Metalloporphyrin-capped calix[4]pyrroles: heteroditopic receptor models for anion recognition and ligand fixation.
Diametrically strapped calix[4]pyrrole-metalloporphyrin conjugates, potential hosts for anionic guests, have been synthesized and characterized. The syntheses rely on the acid-catalyzed condensation of two dipyrromethane bearing Ni(II) porphyrins with acetone. An (1)H NMR spectroscopic titration experiment indicated that the resulting receptors selectively trapped fluoride anions in organic media but not other, larger halide anions. The experimental results from titration and Job plots indicated that the bound fluoride anion must reside inside the cavity. The current systems provide a well-defined illustration of how size-selective anion receptors may be synthesized by incorporating recognition functions, such as Lewis acidity, hydrogen bonding, and encapsulating moieties into established recognition motifs, calix[4]pyrrole in the present instance.
Panda
Pradeepta K
PK
Department of Chemistry and Institute of Basic Science, Kangwon National University, Chun-Chon, 200-701 Korea.
Lee
Chang-Hee
CH
D000838:Anions / Q000737:chemistry*; D047250:Calixarenes; D009682:Magnetic Resonance Spectroscopy; D008665:Metalloporphyrins / Q000138:chemical synthesis / Q000737:chemistry*; D008956:Models, Chemical; D015394:Molecular Structure; D009532:Nickel / Q000737:chemistry; D011166:Porphyrins; D011758:Pyrroles / Q000737:chemistry*; D013237:Stereoisomerism
D000838:Anions; D008665:Metalloporphyrins; D011166:Porphyrins; D011758:Pyrroles; C469811:calix(4)pyrrole; D047250:Calixarenes; D009532:Nickel