Triazatriangulene as Binding Group for Molecular Electronics

Abstract

The triazatriangulene (TATA) ring system was investigated as a binding group for tunnel junctions of molecular wires on gold surfaces. Self-assembled monolayers (SAMs) of TATA platforms with three different lengths of phenylene wires were fabricated, and their electrical conductance was recorded by both conducting probe-atomic force microscopy (CP-AFM) and scanning tunneling microscopy (STM). Similar measurements were performed for phenylene SAMs with thiol anchoring groups as references. It was found that, despite the presence of a sp(3) hybridized carbon atom in the conduction path, the TATA platform displays a contact resistance only slightly larger than the thiols. This surprising finding has not been reported before and was analyzed by theoretical computations of the transmission functions of the TATA anchored molecular wires. The relatively low contact resistance of the TATA platform along with its high stability and directionality make this binding group very attractive for molecular electronic measurements and devices.

Single molecule vs. large area design of molecular electronic devices incorporating an efficient 2-aminepyridine double anchoring group

“…1 In this context, a comprehensive study of different anchor groups has been systematically performed by several research groups. These studies include monodentate molecules using anchor groups such as thiols [14][15][16][17] amines, 14,18,19 methyl sulfides, 20 selenols, 21,22 cyano, 23,24 isocyanides, 25 nitriles, 26 hydroxyl, 27 ethynylbenzenes, 28 isothiocyanates, 29 pyridines, [30][31][32][33][34] N-heterocyclic carbenes, 35 dimethylphosphine, 36 dihydrobenzo[b]thiophenes, 37 4-(methylthio)phenyl groups, 38 thienyl rings, 39 diphenylphosphines, 40 trimethylsilylethynyl, [41][42][43] tetrathiofulvalenes, 44 triazatriangulenes, 45 and fullerenes. [46][47][48] More recently, bidentate molecules such as carboxylic acids, 47,49,50 carbodithioates, 51,52 dithiocarbamates, 53,54 norbornyldithiol, 55 cathecols,…”

Stability of functionalized platform molecules on Au(111)

“…18 The electronic coupling at the molecule-surface interface is mediated by an extended π system. Accordingly, physisorbed platforms were employed as high-conductance contacts between a metal electrode and molecular wires 19,20 and Zn-porphyrin molecules. 21 To reduce the electronic coupling, a spacer may be inserted between the functional molecule and the platform.…”

Triazatriangulene platform for self-assembled monolayers of free-standing diarylethene

“…The adlayer pattern reveals that horizontal TATA platforms should be parallelly adsorbed on Au surface. Moreover, the photoswitchable DAE is mounted perpendicularly to the TATA platform because of the sp 3 hybridization of central carbon [39]. The DAE was loosely packed with obviously enlarged distance of 12.0±0.2 Å.…”