1-Heteroaromatic-substituted tetraphenylboroles: π-π interactions between aromatic and antiaromatic rings through a B-C bond

J Am Chem Soc. 2012 Dec 12;134(49):20169-77. doi: 10.1021/ja309935t. Epub 2012 Dec 4.

Abstract

A series of 2,3,4,5-tetraphenylboroles substituted with different aromatic heterocycles (thiophene, furan, pyrrole, and dithiophene) in the 1-position were synthesized and characterized by means of NMR, elemental analysis, and X-ray crystallography. In contrast to known 2,3,4,5-tetraphenylboroles, X-ray diffraction revealed a nearly coplanar arrangement of the aromatic heterocycles and the antiaromatic borole scaffold as a result of π-conjugation, which could be substantiated by DFT calculations. Furthermore, the 2,2'-dithiophene-bridged bisborole (14) exhibits a large bathochromic shift in the absorption spectrum, demonstrating the exceptional Lewis acidity of the nonannulated borolyl moiety.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Boron Compounds / chemical synthesis
  • Boron Compounds / chemistry*
  • Electrochemical Techniques
  • Furans / chemistry*
  • Models, Molecular
  • Molecular Structure
  • Pyrroles / chemistry*
  • Quantum Theory
  • Spectrophotometry, Ultraviolet
  • Thiophenes / chemistry*

Substances

  • 2,3,4,5-tetraphenylborole
  • Boron Compounds
  • Furans
  • Pyrroles
  • Thiophenes
  • furan