(Benzimidazolin‐2‐ylidene)–Au^I–Alkynyl Complexes: Syntheses, Structure, and Photophysical Properties

Abstract

A series of N-heterocyclic carbene-based Au I -σ-acetylide complexes of the type [(Bimz)Au-CϵCR] (Bimz = benzimidazolin-2-ylidene; R = aryl, silyl groups) (1a-1l, 2, 3) were prepared from the precursor [(Bimz)Au I Cl] by an in situ deprotonation of the terminal alkynes. Steady-state photoluminescence studies revealed that most of these complexes exhibit phosphorescence at room temperature and in 77 K rigidified matrices. Molecular structures were determined by single-

Ligand Exchange at a Gold(I) Carbene Complex

“…1. The Au-C NHC (2.016(2)Å) as well as the Au-C14 (1.988(2)Å) bond lengths of 1 fall in the range previously reported for similar mixed NHC/acetylide gold(I) complexes featuring a benzimidazolin-2-ylidene ligand [45]. Complex 2 exhibits, as expected, almost linear C1-Au-C14 (177.01 (9) • ) and Au-C14-C15 (177.5 (2) [47], which have been observed for many other gold carbene complexes [43,44], are observed for 1.…”

“…These chemical shifts are significantly downfield from the C NHC resonance found for complex 1 (δ = 178.3 ppm) [43] nicely illustrating the dependence of the C NHC resonance on the co-ligand. The C NHC resonance of 2 falls in the range previously reported for a gold(I) NHC/acetylide complex [45,46]. The C NHC resonance of complex 3 cannot be compared to other Au I -NHC-SPh complexes due to lack of available 13 C NMR data.…”

Hierarchically Structured MnO2‐Co/C Nanocomposites: Highly Efficient and Magnetically Recyclable Catalysts for the Aerobic Oxidation of Alcohols

“…Complexes 2 and 3 , which contain different cyclometalated ligands as benzo[ h ]quinoline (bzq) and 2‐(5‐methyl‐2‐thienyl) (5m‐thpy), feature a more redshifted maximum at 372 and 369 nm, respectively, showing the influence of the increased π‐delocalized nature of the chelate on the absorption properties. Despite the fact that the PBE1PBE//SDD/6‐31+G(d) calculations systematically provide underestimated absorption maxima (by approximately 10–20 nm in our previous studies),6, 7, 20 the lowest significant TD‐DFT calculated singlet–singlet transitions S 0 →S 1 for 1 – 4 and S 0 →S 2 for 6 (the oscillator strength of S 0 →S 1 being very small, f =0.0004) at 307, 339, 352, 312, 316 nm, respectively, are in a good agreement with the experimental data (average error=2.6 %, maximum error=4.6 % for 3 ) and reflect very well the redshift observed for 2 and 3 (Table 5). The S 0 →S 1 and S 0 →S 2 transitions derive mainly from the one‐electron excitations HOMO→LUMO for 1 – 4 and HOMO−1→LUMO for 6 .…”

Exploring the Reactivity and Biological Effects of Heteroleptic N‐Heterocyclic Carbene Gold(I)‐Alkynyl Complexes

“…Solvents were distilled prior to use. NHC‐Au I ‐Cl complexes were synthesized by previously reported routes: Chloro(1,3‐diisopropylbenzimidazolin‐2‐ylidene)gold(I) was synthesized as described by Jothibasu et al Chloro‐( N , N ‐dimethylbenzimidazol‐2‐ylidene)gold(I) was synthesized as described by Rodríguez‐Castillo et al Au(Dipp)Cl and Au(Mes)Cl were synthesized as described by Collado et al The synthesis for compounds 1 – 6 was adapted from Garg et al The synthesis for compounds 7 – 12 was adapted from Gao et al 1 H and 13 C NMR spectra were recorded on a Bruker AV400HD or a Bruker AV 500cryo spectrometer. 1 H and 13 C NMR spectra were referenced to the residual solvent signals .…”

“…Bond lengths, angles and intermolecular Au interactions are in accordance with previously reported structures. [19]…”