Colloidal Hollandite Holey Rods Produced by Presynthetic Nanohybridization.

Electrostatically stabilized binary hybrids comprising TiO nanotubes and FeO nanoparticles were self-assembled and investigated as precursors for a KFTO material. Presynthetic nanohybridization is a way to organize the components, with the caveat that the mere nanomaterial combination cannot grant a high degree of control due to their general susceptibility to aggregation, resulting in masses with poor spatial order. Various hybridization conditions were explored, and the effects of the experimental parameters were investigated in detail, considering KCl concentration, Fe/Ti ratio, and hydrothermal treatment temperature.

Photocatalytic oxidation of glycerol with red light employing quinacridone sensitized TiO nanoparticles.

Photocatalytic nanomaterials combining organic dyes and inorganic semiconductor nanoparticles (NPs) are extensively investigated for light-driven production of solar fuels and for conversion of organic feedstocks. However, their applications for the valorization of abundant raw materials by exploiting low-energy visible light remain limited. In this study, we report a facile preparation of TiO nanoparticles sensitized with a quinacridone (QA) industrial pigment for the aqueous oxidation of glycerol to glyceraldehyde with red light ( = 620 nm), reaching 47.

ATP-Regulated Formation of Transient Peptide Amphiphiles Superstructures.

Self-assembly of biotic systems serves as inspiration for the preparation of synthetic supramolecular assemblies to mimic the structural, temporal, and functional aspects of living systems. Despite peptide amphiphiles (PAs) being widely studied in the context of biomimetic and bioactive functional nanomaterials, very little is currently known about the reversible and spatiotemporal control of their hierarchical self-assemblies. Here, it is shown that PA-based supramolecular nanofibers can transiently form superstructures, through binding with oppositely charged adenosine triphosphate (ATP), leading to charge screening and stabilization of bundled nanofibers.

Self-Assembly of Supramolecular Double Helix from a Tetrapeptide and Direct Visualization by Scanning Tunneling Microscopy.

This work reports single-crystal X-ray diffraction (XRD), Scanning Tunneling Microscopy (STM), and quantum mechanics calculations of the 3-helical peptide Z-(Aib)-L-Dap(Boc)-Aib-NHiPr (Aib, α-aminoisobutyric acid; Dap, 2,3-diaminopropionic acid; Z, benzyloxycarbonyl; Boc, t-butoxycarbonyl). The peptide forms a double-helical superstructure, studied by XRD and STM. Such architecture is rare in short peptides.

On-Surface Synthesis and Evolution of Self-Assembled Poly(-phenylene) Chains on Ag(111): A Joint Experimental and Theoretical Study.

The growth of controlled 1D carbon-based nanostructures on metal surfaces is a multistep process whose path, activation energies, and intermediate metastable states strongly depend on the employed substrate. Whereas this process has been extensively studied on gold, less work has been dedicated to silver surfaces, which have a rather different catalytic activity. In this work, we present an experimental and theoretical investigation of the growth of poly--phenylene (PPP) chains and subsequent narrow graphene ribbons starting from 4,4″-dibromo--terphenyl molecular precursors deposited at the silver surface.

Structural evolution under physical and chemical stimuli of metastable Au-Fe nanoalloys obtained by laser ablation in liquid.

Metastable alloy nanoparticles are investigated for their variety of appealing properties exploitable for photonics, magnetism, catalysis and nanobiotechnology. Notably, nanophases out of thermodynamic equilibrium feature a complex "ultrastructure" leading to a dynamic evolution of composition and atomic arrangement in response to physical-chemical stimuli. In this manuscript, metastable Au-Fe alloy nanoparticles were produced by laser ablation in liquid, an emerging versatile synthetic approach for freezing multielement nanosystems in non-equilibrium conditions.

Substrate involvement in dioxygen bond dissociation catalysed by iron phthalocyanine supported on Ag(100).

Dioxygen adsorbs in the end-on configuration on-top of the Fe atoms of an iron phthalocyanine monolayer supported on Ag(100) and is partly cleaved at room temperature to produce O/FePc/Ag(100). Scanning tunnelling microscopy coupled to density functional theory calculations gives the first experimental evidence of the substrate involvement in the O2 bond dissociation.

Switching from Reactant to Substrate Engineering in the Selective Synthesis of Graphene Nanoribbons.

The challenge of synthesizing graphene nanoribbons (GNRs) with atomic precision is currently being pursued along a one-way road, based on the synthesis of adequate molecular precursors that react in predefined ways through self-assembly processes. The synthetic options for GNR generation would multiply by adding a new direction to this readily successful approach, especially if both of them can be combined. We show here how GNR synthesis can be guided by an adequately nanotemplated substrate instead of by the traditionally designed reactants.

Photophysical properties and excited state dynamics of 4,7-dithien-2-yl-2,1,3-benzothiadiazole.

The relationships between the photophysics and structural properties of 4,7-dithien-2-yl-2,1,3-benzothiadiazole as a function of solvent polarity are investigated both experimentally and by computational methods. Stationary fluorescence measurements are consistent with a model envisaging the presence of three types of conformers in equilibrium in the ground state. They are characterized by different relative orientations of the thiophene rings.

Tunable Band Alignment with Unperturbed Carrier Mobility of On-Surface Synthesized Organic Semiconducting Wires.

The tunable properties of molecular materials place them among the favorites for a variety of future generation devices. In addition, to maintain the current trend of miniaturization of those devices, a departure from the present top-down production methods may soon be required and self-assembly appears among the most promising alternatives. On-surface synthesis unites the promises of molecular materials and of self-assembly, with the sturdiness of covalently bonded structures: an ideal scenario for future applications.

On-surface photo-dissociation of C-Br bonds: towards room temperature Ullmann coupling.

The surface-assisted synthesis of gold-organometallic hybrids on the Au(111) surface both by thermo- and light-initiated dehalogenation of bromo-substituted tetracene is reported. Combined X-ray photoemission (XPS) and scanning tunneling microscopy (STM) data reveal a significant increase of the surface order when mild reaction conditions are combined with 405 nm light irradiation.

Control of the intermolecular coupling of dibromotetracene on Cu(110) by the sequential activation of C-Br and C-H bonds.

Dibromotetracene molecules are deposited on the Cu(110) surface at room temperature. The complex evolution of this system has been monitored at different temperatures (i.e.

Molecules-oligomers-nanowires-graphene nanoribbons: a bottom-up stepwise on-surface covalent synthesis preserving long-range order.

We report on a stepwise on-surface polymerization reaction leading to oriented graphene nanoribbons on Au(111) as the final product. Starting from the precursor 4,4″-dibromo-p-terphenyl and using the Ullmann coupling reaction followed by dehydrogenation and C-C coupling, we have developed a fine-tuned, annealing-triggered on-surface polymerization that allows us to obtain an oriented nanomesh of graphene nanoribbons via two well-defined intermediate products, namely, p-phenylene oligomers with reduced length dispersion and ordered submicrometric molecular wires of poly(p-phenylene). A fine balance involving gold catalytic activity in the Ullmann coupling, appropriate on-surface molecular mobility, and favorable topochemical conditions provided by the used precursor leads to a high degree of long-range order that characterizes each step of the synthesis and is rarely observed for surface organic frameworks obtained via Ullmann coupling.

Stereoselective photopolymerization of tetraphenylporphyrin derivatives on Ag(110) at the sub-monolayer level.

We explore a photochemical approach to achieve an ordered polymeric structure at the sub-monolayer level on a metal substrate. In particular, a tetraphenylporphyrin derivative carrying para-amino-phenyl functional groups is used to obtain extended and highly ordered molecular wires on Ag(110). Scanning tunneling microscopy and density functional theory calculations reveal that porphyrin building blocks are joined through azo bridges, mainly as cis isomers.