title: Stretch Out or Fold Back? Conformations of Dinuclear Gold(I) N-Heterocyclic Carbene Macrocycles.
abstract: We report the synthesis and characterization of 12 new dinuclear gold(I) N-heterocyclic carbene (NHC) complexes and the corresponding imidazolium precursors. The focus lies in a systematic study of conformational changes and intra- and intermolecular gold-gold and π-π interactions of dinuclear gold(I) carbene complexes. Common to all members of the series of gold macrocycles are NHC ligands on the basis of imidazole with ethyl side chains and bromide as well as hexafluorophosphate counterions, respectively. The compounds vary in the length of a flexible alkyl linker between the NHC units. For the methylene and ethylene bridged macrocycles, a ring inversion movement can be observed by VT-NMR. In total, 11 molecular structures have been characterized by X-ray diffraction. Open ring conformations with intermolecular π-π and Au-Au interactions prevail, but a backfolded conformation with a short intramolecular Au-Au distance has been found for the ethylene-bridged species. The presence of Au-Au interactions could be proven by quantum chemical calculations.
authors.affiliation: †Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Kobialka
authors.affiliation: †Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Müller-Tautges
authors.affiliation: †Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.
authors.forename: Melanie T S
authors.initials: MT
authors.lastname: Schmidt
authors.affiliation: †Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.
authors.forename: Gregor
authors.initials: G
authors.lastname: Schnakenburg
authors.affiliation: ‡Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstrasse 4, 53115 Bonn, Germany.
authors.forename: Oldamur
authors.initials: O
authors.lastname: Hollóczki
authors.affiliation: ‡Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstrasse 4, 53115 Bonn, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Kirchner
authors.affiliation: †Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.
authors.forename: Marianne
authors.initials: M
authors.lastname: Engeser
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000737:chemistry*; D047028:Macrocyclic Compounds / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008968:Molecular Conformation
chemical_list: D056831:Coordination Complexes; D006571:Heterocyclic Compounds; D047028:Macrocyclic Compounds; C030011:carbene; D006046:Gold; D008697:Methane