Chiral Discrimination of Varied Ammonium Compounds through 1H NMR Using a Binuclear Ti Complex Sensor

Abstract

A simple chiral binuclear titanium complex ((S)-Ti₂L₃Na₄) was first prepared and served as an excellent chiral sensor for discriminating a variety of chiral ammoniums by ¹H NMR. In the presence of trifluoroacetic acid, the in-situ-generated ammoniums of varied amines can be effectively resolved by (S)-Ti₂L₃Na₄. The different binding forces between (S)-Ti₂L₃Na₄ and two enantiomers of analytes generate different shielding effects on two enantiomers, resulting in a split in the distinguishable chemical shift.