9-C-substituted phenalenones as promising precursors for the synthesis of novel stable phenalenyl-type cations and radicals

QD Chemistry

Anamimoghadam, Ommid ; Bucher, Götz

University:University of Glasgow

Department:School of Chemistry

关键词: Pi-radicals, Aromaticity, Photochemistry, Electrochemistry;   

Others  :  http://theses.gla.ac.uk/4433/1/2013AnamimoghadamPhD.pdf

来源: University of Glasgow

【 摘 要 】

Previous research in the Bucher group led to the generation of a novel phenalenyl derived radical, naphtho[2,1,8-mna]xanthenyl (NX). Through the photolysis of 9-phenyl-1H-phenalen-1-one (9-phenyl-PN), a transient 5aH-naphtho[2,1,8-mna]xanthene with a very weak C(sp3)-H bond was formed and could undergo hydrogen abstraction in the presence of an electron acceptor such as tetracyanoethylene (TCNE) or benzoquinone (BQ). As a result, NX was formed which exhibited a long persistence based on electronic stabilisation (Scheme A). This thesis deals with the practical preparation of potential precursors of NX type radicals involving new naphtho[2,1,8-mna]xanthenium (NX+) salts synthesised from 9-aryl-1H-phenalen-1-ones (9-aryl-PNs). 9-aryl-PNs will be prepared by a Michael-type Grignard addition which was introduced by C.F. Koelsch and J.A. Anthes. The key-step to the organic salts is the demethylation of the methoxy group at the o-position of the pendant 9-C aryl substituent of 9-aryl-PNs. Subsequently a reactive hemi-ketal will be formed which undergoes hydrolysis resulting in NX+.