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The structure of the title compound, C30H42N4O2, has orthorhombic (Pbca) symmetry. This compound comprises a 4-amino-1,8-naphthalimide core with a 2,2,6,6-tetramethyl-4-piperidinyl substituent bonded to each nitrogen atom. The structure displays N—H...O hydrogen bonding. The structure exhibits disorder of the main molecule. 

The synthesis and the crystal structure of 1 H -imidazole-1-methanol, C 4 H 6 N 2 O, are described. This compound comprises an imidazole ring with a methanol group attached at the 1-position affording an imine nitrogen atom able to receive a hydrogen bond and an alcohol group able to donate to a hydrogen bond. This imidazole methanol crystallizes with monoclinic ( P 2 1 / n ) symmetry with three symmetry-unique molecules. These three molecules are connected via O—H...N hydrogen bonding in a head-to-tail configuration to form independent three-membered macrocycles. 

This report describes the synthesis of five new colorful 6-aryldibenzo[b,d]pyrylium cation salts, a largely unexplored structural unit. These rare compounds are benzannulated structural derivatives of the well-known flavylium cations found widespread in natural pigments. These new dyes are directly compared to three previously synthesized 6-aryldibenzo[b,d]pyrylium cation salts as well as eight colorful isomeric 9-aryldibenzo[b,e]pyrylium cation, or 9-arylxanthylium, salts. The 9-arylxanthylium unit is commonly found in the biologically important rhodamine and rosamine dyes, yet six of the analogs presented in this study were either previously unreported or not isolated. The visual and spectroscopic properties of all 16 compounds were analyzed as a function of the structural differences between the compounds. All compounds displayed reversible halochromism in organic solution, displaying bright colors under acidic conditions and becoming colorless under basic conditions.