ABSTRACT
Taking advantage of a continuous-flow apparatus, the iridium(III)-containing polytungstate cluster K12Na2H2[Ir2Cl8P2W20O72]·37H2O (1) was obtained in a reasonable yield (13% based on IrCl3·H2O). Compound 1 was characterized by Fourier transform IR, UV-visible, (31)P NMR, electrospray ionization mass spectrometry (ESI-MS), and thermogravimetric analysis measurements. (31)P NMR, ESI-MS, and elemental analysis all indicated 1 was a new polytungstate cluster compared with the reported K14[(IrCl4)KP2W20O72] compound. Intriguingly, the successful isolation of 1 relied on the custom-built flow apparatus, demonstrating the uniqueness of continuous-flow chemistry to achieve crystalline materials. The catalytic properties of 1 were assessed by investigating the activity on catalyzing the electro-oxidation of ruthenium tris-2,2'-bipyridine [Ru(bpy)3](2+/3+). The voltammetric behavior suggested a coupled catalytic behavior between [Ru(bpy)3](3+/2+) and 1. Furthermore, on the highly oriented pyrolytic graphite surface, 1,3,5-tris(10-carboxydecyloxy) benzene (TCDB) was used as the two-dimensional host network to coassemble cluster 1; the surface morphology was observed by scanning tunneling microscope technique. "S"-shape of 1 was observed, indicating that the cluster could be accommodated in the cavity formed by two TCDB host molecules, leading to a TCDB/cluster binary structure.
ABSTRACT
In the present work, we report the fabrication of regular coronene (COR) clusters on surfaces in ambient conditions in the two-dimensional network formed by hexaphenylbenzene derivatives (HPB) via structural transformation. HPB could form a stable snowflake network structure on the highly oriented pyrolytic graphite surface at the air-solid interface. When COR molecules were introduced into the system, the HPB snowflake network could transform to honeycomb structures, and the COR heptamers were subsequently aggregated and entrapped into the cavity. Scanning tunneling microscopic was employed to monitor the assembly behavior of both HPB and HPB/COR at a submolecule scale level, and density functional theory calculations were utilized to reveal that the structural transformation and the entrapment are the energetically favorable. The pores formed from HPB might also give a clue to immobilizing some functional molecule clusters, like COR, to fabricate their ordered monolayer in ambient conditions, so as to obtain complex supramolecular surface structures.
ABSTRACT
Controlling chemical reactions on surface is of great importance to constructing self-assembled covalent nanostructures. Herein, Knoevenagel reaction between aromatic aldehyde compound 2,5-di(5-aldehyde-2-thienyl)-1,4-dioctyloxybenzene (PT2) and barbituric acid (BA) has been successfully performed for the first time at liquid/HOPG interface and vapor/HOPG interface. The resulting surface nanostructures and the formation of CâC bond are recorded through scanning tunneling microscopy (STM), and confirmed by attenuated total reflectance Fourier-transform infrared (ATR/FT-IR) spectrometer and UV-vis absorption. The obtained results reveal that Knoevenagel condensation reaction can efficiently occur at both interfaces. This surface reaction would be an important step toward further reaction to produce innovative conjugated nanomaterial on the surface.
