The reaction of meta- and para-bromomethylene-azobenzenes with 1-methyl-imidazole yields the respective meta-/para-functionalized azobenzenes tagged with an imidazolium group. Similar reactions of ortho- and para-bromo-azobenzene with imidazole and successive quaternation with benzylbromide give the analogues, with an imidazolium group in ortho/para substituted azobenzenes. With the exception of the ortho derivative, all imidazolium salts could be transformed into their respective silver(i) complexes by reaction with Ag2O. Transmetallation of these silver(i) complexes with (Me2S)AuCl gives the azobenzene-containing complexes (NHC)AuCl. Two of these formed crystals suitable for X-ray diffraction, which revealed the typical linear coordination geometry of the NHC-Au-Cl moiety. All gold complexes feature E→Z photo-isomerisation upon irradiation with UV light. The thermal back reaction to the E-isomers is relatively slow and comparable to that of other azobenzene compounds.
The metal-rich halogenides AuBi 14Ϫδ Sn 2ϩδ X 21Ϫδ (δ ഠ 0.4) and PdBi 15Ϫδ Sn 1ϩδ X 21Ϫδ (δ ഠ 0.6) with X ϭ Cl, Br were crystallized from melts of the metals and BiX 3 . In the rhombohedral structures (space group R3; a ഠ 1050 pm; Ͱ ഠ 94°), noble-metal centered pentagonal antiprisms [Au@Bi 10 ] 5ϩ resp. [Pd@Bi 10 ] 4ϩ are embedded in halogenidometallate frameworks 3 ϱ [Bi 4Ϫδ Sn 2ϩδ X 21Ϫδ ] 5Ϫ resp. 3 ϱ [Bi 5Ϫδ Sn 1ϩδ X 21Ϫδ ] 4Ϫ . Mixed Bi III /Sn II site occupation allows the framework to adopt different charges. Further exchange of Bi III X 3 743against Sn II X 2 results in vacancies (δ) on the position of an isolated halide ion. In quantum chemical calculations the naked metal-clusters are found to be stable in D 5d symmetry with interatomic distances close to the observed ones. The significance of interactions between the Wade-type host cluster Bi 10 4ϩ and the closed-subshell guest atoms Au ϩ or Pd 0 is reflected in the molecular orbital diagram, the population analyses and the ELI-D.
We report on the synthesis and characterization of an NHC ligand based on the imidazo[1,5‐a]quinolinol scaffold. The benzyl‐protected NHC precursor was used for the preparation of the corresponding AgI, AuI and AuIII complexes. The molecular structures of the AuI and AuIII halide complexes determined by single‐crystal X‐ray diffraction reveal considerable distortion of the rigid NHC moiety due to steric repulsion between the gold and oxygen atoms. At ambient temperature, the complexes are weakly fluorescent from an intraligand excited state, whereas at 77 K the emission spectra are dominated by intraligand phosphorescence.
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