Two-Dimensional Porous Molecular Networks of Dehydrobenzo[12]annulene Derivatives via Alkyl Chain Interdigitation

Abstract

The self-assembly of a series of hexadehydrotribenzo[12]annulene (DBA) derivatives has been scrutinized by scanning tunneling microscopy (STM) at the liquid-solid interface. First, the influence of core symmetry on the network structure was investigated by comparing the two-dimensional (2D) ordering of rhombic bisDBA 1a and triangular DBA 2a (Figure 1). BisDBA 1a forms a Kagomé network upon physisorption from 1,2,4-trichlorobenzene (TCB) onto highly oriented pyrolytic graphite (HOPG). Under similar experimental conditions, DBA 2a shows the formation of a honeycomb network. The core symmetry and location of alkyl substituents determine the network structure. The most remarkable feature of the DBA networks is the interdigitation of the nonpolar alkyl chains: they connect the pi-conjugated cores and direct their orientation. As a result, 2D open networks with voids are formed. Second, the effect of alkyl chain length on the structure of DBA patterns was investigated. Upon increasing the length of the alkyl chains (DBAs 3c-e) a transition from honeycomb networks to linear networks was observed in TCB, an observation attributed to stronger molecule-substrate interactions. Third, the effect of solvent on the structure of the nonpolar DBA networks was investigated in four different solvents: TCB as a polar aromatic solvent, 1-phenyloctane as a solvent having both aromatic and aliphatic moieties, n-tetradecane as an aliphatic solvent, and octanoic acid as a polar alkylated solvent. The solvent dramatically changes the structure of the DBA networks. The solvent effects are discussed in terms of factors that influence the mobility of molecules at the liquid-solid interface such as solvation.

Two-Dimensional Nanotemplates as Surface Cues for the Controlled Assembly of Organic Molecules

“…Flexible networks can be based on benzoannulene derivatives [114,115]. Several types of benzoannulene derivatives were tested, differing in the length of the of alkyl chains at the periphery of the triangular cores (Fig.…”

Five-vertex Archimedean surface tessellation by lanthanide-directed molecular self-assembly

“…They may represent geometrically frustrated magnets (7) or provide novel routes for constructing photonic crystals (8). However, with the exception of the frequently realized trihexagonal tiling (also known as the Kagomé lattice) (9)(10)(11)(12)(13)(14)(15), the other semiregular Archimedean tiling patterns remain largely unexplored.…”

“…Self-assembly protocols have been developed to achieve regular surface tessellations, including the semiregular Kagomé lattice (11)(12)(13), and even more complex tiling patterns or surface decorations (25)(26)(27)(28)(29)(30). Despite the striking advances, five-vertex structures remain a challenging issue, reflecting the lack of adequate complementary polygonal molecular modules and planar fivefold coordination nodes, respectively.…”

Coadsorption of TbIII–Porphyrin Double-decker Single-molecule Magnets in a Porous Molecular Network: Toward Controlled Alignment of Single-molecule Magnets on a Carbon Surface

“…Although it is difficult to distinguish DBA-OC8 from Tb III (OEP) 2 in the apparent STM images (Figure S1), the presence of DBA-OC8 in the pores is easily confirmed by the fact that even at zero Tb III (OEP) 2 concentration, 4% of the pores show bright spots (Figures 3 and S2). 26,33 In fact, a previous study showed that DBA derivatives in solution can be coadsorbed in the pores of the DBA network. Approximately 4% of the bright spots can be attributed to DBA-OC8, based on the above fitting result; however, the remaining bright spots can be reasonably assigned to Tb Figure S3).…”