Mixture analysis of polycondensates by mass spectrometry: macrocyclic compounds via Wittig polycondensation reactions

Abstract

Mass spectrometrical methods reveal that reaction mixtures of Wittig polycondensation of bivalent ylides and bis-(triflouroacetyl)-benzene (or -thiophene) preferentially consist of cyclic compounds. The determination of ring units (n = 2–13) was performed by use of direct evaporation of solid samples, low energetical ionization and exact mass measurements, to determine elemental compositions. The structures of molecular ions present in the complex reaction mixtures were elucidated by metastable decompositions which show the characteristic fragmentation pattern of cyclic arylenes or heteroarylenes. General procedures of mass spectrometrical analysis are given. The influence of trifluoromethyl moieties on preferential formation of cyclic polycondensates is discussed.

Part III of “MS-Studies of polymers”; Part I and II: Refs. [1,2].