Chapter 7 Eight-membered and larger rings

Abstract

Publisher Summary This chapter provides information on eight-membered and larger rings. The expansion into crystal engineering, has added a focus on the intermolecular interactions within the nanoscale regime. The chapter discusses (1) carbon-oxygen rings, (2) carbon-nitrogen rings, (3) carbon-sulfur rings, and (4) carbon-nitrogen-oxygen rings. 24-Membered macrocycles with chalcone subunits and isobutenyl linkages have been formed through a mixed aldol condensation. Polycondensation of a trifunctional, ketone-activated fluoroarene with bis - or tris -phenoxides under pseudo -high dilution conditions gave rise to a series of very large macropolycyclic aromatic ethereal ketones. The incorporation of diazacrown ethers into a polymeric polyimide backbone has been reported and shown to complex barium(II). Comparative naphtholysis of crown-bearing tetrachlorocyclotriphosphazene, prepared by the treatment of hexachlorocyclotriphosphazatriene with the disodium salt of the tetraethylene glycol, and its acyclic analog revealed a significant macrocyclic effect of the substituent on both the kinetics and regiochemistry of chlorine substitution in the N 3 P 3 ring. 6,11,16,21-Tetraphenylbenziporphyrin, in which one pyrrole is replaced by a benzene ring, is formed in good yields by the condensation of the appropriate precursor with pyrrole and benzaldehyde.