Determination of the structure and geometry of N-heterocyclic carbenes on Au(111) using high-resolution spectroscopy

Abstract

The geometry and bonding of N-heterocyclic carbenes to metal surfaces depends on the substituents on the N-atoms.

Flexible NO2‐Functionalized N‐Heterocyclic Carbene Monolayers on Au (111) Surface

“…NHCs with small side groups, such as methyl (marked by yellow disks in Scheme ), which do not lead to strong lateral interactions, form planar bis‐carbene metal complexes on metal surfaces . NHCs with larger dimethyl substituents formed films with mixtures of flat and upright orientations, whereas surface‐anchored NHCs with larger diisopropyl and diisopropylphenyl groups (marked by blue spheres in Scheme ) were detected only in an upright position . Density functional theory (DFT) calculations also support the hypothesis that the orientation of surface‐anchored NHCs is directed by the steric properties of their side groups .…”

“…Density functional theory (DFT) calculations also support the hypothesis that the orientation of surface‐anchored NHCs is directed by the steric properties of their side groups . Interestingly, NHCs functionalized with isopropyl groups were anchored in a titled position on Au (111) surface when adsorbed at low temperature (−20 °C), but after annealing to 90 °C the NHCs geometry was changed into a flat‐lying position . These changes indicated that at an intermediate size of substituents the NHC adsorption geometry can represent a local minimum and the optimized orientation is achieved following annealing.…”

Transition metal-based catalysts for the electrochemical CO2reduction: from atoms and molecules to nanostructured materials

“…Moreover, a spectroscopic investigation of the spatial orientation and coordination mode of NHC moieties on different metallic surfaces will provide useful insights to modulate the reactivity of the organic/inorganic interface towards CO 2 RR. [458][459][460][461][462]…”

Synergistic adsorptions of Na2CO3and Na2SiO3on calcium minerals revealed by spectroscopic andab initiomolecular dynamics studies

“…At the moment, although the adsorption of Na 2 SiO 3 species has been considerably investigated, 29,[32][33][34][35] very few studies have been conducted on the Na 2 CO 3 /Na 2 SiO 3 system in otation 17,28,31,36 and the synergistic effects exhibited by this reagent combination are still poorly understood. Some authors have successfully investigated surface reactivity and synergistic adsorptions/ reactions by Fourier transform infrared spectroscopy (FTIR), [37][38][39][40] by X-ray photoelectron spectroscopy (XPS), [41][42][43] and by ab initio molecular dynamics (AIMD) 37,[44][45][46] with couplings between the above-mentioned techniques. In the present study, we use a combination of diffuse reectance infrared Fourier transform spectroscopy (DRIFTS), XPS, and AIMD simulations to gain an understanding of the molecular mechanisms involved in the Na 2 SiO 3 adsorption onto bare surfaces and onto surfaces prior treated with Na 2 CO 3 .…”