The Curious Case of 2-Propyl-1H-benzimidazole in the Solid State: An Experimental and Theoretical Study.

2-propy1-1H-benzimidazole (2PrBzIm) is a small molecule, commercially available, which displays a curious behayior in the solid state. 2PrBzIm, although devoid of chirality by fast rotation about a single bond of the propyl group in solution, crystallizes as a conglomerate showing chiroptical properties. An exhaustive analysis of its crystal structure and a wide range of experiments monitored by vibrational circular dichroism spectroscopy eliminated all possibilities of an artifact. What remains is a new example of the unexplained phenomenon of persistent supramolecular chirality.