Insight into the electronic structure of the supramolecular 鈥渞ods-in-belt鈥?Au^ICu^I and Au^IAg^I self-assembled complexes from X-ray photoelectron and absorption spectroscopy

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• 作者：Anna A. Makarova^a ; ^b ; Elena V. Grachova^c ; Dmitry V. Krupenya^c ; Oleg Vilkov^a ; ^b ; Alexander Fedorov^a ; ^d ; Dmitry Usachov^a ; Alexander Generalov^a ; ^b ; Igor O. Koshevoy^c ; ^e ; Sergey P. Tunik^c ; Eckart Rü ; hl^f ; Clemens Laubschat^b ; Denis V. Vyalikh^a ; ^b ; ^{vyalikh@physik.phy.tu-dresden.de" class="auth_mail}
• 关键词：Supramolecular complexes ; Metallophilic interactions ; Copper subgroup metals ; Electronic structure ; Photoelectron spectroscopy ; NEXAFS
• 刊名：Journal of Electron Spectroscopy and Related Phenomena
• 出版年：January, 2014
• 年：2014
• 卷：192
• 期：Complete
• 页码：26-34
• 全文大小：2308 K

文摘

The recently discovered 鈥渞ods-in-belt鈥?supramolecular complexes with AuCu or AuAg cluster cores exhibit self-assembly behavior, have a very unusual structural motif, and what is most important, show remarkable light emitting properties. The electronic and photophysical characteristics of these unique objects can be relatively easy tuned by modifying the ligand (alkynyl and phosphine) environment. Because of these properties the 鈥渞ods-in-belt鈥?supramolecules could serve as building blocks for next generation electronics, and in particular, for light-emitting devices and in bioimaging applications.

Herein, we report a comprehensive characterization of the electronic structure of two families of alkynyl-diphosphine supramolecular complexes with the heterometallic AuCu and AuAg cores. Using X-ray photoemission and absorption spectroscopy we disentangled the structure of their occupied and unoccupied electronic states close to the Fermi level. The results obtained suggest that the major contribution to the highest occupied molecular orbitals is made by the triple bonded carbons hosted in the dialkynyl-gold 鈥渞ods鈥?and the copper (silver) atoms from the central cluster core of the heterometallic AuCu (AuAg) molecules. The lowest unoccupied molecular orbitals are located on the carbon skeleton of the complexes and include 蟺*-CC and 蟺*-CC_aromatic orbitals. The onset of the valence band in the AuAg systems starts at about 0.3 eV lower than that in the AuCu complexes, implying a slightly larger energy gap for the silver-based systems. It was also established that with increasing size of the complexes, the molecule becomes more and more sensitive to X-ray damage effects.