Novel η<sup>1</sup>-N,η<sup>2</sup>-C,C-Binding Mode between Pyridinyl-Functionalized Cyclopentadienyl Ligands and Iridium
作者:Alex S. Ionkin、William J. Marshall
DOI:10.1021/ic0505854
日期:2005.9.1
The reaction between 2- (2,3,4,5-tetramethyl-cyclopenta-1,3-dienyl)-pyridine 1 and 103 was performed in an attempt to synthesize a cyclometalated system with decreased A conjugation in the ligand. An unexpected reduction and. rearrangement of bis-pyridinyl-cyclopentadienyl cyclometalated Ir(III) intermediate 2 took place yielding bis-pyridinyl-fulvene lr(l) complex 4, which exhibits a novel bis-eta(1)-N,eta(2)-C C-binding mode between the pyridinyl-functionalized fulvene ligand and iridium. The iridium atom in 4 is not sandwiched between two cyclopentadienyl moieties; rather, the two cyclopentadienyl groups adopt a pi-pi stacking arrangement with a centroid-centroid distance of 3.494 A. The Cl/P<^>O ligand-exchange reaction between 4 and 2-[(diphenylphosphanyl)-methyll-1,1,1,3,3,3-hexafluoro-propan2-ol 5 led to loss of one pyridinyl-functionalized fulvene ligand and produced complex 6, in which the remaining pyridinyl-functionalized fulvene ligand exhibits the mono-eta(1)-N, eta(2)-C, C-binding mode.