Mechanistic Insight into the Formation of Tetraarylazadipyrromethenes

Grossi, Marco, Palma, Aniello, McDonnell, Shane O., Hall, Michael J., Rai, Dilip K., Muldoon, Jimmy, O’Shea, Donal F. (2012) Mechanistic Insight into the Formation of Tetraarylazadipyrromethenes. The Journal of Organic Chemistry, 77 (20). pp. 9304-9312. ISSN 0022-3263. (doi:10.1021/jo301972w) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
https://doi.org/10.1021/jo301972w

Abstract

The tetraarylazadipyrromethene chromophore class has gained increasing attention in the past decade for a diverse set of scientific interests and applications. The most direct synthetic route available for their generation is heating of 4-nitro-1,3-diarylbutan-1-ones with an ammonium source in an alcohol solvent. Despite the practical simplicity, the reaction pathway(s) for these conversions are lengthy and unclear. To gain insight into the steps involved, 15N labeling experiments with MS and NMR analysis were utilized for conversion of 4-nitro-1,3-diphenylbutan-1-one 1 into tetraphenylazadipyrromethene 2 with 15NH4OAc. To permit examination of later stages of the reaction sequence to 2, the 15N-labeled potential intermediate 3,5-diphenyl-1H-pyrrol-2-amine 10 was synthesized. A study of the dimerization pathway utilizing 15N-labeled 10 revealed an unprecedented nitrogen rearrangement in the final stages of the pathway involving a ring-opening/closing of a pyrrole ring. Utilizing 15N labeling experiments we have shown that 2,4-diphenylpyrrole 8 can also react under the reaction conditions with 3,5-diphenyl-2H-pyrrol-2-imine 7 (from oxidation of 10) to produce 2. Overall in the conversion of 1 into 2, two related pathways are ongoing concurrently; the first involves a dimerization of 3,5-diphenyl-2H-pyrrol-2-imine 7, and the other a reaction of 7 with 2,4-diphenylpyrrole 8.

Item Type: Article
DOI/Identification number: 10.1021/jo301972w
Subjects: Q Science > QD Chemistry > QD431 Organic Chemistry- Biochemistry- Proteins, peptides, amino acids
Divisions: Faculties > Sciences > School of Physical Sciences
Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Aniello Palma
Date Deposited: 22 Nov 2017 11:27 UTC
Last Modified: 29 May 2019 19:52 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/64613 (The current URI for this page, for reference purposes)
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