title: Chelate effects in sulfate binding by amide/urea-based ligands.
abstract: The influence of chelate and mini-chelate effects on sulfate binding was explored for six amide-, amide/amine-, urea-, and urea/amine-based ligands. Two of the urea-based hosts were selective for SO4(2-) in water-mixed DMSO-d6 systems. Results indicated that the mini-chelate effect provided by a single urea group with two NH binding sites appears to provide enhanced binding over two amide groups. Furthermore, additional urea binding sites incorporated into the host framework appeared to overcome to some extent competing hydration effects with increasing water content.
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA. kbjames@ku.edu.
authors.forename: Chuandong
authors.initials: C
authors.lastname: Jia
authors.forename: Qi-Qiang
authors.initials: QQ
authors.lastname: Wang
authors.forename: Rowshan Ara
authors.initials: RA
authors.lastname: Begum
authors.forename: Victor W
authors.initials: VW
authors.lastname: Day
authors.forename: Kristin
authors.initials: K
authors.lastname: Bowman-James
mesh_terms: D000577:Amides / Q000737:chemistry*; D001665:Binding Sites; D002614:Chelating Agents / Q000737:chemistry*; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D008024:Ligands; D008958:Models, Molecular; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry*; D014508:Urea / Q000031:analogs & derivatives*; D014867:Water / Q000737:chemistry
chemical_list: D000577:Amides; D002614:Chelating Agents; D008024:Ligands; D000644:Quaternary Ammonium Compounds; D013431:Sulfates; D014867:Water; D014508:Urea; C009405:tetrabutylammonium; D004121:Dimethyl Sulfoxide