2-[(3,3-Di-methyl-indolin-2-yl-idene)meth-yl]-4-[(3,3-dimethyl-3H-indol-1-ium-2-yl)methyl-idene]-3-oxo-cyclo-but-1-en-1-olate chloro-form disolvate.

ABSTRACT

In the title squaraine dye solvate, C26H24N2O2·2CHCl3, the dye mol-ecule is essentially planar, except for the methyl groups, having a maximum deviation over the 26-membered delocalized bond system of 0.060 (2) Å. It possesses crystallographic twofold rotational symmetry with the indole ring systems adopting a syn conformation. The mol-ecular structure features intra-molecular N-H⋯O hydrogen bonds enclosing conjoint S7 ring motifs about one of the dioxo-cyclo-butene O atoms, while the two chloro-form solvent mol-ecules are linked to the second O atom through C-H⋯O hydrogen bonds.