Prominent Electron Transport Property Observed for Triply Fused Metalloporphyrin Dimer: Directed Columnar Liquid Crystalline Assembly by Amphiphilic Molecular Design

Abstract

A triply fused copper porphyrin dimer, when site-specifically modified on its periphery with hydrophobic and hydrophilic wedges (1C12/TEG), self-assembles into a columnar liquid crystalline (LC) mesophase over a wide-temperature range from -17 to 99 degrees C but gives rise to an amorphous solid when modified with only hydrophobic (1C12/C12) or hydrophilic wedges (1TEG/TEG). A LC film of 1C12/TEG displays at 16 degrees C a top-class one-dimensional electron mobility (0.27 cm2/V x s), as evaluated from its maximum flash-photolysis time-resolved microwave conductivity.

Columnar Mesophases Based on Zinc Chlorophyll Derivatives Functionalized with Peripheral Dendron Wedges

“…[8,9] Ever since the first DLCs were observed for hexa(alkanoyloxy)benzenes, [10] representative DLCs based on a broad class of p-conjugated materials such as triphenylenes, [11] hexabenzocoronenes (HBCs), [5] contorted HBCs, [9] phthalocyanines, [12] porphyrins, [13] perylene bisimides, [14] coronenes, [15] porphycenes [16] have been developed, and intensively investigated with regard to their applications in (opto)electronics. In the context of photovoltaic [17] and electronic applications, [6] porphyrinoid liquid crystalline (LC) materials have been of prime interest due to their large p-electron systems, favorable redox and photochemical properties and thermal stability.…”

“…They constitute a valuable structural motif for the construction of metallomesogens [18] and induced various types of mesomorphism, from calamitic, lamellar to discotic, are obtainable by alteration of substituents and/or substituted positions. [6,12,13] In many cases, zinc coordination has been applied and shown to provide an improved stability to porphyrin-based mesophases compared to the related free base porphyrins. [18a,b] A major inspiration for the hierarchical ordering of dyes/pigments into functional supramolecular architectures comes from nature.…”

Design amphiphilic dipolar π-systems for stimuli-responsive luminescent materials using metastable states

“…The p-conjugated molecule can adopt a segregated solid structure by aggregating its hydrophobic and hydrophilic moieties separately (Fig. 1a) [22][23][24] . The segregated structure would force the molecules to align in the same direction, thereby generating a conflict between the side-chain aggregation and dipolar stabilization of the core 22 .…”

Side Chain-Directed Assembly of Large Discotic π-Conjugated Molecules: Toward Tuning and Stabilization of Mesophases

“…This structure can be explained as a result of side-chain immiscibility. 10,11,22) Namely, dodecyl chains prefer to assemble with themselves and vice versa for the semifluoroalkyl chains. Therefore, to minimize the contact between dodecyl and fluoroalkyl domains, PDI F/C12 molecules stack up to form columnar structures that further integrate into alternate immiscible nano-scale layers (Fig.…”

“…[6][7][8] In contrast, large -system can form, without such additional interactions, columnar structures with two-dimensional periodic packing since strong -stacking interaction operates together with the core/chain nano-segregation. [2][3][4][5] However, when incompatible side chain pairs were introduced to large -conjugated cores, structural changes [9][10][11][12][13] were also observed, leading to the unique properties including enhancement of charge carrier mobility, 9) switching of dominant charge carriers, 11) photoluminescence color change 13) , and so on. Here we report that perylenediimide (PDI) molecules carrying taper-shaped semi-fluoroalkyl chains at one imide position self-assembled into various type of ordered structures due to the strong self-aggregation character of fluoroalkyl segments.…”