Structural Dependence of the Luminescence from Bis(substituted- benzenethiol)-(2,9-dimethyl-1,10-phenanthroline)zinc(2) Complexes

Changes in luminescence spectra and lifetimes of crystalline samples of the title compounds at 77 K are correlated with phase changes of the solids. The ease of conversion among phases is a general property of this class of materials. For bis benzenethiol-2,9-dimethyl-1,10-phenanthrolinezinc II complete structure determinations were made of both phases. The attendant changes of the optical properties are ascribed to rotation of the planes of the two thiol rings on a single zinc ion from an approximately perpendicular to a nearly face-to-face conformation as the slowly heated crystal undergoes the phase change. The relevance of these results to the problem of charge-separation in solids is discussed.