Orthogonal Actuation of a Supramolecular Double-Porphyrin Tweezer

• Published in: Journal of organic chemistry 2010-09, Vol.75 (17), p.5911-5919
• Main Authors: Schmittel, Michael, Samanta, Soumen K
• Format: Article
• Language: English
• Subjects: Chemistry; Cross-disciplinary physics: materials science; rheology; Crystallography, X-Ray; Exact sciences and technology; Heterocyclic compounds; Heterocyclic compounds with several n hetero atoms in the same ring, in separated rings or in fused rings; Macromolecular Substances - chemical synthesis; Macromolecular Substances - chemistry; Materials science; Methods of nanofabrication; Models, Molecular; Molecular Structure; Organic chemistry; Organometallic Compounds - chemical synthesis; Organometallic Compounds - chemistry; Physics; Piperazines - chemistry; Porphyrins - chemical synthesis; Porphyrins - chemistry; Preparations and properties; Pyrazines - chemistry; Supramolecular and biochemical assembly; Zinc - chemistry
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo101169f

A supramolecular three-component double-porphyrin tweezer (PT) is prepared quantitatively using heteroleptic complex formation along the HETTAP methodology. Insertion of guest molecules, such as DABCO or pyrazine, into the coupled porphyrin cavities of PT leads to an actuation of the double-porphyrin tweezer function. Evidence from 1H NMR, VT NMR, and UV−vis titration suggests a rapid association/dissociation of the DABCO molecules at the central porphyrin. Upon addition of an equimolar mixture of DABCO and pyrazine to PT, a dynamic five-component self-assembled structure was furnished exclusively. 1H NMR and K assoc values validate the greater stability of the heteroloaded PT-(DABCO)(py) system in comparison to the two homoloaded systems, PT-(DABCO)2 and PT-(py)2. The higher stability of PT-(DABCO)(py) seems to be the result of charge transfer from DABCO to the vacant π* orbital of pyrazine across the porphyrin plane.