“Synthesis and investigation of new bridged benzoxazepine[3,2-a]indole derivatives as ultrafast photochromic switches” Doctoral Thesis

Author, institution: Greta Ragaitė, Kaunas University of Technology

Science area, field: Physical Sciences, Chemistry

The Doctoral Dissertation is available at the library of Kaunas University of Technology (K. Donelaičio St. 20, Kaunas).

Scientific Supervisor: Prof. Habil. Dr. Algirdas ŠAČKUS (Kaunas University of Technology, Physical Sciences, Chemistry – 03P)

Scientific consultant: Prof. Dr. Vytas MARTYNAITIS (Kauno technologijos universitetas, Physical Sciences, Chemistry – 03P)

Dissertation defence board of Chemistry Science Field

Prof. Dr. Vytautas GETAUTIS Kaunas University of Technology, Physical Sciences, Chemistry – 03P) – Chairman;
Dr. Eglė ARBAČIAUSKIENĖ (Kaunas University of Technology, Physical Sciences, Chemistry – 03P);
Dr. Svajus ASADAUSKAS (Institute of Chemistry of Center for Physical Sciences and Technology, Physical Sciences, Chemistry – 03P);
Prof. habil. dr. Vytautas MICKEVIČIUS (Kaunas University of Technology, Physical Sciences, Chemistry – 03P);
Dr. Gytė VILKAUSKAITĖ (MSD Animal Health, Austrija, Physical Sciences, Chemistry – 03P).

Annotation:

In this dissertation we investigated a new concept for the preparation of a fast and stable light-driven molecular switch. Known photochromic spiropyrans under UV-irradiation undergo fast C–O bond cleavage, converting to the planar colored trans-merocyanine form which possesses a 4-nitrophenolate moiety. However, the subsequent thermal reversion of trans-merocyanine to the starting spiro-compound is relatively slow due to the required structural changes, such as trans-cis isomerisation. A new bridged benzoxazepine[3,2-a]indole derivatives contain a relatively rigid ring structure, which could make the spontaneous thermal reversion of the photoinduced form occur more rapidly. The latter compounds were identified as ultrafast photohromic compounds because of their fast relaxation time measured in a nanosecond time scale. The introduction of functional groups into the 5-position of the indole ring was driven by changes in photochemical characteristics of the products while the modification of the carboxamide group of benzoxazepine[3,2-a]indole derivatives did not deliver any significant photochemical changes. The transformations of benzoxazepine[3,2-a]indole derivatives in the presence of acids and bases were also investigated.