title: Glycoluril-Derived Molecular Clips are Potent and Selective Receptors for Cationic Dyes in Water.
abstract: Molecular clip 1 remains monomeric in water and engages in host-guest recognition processes with suitable guests. We report the Kavalues for 32 1⋅guest complexes measured by1H NMR, UV/Vis, and fluorescence titrations. The cavity of 1 is shaped by aromatic surfaces of negative electrostatic potential and therefore displays high affinity and selectivity for planar and cationic aromatic guests that distinguishes it from CB[n] receptors that prefer aliphatic over aromatic guests. Electrostatic effects play a dominant role in the recognition process whereby ion-dipole interactions may occur between ammonium ions and the C=O groups of 1, between the SO3-groups of 1 and pendant cationic groups on the guest, and within the cavity of 1 by cation-π interactions. Host 1 displays a high affinity toward dicationic guests with large planar aromatic surfaces (e.g. naphthalene diimide NDI+ and perylene diimide PDI+) and cationic dyes derived from acridine (e.g. methylene blue and azure A). The critical importance of cation-π interactions was ascertained by a comparison of analogous neutral and cationic guests (e.g. methylene violet vs. methylene blue; quinoline vs. N-methylquinolinium; acridine vs. N-methylacridinium; neutral red vs. neutral red H+) the affinities of which differ by up to 380-fold. We demonstrate that the high affinity of 1 toward methylene blue (Ka=3.92×107m-1; Kd=25 nm) allows for the selective sequestration and destaining of U87 cells stained with methylene blue.
authors: Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan, 430079, P. R. China.|Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742, USA.
authors: Nengfang
authors: N
authors: She
authors: Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA.
authors: Damien
authors: D
authors: Moncelet
authors: Department of Chemistry and RECETOX, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.
authors: Laura
authors: L
authors: Gilberg
authors: Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742, USA.
authors: Xiaoyong
authors: X
authors: Lu
authors: Department of Chemistry and RECETOX, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.
authors: Vladimir
authors: V
authors: Sindelar
authors: Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA.
authors: Volker
authors: V
authors: Briken
authors: Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742, USA. LIsaacs@umd.edu.
authors: Lyle
authors: http://orcid.org/0000-0002-4079-332X
authors: L
authors: Isaacs
mesh_terms: D000166:Acridines / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D004396:Coloring Agents / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D007094:Imides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry*; D010569:Perylene / Q000031:analogs & derivatives* / Q000737:chemistry; D055672:Static Electricity; D014867:Water / Q000737:chemistry*; D006574:Heterocyclic Compounds, 2-Ring; D048289:Imidazolidines
chemical_list: D000166:Acridines; D000480:Alkynes; D004396:Coloring Agents; D007093:Imidazoles; D007094:Imides; D009281:Naphthalenes; D010569:Perylene; D014867:Water; C521332:perylenediimide; C028189:N-methylacridine; C542131:naphthalenediimide; C092018:glycoluril; D006574:Heterocyclic Compounds, 2-Ring; D048289:Imidazolidines
keywords: cation-π interactions; dyes; glycoluril; hydrophobic effects; molecular clip