Tris(2-aminoethyl)amine, a Suitable Spacer for Phosphate and Sulfate Receptors

Tris(2-aminoethyl)amine and cis-1,3,5-tris(aminomethyl)cyclohexane have been checked as spacers for phosphate receptors. Ureas are better binding arms than thioureas for these spacers while the combination of this first functional group with chromenone fragments permits further increases in the phosphate and sulfate association constants.