CLUSTERING OF A HYDROGEN-BONDING COMPLEX BETWEEN INDOLE AND ISOQUINOLINE - CORRELATION WITH NUCLEATION OF INTERMOLECULAR COMPOUNDS

Upon crystallization from mixtures containing indole and isoquinoline, intermolecular compounds of 1:1 molecular ratio have been isolated as crystals. This crystallisation process, i.e., molecules --> clusters --> nucleus was studied in a specially designed mass spectrometer. Fro m the mass spectrometric analysis of clusters isolated from liquid dro plets containing indole, isoquinoline and acetonitrile, clusters compo sed of equimolecular indole and isoquinoline, i.e. (indole)(n)(isoquin oline)(n) : n = 1, 2, 3,..., were observed as prominent species. This suggested that the hydrogen-bonded complex of indole and isoquinoline works as a unit species for the nucleation of the intermolecular compo unds.