Perfluorophenyl‐Directed Giant Porphyrin J‐Aggregates

Abstract

Quadrupolar interactions of porphyrin bearing two pentafluorophenylethynyl terminals (1) drove the formation of a successive one‐dimensional staircase structure, i.e., J‐aggregates, to yield millimeter‐length needles with a single‐crystalline character in methylcyclohexane solution. In contrast, π‐stacked interactions of porphyrin bearing two nonfluorinated phenyl terminals (2) formed no aggregates in solution. A spin‐cast film of 1 also showed bathochromic shift of the Soret and Q bands, indicating the formation of J‐aggregates. The molecular arrangement of the J‐aggregates was revealed by microbeam glazing‐incidence wide‐angle X‐ray diffraction (GIWAXD), and was in good agreement with the optimized structure generated by density functional theory (DFT) calculations.

Investigation of Morphology‐Controlled Ultrafast Relaxation Processes of Aggregated Porphyrin

“…Jtype or edge to edge arrangement and H-type or face to face arrangement. [16][17][18][19] J-type and H-type aggregated porphyrin exhibit red and blue absorption shift from their monomeric entity, respectively [20,21] and the J-type aggregation exhibits the faster energy transfer. [15,[22][23][24] The morphologies of porphyrinoid assembly are controlled by polarity, pH, concentration of porphyrin, porphyrin structure, aging time and counter ions of inorganic salt.…”

Evidence of C–F···H–C Attractive Interaction: Enforced Coplanarity of a Tetrafluorophenylene-Ethynylene-Linked Porphyrin Dimer

“…The concentration dependence of the spectral changes are also rationally interpreted as the double-strand formation with the binding constant K a = 4.3 × 10 6 M –1 at 298 K (Figure S20), in excellent agreement with the estimated Δ H and Δ S values. This binding strength is greater by 2 orders of magnitude than that of 2 ( K a = 7.2 × 10 4 M –1 ), suggesting a quadrupolar interaction between the tetrafluorobenzene ring and porphyrin rings. ,, Although an aromatic solvent should disturb the quadrupolar interaction, the π-stacking propensity of 1 remains at the concentrations above ∼10 –4 M in the absence of pyridine as the axially coordinating ligand for the central zinc in toluene- d 8 (Figure S18). The enforced coplanarity directed by the C–F···H–C interactions is certainly accompanied by an outstanding π-stacking propensity.…”

“…This binding strength is greater by 2 orders of magnitude than that of 2 (K a = 7.2 × 10 4 M −1 ), suggesting a quadrupolar interaction between the tetrafluorobenzene ring and porphyrin rings. 52,53,87 Although an aromatic solvent should disturb the quadrupolar interaction, the π-stacking propensity of 1 remains at the concentrations above ∼10 −4 M in the absence of pyridine as the axially coordinating ligand for the central zinc in toluene-d 8 (Figure S18). proportions of the individual contributions, including electrostatics, polarization, charge transfer, and dispersion.…”

Glassy Porphyrin/C60 Composites: Morphological Engineering of C60 Fullerene with Liquefied Porphyrins

“…Our strategy employs glassy porphyrins composed of two structural compartments, such as the polarized rigid porphyrin core and nonpolar elastic 3,4,5-tri­(( S )-dihydrocitronellyloxy)­phenyl groups at the diagonal meso positions (Chart ). Because of the large conformational freedom of the paraffinic branched alkyl chains, the glassy porphyrins are highly difficult to crystallize, and the glassy nature is tolerant of the extensive functionalization of the porphyrin ring through an extended meso -ethynylene π-conjugation, contrasting the cases of 3,4,5-tri­( n -alkoxy)­phenyl groups . Among the glassy porphyrins, 1 and 2 displayed a viscous fluidic nature at room temperature under solvent-free conditions because of their low glass transition temperature ( T g ) .…”