Alexandria Digital Research Library

Design and Development of Donor-Acceptor Stenhouse Adducts : A New Visible Light Activated Photochromic Compound

Author:
Helmy, Sameh
Degree Grantor:
University of California, Santa Barbara. Chemistry and Biochemistry
Degree Supervisor:
Javier Read de Alaniz
Place of Publication:
[Santa Barbara, Calif.]
Publisher:
University of California, Santa Barbara
Creation Date:
2015
Issued Date:
2015
Topics:
Organic chemistry
Keywords:
Photochromism
Dyes
Molecular switches
Genres:
Dissertations, Academic and Online resources
Dissertation:
Ph.D.--University of California, Santa Barbara, 2015
Description:

The development of an easily synthesized, modular, and tunable organic photoswitch that responds to visible light has been a long-standing pursuit. Herein we provide a detailed account of the design and synthesis of a new class of photochromes based on furfural, termed donor--acceptor Stenhouse adducts (DASAs). A wide variety of these derivatives are easily prepared from commercially available starting materials, and their photophysical properties are shown to be dependent on the substituents of the push--pull system. Analysis of the switching behavior provides conditions to access the two structural isomers of the DASAs, reversibly switch between them, and use their unique solubility behavior to provide dynamic phase-transfer materials. Overall, these negative photochromes respond to visible light and heat and display an unprecedented level of structural modularity and tunabilty. We demonstrate the considerable potential of DASA photoswitches in two unique and powerful applications. First we have applied DASAs for the visible light-initiated recycling of homo-geneous organic catalysts. This catalyst-photoswitch construct effectively polymerized lac-tide with control over molecular weight and a low PDI. The visible-light mediated phase transfer and subsequent recovery of the thiourea catalyst allowed recycling of the organocat-alyst. Further, the potential of these photoswitches in biological applications is demonstrated through the synthesis of a functional amphiphile that displays on-demand light-mediated disassembly and cargo release. This one-photon visible light-responsive micellar system served as an efficient, on-demand drug delivery system. The efficiency and effectiveness of this system was demonstrated in an in-vitro setting, delivering the chemotherapeutic paclitaxel only on exposure to visible light.

Physical Description:
1 online resource (213 pages)
Format:
Text
Collection(s):
UCSB electronic theses and dissertations
ARK:
ark:/48907/f3rv0kwx
ISBN:
9781339084213
Catalog System Number:
990045715680203776
Rights:
Inc.icon only.dark In Copyright
Copyright Holder:
Sameh Helmy
File Description
Access: Public access
Helmy_ucsb_0035D_12553.pdf pdf (Portable Document Format)