Practical Syntheses of N-Hexylcarbazol-2-yl- and -3-yl-boronic Acids, Their Cross-Coupled Products and a Derived Tris-cyclometalated (Pyridin-2-yl)carbazole Iridium(III) Complex

Abstract

The syntheses of N-hexylcarbazol-2-yl- and -3-yl-boronic acids (1 and 2) are described on a ca. 7 g scale, starting from commercially available 2,5-dibromonitrobenzene (4) and carbazole (11), respectively. Compounds 1 and 2 underwent efficient palladium-catalyzed cross-coupling reactions under Suzuki-Miyaura conditions to yield products 17, 18 and 20. Compound 18 reacted with IrCl₃ to give the tris-cyclometalated (pyridin-2-yl)carbazole iridium(III) complex 21, the X-ray crystal structure of which is reported.

Key words

carbazole - boronic acid - fluorene - cross-coupling reaction - cyclometalating ligands - iridium complex

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21

CCDC No.: 257962. Supplementary data available in CIF format from the authors.

22

Compound 21, CCDC No.: 260850; compound 21·2CH₂Cl₂·0.5Me₂CO, CCDC No.: 260851. Supplementary data available in CIF format from the authors.