Chemistry Reference
In-Depth Information
Fig. 11 Crystal structure of a metal-organic framework material Zn
2
(fma)
2
(bipy) prepared by
mechanochemical synthesis, with the structure determined directly from powder XRD data. The
structure is viewed (a) along the
c
-axis and (b) along the
b
-axis. The two (identical) interpenetrated
frameworks are indicated by
yellow
and
purple shading
. For comparison, (c) and (d) show the
corresponding views of the structure of a DMF solvate material Zn
2
(fma)
2
(bipy)(DMF)
0.5
prepared by a solvothermal route. Although there is some similarity between these structures,
there are nevertheless important structural differences between them
framework material with composition Co(dibenzoylmethanate)
2
(nicotinamide)
2
.
This material was obtained by thermal desolvation of the corresponding acetone
solvate, which was prepared under conditions of liquid-assisted grinding [
114
]. The
structure determined from the powder XRD data comprises “wheel-and-axle” units
of composition Co(dibenzoylmethanate)
2
(nicotinamide)
2
, which are assembled
through hydrogen-bonded amide-amide interactions involving the nicotinamide
molecules of neighbouring units, giving rise to antiparallel chains of amide
functionalities in a ladder-type motif. The structure contains tunnels with approxi-
mately hexagonal cross-section running parallel to the direction of the hydrogen-
bonded amide ladders.
Examples of other organic materials prepared by mechanochemical procedures,
for which structure determination has been carried out directly from powder XRD
data, include a hydrate cocrystal of 5-methyl-2-pyridone and trimesic acid, which
was prepared by grinding a methanol solvate cocrystal of the same components
