A dibenz[a,c]phenazine-Supported N-heterocyclic Carbene and Its Rhodium and Iridium Complexes
Chemistry & Biochemistry
A new polycyclic N-heterocyclic carbene featuring a fused dibenz[a,c]phenazine moiety was generated in situ from the corresponding tetrafluoroborate salt. The synthesis and NMR data of its corresponding precursors, its sulfur adduct and dimer are reported. Complexes of type [MCl(COD)(1)] and [MCl(CO)2(1)] (M = Rh and Ir, 1 = 1,3-dibutyldibenzo[a,c]phenazino[11,12-d]imidazol-2-ylidene) were prepared and characterized using spectroscopic and crystallographic methods. The electron-releasing capacity of this new carbene was investigated by evaluation of its corresponding IrCl(COD) and IrCl(CO)2 complexes by IR spectroscopy (νav) and cyclic voltammetry (E1/2). These studies revealed that the electron donicity of this ligand is comparable to that of the previously reported naphthoquinone-annulated imidazolin-2-ylidene. Some preliminary studies of the photophysical properties and catalytic activity of these metal complexes are reported.
Tapu D, McCarty Z, Hutchinson L, Ghattas C, Chowdhury M, Salerno J, VanDerveer D. 2014. A dibenz[a,c]phenazine-supported N-heterocyclic carbene and its rhodium and iridium complexes. Journal of Organometallic Chemistry 749:134-41.