MOLECULAR SELF-ASSEMBLY CONTROLLED BY ACID-BASE NONCOVALENT INTERACTIONS - A MASS-SPECTROMETRIC STUDY OF SOME ORGANIC-ACIDS AND BASES

Molecular clusters generated from vacuum adiabatic expansion of liquid droplets including acid and base molecules provide an insight into mo lecular self-assembly through non-covalent interactions. The mass spec trometric analysis for the resulting clusters indicates a systematic s tructure change which is dependent on the acid-base interaction: a mul tilayer stacking structure for relatively strong acid-base pairs (phen ol-pyridine, phenol-N,N-dimethylaniline, etc.), and a monolayer struct ure for relatively weak acid-base pairs (phenol-pyrazine, cyclohexanol -pyridine, etc.). As another viewpoint, mass spectrometry of the molec ular clusters composed of acid and base molecules can be presented as a new method to characterise the acid-base interaction.