New journal of chemistry vol:31 issue:5 pages:691-696
The synthesis of a N-confused calix[ 4] pyrrole-alpha-carbaldehyde is reported, together with its Knoevenagel reaction derivatives. The X-ray crystal structure of the aldehyde and two derivatives are reported showing the macrocycles adopting 'confused 1,3-alternate' conformations in all cases. The affinity of these macrocycles for a range of anionic guests has been measured in DMSO-d(6)/ 0.5% water, and the results compared with the parent N-confused calix[ 4] pyrrole parent macrocycle. These studies show that the derivatives have a significantly higher affinity for anionic guests than the parent system.