74976-35-5Relevant academic research and scientific papers
Donor-Acceptor Complexes of Organotellurium Compounds. Physical Studies: Tellurium-125 Moessbauer Spectroscopy for the Measure of Charge Transfer. Crystal and Molecular Structure of the Complex Dibenzotellurophene-7,7,8,8-Tetracyano-p-quinodimethane
Singh, Harkesh B.,McWhinnie, William R.,Ziolo, Ronald F.,Jones, Colin H. W.
, p. 1267 - 1274 (2007/10/02)
A range of organotellurium(II) compounds, together with two selenium compounds are used as donors to form donor - acceptor complexes with 7,7,8,8-tetracyano-p-quinodimethane (tcnq).Generally, the stoicheiometry is 1 : 1 but two ditellurides provide an exception in giving R2Te2*2tcnq (R = Ph or C6H4OEt-p).The complexes are electrical insulators although the conductivities vary over several orders of magnitude.The two ditelluride complexes show evidence of semiconducting properties.E.s.r. and i.r. data are discussed and it is concluded that in most cases the degree of charge transfer is small.Exceptions to the rule appear to be the tcnq complex of 1,3-dihydro-2-telluraindene and Ph2Te2*2tcnq which do involve significant charge transfer as assessed from a 125Te Moessbauer study.A method of assessing the degree of charge transfer for donor - acceptor complexes of organotellurium compounds using Moessbauer spectroscopy is given.The crystal and molecular structure of the tcnq complex of dibenzotellurophene has been determined and molecular parameters compared with the known structures of the component molecules.The structural data confirm conclusions from i.r. and Moessbauer studies that, in this instance, the degree of charge transfer is very small.A novel feature of the structure is that in addition to intermolecular interactions within the mixed stacks, there are significant Te * * * N interaction between stacks.As a consequence, two different orientations of tcnq occur in the complex.
A study of the donor properties of the phenoxachalcogenines II: 7,7,8,8-tetracyanoquinodimethane as the acceptor
Rainville, David P.,Zingaro, Ralph A.,Ferraris, John P.
, p. 1133 - 1137 (2007/10/02)
The phenoxachalcogenines have been studied as donors towards 7,7,8,8-tetracyanoquinodimethane.For the 1:1 complexes studied, the equilibrium constant, K, vary over the range 4-16; the entalphy, ΔH0, is about -2.0 kcal/mol; the free energy, ΔG0, is -1.4 - 1.0 kcal/mol, and the entropy change, ΔS0, is -7.3 to -3.5 eu.The entropy change is greatest in the case of the dibenzo-1,4-dioxane - 7,7,8,8-tetracyanoquinodimethane charge-transfer complex.This is attributed to the planarity of the dibenzo-1,4-dioxane molecule.The extinction coefficient, ε, for the series studied varies from 115 to 230, and no regularity in the trend has been noted.The lack of any significant changes (with change in the chalcogen atom) in the thermodynamic values for the phenoxachalcogenine - 7,7,8,8-tetracyanoquinodimethane charge-transfer complexes is interpreted in terms of a similar Π to Π type interaction involving a delocalized Π orbital of the phenoxachalcogenine rather than a localized n orbital of the hetero atom.The room temperature four-probe dc conductivities of single crystals of PSe-TCNQ and PS-TCNQ were found to be 4x10-8 and 3x10-7 ohm-1 cm-1, respectively.
