A benzothiadiazole-supported N-heterocyclic carbene and its rhodium and iridium complexes

作者：Tapu Daniela; Buckner Ossie J; Boudreaux Chance M; Norvell Bradley; Vasiliu Monica; Dixon David A; McMillen Colin D

来源：Journal of Organometallic Chemistry, 2016, 823: 40-49.

DOI：10.1016/j.jorganchem.2016.09.016

• Fused N-heterocyclic carbene
• 5H-imidazo[4,5-f]-2,1,3-benzothiadiazol
• Rhodium
• Iridium
• Catalytic activity
• Hydrosilylation
• Annulation

A new N-heterocyclic carbene containing a fused benzothiadiazole (BTD) moiety, 5,7-bis(1,1-dimethylethyl)-5H-imidazo[4,5-f]-2,1,3-benzothiadiazol-6-ylidene (1), was generated by deprotonation of the corresponding tetrafluoroborate salt. The salt precursor was accessed in six steps from the commercially available 1,2-phenylenediamine. This carbene was found to be stable under inert conditions and it was fully characterized by NMR spectroscopy. The sulfur adduct of this carbene was also synthesized and fully characterized. The X-ray structure analysis of the thione revealed that the carbene carbon and the sulfur atom deviate from the plane containing the BTD moiety and the two nitrogen atoms of the imidazole ring by 0.231 and 0.890 A, respectively. Complexes of type [MCI(COD)(1)] (where M = Rh and Ir) were prepared and characterized using spectroscopic and crystallographic methods. The donor strength of this new carbene was determined by IR spectroscopy (nu(av)) and cyclic voltammetry (E-1/2). Preliminary catalytic studies show that the new carbene is a suitable ligand for rhodium and iridium catalysts in the hydrosilylation of acetophenones.

• 出版日期2016-11-15