Iron, thioether macrocyclic complexes

It is well known that sulfide ligands form stable complexes with soft metal cations [30] and numerous complexes of macrocyclic thioethers with various metal salts have been prepared and characterized [31]. The iron atom of ferrocene is also basic and therefore affords a potential coordination site as evidenced by derivatives of ferrocene that are known to form complexes with certain metal salts [32]. Thus,... 

Macrocyclic sulfoxides and sulfones have begun to attract interest as phase transfer catalysts <81H(16)1701, 86JCS(Pi)465> they are best obtained by oxidation of the parent crown thioether. By way of illustration, mono(sulfoxide) of 9S3 has been isolated as an iron(II) complex (Section 9.30.3.4), while the tris(sulfone) can be prepared from 9S3 with excess permanganate <871C3762>. Cyclic sulfones extrude SO2 at 500°C (60-80 Pa) to give cyclophanes <89JOC2632,90CC1066>. 

---