Isoquinoline

Isoquinoline, C9H7N, is a ligand which is used as a complexing agent for di fferent metals. In order to compare geometric features of free isoquinoline and isoquinoline as a complexing ligand, we determined its crystal structu re. Regrettably, the molecule is located on a centre of inversion and is th erefore disordered; it is also isostructural with naphthalene. By refinemen t experiments and packing considerations, we were able to discard the possi bility of fourfold disorder, which has been found for several beta-substitu ted naphthalene compounds, and performed the structure determination employ ing a model of twofold disorder.