The adsorption and monolayer self-assembly of functional metal–organic blocks on solid surfaces are critical for the physicochemical properties of these low-dimensional materials. Although modern microscopy tools are very sensitive to the lateral arrangement of such blocks, they are still unable to offer directly the complete structural analysis especially for nonplanar molecules containing different atoms. Here, we apply a combinatorial approach for the characterization of such interfaces, which enables unexpected insights. An archetypal metalloporphyrin on a catalytically active surface as a function of its molecular coverage and substituent arrangement is characterized by low-energy electron diffraction, scanning probe microscopy, X-ray photoelectron spectroscopy, normal-incidence X-ray standing waves, and density functional theory. We look into Ru tetraphenyl porphyrin (Ru-TPP) on Ag(111), which is also converted into its planarized derivates via surface-assisted cyclodehydrogenation reactions. Depending on the arrangement of the phenyl substituents, the Ru atoms have distinct electronic structures and the porphyrin macrocycles adapt differently to the surface: saddle shape (pristine Ru-TPP) or bowl shape (planarized Ru-TPP derivates). In all cases, the Ru atom resides close to the surface (2.59/2.45 Å), preferably located at hollow sites and in the interface between the plane of the porphyrin macrocycle and the Ag surface. For the more flexible pristine Ru-TPP, we identify an additional self-assembled structure, allowing the molecular density of the self-assembled monolayer to be tuned within ∼20%. This precise analysis is central to harnessing the potential of metalloporphyrin/metal interfaces in functional systems.

A2 Dm etal-organic framework (2D-MOF) was formed on aCu(111) substrate using benzenehexol molecules. By means of acombination of scanning tunneling microscopy and spectroscopy, X-rayp hotoelectron spectroscopya nd density-functional theory,t he structure of the 2D-MOF is determined to be Cu 3 (C 6 O 6 ), which is stabilized by O-Cu-O bonding motifs.W efind that upon adsorption on Cu(111), the 2D-MOF features asemiconductor band structure with adirect band gap of 1.5 eV.The O-Cu-O bonds offer efficient charge delocalization, which gives rise to ah ighly dispersive conduction band with an effective mass of 0.45 m e at the band bottom, implying ahigh electron mobility in this material. Scheme 1. On-surfacesynthesis of single layer of 2D-MOF Cu 3 (C 6 O 6 ).Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

The controlled arrangement of N-heterocyclic carbenes (NHCs) on solid surfaces is a current challenge of surface functionalization. We introduce a strategy of using Ru porphyrins in order to control both the orientation and lateral arrangement of NHCs on a planar surface. The coupling of the NHC to the Ru porphyrin is a facile process which takes place on the interface: we apply NHCs as functional, robust pillars on welldefined, preassembled Ru porphyrin monolayers on silver and characterize these interfaces with atomic precision via a battery of experimental techniques and theoretical considerations. The NHCs assemble at room temperature modularly and reversibly on the Ru porphyrin arrays. We demonstrate a selective and complete functionalization of the Ru centers. With its binding, the NHC modifies the interaction of the Ru porphyrin with the Ag surface, displacing the Ru atom by 1 Å away from the surface. This arrangement of NHCs allows us to address individual ligands by controlled manipulation with the tip of a scanning tunneling microscope, creating patterned structures on the nanometer scale.

We assess the crucial role of tetrapyrrole flexibility in the CO ligation to distinct Ru-porphyrins supported on an atomistically well-defined Ag(111) substrate.O ur systematic real-space visualisation and manipulation experiments with scanning tunnelling microscopyd irectly probe the ligation, while bond-resolving atomic force microscopya nd X-ray standing-wave measurements characterise the geometry,X-ray and ultraviolet photoelectron spectroscopyt he electronic structure,a nd temperature-programmed desorption the binding strength. Density-functional-theory calculations provide additional insight into the functional interface.W eu nambiguously demonstrate that the substituents regulate the interfacial conformational adaptability,e ither promoting or obstructing the uptake of axial CO adducts.

Utilizing the Watson-Crick base pairing mechanism [ 23 ] and the interconnection by Holliday junctions, [ 24,25 ] the robust DNA origami technique allows the formation of arbitrary 2D [ 4 ] and 3D nanostructures. [5][6][7][8][9][10][11][12][13][14][15][16][17] Functionalization of these nanostructures with biomolecules, fl uorophores, metal nanoparticles, or semiconductor quantum dots opens interesting opportunities for biomedical applications, [ 18,19 ] analytics and microscopy, [ 26,27 ] nanoelectronics, [ 28 ] or nanoplasmonics and nanophotonics. [19][20][21][22][29][30][31][32][33][34] However, not only isotropic aqueous dispersions or surfaces containing well-defi ned nanoobjects, [ 35 ] but also bulk materials may be targeted, where these objects exhibit a well-defi ned orientation or are arranged in an array with well-defi ned positions. For this purpose, self-organization on a micrometer scale or mesoscale would be very useful. Liquid crystals (LCs), ordered fl uids, are ideal candidates for bridging the gap between ordering on the sub-µm and µm length scales. LCs show a collective behavior of anisometric molecules or molecular aggregates: the resulting phenomena, like elastic behavior, surface alignment, or interaction with external electric and magnetic fi elds are described by characteristic lengths, which are typically in the µm range.[ 36 ] This is not only important for fl at panel displays, where LC fi lms with a thickness of a few µm are realigned by electric fi elds, but can also be used to control the alignment of rod-like or disk-like nanoparticles, for example, gold or semiconductor nanorods, carbon nanotubes,