A Second Polymorphic Form of Trimethylindium: Topology of Supramolecular Architectures of Group 13 Trimethyls

Crystallization of Me3In from hexane solution at ambient temperature allows for the
isolation of a new phase that cannot be obtained by classical sublimation routes. The crystal
structure analysis revealed that this new polymorph of Me3In crystallizes in the rhombohedral space group R3̄. The primary structural effect of the In−CH3···In intermolecular
interactions results in the formation of cyclic hexamers with 12-membered (InC)6 rings of
an extended-chair conformation. The shortest intermolecular In···C contact is 3.028(4) Å
with In···H distances between 2.74 and 2.79 Å. The hexamers are further linked by longer
In−CH3···In bridges into the 3D network. In addition, the tetragonal form of Me3In was
redetermined at 100 K. The presented results demonstrate that the impact of both crystal-lization conditions and the character of intermolecular forces on clustering events is evident.
Finally, the network topology of a family of the group 13 trimethyls is analyzed and
correlated.