No abstract

A new synthetic approach has led to the incorporation of TCNQ and F4TCNQ dianions into a wide variety of structures.

Diffusion coefficients in air at 298.2 "K and I atm pressure are reported for ethane, ethene, ethyne, cyclopropane, propene, propadiene, propyne, butane, I-butene, 2-methylpropene, cis-2-butene, trans-2-butene, 1,3-butadiene, I-butyne, 2-methylbutane, 2,2-dimethylpropane, cyclopentane, and 1-pentene.A linear relationship, valid for alkanes and alkenes, has been found between the diffusion coefficient and the reduced molecular weight of the members of a homologous series and air.Diffusion coefficients calculated by ten prediction equations were generally lower than those observed.Les coefficients de diffusion dans l'air a 298.2 "K et sous une pression de une atmosphere sont rapportes pour l'ethane, Pethene, l'ethyne, le cyclopropane, le propkne, le propadiene, le propyne, le butane, le butene-I, le methyl-2 propene, le butkne-2 cis, le butine-2 trans, le butadiine-1,3, le butyne-I, le methyl-2 butane, le dimethyl-2,2 propane, le cyclopentane et le pentine-I. Une relation lineaire, valable pour les alcanes et les alcenes, existe entre le coefficient de diffusion et la masse mol6culaire reduite des membres d'une sirie homologue et l'air.Les coefficients de diffusion, calculCs a partir de dix equations de prediction, sont generalement plus bas que ceux observes.

The dianion of tetracyanoquinodimethane, TCNQ 2À , is able to act as a ligand capable of binding four metal ions at the corners of a rectangle. When the ligand is combined with divalent metal ions in the presence of appropriate counterions, infinite anionic networks may be formed of composition [M 2 TCNQ 3 ] 2À (M ¼ Mn, Zn, Cd). In the structures reported here the cyano groups from six separate TCNQ dianions provide an octahedral coordination environment around the metal centres. Large hexagonal channels in the anionic network are occupied by highly disordered countercations.

3,4,5-tetrafluoroquinodimethane (F 4 TCNQ) in its dianionic form, F 4 TCNQ 2− , is shown to form charge transfer complexes with a wide variety of organic cations. The structures and spectroscopic properties of fourteen F 4 TCNQ 2− salts are described, thirteen of which have colours consistent with the formation of charge transfer complexes. Unlike neutral F 4 TCNQ charge transfer complexes, the dianion, F 4 TCNQ 2− is able to act as a donor in its interaction with suitable cations that serve as acceptors in solid-state complexes. The F 4 TCNQ 2− salts described in this work have been categorised into five different structural types according to the relative arrangements of cations and anions. In each case, structural and IR spectroscopic data indicate that the anions retain a formal −2 charge upon formation of the salt. The optical band gaps, determined from Vis-NIR spectra, are found to have the lowest values when the cation is a viologen, either methyl viologen or diphenylmethyl viologen.