ESI-FTICR mass spectrometric study of alcohol complexation properties of mono- and diphosphonate-bridged cavitands

Alcohol complexation properties of eight mono- and diphenyl phosphonate-bridged cavitands were studied by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR) and theoretical calculations. The cavitands varied in number and position of phenyl phosphonate bridges and their orientation with respect to the cavity, length of the lower rim alkyl chains, and substituents at apical positions of the resorcarene skeleton. The specificities of the different cavitands toward primary, secondary, and tertiary alcohols varying long of the alkyl chain were investigated, together with the stabilities of the formed complexes. The number, position, and orientation of the P = O moieties affected the complex formation of the cavitands and stability of the complexes dramatically. Methyl groups at apical positions of the resorcarene skeleton also affected the complexation properties. Although length and branching of the alkyl chain of the alcohol influenced the complex formation, the effect on stability of the complexes was negligible.