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Abstract Photoresponsive conjugated polymers are a promising target for modern organic electronics. Numerous photoswitchable repeat units have been included covalently within polymeric structures to enable responsive chromic materials, most commonly through side‐chain appendages or through formal conjugation along a π‐conjugated backbone. We recently disclosed a new design whereby the photoswitch elements are cross conjugated to a conjugated polymer main chain. In this case, we found that the extent of photoconversion was dictated in part by competitive main chain light absorption, which could be suppressed by using a photoswitching motif that carried most of the frontier molecular orbital densities. Here, we report the modeling and synthesis of a series of thieno[3,4‐b]thiophene (TT)‐based photochromes with various aromatic flankers imparting varying degrees of steric bulk and π‐conjugation in order to elucidate the balancing act between steric and electronic factors to promote photochromism. These model systems provide a better understanding of the behavior of photochromic units within extended oligomeric and polymeric π‐conjugated materials.
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Unconventional conjugation in macromonomers and polymers
Multiple reviews have been written concerning conjugated macromonomers and polymers both as general descriptions and for specific applications. In most examples, conjugation occurs via electronic communication via continuous overlap of π orbitals, most often on carbon. These systems can be considered to offer traditional forms of conjugation. In this review, we attempt to survey macromonomers and polymers that offer conjugation involving novel forms of carbon and/or other elements but with conjugation achieved via other bonding formats, including many where the mechanism(s) whereby such behavior is observed remain unresolved. In particular, this review emphasizes silsesquioxane containing polymeric materials that offer properties found typically in conjugated polymers. However, conjugation in these polymers appears to occur via saturated siloxane bonds within monomeric units that make up a variety of polymer systems. Multiple photophysical analytical methods are used as a means to demonstrate conjugation in systems where traditional conjugation is not apparent.
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- Award ID(s):
- 2103602
- PAR ID:
- 10439037
- Date Published:
- Journal Name:
- Chemical Communications
- Volume:
- 58
- Issue:
- 76
- ISSN:
- 1359-7345
- Page Range / eLocation ID:
- 10596 to 10618
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d2cc03968k
