title: Anion binding with a tripodal amine.
abstract: Binding studies of the tren-based amine, L (N,N',N' '-tris(2-benzylaminoethyl)amine), with inorganic anions and two crystal structures, [H(3)L][H(2)PO(4)](3).H(3)PO(4) and [H(3)L][Br](3), are reported. NMR titration results indicate that the ligand binds H(2)PO(4)(-) and HSO(4)(-) more strongly than NO(3)(-) and halides. In the crystal structure of the phosphate complex, the ligand is triprotonated with the three arms pointing outward in a trigonal-planar-like arrangement. Four phosphate species are associated with the receptor, and have been assigned as three H(2)PO(4)(-) counterions located between each of the tren arms, and an additional H(3)PO(4) molecule above the quasi-planar tren. The structure of the bromide complex is slightly different, although again the tren receptor is triprotonated and quasi-planar, but in this case C(2v)-like symmetry is seen with two of the arms pointed in the same direction with a bromide ion in between. The other two bromides lie outside of the tren arms.
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
authors.forename: Md Alamgir
authors.initials: MA
authors.lastname: Hossain
authors.forename: Jennifer Ann
authors.initials: JA
authors.lastname: Liljegren
authors.forename: Douglas
authors.initials: D
authors.lastname: Powell
authors.forename: Kristin
authors.initials: K
authors.lastname: Bowman-James