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CHESS is proud and happy to congratulate user William Dichtel on his recent award of a MacArthur Fellowship for his “innovations in synthetic and supramolecular chemistry [that] hold promise for bringing a new class of nanostructured materials out of the lab and into daily use.” Dichtel, an associate professor in the Department of Chemistry and Chemical Biology at Cornell University, has made continuous use of CHESS over the past few years to aid his group’s studies of covalent organic frameworks (COFs). The group regularly relies on the G2 station at CHESS to characterize the crystalline and orientational order of different COFs and under different conditions [1-3], including different substrates such as single-layer graphene. Those results have contributed to the group’s development of COFs for various applications, such as vapor detection [4]. CHESS highlighted his work on “Organic Crystals Made to Order” a few years ago http://news.chess.cornell.edu/articles/2011/WollOrganic.html, summarizing his group’s publication in Science Magazine of work using grazing incidence x-ray diffraction measurements (figure), performed at the G2 station at CHESS, show that the layers are stacked perpendicular to the substrate surface.

thin COF films

Figure: Dichtel’s group fabricated thin, oriented COF films for the first time. The crystallites in the film are composed of stacks of layers, each of which resembles a microscopic chain-link fence (left). The "fence" itself is composed of periodic arrays of molecules which can be selected to best suit the application. Grazing incidence x-ray diffraction measurements (upper right), performed at the G2 station at CHESS, show that the layers are stacked perpendicular to the substrate surface. UV spectroscopy (lower right) shows that the molecules of interest retains the light-absorbing properties essential for applications.

References:

[1] John W. Colson, Arthur R. Woll, Arnab Mukherjee, Mark P. Levendorf, Eric L. Spitler, Virgil B. Shields, Michael G. Spencer, Jiwoong Park, William R. Dichtel, "Oriented 2D Covalent Organic Framework Thin Films on Single-Layer Graphene," Science 332, 228 (2011), DOI: 10.1126/science.1202747

[2] Spitler EL, Colson JW, Uribe-Romo FJ, Woll AR, Giovino MR, Saldivar A, Dichtel WR, "Lattice Expansion of Highly Oriented 2D Phthalocyanine Covalent Organic Framework Films," Angewandte Chemie, PMID:22223402 124(11), 2677-2681 (2012).

[3] Colson JW, Mann JA, DeBlase CR, Dichtel WR, "Patterned Growth of Oriented 2D Covalent Organic Framework Thin Films on Single-Layer Graphene," JOURNAL OF POLYMER SCIENCE 53(2), 378-384 (2014).

[4] Gopalakrishnan D and Dichtel WR, "Direct Detection of RDX Vapor Using a Conjugated Polymer Network," J. Am. Chem. Soc. 135(22), 8357-8362 (2013).

Read the Cornell Chronicle article here:
http://www.news.cornell.edu/stories/2015/09/chemist-will-dichtel-earns-macarthur-genius-award or PDF

 

 

Submitted by: Ernest Fontes, CHESS, Cornell University
09/30/2015