Synthesis and characterization of new non-aromatic texaphyrin-type expanded porphyrins

The synthesis and X-ray diffraction-based characterization of a texaphyrin- type non-aromatic expanded porphyrin, 13,18,22,27-tetraethyl 14, 17,23,26-t etramethyl-20-p-nitrophenyl-3,10,28,29,30,31 -hexaazahexacyclo[23.2. 1.0(4, 9).1(12,15).1(16,19).1(21,24)]untriaconta-2, 4, 5, 7, 10,12,14,16, 18,20,22 ,24(30),25,27-tetradecaene (1), is reported. This Schiff base macrocycle wa s prepared in good yield via the 1:1 HCl-catalyzed condensation of a tetrap yrrole dialdehyde precursor, (di(5 -formyl-4,4'-diethyl-3,3'- dimethyl-2,2' -bipyrrole)-p-nitrophenylmethine), with 1,2-phenylenediamine. Compound 1 w as assigned as being a 26 pi-electron nonaromatic benzannulene on the basis of both proton NMR and single-crystal X-ray diffraction analyses. The latt er studies, in particular, revealed a non-planar macrocyclic structure co-c rystallized with a molecule of water. By varying either the diamine used in the cyclization step and/or the substituent in the meso-position of the te trapyrrolic precursor, a range of other systems analogous to 1 could be obt ained. The resulting systems were found to present good stability both in t he solid state and in solution. Copyright (C) 1999 John Wiley & Sons, Ltd.