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. Finally, [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.