985

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The electrical resistivities of organic charge transfer complexes namely dithionaphthalene-iodine (1:1), anthracene-trinitrobenzene (1 : 1), pyrene-212 and benzidine-rCNQ (dichloromethane) have been studied upto 2-8 GPa pressure. An increase in the electrical resistivities shows that the conduction is due to a hopping mechanism involving localized levels near the band edges or is trap-limited. Pressure can increase both the density of defects and intermolecular orbital overlap as opposite effects.

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“…Depending on the forces exerted by the organic counterions (chemical pressure), PIs exhibit useful electrochemical properties, such as charge‐carrier transportation, high electrolyte energy densities, high redox reaction reversibility, and a wide range of electrical conductivity properties, from insulating to metallic behavior . Hence, PIs have found technical applications in electronic and electrochemical devices such as flow batteries, fuel cells, dye‐sensitized solar cells, and optical devices …”

Section: Figurementioning

confidence: 99%

Pressure‐Induced Polymerization and Electrical Conductivity of a Polyiodide

Poręba

¹

,

Ernst

²

,

Zimmer

³

et al. 2019

View full text Add to dashboard Cite

We report the high-pressure structural characterization of an organic polyiodide salt in which ap rogressive addition of iodine to triiodide groups occurs.C ompression leads to the initial formation of discrete heptaiodide units, followed by polymerization to a3Danionic network. Although the structural changes appear to be continuous,t he insulating salt becomes as emiconducting polymer above1 0GPa.T he features of the pre-reactive state and the polymerized state are revealed by analysis of the computed electron and energy densities.T he unusually high electrical conductivity can be explained with the formation of new bonds.Polyiodides (PIs) in crystal form were discovered about 200 years ago. [1] Their structural diversity,which is due to the bonding flexibility of iodine,r emains the subject of continuous interest. [2][3][4] Nowadays,v arious PIs are known, ranging from I 3 À to I 29 3À ,with the general formula I nÀ 2 m+n and n up to 4. Their building blocks consist of I 3 À as adonor and I 2 as an acceptor forming ac harge transfer (CT) complex. CT complexes can interact further to form extended structures with various topologies,u pt oc ubic networks.A st he aggregation of iodine units is somewhat unpredictable,t he design of PIs is not easy.Moreover,the classification of higher units is,thus far,pragmatically based on the distance between iodine atoms,but universal criteria are still lacking.Different theoretical approaches to study bonds in PIs exist, for example,calculations of the potential energy surface and bond order, [5] energy decomposition analysis (EDA), [6] analysis of the electron density and its Laplacian at bond critical points (BCP), [7] theelectron localization function, and the one-electron potential. [8] Furthermore,t he energy den-

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Electrical conduction in organic polyiodide chain complexes

Cited by 19 publications

References 23 publications

Pressure‐Induced Polymerization and Electrical Conductivity of a Polyiodide

Pressure‐Induced Polymerization and Electrical Conductivity of a Polyiodide

Pressure dependence of electrical resistivities of some charge transfer complexes

Pressure‐Induced Polymerization and Electrical Conductivity of a Polyiodide

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