The formation of complexes between aza-derivatives of crown ethers and primary alkylammonium salts. Part 6. Bis(mono-aza)crown ethers

Abstract

The bis mono-aza-crown ethers (4) form 2 : 1 (G : H ratio) complexes with benzylammonium thiocyanate. In the case of the mono-aza-15-crown-5-derivatves (4a–g) the complexes have cis,cis-stereochemistry (10) but the 2 : 1 complexes of the mono-aza-18-crown-6 derivatives (4h–m) are mixtures of the cis,cis-(10), cis,trans-(11), and trans,trans-(12) isomers. The host molecules (4a–f) form 1 : 1 complexes with the bis(primary alkylammonium)thiocyanate (14); in the cases of (4a) and (4b) only a well-defined intramolecular complex (16) is formed but in the other cases both intramolecular and intermolecular (polymeric) complexes are formed. Hosts (4h–j) also form intramolecular complexes, with probably an increasing proportion of intermolecular complex as the distance between the macrocycles increases.