Covalent, Organometallic, and Halogen-Bonded Nanomeshes from Tetrabromo-Terphenyl by Surface-Assisted Synthesis on Cu(111)
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- 作者：Qitang Fan ; Cici Wang ; Liming Liu ; Yong Han ; Jin Zhao ; Junfa Zhu ; Julian Kuttner ; Gerhard Hilt ; J. Michael Gottfried
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：June 19, 2014
- 年：2014
- 卷：118
- 期：24
- 页码：13018-13025
- 全文大小：560K
- 年卷期：v.118,no.24(June 19, 2014)
- ISSN：1932-7455
文摘
The selective temperature-controlled surface-assisted synthesis of covalent, organometallic, and halogen-bonded nanomeshes based on a 3,5,3鈥?5鈥?tetrabromo-para-terphenyl (TBrTP) precursor was studied with scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (STM) in ultrahigh vacuum. Vapor deposition of TBrTP onto Cu(111) at 90 K leads to a highly ordered organic monolayer stabilized by Br路路路Br and Br路路路H intermolecular bonds between the intact T-type assembled TBrTP molecules, as confirmed by density functional theory (DFT) calculations. Annealing the monolayer to 300 K results in C鈥揃r bond scission and the formation of C鈥揅u鈥揅 bonds, which link adjacent para-terphenyl fragments such that stable organometallic frameworks are formed. Pore sizes correlate with the number of enclosed adatoms (most likely Br atoms), which presumably play a size-determining role during the process of the pore formation. Larger islands of the organometallic framework are obtained by deposition of TBrTP onto the copper surface held at 460 K. A further increase in sample temperature to 570 K during deposition gives rise to the formation of covalent organic frameworks with pores of tetragonal and trigonal symmetry. The covalent nanostructures are not completely planar, but contain phenylene units which are tilted relative to the surface plane, most likely due to steric hindrance between the C鈥揌 bonds inside the pores. Comparison of the three different bonding regimes reveals that the degree of long-range order correlates inversely with the strength of the bonds between the building blocks.