Simulations of X-ray absorption spectroscopy and energetic conformation of N-heterocyclic carbenes on Au(111)

Autor(es)

de Lima, F. Crasto ^[1] ; Fazzio, A. ^[1] ; McLean, A. B. ^[2] ; Miwa, R. H. ^[3]

Afiliação do(s) autor(es)

^[1] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Nanotechnol Natl Lab LNNano, BR-13083970 Campinas, SP - Brazil

^[2] Queens Univ, Dept Phys Engn Phys & Astron, Kingston, ON K7L 3N6 - Canada

^[3] Univ Fed Uberlandia, Inst Fis, CP 593, BR-38400902 Uberlandia, MG - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Physical Chemistry Chemical Physics; v. 22, n. 37, p. 21504-21511, OCT 7 2020.
• Citações Web of Science: 0

Resumo

It has recently been demonstrated that N-heterocyclic carbenes (NHCs) form self-assembled monolayers (SAMs) on metal surfaces. Consequently, it is important to both characterize and understand their binding modes to fully exploit NHCs in functional surface systems. To assist with this effort, we have performed first-principles total energy calculations for NHCs on Au(111) and simulations of X-ray absorption near edge structure (XANES). The NHCs we have considered areN,N-dimethyl-,N,N-diethyl-,N,N-diisopropylbenzimidazolylidene ((NHCX)-N-B, with X = Me, Et, and iPr, respectively) and the bis-(NHCX)-N-B-Au complexes derived from these molecules. We present a comprehensive analysis of the energetic stability of both the(B)NHC(X)and the complexes on Au(111) and, for the former, examine the role of the wing group in determining the attachment geometry. Further structural characterization is performed by calculating the nitrogen K-edge X-ray absorption spectra. Our simulated XANES results give insight into (i) the relationship between the(B)NHC(X)/Au geometry and the N(1s) -> pi{*}/sigma{*}, pre-edge/near-edge, absorption intensities, and (ii) the contributions of the molecular deformation and molecule-surface electronic interaction to the XANES spectrum. These simulated spectra work not only as a map to the(B)NHC(X)conformation, but also, combined with electronic structure calculations, provide a clear understanding of recent experimental XANES findings on(B)NHC(X)/Au. (AU)

• Processo FAPESP: 19/20857-0 - Materiais bidimensionais e fases topológicas: predição e controle de suas propriedades
• Beneficiário: Felipe David Crasto de Lima
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado