A long-range ordered array of copper tetrameric units embedded in an on-surface metal organic framework.

We report on the assembly of a highly ordered array of copper tetrameric clusters, coordinated into a metal-organic network. The ordered cluster array has been achieved by the deposition of tetrahydroxyquinone molecules on the Cu(111) surface at room temperature, and subsequent thermally activated dehydrogenation with the formation of tetraoxyquinone tetra-anions with a 4 × 4 periodicity. The supramolecular organic network acts as a spacer for the highly ordered two-dimensional network of copper tetramers at the very surface.

Two-Dimensional Ketone-Driven Metal-Organic Coordination on Cu(111).

Two-dimensional metal-organic nanostructures based on the binding of ketone groups and metal atoms were fabricated by depositing pyrene-4,5,9,10-tetraone (PTO) molecules on a Cu(111) surface. The strongly electronegative ketone moieties bind to either copper adatoms from the substrate or codeposited iron atoms. In the former case, scanning tunnelling microscopy images reveal the development of an extended metal-organic supramolecular structure.

Anomalous coarsening driven by reversible charge transfer at metal-organic interfaces.

The unique electronic properties and functional tunability of polycyclic aromatic hydrocarbons have recently fostered high hopes for their use in flexible, green, portable, and cheap technologies. Most applications require the deposition of thin molecular films onto conductive electrodes. The growth of the first few molecular layers represents a crucial step in the device fabrication since it determines the structure of the molecular film and the energy level alignment of the metal-organic interface.

Pressure-induced conformation transition of o-phenylene solvated in bulk hydrocarbons.

The conformational behavior of o-phenylene 8-mers and 10-mers solvated in a series of linear alkane solvents by means of classical molecular dynamics and first-principles calculations was studied. Irrespective of the solvent used, we find that at ambient pressure the molecule sits in the well-defined close-helical arrangement previously observed in light polar solvents. However, for pressures greater than 50 atm, and for tetradecane or larger solvent molecules, our simulations predict that o-phenylene undergoes a conformational transition to an uncoiled, extended geometry with a 35% longer head-to-tail distance and a much larger overlap between its lateral aromatic ring groups.

Self-assembly of decoupled borazines on metal surfaces: the role of the peripheral groups.

Two borazine derivatives have been synthesised to investigate their self-assembly behaviour on Au(111) and Cu(111) surfaces by scanning tunnelling microscopy (STM) and theoretical simulations. Both borazines form extended 2D networks upon adsorption on both substrates at room temperature. Whereas the more compact triphenyl borazine 1 arranges into close-packed ordered molecular islands with an extremely low density of defects on both substrates, the tris(phenyl-4-phenylethynyl) derivative 2 assembles into porous molecular networks due to its longer lateral substituents.

"Magic" surface clustering of borazines driven by repulsive intermolecular forces.

It's a kind of magic: Hydroxy pentaaryl borazine molecules self-assemble into small clusters (see structure) on Cu(111) surfaces, whereas with symmetric hexaaryl borazine molecules large islands are obtained. Simulations indicate that the observed "magic" cluster sizes result from long-range repulsive Coulomb forces arising from the deprotonation of the B-OH groups of the hydroxy pentaaryl borazine.

Confined 3D microenvironment regulates early differentiation in human pluripotent stem cells.

The therapeutic potential of human pluripotent stem (hPS) cells is threatened, among various problems, by the difficulty to homogenously direct cell differentiation into specific lineages. The transition from hPSC into committed differentiated cells is accompanied by secretome activity, remodeling of extracellular matrix and self-organization into germ layers. In this work, we aimed to investigate how different three-dimensional microenvironments regulate the early differentiation of the three germ layers in human embryonic stem (hES) cells derived embryoid bodies.