Crystallographic and Computational Study of 4'-(Isoquinolin-5-yl)-2,2':6',2''-terpyridine and the Comparison with Its Structural Isomer 4'-(Isoquinolin-4-yl)-2,2':6',2''-terpyridine

The title compound consists of a 2,2':6',2"-terpyridine nucleus (tpy) completed by a pendant isoquinoline group (isq) bound at the central pyridine (py) ring. The tpy nucleus departs slightly from planarity, with py(lateral)-py(central) interplanar angles in the range 2.24(7)degrees-7.90(7)degrees, but the isq group is instead rotated significantly from the central pyridine ring associated to a short Htpy center dot center dot center dot Hisq contact. There are no strong noncovalent interactions in the structure, the main ones being of the pi center dot center dot center dot pi type giving rise to columnar arrays along [010], further linked by C-H center dot center dot center dot N and C-H center dot center dot center dot pi bonds into a 3D supramolecular structure. Analogies and differences with a recently published structural isomer (4'-(isoquinolin-4-yl)-2,2':6',2''-terpyridine are discussed. As a way to highlight the nature of the crystallographic differences an analysis of the pairwise intermolecular interactions energies and Hirshfeld surfaces was carry out.