Crystal structure of a second polymorph of tetra-kis-(pyridin-2-yl)methane.

A second polymorph of the title compound, C21H16N4, is reported. The original polymorph was solved by our group [Matsumoto et al. (2003 ▶). Tetra-hedron Lett. 44, 2861-2864] in the monoclinic space group C2/c and refined to R = 0.050. Now the crystal structure of a tetra-gonal polymorph (space group P-421 c) has been solved and refined to R = 0.036. In the crystal, there are no strong inter-molecular inter-actions. Reflecting the high symmetry of the mol-ecular structure, the asymmetric unit is a quarter of the mol-ecule, and the mol-ecule exhibits S4 symmetry along the c axis in the crystal.