One-Step Template-Directed Synthesis of a Macrocyclic Tetraarylporphyrin Hexamer Based on Supramolecular Interactions with a C3-Symmetric Tetraarylporphyrin Trimer

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• 作者：Simona Rucareanu ; Anne Schuwey ; and Albert Gossauer
• 刊名：Journal of the American Chemical Society
• 出版年：2006
• 出版时间：March 15, 2006
• 年：2006
• 卷：128
• 期：10
• 页码：3396 - 3413
• 全文大小：355K
• 年卷期：v.128,no.10(March 15, 2006)
• ISSN：1520-5126

文摘

Taking into consideration the model geometry of the macrocyclic hexaporphyrin 1 as a hostmolecule, the structure of a benzene-centered porphyrin trimer bearing pyridine rings at the apical positionshas been designed with the aim to use the latter as a template for the synthesis of its own host. Indeed,in the presence of the porphyrin trimer 5, the yield of the cyclization of a linear porphyrin hexamer, as aprecursor of 1, could be improved from 8 to 30% (variable yield) to 50% (reproducible yield). Even thecondensation of equimolecular amounts of porphyrin monomers 20b and 21b in the presence of 5 led-probably through a loose preorganized complex between the latter and the Zn(II) chelate 20b-to theformation of 1 in only five steps from 19, as compared with 13 steps of the synthesis via linear porphyrinhexamer in the absence of template. As evidenced by ¹H NMR spectroscopic analysis of the supramolecularcomplex between 5 and an analogue of 1b in which all H-atoms at the pyrrole rings have been replacedby deuterium, in the presence of unlabeled 1b, a rapid dissociation and recombination of the host andguest molecules forming the supramolecular complex takes place even at low temperature (-40 C). Asat 55 C all six Zn(II) porphyrinate rings of the complex 1b + 5 become magnetically equivalent in the 500MHz ¹H NMR time scale, approximate kinetic data for the ligand exchange process could be obtained.