Immobilization of paracetamol and benzocaine pro-drug derivatives as long-range self-organized monolayers on graphite

Graphene and graphene-based nanocomposites: biomedical applications and biosafety

Graphene is the first carbon-based two dimensional atomic crystal and has gained much attention since its discovery by Geim and co-workers in 2004.

Synthesis and 2D self-assembly at the liquid–solid interface of novel H-bonding linear π-conjugated oligomers terminated by uracil and melamine units

2D self-assembly of a novel π-conjugated oligomer terminated by two uracil units is solvent dependent and involves multiple intermolecular H-bonds.

Surface-mediated two-dimensional growth of the pharmaceutical carbamazepine

Scanning tunneling microscopy (STM) has become a staple surface microscopy technique for a number of research fields ranging from semiconductor research to heterogeneous catalysis. Pharmaceutical compounds, however, remain largely unstudied. Here we report the first STM study of carbamazepine (CBZ), an anti-epileptic drug, on Au(111) and Cu(111) surfaces. The analysis reveals that CBZ adopts unusual chiral molecular architectures on both metals. These previously unreported structures, which are strikingly different from CBZ packing arrangements observed in 3D crystal structures, indicate that the main molecular architecture is driven by a combination of CBZ intermolecular hydrogen bonding and metal-CBZ interactions. Comparison of the 2D molecular structures reveals large differences in local geometry and packing density that are dependent on the nature of the metal surface. These results have implications for the potential role of metal surfaces as heteronuclei or templating agents for controlling polymorph formation, which continues to be a problem for many compounds in the pharmaceutical industry including CBZ.

Tuning the packing density of 2D supramolecular self-assemblies at the solid-liquid interface using variable temperature

The two-dimensional (2D) crystal engineering of molecular architectures on surfaces requires controlling various parameters related respectively to the substrate, the chemical structure of the molecules, and the environmental conditions. We investigate here the influence of temperature on the self-assembly of hexakis(n-dodecyl)-peri-hexabenzocoronene (HBC-C(12)) adsorbed on gold using scanning tunneling microscopy (STM) at the liquid/solid interface. We show that the packing density of 2D self-assembled HBC-C(12) can be precisely tuned by adjusting the substrate temperature. Increasing the temperature progressively over the 20-50 degrees C range induces three irreversible phase transitions and a 3-fold increase of the packing density from 0.111 to 0.356 molecule/nm(2). High-resolution STM images reveal that this 2D packing density increase arises from the stepwise desorption of the n-dodecyl chains from the gold surface. Such temperature-controlled irreversible phase transitions are thus a versatile tool that can then be used to adjust the packing density of highly ordered functional materials in view of applications in organic electronic devices.