Affiliation:
1. Department of Chemistry Collin College, Preston Ridge Campus Frisco TX 75035 USA
2. Department of Chemistry University of Washington Seattle WA 98195-1700 USA
3. Department of Chemistry Drexel University 32 S. 32nd St. Philadelphia PA 19104 USA
Abstract
AbstractThe complexes Cp(MeIm)IrI2 and CpMe4(MeIm)IrCl2 have been prepared and subsequently methylated to form Cp(MeIm)IrMe2 and CpMe4(MeIm)IrMe2 (Cp=η5‐C5H5, CpMe4=η5‐C5HMe4, MeIm=1,3‐dimethylimidazol‐2‐ylidene). We attempted unsuccessfully to use the dimethyl complexes to study C−D bond activation via methyl‐group abstraction. Protonation with one equivalent of a weak acid, such as 2,6‐dimethylpyridinium chloride, affords methane and IrIII methyl chloride complexes. 1H‐NMR experiments show addition of pyridinium [BArF20]− (BArF20=[B(C6F5)4]−) to the dimethyl species forms [Cp(MeIm)IrMe(py)]+[BArF20]− (py=pyridine) or [CpMe4(MeIm)IrMe(py)]+[BArF20]− respectively, alongside methane, while use of the [BArF20]− salts of more bulky 2,6‐dimethylpyridinium and 2,6‐di‐tert‐butylpyridinium gave an intractable mixture. Likewise, the generation of 16 e− species [CpMe4(MeIm)IrMe]+[BArF20]− or [Cp(MeIm)IrMe]+[BarF20]− at low temperature using 2,6‐dimethylpyridinium or 2,6‐di‐tert‐butylpyridinium in thawing C6D6 or toluene‐d8 formed an intractable mixture and did not lead to C−D bond activation. X‐ray structures of several IrIII complexes show similar sterics as that found for the previously reported Cp* analogue.