Metal-organic anion receptors: arranging urea hydrogen-bond donors to encapsulate sulfate ions.
A new class of synthetic receptors for anions can be prepared by arranging urea hydrogen-bond donor groups on a simple metal-organic scaffold. The complex cation [PtL4]2+ (L = 8-(n-butylurea)iso-quinoline) can adopt four conformations reminiscent of calix[4]arene-based receptors; "cone", "partial cone", "1,2-alternate", or "1,3-alternate". 1H NMR solution data and solid-state X-ray structures show that a "1,2-alternate" conformation is used to bind spherical halide ions while a "cone" conformation is involved in strong binding with the tetrahedral oxy-anions such as the sulfate ion; even in a strongly competitive solvent such as DMSO.
Bondy
Chantelle R
CR
Department of Chemistry and Biochemistry, University of Windsor, Ontario, Canada.
Gale
Philip A
PA
Loeb
Stephen J
SJ
D000838:Anions / Q000737:chemistry; D001665:Binding Sites; D018360:Crystallography, X-Ray; D004121:Dimethyl Sulfoxide; D006860:Hydrogen Bonding; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry*; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000737:chemistry*; D009944:Organoplatinum Compounds / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry*; D014508:Urea / Q000737:chemistry*
D000838:Anions; D008024:Ligands; D008670:Metals; D009942:Organometallic Compounds; D009944:Organoplatinum Compounds; D013431:Sulfates; D014508:Urea; D004121:Dimethyl Sulfoxide