Kyushu University · Materials Science
Professor Soji Shimizu's research lab specializes in the synthesis and characterization of expanded and contracted porphyrinoids, with a focus on novel macrocyclic architectures such as subporphyrins, expanded porphyrins, and aza-BODIPY analogues. The lab explores their unique electronic structures, nonlinear optical properties, and metal coordination behaviors, particularly in systems with large cavities and tunable optical properties. Recent work emphasizes molecular design for near-infrared absorption and emission, leveraging DFT calculations and advanced spectroscopic techniques to develop functional chromophores for optoelectronic and sensing applications.
Figures are computed from collected data and may differ slightly.
Subporphyrinato boron (subporphyrin) was elusive until the syntheses of tribenzosubporphine in 2006 and meso-aryl-substituted subporphyrin in 2007. These novel contracted analogues possess a 14π-electron conjugated system embedded in a bowl-shaped structure. They exhibit absorption and fluorescence in the UV/vis region and nonlinear optical properties due to their octupolar structures. The unique coordination geometry around the central boron atom in the structure of subporphyrin enabled investi
Pyrrolopyrrole aza-BODIPY analogues were synthesized from diketopyrrolopyrrole and heteroaromatic amines in the presence of titanium tetrachloride. These novel compounds exhibit intense absorption in the visible region and strong emission with high fluorescence quantum yields greater than 0.8.
A series of meso-trifluoromethyl-substituted expanded porphyrins, including N-fused [24]pentaphyrin 3, [28]hexaphyrin 4, [32]heptaphyrin 5, [46]decaphyrin 6, and [56]dodecaphyrin 7, were synthesized by means of an acid-catalyzed one-pot condensation reaction of 2-(2,2,2-trifluoro-1-hydroxyethyl)pyrrole (1) as the first examples bearing meso-alkyl substituents. Besides these products, porphyrin 2 and two calix[5]phyrins 8 and 9 were also obtained. [28]Hexaphyrin 4 was quantitatively oxidized to [
Abstract meso ‐Aryl‐substituted expanded porphyrins are structural analogues of meso ‐aryl‐substituted porphyrins. They exhibit rich and novel coordination behaviors, including multi‐metal chelation due to the large cavities, spin–spin interaction arising from the proximity of metal centers, and large changes in their structural and electrochemical properties upon metalation. The recent discovery of a facile, one‐pot synthesis of a series of meso ‐aryl‐substituted expanded porphyrins enables us
Twisted figure-of-eight structures are found for the perfluorinated meso-aryl-substituted expanded porphyrins synthesized from 3,4-difluoropyrrole and pentafluorobenzaldehyde under modified Rothemund–Lindsey conditions. The crystal structure of the [26]hexaphyrin (see picture) consists of two almost planar tripyrrolic subunits which are tilted by approximately 60° in which a distinct alternation in the bond lengths of the π-electronic system is evident. Supporting information for this article is
Pyrrolopyrrole aza-BODIPY (PPAB) developed in our recent study from diketopyrrolopyrrole by titanium tetrachloride-mediated Schiff-base formation reaction with heteroaromatic amines is a highly potential chromophore due to its intense absorption and fluorescence in the visible region and high fluorescence quantum yield, which is greater than 0.8. To control the absorption and fluorescence of PPAB, particularly in the near-infrared (NIR) region, further molecular design was performed using DFT ca
The copper metalation into the hexaphyrins is accompanied by large structural changes to give four complexes exhibiting gable structures and varying antiferromagnetic couplings.
aza-BODIPY is a class of heteroatom-containing BODIPY analogues targeting near infrared (NIR) chromophores and fluorophores. As a synthetic strategy towards aza-BODIPY structures, we have, recently, developed a Schiff base forming reaction using readily available lactams and heteroaromatic amines. Absorption and fluorescence of a series of compounds cover the whole range of the ultraviolet (UV)/visible (vis)/NIR regions. In addition, some compounds exhibit solid state emission, aggregation-induc
Acid-specific conformational changes: Protonation of meso-aryl-substituted rubyrin 1 with HCl or CF3CO2H causes different conformational changes, as revealed by specific shifts in the UV/Vis absorption bands relative to those of the free-base form (Cl−: blue shift; CF3CO2−: red shift). The distinct counteranion-dependent color changes upon addition of the acids to the “anion sensor” 1 are easily detected. Supporting information for this article is available on the WWW under http://www.wiley-vch.
A pyrene-fused subphthalocyanine synthesized from a reaction of 2,7-di-tert-butyl-4,5,9,10-tetracyanopyrene and tetrafluorophthalonitrile exhibits red-shifted Q-band absorption and a unique linear arrangement in the solid state caused by a π-π stacking interaction. The concave conjugation of the SubPc moiety and the planar conjugation of the pyrene moiety enhanced its co-crystallization with C(60) molecules.
A series of symmetric and asymmetric benzo[c,d]indole-containing aza boron dipyrromethene (aza-BODIPY) compounds was synthesized by a titanium tetrachloride-mediated Schiff-base formation reaction of commercially available benzo[c,d]indole-2(1H)-one and heteroaromatic amines. These aza-BODIPY analogues show different electronic structures from those of regular aza-BODIPYs, with hypsochromic shifts of the main absorption compared to their BODIPY counterparts. In addition to the intense fluorescen
Teilstrukturen in Form einer verdrehten Acht weisen die perfluorierten meso-Aryl-substituierten expandierten Porphyrine auf, die man aus 3,4-Difluorpyrrol und Pentafluorbenzaldehyd unter modifizierten Rothemund-Lindsey-Bedingungen erhält. Das [26]Hexaphyrin enthält zwei nahezu planare Tripyrrol-Untereinheiten, die um ca. 60° geneigt sind. Aus der Struktur im Kristall (siehe Bild) wird auf eine ausgeprägte Alternanz der Bindungslängen des π-Elektronensystems geschlossen. Supporting information fo
Following the first suggestion of inherent molecular chirality in asymmetrically substituted subphthalocyanines by Torres and co-workers in 2000, elucidation of the relationship between structure and chirality has become an important issue. However, separation of the enantiomers has been prevented by the low solubility of the molecules synthesized to date, and it has not been possible to link the CD signs and intensities to their absolute structures. Recently, we observed that 1,2-subnaphthalocy
This feature article summarizes recent contributions of the authors in the synthesis of structurally-modified subphthalocyanines. The structural modification covers (1) modification of the conjugated system of subphthalocyanines to create novel conjugated systems comprising three pyrroles or pyrrole-like subunits, (2) core-modification by expansion of the inner pyrrolic five-membered ring to larger six- and seven-membered ring units, and (3) exterior-modification by annulation of functional unit
meso-Aryl substituted rubyrin ([26]hexaphyrin(1.1.0.1.1.0)) 2 and a series of rubyrin-type large expanded porphyrins were obtained from a facile one-pot oxidative coupling reaction of meso-pentafluorophenyl substituted tripyrrane 1. The structures of two of the resulting products were determined by single-crystal X-ray diffraction analysis. Whereas [52]dodecaphyrin(1.1.0.1.1.0.1.1.0.1.1.0) 4 takes a symmetric helical conformation, the larger species, [62]pentadecaphyrin(1.1.0.1.1.0.1.1.0.1.1.0.1
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