The development of nanoscale masking for particle deposition is exceedingly important to push the future of nanoelectronics beyond the current limits of lithography. We present the first example of ordered hexagonal covalent nanoporous structures deposited in extended arrays of near monolayer coverage across a Ag(111) surface. The networks were formed from the deposition of the reagents from a heated molybdenum crucible between 370 and 460 K under ultrahigh vacuum (UHV) onto a cleaned Ag(111) substrate and imaged using a scanning tunneling microscope (STM). Two surface covalent organic frameworks (SCOFs) are presented; the first is formed from the deposition of 1,4-benzenediboronic acid (BDBA) and its dehydration to form the boroxine-linked SCOF-1, the second is formed from the co-deposition of BDBA and 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) to form a dioxaborole-linked SCOF-2 network. The networks were found to produce nanoporous structures of 15 A for SCOF-1 and 29 A for SCOF-2, which agreed with theoretical pore sizes determined from DFT calculations. Both SCOFs were found to have exceptional thermal stability, maintaining their structure until approximately 750 K, which was found to be the polymer degradation temperature from thermal gravimetric analysis (TGA).

Supramolecular chemistry on a surface has produced a large variety of atomically controlled systems, but practical applications are seriously restricted by the use of weakly cohesive non-covalent bonds and by the confinement to a metal surface. Here we report on the formation of a well-ordered organometallic sheet consisting of two-dimensional polymeric phthalocyanine. Remarkably, the growth demonstrated on a metal surface can be extended onto a thin insulating film. We thus expect the intrinsic properties to be preserved, and the system should be easily transferable to real devices.