Synthesis and Characterization of Organometallic Ionic Liquids and a Heterometallic Carbene Complex Containing the Chromium Tricarbonyl Fragment

Direct reaction between [Cr(CO)6] and arenes with ionic substituents affords the corresponding arene−chromium tricarbonyl complexes, [Cr(CO)3(arene)], in only modest yield.
In contrast, these complexes can be prepared in pure form in excellent yield from the reaction
of [Cr(CO)3(η6-C6H5CH2Br)] with, for example, N-methylimidazole. The structures of [Cr(CO)3(η6-C6H5CH2MIM)]Br (MIM = 3-methylimidazolium), [Cr(CO)3(η6-C6H5CH2MMIM)]Br
(MMIM = 2,3-dimethylimidazolium), and [Cr(CO)3(η6-C6H5CH2NMe2(CH3)2OH)]Br have been
established by X-ray diffraction analysis. Subsequent exchange of the bromide anion for
Tf2N- affords new organometallic salts with melting points below 70°C. Reaction of the
bromide salts include tosylation of [Cr(CO)3(η6-C6H5CH2NMe2(CH3)2OH)]Br to afford [Cr(CO)3(η6-C6H5CH2NMe2(CH2)2OTs)]Br and the formation of the heterometallic carbene
complex [Ru(η6-p-cymene)Cl2{C4H5N2CH2Ph-η6-Cr(CO)3}]. Both compounds were characterized in the solid state by X-ray diffraction.