Photochemical Rearrangements of Tetraarylborate Salts: Direct Irradiation, Triplet Sensitization, and Single Electron Transfer

The photochemistry of tetraarylborate salts has been investigated by direct irradiation, triplet sensitization and under single electron transfer conditions. Irradiation of sodium tetraphenylborate at 254 nm in either acetonitrile or THF produces 2,7,7-triphenyl-7-boratabicyclo (4.1.0) hepta-2,4-diene. The rearrangement was also observed to occur with other tetraarylborate salts. The mechanism which produces these novel boratanorcaradienes is similar to the well-known di-π-methane rearrangement of 1,4-dienes. The "di-π-borate" rearrangement has also been shown to occur under conditions of triplet sensitization. The boratanorcaradienes are oxygen- and water-sensitive compounds which possess many unique properties. Among these are a broad absorption in the visible region of the UV-vis spectrum, which gives rise to the observed color, and an extremely low oxidation potential. Interesting sigmatropic and electrocyclic rearrangements have also been recognized in these systems. Oxidation of tetraphenylborate by excited state electron acceptors results in decomposition of the borate and formation of biphenyl in quantitative yield.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Wilkey, John David

• Chemistry, Organic

Identifier

(UMI)AAI8908889

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70434