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A series of oxazoline compounds have been prepared by reaction of 2,6‐diformyl‐4‐chlorophenol, 2,6‐diformylpyridine or 2,5‐diformylthiophen with o‐aminophenol or o‐aminothiophenol respectively. The oxazoline derivatives are stable both in solid state and in solution while the thiazoline derivatives easily oxidize to the corresponding thiazoles. Physico‐chemical data confirm this oxidation process. The 70 eV electron impact induced decomposition pathways of these compounds, obtained with the aid of exact mass measurements, B/E linked scans and collisional spectroscopy, are discussed in detail.

Macrocyclic and macroacyclic ligands containing ferrocene groups at the periphery of their coordinating moiety have been prepared and extensively studied, owing to their role in redox processes and in the preparation of molecular devices.IJ More recently they have been proposed as very promising carriers for the selective recognition, transport and separation of metal ions.&' In these processes these systems act as 'chemical switches'. Generally, chemical switching ligands are designed and synthesized in such a way that their complexing behaviour can be controlled reversibly by changing the pH, by photochemical or redox processes.If the ligand used in separation processes is modified by the incorporation of redox moieties, their reduction and oxidation will drastically alter their binding constant towards metal ions.5 This metal ion recognition by redox ligand systems has been recently reviewed.54 These systems are designed to have a redox-active centre in close proximity to a host binding site which can, depending on the complementary nature of the host cavity, electrochemically detect the complexation of any charged inorganic and organic guest species either through space electrostatic interaction or via various bond linkages. The redox centre used in these systems is the transition metal organometallic moiety ferrocene, which shows a reversible one-electron oxidation in most common solvents. Depending on the binding site incorporated with ferrocene, ligands can be developed to electrochemically recognize cations of Groups 1 and 2 and ammonium, transition metal cations and some anions.In order to develop these concepts we have prepared the Schiff bases 1-6 by condensation of ferrocene carboxaldehyde with the polyamines H2N-R-NH2 (R =-CHz-CHZ-O-CHZ--CHz-, 4 H Z 4 H 2 6 CHz--CH2wH2--CHz-, -HZC4H2-S