th  - 1987 - 51st ENC Conference

MF23
CESIUM-133 SOLID STATE NMR OF ALKALIDES AND ELECTRIDES
Lauren E. Hill," Steven B. Dawes and James L. Dye, Department of
Chemistry, Michigan State University, East Lansing, HI 48824
Alkalldes and electrldes are crystalline salts In which metal
cations are complexed with cyclic polyethers or polyamines and the
resultant anions are either alkali metal anions or trapped electrons.
Solid state NMR spectroscopy has been extremely useful as a means of
Identlfying a particular compound and as a probe of the types of
interactions between an ion and its environment. For example, NMR
data in combination with structural data on Cs (18C6)2.e" may be used
to better understand the nature of the trapped electron. The
temperature dependence gives the contact density of the cesium
nucleus. A s~udy of the mixed alkalide-electride salt
Cs (18C6)^.Na e. revealed spectra which consisted of five lines, two
of which are ~ue To Cs (.8C6) 2 In the pure sodide (-61 ppm) and in the
pure electrlde (+73 ppm). The other three peaks are evenly spaced
between th~ electrlde peak a~d sodlde posltions. Since the structures
of both Cs (18C6)~-e and Cs (18C6)2.Na are known, a superlattice
which includes ~raered substitution of sodium anions into anionic
sites in the Cs (18C6)p.e- lattice has been postulated$ Another
example of the utility-of NMR methods is the ceside CS C222.Cs- in
which the NMR spectrum consists of two peaks_whlch have been assigned
to an inclusive and exclusive cation. No Cs peak has been observed.
The system probably contains a mixture of crystallltes, one type
having inclusive complexed cations, the other exclusive complexed
cations. The absence of a Cs signal can be rationalized from the
structure of thls ceside. These are some examples of how NMR
spectroscopy in conjunction with x-ray crystallography can be used to
investigate the nature of these compounds.