Deprotonation of resorcinarenes by mono- and diamine bases: complexation and intermolecular interactions in the solid state

Abstract

The deprotonation of resorcinarenes by mono- and dibasic amines, viz. triethylamine (TEA) and its dibasic analogue, N,N′-dimethylpiperazine (DMPip), was studied and the resulting supramolecular complexes were analysed in the solid state, in solution and in the gas phase. In the solid state, 1 : 1 (2TEAH⁺·(ethyl-resorcinarene)²⁻·MeOH), 3 : 2 [DMPip·2DMPipH⁺·2(ethyl-resorcinarene⁻)] and 3 : 2 [2DMPip·DMPipH₂²⁺@(2methyl-ethyl-resorcinarene⁻)₂·2MeOH] solid state complexes and interesting resorcinarene⁻⋯resorcinarene⁻ supramolecular networks formed via enhanced hydrogen bonds involving the hydroxyl groups and the deprotonated hydroxyl groups of the resorcinarenes were observed. The host–guest complexes manifest multiple cation⋯π and C–H⋯π interactions as in neutral resorcinarene inclusion complexes. The deprotonation of the resorcinarenes was observed in solution through titration studies. In the gas phase, the deprotonation of the resorcinarene and the encapsulation of the resulting ammonium ions were observed in the negative and positive ion modes, respectively.