Reactions of noble-metal oxides in ionic liquids near room temperature

The reaction of Ag$_{2}$O, Au$_{2}$O$_{3}$, and HgO with CuCl, CuI, AgCl, AgI, AuCl, and AuI in ionic liquids ([EMIm]Cl, [BMIm]Cl) near room temperature (20–80 °C) is evaluated and results in the new compounds (C$_{8}$H$_{14}$N$_{2}$)CuCl, (C$_{8}$H$_{14}$N$_{2}$)AgI, (C$_{6}$H$_{10}$N$_{2}$)AuCl, [(C$_{8}$H$_{14}$N$_{2}$)$_{2}$Hg][CuCl$_{3}$], [(C$_{8}$H$_{14}$N$_{2}$)$_{2}$Hg][AgCl$_{3}$], and [EMIm][Ag$_{2}$I$_{2}$Cl]. Thereof, (C$_{8}$H$_{14}$N$_{2}$)CuCl, (C$_{8}$H$_{14}$N$_{2}$)AgI, (C$_{6}$H$_{10}$N$_{2}$)AuCl, [(C$_{8}$H$_{14}$N$_{2}$)$_{2}$Hg][CuCl$_{3}$], and [(C$_{8}$H$_{14}$N$_{2}$)$_{2}$Hg][AgCl$_{3}$] are NHC complexes (NHC: N-heterocyclic carbene) with M–C bonds (M: Cu, Ag, Au, Hg). Whereas (C$_{8}$H$_{14}$N$_{2}$)CuCl and (C$_{8}$H$_{14}$N$_{2}$)AgI crystallize as single molecules, (C$_{6}$H$_{10}$N$_{2}$)AuCl is dimerized via aurophilic interactions. [(C$_{8}$H$_{14}$N$_{2}$)$_{2}$Hg][CuCl$_{3}$] and [(C$_{8}$H$_{14}$N$_{2}$)$_{2}$Hg][AgCl$_{3}$] exhibit Hg atoms with two Hg–C bonds. Moreover, (C$_{8}$H$_{14}$N$_{2}$)AgI shows intense green fluorescence at room temperature with a quantum yield of 44%, whereas all other compounds do not show any emission at room temperature. ... mehrFinally, [EMIm][Ag$_{2}$I$_{2}$Cl] is not an NHC compound but contains $_{∞}$$^{1}$[AgI$_{1/2}$I$_{2/4}$Cl$_{1/2}$]− chains with infinite d$^{10}$–d$^{10}$ interaction of the silver atoms. The title compounds are characterized by single-crystal structure analysis, infrared spectroscopy, thermogravimetry, and fluorescence spectroscopy.