title: Chemical Conversion of Linkages in Covalent Organic Frameworks.
abstract: The imine linkages of two layered, porous covalent organic frameworks (COFs), TPB-TP-COF ([C6H3(C6H4N)3]2[C6H4(CH)2]3, 1) and 4PE-1P-COF ([C2(C6H4N)4][C6H4(CH)2]2, 2), have been transformed into amide linkages to make the respective isostructural amide COFs 1' and 2' by direct oxidation with retention of crystallinity and permanent porosity. Remarkably, the oxidation of both imine COFs is complete, as assessed by FT-IR and13C CP-MAS NMR spectroscopy and demonstrates (a) the first chemical conversion of a COF linkage and (b) how the usual "crystallization problem" encountered in COF chemistry can be bypassed to access COFs, such as these amides, that are typically thought to be difficult to obtain by the usual de novo methods. The amide COFs show improved chemical stability relative to their imine progenitors.
authors.affiliation: Department of Chemistry, University of California-Berkeley , Materials Sciences Division, Lawrence Berkeley National Laboratory, Kavli Energy NanoSciences Institute at Berkeley, and Berkeley Global Science Institute, Berkeley, California 94720, United States.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Waller
authors.affiliation: Department of Chemistry, University of California-Berkeley , Materials Sciences Division, Lawrence Berkeley National Laboratory, Kavli Energy NanoSciences Institute at Berkeley, and Berkeley Global Science Institute, Berkeley, California 94720, United States.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Lyle
authors.affiliation: Department of Chemistry, University of California-Berkeley , Materials Sciences Division, Lawrence Berkeley National Laboratory, Kavli Energy NanoSciences Institute at Berkeley, and Berkeley Global Science Institute, Berkeley, California 94720, United States.|Department of Chemical and Biomolecular Engineering, University of California-Berkeley, and Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Osborn Popp
authors.affiliation: Department of Chemistry, University of California-Berkeley , Materials Sciences Division, Lawrence Berkeley National Laboratory, Kavli Energy NanoSciences Institute at Berkeley, and Berkeley Global Science Institute, Berkeley, California 94720, United States.
authors.forename: Christian S
authors.initials: CS
authors.lastname: Diercks
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of California-Berkeley, and Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Reimer
authors.affiliation: Department of Chemistry, University of California-Berkeley , Materials Sciences Division, Lawrence Berkeley National Laboratory, Kavli Energy NanoSciences Institute at Berkeley, and Berkeley Global Science Institute, Berkeley, California 94720, United States.|King Fahd University of Petroleum and Minerals , Dhahran 34464, Saudi Arabia.
authors.forename: Omar M
authors.initials: OM
authors.lastname: Yaghi