Nuclear magnetic resonance has been carried out on all nuclei with nonzero magnetic moments present in the alkali ion pairs of deuterated and nondeuterated naphthalene radical anion in 1,2-dimethoxyethane. Both the sign and magnitude of the hyperfine splitting constant (h.f.s.c.) were measured, the alkali h.f.s.c. being studied as a function of the temperature. The Li and Na h.f.s.c. appear to be positive, those of Rb and Cs are negative, whereas that of K changes sign with temperature.The proton and deuterium linewidths were studied as a function of the concentration and were found to vary linearly with the reciprocal of the concentration, pointing to the predominance of the Fermi contact interaction.An analysis of the alkali linewidth is given in terms of the intramolecular relaxation processes. Especially in cases where two isotopes could be studied, i.e. (1H , 2D), (6Li, 7Li) and (85Rb, 87Rb), a quantitative interpretation is presented. . I n t r o d u c t i o nSince the pioneering work o f Atherton and Weissman on the association between sodium and naphthalenide ions [1], many papers have appeared on E.S.R. studies o f ion pairs and much information on alkali metal hyperfine splitting constants (h.f.s.c.) has been collected [2], The alkali metal hyperfine coupling was found to be very sensitive to the solvent and the temperature, suggesting that transfer o f spin density from the aromatic radical to the metal proceeds in a complex manner. Unfortunately E.S.R. experiments only give the absolute value o f the h.f.s.c., whereas in determining the mechanism o f spin transfer the sign o f the h.f.s.c. is also o f importance. D e Boer [3], in an E.S.R. study o f the pyracene anion radical, observed that the Cs and Rb h.f.s.c. exhibited an anomalous temperature dependence. He suggested that the h.f.s.c. o f these ions could be negative as well as positive.Negative alkali spin densities were also proposed by Dodson and Reddoch [4] and Hirota [5], in studying the alkali naphthalene ion pairs. They noticed that regularly decreasing plots o f spin density at the alkali nucleus (calculated as the ratio o f the observed hyperfine splitting in the ion pair to that o f the atom in the gas phase [6]) versus the radius r of the alkali ion, were obtained if the spin density at the Rb and Cs nucleus was taken negative. This correlation between spin density and ionic radius has also been observed for other systems, e.g. alkali anthracenides [5],

The proton N .M .R. spectra of biphenyl-, fiuorenone-and phenanthreneand the deuterium N .M .R. spectra of biphenyl-dlO-and phenanthrene-dlOhave been measured in ethereal solutions at room temperature. Sign and magnitude of the hyperfine splitting constants derived from the measured contact shifts are reported and compared with E.S.R. data and predictions from theory. From the measured proton and deuterium relaxation times values for the electron spin and the rotational correlation times have been obtained.

MO calculations predict that the monoanion of 1,3,5-triphmylbenzene (Tpb) is in an orbitally degenerate ground state. Nevertheless, the ESR spectrum in liquid NHj is well resolved; the derivative linewidth is equal to 0.06 Oe only. The g value and the electronic relaxation times Ti and T-t were comparable in magnitude to those of orbitally nondegenerate radicals. It is suggested that twisting of the phenyl rings out of the plane of the molecule, which may lift the orbital degeneracy, is the principal reason of this behavior. 'H and ZD N M R experiments were performed on a reduced sample of Tpb, containing both normal and perdeutero-Tpb. From the Fermi contact shifts signs and magnitudes of all hyperfine splitting constants have been determined, and they agreed very well with the ESR splitting constants. From the proton linewidths the electronic and dipolar correlation times were inferred. Quadrupole coupling constants for all deuterium nuclei were calculated from the 2D linewidths.

The JCAMP-DX format provides a Standard for the exchange of data on IR spectra. Extensions of this format to other spectral data are being developed. Spectral data should always be accompanied by information on the chemical structure of the investigated compounds. The JCAMP-CS format provides definitions for exchanging information on the composition and the stereochemistry, as well as on the 2D and 3D atomic coordinates, of chemical structures. Where possible, the standard was designed to adhere to the conventions of JCAMP-DX. In addition, care was taken to make as simple as possible the conversion to other formats in use for representing chemical structures.