Solvent dependent competition between fluorescence resonance energy transfer and through bond energy transfer in rhodamine appended hexaphenylbenzene derivatives for sensing of Hg(2+) ions.

Hexaphenylbenzene (HPB) derivatives 5 and 7 having rhodamine B moieties have been designed and synthesized, and have been shown to display solvent dependent. Fluorescence resonance energy transfer (FRET) and through bond energy transfer (TBET) in the presence of Hg(2+) ions among the various cations (Cu(2+), Pb(2+), Zn(2+), Ni(2+), Cd(2+), Ag(+), Ba(2+), Mg(2+), K(+), Na(+), and Li(+)) have been tested. Derivative 5 displays quite high through bond energy transfer efficiency in the presence of Hg(2+) ions in methanol whereas derivative 7 exhibits better FRET efficiency in the presence of Hg(2+) ions in THF and CH(3)CN than derivative 5.