Building and Breaking Molecular Ladders to Develop Antiaromatic and Force-Responsive Materials
Yan Xia
Professor Yan Xia (Stanford University, Department of Chemistry)
Host: Professor Steve Craig
Tuesday, October 16, 2018 - 11:40am to 1:10pm
Location: French Family Science Center 2237
Rosenthal, Janet

Link for Professor Xia

Abstract:  Our interest in utilizing and incorporating strained rings in ladder-shaped molecular structures led to the development of unusual functional materials. We developed Catalytic Arene-Norbornene AnnuLation (CANAL) to synthesize π-systems containing antiaromatic cyclobutadienoid from readily accessible oxanorbornenes and aryl bromides.[1] These extended conjugated ladder molecules exhibit tunable degrees of antiaromaticity, which in turn affect their bonding, frontier orbital levels, and optoelectronic properties. In the quest for synthetic materials that transduce mechanical stimulation to multifaceted signals in response to force, we developed a unique class of polyladderenes, which rapidly unzip under force into polyacetylene with long conjugation.[2] The force-induced breaking of macromolecular ladders opens new avenues for smart materials that transform their intrinsic properties drastically under force and understanding details of mechanotransduction in polymers.

[1] J. Am. Chem. Soc. 2017, 139, 1806; 2017, 139, 15933.

[2] Science 2017, 357, 475.