title: An Alignment Medium for Measuring Residual Dipolar Couplings in Pure DMSO: Liquid Crystals from Graphene Oxide Grafted with Polymer Brushes.
abstract: Residual dipolar couplings (RDCs) have attracted attention in light of their great impact on the structural elucidation of organic molecules. However, the effectiveness of RDC measurements is limited by the shortage of alignment media compatible with widely used organic solvents, such as DMSO. Herein, we present the first liquid crystal (LC) based alignment medium that is compatible with pure DMSO, thus enabling RDC measurements of polar and intermediate polarity molecules. The liquid crystals were obtained by grafting polymer brushes onto graphene oxide (GO) using free radical polymerization. The resulting new medium offers several advantages, such as absence of background signals, narrow line shapes, and tunable alignment. Importantly, this medium is compatible with π-conjugated molecules. Moreover, sonication-induced fragmentation can reduce the size of GO sheets. The resulting anisotropic medium has moderate alignment strength, which is a prerequisite for an accurate RDC measurement.
authors.affiliation: College of Chemistry & Materials Engineering, Wenzhou University, Wenzhou, 325035, P.R. China.
authors.forename: Wen
authors.initials: W
authors.lastname: Zong
authors.affiliation: Institute of Functional Biomolecules, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210093, P.R. China.
authors.forename: Gao-Wei
authors.initials: GW
authors.lastname: Li
authors.affiliation: Institute of Functional Biomolecules, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210093, P.R. China.
authors.forename: Jiang-Ming
authors.initials: JM
authors.lastname: Cao
authors.affiliation: College of Chemistry & Materials Engineering, Wenzhou University, Wenzhou, 325035, P.R. China. xxlei@wzu.edu.cn.
authors.forename: Xinxiang
authors.initials: X
authors.lastname: Lei
authors.affiliation: College of Chemistry & Materials Engineering, Wenzhou University, Wenzhou, 325035, P.R. China.
authors.forename: Mao-Lin
authors.initials: ML
authors.lastname: Hu
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Roessle-Strasse 10, 13125, Berlin, Germany. hsun@fmp-berlin.de.
authors.forename: Han
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, 37077, Göttingen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Griesinger
authors.affiliation: Institute of Functional Biomolecules, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, 210093, P.R. China. rxtan@nju.edu.cn.
authors.forename: Ren Xiang
authors.initials: RX
authors.lastname: Tan
keywords: NMR spectroscopy; alignment medium; functionalized graphene oxide; liquid crystals; residual dipolar coupling