Abstract
Cyanine dye cations and oxonol dye anions are shown to form multiple polymorphic and pseudopolymorphic crystal forms, many of which undergo thermochromic solid-state phase transformations. The crystal structures of two polymorphs of a cyanine-oxonol dye salt, 3,3′-dimethylthiacarbocyanine and 3,3′,5,5′-tetramethyltrimethine-oxonol, both containing chloroform of solvation, have been determined by X-ray crystallography which shows that mixed dye stacks are present in both crystal forms. The cyanine and oxonol ions form mixed stacks, with the long molecular axes of the ions nearly orthogonal in one form, but parallel in the other. The thermochromic desolvation of these polymorphs is discussed in detail, and a summary is given of the phase transformations observed for several of the other crystal forms. Crystal data: (C19H17N2S2)(C15H15-N4O6)(CHCl3), Ia, a = 7.660 (1) Å, b = 23.950 (5) Å, c = 20.201 (3) Å, β = 82.35 (2)°, Z = 4, P21/c, R = 0.096 (1032 observations); lb, a = 14.528 (4) Å,b= 13.676 (3) Å, c = 18.548 (5) Å, β = 90.54 (2)°, P21/a, Z = 4, R = 0.083 (1610 observations).
Original language | English |
---|---|
Pages (from-to) | 6921-6927 |
Number of pages | 7 |
Journal | Journal of the American Chemical Society |
Volume | 106 |
Issue number | 23 |
DOIs | |
State | Published - 1 Jan 1984 |
ASJC Scopus subject areas
- Catalysis
- General Chemistry
- Biochemistry
- Colloid and Surface Chemistry