Synthesis, Structure, and Cyclic Voltammetry of 4,6-Bis(dimesitylboryl)dibenzofuran: Isolation of 4,6-Dilithiobenzofuran and 4,5-Dilithio-9,9-dimethylxanthene as tmeda Adducts
作者:Huadong Wang、François P. Gabbaï
DOI:10.1021/om050165m
日期:2005.6.1
The reaction of dibenzofuran and 9,9-dimethylxanthene with sec-BuLi and n-BuLi, respectively, in the presence of N,N,N ',N '-tetramethylethylenediamine (tmeda) in hexane followed by storage at -20 degrees C results in the precipitation of 4,6-dilithiodibenzofuran-1.5(tmeda) (1) and 4,5-dilithio-9,9-dimethylxanthene-1.5(tmeda) (2). Both of these adducts form tetranuclear dimers with the lithium atoms bridging the deprotonated aromatic ligands. The reaction of 1 with dimesitylboronfluoride affords 4,6-bis(dimesitylboryl)dibenzofuran (3), which has been fully characterized. Cyclic voltammetry of compound 3 shows two reduction waves at E-1/2 -2.45 and -2.81 V (vs Fc/Fc(+)), which substantiates significant electronic coupling of the two boron centers. Computational studies show that the p-orbital of the two boron centers participates equally to the LUMO, thus providing grounds for the observed electronic coupling.
Concise Synthesis of Diborylxanthenes
作者:Shinichi Saito、Takeshi Makino、Ryu Yamasaki
DOI:10.1055/s-2008-1032207
日期:2008.3
A simple and efficient synthesis of a series of bidentate diborylxanthene derivatives is described.