Furan-Based Porphyrins: Tetraoxa[4n+2]porphyrin Dications with 18π-, 22π-, or 26π-Electron Systems

✍ Scribed by Emanuel Vogel; Norbert Jux; Joachim Dörr; Thomas Pelster; Thorsten Berg; Horst-Stefan Böhm; Frank Behrens; Johann Lex; Dominik Bremm; Georg Hohlneicher

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 147 KB
• Volume: 39
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/(sici)1521-3773(20000317)39:6<1101::aid-anie1101>3.0.co;2-f

✦ Synopsis

The D 4h -symmetric tetraoxa [18]porphyrin dication 1, [1] which is isoelectronic with diprotonated porphyrin, and the N,N',N'',N'' '-tetramethyl[26]porphyrin-(3.3.3.3) dication (3 with NCH 3 instead of O; as the octaethyl derivative) described by Franck et al. [2] are prototypes of chalcogenaporphyrins [3] and symmetrically expanded porphyrins, respectively. [4] These dicationic porphyrin variants should be viewed as resonance hybrids (carbenium and onium ion structures) in which special importance is attributed to carbenium ion structures with 4n2 p electrons on the 4(n1) carbon perimeterÐin agreement with both experiment and theory. [5]