Structural Data Showing the Existence of LDI Bonds between the Rings of Dimeric Cofacial Siloxysilicon Phthalocyanines

In
a pair of earlier papers, the existence of long directional
interaction bonds, LDI bonds, was postulated on the basis of data
for cofacial oligomeric siloxysilicon phthalocyanines from this laboratory
and data for other cofacial oligomeric phthalocyanines from the literature.
However, the combined data are not fully suited to the purpose for
which they were used. Here an alternative approach is taken in which
a carefully chosen group of dimeric cofacial siloxysilicon phthalocyanines
is used. Structural data derived from these phthalocyanines is examined
in some detail to determine where it conforms to normal expectations
and where it does not. To a high degree of certainty, consideration
of the results obtained shows that long directional (LDI) bonds exist
in dimeric cofacial siloxysilicon phthalocyanines. The new data also
provide an opportunity for other research on chemical bonds.