We present a systematic study of metal−organic honeycomb lattices assembled from simple ditopic molecular bricks and Co atoms on Ag(111). This approach enables us to fabricate size-and shape-controlled open nanomeshes with pore dimensions up to 5.7 nm. The networks are thermally robust while extending over µm 2 large areas as single domains. They are shape resistant in the presence of further deposited materials and represent templates to organize guest species and realize molecular rotary systems.
The confinement of surface-state electrons by a complex supramolecular network is studied with low-temperature scanning tunneling microscopy and rationalized by electronic structure calculations using a boundary element method. We focus on the self-assembly of dicarbonitrile-sexiphenyl molecules on Ag(111) creating an open kagomé topology tessellating the surface into pores with different size and symmetry. This superlattice imposes a distinct surface electronic structure modulation, as observed by tunneling spectroscopy and thus acts as a dichotomous array of quantum corrals. The inhomogenous lateral electronic density distribution in the chiral cavities is reproduced by an effective pseudopotential model. Our results demonstrate the engineering of ensembles of elaborate quantum resonance states by molecular self-assembly at surfaces.
The confinement of Ag(111) surface state electrons by self-assembled, nanoporous metal-organic networks is studied using low-temperature scanning tunneling microscopy/spectroscopy and electronic structure calculations. The honeycomb networks of Co ligands and dicarbonitrile-oligophenyl linkers induce surface resonance states confined in the cavities with a tunable energy level alignment. We find that electron scattering on the molecules is repulsive and stronger than on the weakly attractive Co and that the networks represent periodic arrays of coupled quantum dots featuring uniform electronic levels.
In this paper we conclude the study of the reaction of water with the first row transition metal ions.
We report the study of the reaction of water with the late (Co+, Ni+, and Cu+) first row transition metal
cations in both high- and low-spin states. In agreement with experimental observations, no exothermic products
are found and the oxides are predicted to be more reactive than the metal ions. Formation of endothermic
products is examined. An in-depth analysis of the reaction paths possible for these reactions is given, including
various minima and several important transition states. All results have been compared with existing experimental
and theoretical data, and our earlier works covering the (Sc+-Fe+) + H2O reactions to observe existent trends
for the first row transition metal ions.
Self‐assembly of functional supra‐molecular nanostructures is among the most promising strategies for further development of organic electronics. However, a poor control of the interactions driving the assembling phenomena still hampers the tailored growth of designed structures. Here exploration of how non‐covalent molecule‐substrate interactions can be modified on a molecular level is described. For that, mixtures of DIP and F16CuPc, two molecules with donor and acceptor character, respectively are investigated. A detailed study of their structural and electronic properties is performed. In reference to the associated single‐component layers, the growth of binary layers results in films with strongly enhanced intermolecular interactions and consequently reduced molecule‐substrate interactions. This new insight into the interplay among the aforementioned interactions provides a novel strategy to balance the critical interactions in the assembly processes by the appropriate choice of molecular species in binary supra‐molecular assemblies, and thereby control the self‐assembly of functional organic nanostructures.
Uniaxial anisotropy in two-dimensional self-assembled supramolecular structures is achieved by the coadsorption of two different linear molecules with complementary amine and imide functionalization. The two-dimensional monolayer is defined by a one-dimensional stack of binary chains, which can be forced to line up along steps in vicinal surfaces. The competing driving forces in the self-organization process are discussed in light of the structures observed during single molecule adsorption and coadsorption on flat and vicinal surfaces and the corresponding theoretical calculations.
We report a comprehensive study of the self-assembly of a diindenoperylene (DIP) monolayer on Au(111)
single crystals exploiting different electron probes ranging from STM and LEED to photoelectron spectroscopy
and NEXAFS. By this multitechnique approach, we obtain a full picture of the crystallographic and electronic
structure of the DIP layer as well as an insight into the assembly process and the role of the DIP−Au
interactions. We contrast these experimental findings with theoretical calculations.
The stable isomers of the ferrocene--lithium cation gas-phase ion complex have been studied with the hybrid density functional theory. The method of calculation chosen has been tested checking its performance for the more studied protonated ferrocene species. Our calculations demonstrate that the procedure used is reliable. We have found two isomers of the ferrocene--lithium cation complex separated by a barrier of 25.6 kcal/mol. The most stable isomer of this complex has Li(+) on-top of one of the cyclopentadienyls, while in the least stable isomer Li(+) binds the central iron metal. The latter isomer has been characterized as a planetary system in the sense that Li(+) has one thermally accessible planar orbit around the central ferrocene moiety. Our calculations lead to a value of ferrocene's gas-phase lithium cation basicity of 37.4 kcal/mol for the on-top complex and 29.4 kcal/mol for the metal-bound complex.
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