Triply Linked Porphyrinoids Tanaka, Takayuki; Osuka, Atsuhiro
Chemistry : a European journal,
November 22, 2018, Letnik:
24, Številka:
65
Journal Article
Recenzirano
Triply linked porphyrin arrays, so called porphyrin tapes, are intriguing molecules in terms of their planar structures, far red‐shifted absorption bands, multi‐charge storage abilities, and high ...conductivities. Recently, porphyrin tape variants such as porphyrin‐expanded porphyrin hybrid tapes, porphyrin arch‐tapes, corrole tapes, and a subporphyrin tape have been explored as novel π‐conjugated materials. These new molecules exhibit electronic and structural characteristics owing to direct triple linkages. This Minireview first discusses the fundamental properties of the parent porphyrin tapes and the peripherally functionalized porphyrin tapes. Then, a focus has been placed on the syntheses, structures, and unique properties of the recently explored porphyrin tape variants.
The best things come in threes: Triply linked porphyrin arrays, so called porphyrin tapes, are intriguing molecules in terms of their stability, far red‐shifted absorption band, multi‐charge storage ability, and conductivity. Recent advances in the chemistry of porphyrin tape are summarized in this Minireview, in particular, the development of porphyrin tape variants such as expanded porphyrin hybrid tape, porphyrin arch‐tape, corrole tape, and subporphyrin tape.
Advances in micro-electro-mechanical systems technology have led to the emergence of compact attitude measurement sensor products that integrate acceleration, magnetometer, and gyroscope sensors on a ...single chip, making them important devices in the field of three-dimensional (3D) attitude measurement for unmanned aerial vehicles, smartphones, and other devices. Sensor fusion algorithms for posture measurement have become an indispensable technology in cutting-edge research, such as human posture measurement using wearable sensors, and stabilization problems in robot position and posture measurement. We have also developed wearable sensors and powered suits in our previous research. We needed a technology for the real-time measurement of a 3D human body motion. It is known that quaternions can be used to algebraically handle 3D rotations; however, sensor fusion algorithms for three sensors are presently complex. This is because these algorithms deal with the post-rotation attitude (pure quaternions) rather than rotation information (the rotor) to avoid a double covering problem involving the rotor. If we are dealing with rotation, it may be possible to make the algorithm simpler and faster by dealing directly with the rotor. In this study, to solve the double covering problem involving the rotor, we propose a stateful rotor and develop a technique for uniquely determining the time-varying states of the rotor. The proposed stateful rotor guarantees the continuity of the rotor parameters with respect to angular changes, and this paper confirms its effectiveness by simulating two rotations around an arbitrary axis. In addition, we verify experimentally that a fast sensor fusion method using stateful rotor can be used for attitude calculation. Experiments also confirm that the calculated results converge to the desired rotation angle for two spatial rotations around an arbitrary axis. Since the proposed stateful rotor extends and stabilizes the definition of the rotor, it is applicable to any algorithm that deals with time-varying quaternionic rotors. In this research, an algorithm based on a multiply–add operation is designed to reduce computational complexity as a high-speed calculation for embedded systems. This method is theoretically equivalent to other methods, while contributing to power saving and the cost reduction of products.
N,N’‐Diarylated tetrabenzotetraaza8circulenes 3 a and 3 b were synthesized in good yields by a reaction sequence involving oxidation of tetrabenzodiazadithia8circulene 5‐Oct and SNAr reaction with ...aniline derivatives. The obtained aza8circulenes 3 a and 3 b were easily oxidized to give their radical cations 3 a+ and 3 b+, which are highly stable under ambient conditions. X‐ray diffraction analysis of radical cation 3 a+ showed a face‐to‐face dimer arrangement with an interplanar separation of 3.320 Å. The spin density of 3 a+ was calculated to be delocalized over the whole circulene π‐systems with spin–spin exchange integral (J=−144 cm−1) in the dimeric part. These radical cations displayed far red‐shifted absorption bands reaching to 2000 nm. Thus this study has proved the hetero8circulene scaffold to be a new entry of promising electronics and spin materials.
Radical cations: N,N’‐Diaryl tetrabenzotetraaza8circulenes were synthesized in good yields from tetrabenzodiazadithia8circulene by a reaction sequence that included oxidation to thiophene S,S‐dioxide and subsequent SNAr reaction. The circulenes were easily oxidized to give stable radical cations. The deformed structures and magnetic properties of the radical cations have been unraveled.
The self-assembly of discrete cyanometallates has attracted significant interest due to the potential of these materials to undergo soft metallophilic interactions as well as their optical ...properties. Diblock copolypeptide amphiphiles have also been investigated concerning their capacity for self-assembly into morphologies such as nanostructures. The present work combined these two concepts by examining supramolecular hybrids comprising cyanometallates with diblock copolypeptide amphiphiles in aqueous solutions. Discrete cyanometallates such as Au(CN)
, Ag(CN)
, and Pt(CN)
dispersed at the molecular level in water cannot interact with each other at low concentrations. However, the results of this work demonstrate that the addition of diblock copolypeptide amphiphiles such as poly-(L-lysine)-
-(L-cysteine) (Lys
-
-Cys
) to solutions of these complexes induces the supramolecular assembly of the discrete cyanometallates, resulting in photoluminescence originating from multinuclear complexes with metal-metal interactions. Electron microscopy images confirmed the formation of nanostructures of several hundred nanometers in size that grew to form advanced nanoarchitectures, including those resembling the original nanostructures. This concept of combining diblock copolypeptide amphiphiles with discrete cyanometallates allows the design of flexible and functional supramolecular hybrid systems in water.
Recently we have reported that 1,14-diaminated tripyrrins form a double helical structure via interstrand hydrogen bonding interaction in non-polar solvents. In this work, ethoxycarbonyl-substituted ...1,14-di(arylamino)tripyrrins were prepared by nucleophilic substitution reaction. The structure has been revealed by X-ray analysis to be a (
Z
-syn,
E
-syn) conformer stabilized by intramolecular hydrogen bonding between the pyrrolic NH proton and the ester carbonyl oxygen atom. This conformer was likely formed as a meta-stable state in solution since thermal isomerization into a (
Z
-syn,
Z
-syn) conformer was observed in DMSO via NH tautomerization.
1,14-Di(arylamino)-5,10-di(ethoxycarbonyl)tripyrrin was synthesized by a nucleophilic substitution reaction. The structure has been revealed by X-ray analysis to be a (Z-syn, E-syn) conformer stabilized by intramolecular hydrogen bonding between the pyrrolic NH proton and the ester carbonyl oxygen atom. Reorganization of the NH protons associated with conformatinal change from (Z-syn, E-syn) to (Z-syn, Z-syn) was observed in polar solvents.
Polycyclic heteroaromatic compounds including pyrrole units are promising functional scaffolds owing to their electron‐rich nature, bright fluorescence, and applicability to anion recognition at the ...pyrrolic hydrogen atom. We report herein the effective synthesis of pseudo‐aza5helicene and aza7helicene derivatives, and unexpected formation of azahepta8circulenes by oxidative fusion reactions. By choosing reaction conditions and peripheral substituents attached at the terminal indole moieties, we obtained aza7helicenes 10 a–c and azahepta8circulenes 11 a,c selectively in moderate to good yields. Their solid‐state structures have been revealed by X‐ray diffraction analysis. UV/Vis absorption, emission, and cyclic voltammetry of these compounds were studied in comparison with those of previously reported tetraaza8circulene (TA8C), a symmetric and planar molecule. Furthermore, the enantiomeric separation of dimethyl‐substituted aza7helicene 10 b was achieved, and the racemization kinetics have been elucidated both theoretically and experimentally. This work illustrates a wealth of advantages of pyrrole incorporation into the polycyclic aromatic scaffolds in terms of synthetic aspects, structural variation, and optical tuning.
Fused‐ring systems: Dibenzotriaza5helicene, dibenzotriaza7helicene, and dibenzotriazahepta8circulene derivatives have been synthesized by oxidative fusion reactions in a selective manner. Structures have been revealed by X‐ray diffraction analysis and their optical and electrochemical properties investigated (see figure)
In contrast to the extensive development of the meso‐functionalization of porphyrins, that of corroles had rarely been explored until the development of practical synthetic methods for meso‐free ...corroles in 2015. The ready availability of meso‐free corroles opened up meso‐functionalization chemistry of corroles, giving rise to successful synthesis of various meso‐substituted corroles such as meso‐halogen, meso‐nitro, meso‐amino, meso‐oxo, and meso‐iminocorroles as well as meso–meso‐linked corrole dimers and corrole tapes. In some cases, 2NH corroles exist as stable or transient radical species. The impact of meso‐functionalization on the structures, electronic properties, optical characteristics, and aromaticity of corroles are highlighted in this Minireview.
Since reliable synthetic methods for meso‐free corroles were developed, the peripheral functionalization chemistry of corroles has blossomed again. In this Minireview, classical electrophilic reactions, SNAr reactions, and unique oxidation behavior are introduced, and their impact on the structures, electronic states, optical properties, and aromaticities of corroles are highlighted.
Carbazole‐based aza7helicenes and hetero9helicenes were successfully obtained via the intramolecular Scholl reaction of 3,6‐bis(biphenyl‐2‐yl)carbazole congeners, while the reaction of ...3,6‐bis(naphthylphenyl)‐appended carbazole gave a triple helicene via an unexpected simultaneous double aryl rearrangement. DFT calculations suggested that the rearrangement proceeded via an arenium cation intermediate. In addition, the reaction of methoxy‐appended substrate gave an azahepta8circulene via the concurrent C−C bond formation. These helical dyes showed circularly polarized luminescence. The azahepta8circulene was further transformed into deeply saddle‐distorted dibenzodiaza8circulenes as the first example of its solution‐based synthesis and unambiguous structural determination.
Intramolecular Scholl reaction of carbazole derivatives afforded highly strained azahelicenes and azahepta8circulene, which was transformed into dibenzodiaza8circulenes. The diaza8circulene structure was characterized for the first time by X‐ray diffraction analysis, which revealed the saddle‐shaped π‐conjugated polyaromatics.
Directly meso‐meso linked porphyrin‐tetrabromo36octaphyrin‐porphyrin hybrid trimer 10 was successfully synthesized via acid‐catalyzed condensation reaction and subsequent oxidation. ZnII‐metalation ...of 10 induced transannular meso‐meso bond formation to give Möbius aromatic bis‐ZnII octaphyrin 11, which was oxidized by DDQ/Sc(OTf)3 to provide fully conjugated porphyrin‐36octaphyrin‐porphyrin hybrid tape 12 as the first example of porphyrin tape exhibiting Möbius aromaticity. Hybrid tape 12 displays significantly red‐shifted absorption and small electrochemical HOMO‐LUMO gap, indicating the effective conjugation through the whole chromophores.
Oxidative fusion of meso‐meso linked porphyrin‐bis‐ZnII 36octaphyrin‐porphyrin hybrid trimer afforded a triply‐linked hybrid tape as the first example of porphyrin tapes exhibiting Möbius aromaticity. The electronic conjugation was fully extended over the whole molecule, showing red‐shifted absorption up to 1274 nm. The extent of electronic perturbation was compared with planar porphyrin‐26hexaphyrin‐porphyrin hybrid tape to illuminate the consequence of twisted π‐surface. A Fully Conjugated Porphyrin‐36Octaphyrin‐Porphyrin Hybrid Tape Exhibiting Mobius Aromaticity (Tanaka, Osuka et al.)
Understanding biodiversity patterns on islands has long been a central aim in ecology and conservation biology. Island‐specific biogeographical processes play substantial roles in the formation of ...endemic biota. Here, we examined how climate niche conservatism and geohistorical factors are interactively associated with in situ diversification of Tertiary relict flora in the east Asian continental islands. We generated two novel datasets for species distribution and phylogeny that included all of the known vascular plant species in Japan (5575). Then we tested phylogenetic signal of climatic tolerance, in terms of absolute minimum temperature and water balance, and explored environmental predictors of phylogenetic structure (evolutionary derivedness and clustering) of species assemblages. Although phylogenetic signal of climatic tolerance was significant across the phylogeny of most species, the strength of climatic niche conservatism differed among ferns, gymnosperms, angiosperm trees, and angiosperm herbs. For angiosperm trees, cold temperatures acted as environmental filters that generated phylogenetic derivedness/clustering of species assemblages. For fern and angiosperm herb species, however, phylogenetic properties were not associated with climatic harshness. These contrasting patterns among groups reflected climate niche evolution in vascular plants with different growth forms and traits; for example, diversification of angiosperm trees (but not fern and herb) occurred in response to historical climatic cooling. More importantly, geographical constraints contributed to evolutionary radiation that resulted from isolation by distance from the continent or by elevation. Quaternary climate change was also associated with clade‐specific radiation in refugial habitats. The degree to which geographical, geological, and palaeoclimatic variables explain the phylogenetic structure underscores the importance of isolation‐ and habitat‐stability‐related geohistorical processes in driving in situ diversification despite climatic niche conservatism. We propose that the highly endemic flora of the east Asian islands resulted from the interplay of idiosyncratic regional factors, and ecological and evolutionary processes, such as climate niche assembly and adaptive/nonadaptive radiation.
