Self-Organization of Self-Assembled Tetrameric Porphyrin Arrays on Surfaces

Abstract

The incorporation of designed self-assembled supramolecular structures into devices requires deposition onto surfaces with retention of both structure and function. This remains a challenge and can present a significant barrier to developing devices using self-organizing materials. To examine the role of peripheral groups in the self-organization of self-assembled multiporphyrinic arrays on surfaces, Pd(II)-linked square and Pt(II)-linked trapezoidal tetrameric porphyrin arrays with peripheral tert-butylphenyl or dodecyloxyphenyl functionalities were investigated using various spectroscopies and atomic force microscopy. The Pd(II) assembled squares disassemble upon deposition on glass surfaces, while the Pt(II) assembled trapezoids are more robust and can be routinely cast on these surfaces. The orientation and length of the peripheral alkyl substituents influence the resultant structures on surfaces. The tert-butylphenyl-substituted porphyrin array forms discrete columnar stacks, which assemble in a vertical direction via pi-stacking interactions among the macrocycles. The tetrameric porphyrin array with dodecyloxyphenyl groups forms a continuous film via van der Waals interactions among the peripheral hydrocarbon chains. The super-molecules with liquid crystal-forming moieties also form three-dimensional crystalline structures at higher deposition concentrations. These observations clearly demonstrate that the number, position, and nature of the peripheral groups and the supramolecular structure and dynamics, as well as the energetics of interactions with the surface, are of key importance to the two-dimensional and three-dimensional self-organization of assemblies such as porphyrin arrays on surfaces.

Porous Porphyrin Nanoarchitectures on Surfaces

“…Chem. 2010, [3715][3716][3717][3718][3719][3720][3721][3722][3723][3724]anticipated to mimic the conditions that led to the formation of the square packing structure of the supramolecularly assembled nonamers, reported by Drain et al, [20][21][22] as mentioned in the previous section. However, no structural results providing evidence for such a packing order were reported.…”

“…[20][21][22] Specifically, a tessellated porphyrin nonamer with a size of 25 nm 2 can be successfully obtained by solvothermal synthesis from suitably designed porphyrin molecular precursors and appropriate linker units. [20] In order to go beyond oligomers and construct larger sizes of 2D architectures, assembling on substrate surfaces is necessary so that the long-range planar shape can be retained.…”

Chemical Synthesis and Medicinal Applications of Glycoporphyrins

“…Current interest in the synthesis of lipid porphyrins aims at the construction of self-organized porphyrin assemblies for modeling electron transfer processes and oxygen transport [60][61][62] . The inclusion of porphyrins into monolayer, bilayer and micellular lipid aggregates forms supramolecular structures with unique physical-chemical properties [63,64] as do nanoformulations [65] . Also, phospholipid vesicles containing porphyrins have been prepared as model systems for haemoproteins for investigating O 2 transport systems [66] and electron transfer reactions [67] .…”

“…These were the expected fully protected porphyrin 62 in 2 % yield, accompanied by monodeprotected porphyrin in 1 % and the bisdeprotected porphyrin in 4 % yield. The other isomers and derivatives (63)(64)(65) were synthesized in similar yields. All derivatives were fully deprotected yielding water soluble compounds for possible use in chiral recognition and asymmetric catalysis in aqueous medium [169] .…”

Investigating the possible use of a tetra (hydroxyphenyl) porphyrin as a fluorescence probe for the supramolecular detection of phospholipids

“…In addition, supramolecular assemblies on the basis of amphiphilic porphyrin derivatives and lipids are prospective subjects for numerous fields. The introduction of tetrapyrrol compounds in monolayer [8], bilayer [9] and micellar [10] lipid aggregates yield to supramolecular assemblies with unique physicochemical properties. These complexes have been widely applied to the modelling of biological processes.…”