Self-Assembly of Covalently Linked Porphyrin Dimers at the Solid–Liquid Interface

Abstract

The synthesis and surface self-assembly behavior of two types of metal-porphyrin dimers is described. The first dimer type consists of two porphyrins linked via a rigid conjugated spacer, and the second type has an alkyne linker, which allows rotation of the porphyrin moieties with respect to each other. The conjugated dimers were equipped with two copper or two manganese centers, while the flexible dimers allowed a modular built-up that also made the incorporation of two different metal centers possible. The self-assembly of the new porphyrin dimers at a solid–liquid interface was investigated at the single-molecule scale using scanning tunneling microscopy (STM). All dimers formed monolayers, of which the stability and the internal degree of ordering of the molecules depended on the metal centers in the porphyrins. While in all monolayers the dimers were oriented coplanar with respect to the underlying surface (‘face-on’), the flexible dimer containing a manganese and a copper center could be induced, via the application of a voltage pulse in the STM setup, to self-assemble into monolayers in which the porphyrin dimers adopted a non-common perpendicular (‘edge-on’) geometry with respect to the surface.

Supramolecular Porphyrin Nanostructures Based on Coordination-Driven Self-Assembly and Their Visible Light Catalytic Degradation of Methylene Blue Dye

“…The fabrication of highly ordered and diversified morphologies of nano- and micro-structured optoelectronic materials is of great contemporaneous interest, especially for their applications in catalysis, sensing, solar energy conversion, and storage [ 1 , 2 , 3 , 4 , 5 , 6 ]. Among the various building blocks, porphyrins are attractive components for the construction of self-assembled nanomaterials with well-defined shapes and dimensions [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Combination of porphyrins and other optoelectronic functional materials has been extensively studied to develop new nanohybrid systems which can intensify light-harvesting and charge-transfer functions [ 16 , 17 , 18 , 19 , 20 ].…”

Regulation of a Porphyrin Derivative Containing Two Symmetric Benzoic Acids by Different Pyridines

“…Generally speaking, whether a supramolecular self-assembly structure is stably ordered or not depends on the solvent, the type of functional group, and the interaction force between molecules. These interactions are noncovalent forces, which include hydrogen bonding, π–π stacking effect, van der Waals interaction, metal–ligand coordination, and so on. − Supramolecules are able to self-regulate and thus balance the forces between molecules and molecules, and molecules and substrates to reach the equilibrium state ultimately . The investigation on porphyrin assemblies through hydrogen bonding on a two-dimensional surface has become a hot topic of study. , Due to the selectivity and saturation of hydrogen bonding, an increasing number of research have reported that porphyrin with a carboxyl functional group interacts with other molecules by hydrogen bonding to form supramolecular nanostructures. ,,, …”

Octahydropyrimido[4,5-g]quinazoline-5,10-diones: their multicomponent synthesis, self-assembly on graphite and electrochemistry

“…While similar π–π interactions could be expected for the aniline groups at the outside of the molecules, these groups were observed to self-assemble edge-on to the surface to enhance π–π interactions between adjacent aniline groups in a parallel displaced stacking. The edge-on orientation on the surface has been reported for molecules containing largely conjugated systems, such as porphyrins, 22 or other strong directional intermolecular interactions, such as hydrogen bonding. 23 However, the results obtained from these experiments show that a parallel displaced stacking of substituted aniline groups can be sufficient to act as directional intermolecular interactions in the SAMN and convert the aniline groups to an edge on-orientation.…”