Two‐Sidedness of Surface Reaction Mediation

Chen, Haoran; Zhu, Hao; Huang, Zhichao; Rong, Wenhui; Wu, Kai

doi:10.1002/adma.201902080

Cited by 16 publications

(8 citation statements)

References 104 publications

(126 reference statements)

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“…构筑和调控有机大分子和超分子在规整衬底上的组装结构 [1,2] , 对于多个表面和纳米科学研究领域, 如表面合成 [3,4] 、多相催化 [5][6][7] 、分子自旋电子学 [8][9][10] 以及光电子学 [11,12] 等, 具有重要科学价值. 作为一类重要的金属有机大分子配合物, 金属卟啉受到了研究者的广泛关注.…”

Section: 引言unclassified

Adsorption and Self-assembly of meso-tetra(p-methoxyphenyl)-porphyrinatocobalt(II) on Coinage Metal Surfaces

Yin¹,

Wang²,

Liú³

et al. 2020

Acta Chim. Sinica

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The adsorption and self-assembly of meso-tetra(p-methoxyphenyl)porphyrinatocobalt(II) [Co(TAP)] on Au(111), Ag(111) and Cu(111) have been systematically studied by ultrahigh vacuum low-temperature scanning tunneling microscopy (STM). The atomically flat metal substrate surfaces are prepared by cycled ion sputtering and subsequent annealing at 750 K. Co(TAP) molecules are deposited onto the substrate surfaces via thermal evaporation from a home-made tantalum boat. The as-prepared samples are then annealed to achieve energetically stable self-assembly structures and transferred to the STM chamber for further analyses. All STM measurements are carried out at about 4.4 K. On these metal surfaces, Co(TAP) molecules mainly form two types of two-dimensional molecular assembly structures A and B. Structure A only exists on Au(111) and Ag(111), while Structure B merely appears on Ag(111) and Cu(111). The intermolecular interactions in Structures A and B are due to π-π stacking and hydrogen bonding, respectively. The difference in strength of the molecule-substrate interaction, which induces conformational changes of peripheral p-methoxyphenyl substituent in Co(TAP) on difference substrate, is attributed to govern the formation of different self-assembly structures on the aforementioned surfaces. The substrate surface also has an effect on the formation of the self-assembly structures. At similar coverage, the percentage of dispersed Co(TAP) molecules follow the sequence: Cu(111)＞Au( 111)＞Ag(111). With the coverage increase, the percentage of dispersed Co(TAP) molecules decreases on all metal surfaces employed in this study. Specifically, on Au(111) and Ag(111), the dispersed Co(TAP) molecules disappear at coverages of about 1 ML and 0.1 ML, respectively, while on Cu(111) they survive even at the coverage of about 0.85 ML. In addition, Structure A gradually dominates on Au(111). On Cu(111), Structure B only occupies half of the surface structures even at nearly saturated coverage. The ratio of Structures A to B almost retains over the whole coverage range on Ag(111). Thermal annealing of the molecule-covered Ag(111) substrate helps the transformation from Structure B to A, and the elimination of the structural domain boundaries as well.

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Section: 引言unclassified

Adsorption and Self-assembly of meso-tetra(p-methoxyphenyl)-porphyrinatocobalt(II) on Coinage Metal Surfaces

Yin¹,

Wang²,

Liú³

et al. 2020

Acta Chim. Sinica

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“…In the past decades, surface chemistry has been widely applied to precisely construct surface nanostructures and help understand surface reaction mechanisms at the atomic level. − Various strategies , have been adopted to steer on-surface reactions, including specifically designed precursors, ,, introduced directing groups, , specific metal substrates , and surface lattices, , secondary templates, gas mediation, and molecular self-assemblies as well. − These strategies have been successfully applied to construct low-dimensional and atomically precise nanostructures via covalent coupling reactions. Halogen atoms can help steer on-surface reactions structurally and electronically, which has received increasing attention in recent years.…”

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confidence: 99%

Steering Effect of Bromine on Intermolecular Dehydrogenation Coupling of Poly(p-phenylene) on Cu(111)

et al. 2020

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Among the multitudinous methodologies to steer on-surface reactions, less attention has been paid to the effect of externally introduced halogen atoms. Herein, highly selective trans-dehydrogenation coupling at the specific meta-C−H site of two poly(p-phenylene) molecules, p-quaterphenyl (Ph 4 ) and p-quinquephenyl (Ph 5 ), is achieved on Cu(111) by externally introduced bromine atoms. Scanning tunneling microscopy/ spectroscopy experiments reveal that the formed molecular assembly structure at a stoichiometric ratio of 4:1 for Br to Ph 4 or 5:1 for Br to Ph 5 can efficiently promote the reactive collision probability to trigger the trans-coupling reaction at the meta-C−H site between two neighboring Ph 4 or Ph 5 molecules, leading to an increase in the coupling selectivity. Such Br atoms can also affect the electronic structure and adsorption stability of the reacting molecules. It is conceptually demonstrated that externally introduced halogen atoms, which can provide an adjustable halogen-to-precursor stoichiometry, can be employed to efficiently steer on-surface reactions.

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“…On‐surface synthesis of organic nanoarchitectures attracts a lot of attention in the last decade . The topology of the on‐surface organic nanostructures can be delicately tailored with the single‐atom precision, allowing for the tunable functionalities at the molecular level, which promises great potential in the applications for nano electronic devices and sensors .…”

Section: Methodsmentioning

confidence: 99%