Systematic variation of thiophene substituents in photochromic spiropyransElectronic supplementary information (ESI) available: X-ray crystallography of SP-T (CIF) and SP-T-Br (CIF). CCDC 1520537 and 1520538. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c7pp00057j

• Main Authors: Dissanayake, Dushanthi S, McCandless, Gregory T, Stefan, Mihaela C, Biewer, Michael C
• Format: Article
• Language: English
• ISSN: 1474-905X; 1474-9092
• DOI: 10.1039/c7pp00057j

Spiropyrans are notable among different classes of photochromic compounds due to their large structural and electronic transformation upon isomerization. In order to parlay the electronic differences associated with the two isomeric forms into a materials based switch, the spiropyran ultimately requires a covalent attachment through a conjugated pathway. In this work a synthetic method was developed to incorporate spiropyran (SP) into thiophene based materials. A series of compounds with a systematic variation of substituents were synthesized ( SP-T , SP-T-Br , SP-T-T , SP-T-T-T and SP-T-T-T-T-SP ) and their photochromism in both polar (methanol) and non-polar (toluene) solvents were studied. These compounds showed a systematic variation of photochromic properties. A new synthetic method was developed to incorporate spiropyran into thiophene based materials via a conjugated pathway. As the number of thiophene units increased, the thermal decay rate of the reverse reaction decreased in methanol, thus increasing the half-life of merocyanine.