Yoshihiro Matano

Publications of Yoshihiro Matano

• Nickel(II) and Copper(II) Complexes of β-Unsubstituted 5,15-Diazaporphyrins and Pyridazine-Fused Diazacorrinoids: Metal-Template Syntheses and Peripheral Functionalizations.

  Authors: Yoshihiro Matano, Tarou Shibano, Haruyuki Nakano, Hiroshi Imahori

  Chemistry (Weinheim an der Bergstrasse, Germany). 03/2012;

  The present paper reports the first comprehensive study on the synthesis, structures, optical and electrochemical properties, and peripheral functionalizations of nickel(II) and copper(II) complexesThe present paper reports the first comprehensive study on the synthesis, structures, optical and electrochemical properties, and peripheral functionalizations of nickel(II) and copper(II) complexes of β-unsubstituted 5,15-diazaporphyrins (M-DAP; M=Ni, Cu) and pyridazine-fused diazacorrinoids (Ni-DACX; X=N, O). These two classes of compounds were constructed starting from mesityldipyrromethane by a metal-template method. Ni-DAP and Cu-DAP were prepared in high yields by the reaction of the respective metal-bis(dibromodipyrrin) complexes with NaN(3) -CuX (X=I, Br), whereas Ni-DACN and Ni-DACO were formed as predominant products by the reaction with NaN(3) . In both cases, the metal centers change their geometry from tetrahedral to square planar during the aza-annulation; X-ray crystallographic analyses of M-DAPs showed highly planar diazaporphyrin π planes. The Q band of Ni-DAP was redshifted and intensified compared with that of a nickel-porphyrin reference, due to the involvement of electronegative nitrogen atoms at the meso positions. It was found that the peripheral bromination of Ni-DAP and Ni-DACO occurred regioselectively to afford Ni-DAP-Br(4) and Ni-DACO-Br, respectively. These brominated derivatives underwent Stille reactions with tributyl(phenyl)stannane to give the corresponding phenylated derivatives, Ni-DAP-Ph(4) and Ni-DACO-Ph. On the basis of the absorption spectra and X-ray analysis, it has been concluded that the attached phenyl groups efficiently conjugate with the diazaporphyrin π system. The present results unambiguously corroborate that the β-unsubstituted DAPs and DACXs are promising platforms for the development of a new class of π-conjugated azaporphyrin-based materials.

• Preparation and photophysical and photoelectrochemical properties of a covalently fixed porphyrin-chemically converted graphene composite.

  Authors: Tomokazu Umeyama, Junya Mihara, Noriyasu Tezuka, Yoshihiro Matano, Kati Stranius, Vladimir Chukharev, Nikolai V Tkachenko, Helge Lemmetyinen, Kei Noda, Kazumi Matsushige, Tetsuya Shishido, Zheng Liu, Kaori Hirose-Takai, Kazu Suenaga, Hiroshi Imahori

  Chemistry (Weinheim an der Bergstrasse, Germany). 02/2012; 18(14):4250-7.

  Chemically converted graphene (CCG) covalently linked with porphyrins has been prepared by a Suzuki coupling reaction between iodophenyl-functionalized CCG and porphyrin boronic ester. The covalentlyChemically converted graphene (CCG) covalently linked with porphyrins has been prepared by a Suzuki coupling reaction between iodophenyl-functionalized CCG and porphyrin boronic ester. The covalently linked CCG-porphyrin composite was designed to possess a short, rigid phenylene spacer between the porphyrin and the CCG. The composite material formed stable dispersions in DMF and the structure was characterized by spectroscopic, thermal, and microscopic measurements. In steady-state photoluminescence spectra, the emission from the porphyrin linked to the CCG was quenched strongly relative to that of the porphyrin reference. Fluorescence lifetime and femtosecond transient absorption measurements of the porphyrin-linked CCG revealed a short-lived porphyrin singlet excited state (38 ps) without yielding the porphyrin radical cation, thereby substantiating the occurrence of energy transfer from the porphyrin excited state to the CCG and subsequent rapid decay of the CCG excited state to the ground state. Consistently, the photocurrent action spectrum of a photoelectrochemical device with a SnO(2) electrode coated with the porphyrin-linked CCG exhibited no photocurrent response from the porphyrin absorption. The results obtained here provide deep insight into the interaction between graphenes and π-conjugated systems in the excited and ground states.

• Effects of carbon-metal-carbon linkages on the optical, photophysical, and electrochemical properties of phosphametallacycle-linked coplanar porphyrin dimers.

  Authors: Yoshihiro Matano, Kazuaki Matsumoto, Hironobu Hayashi, Yoshihide Nakao, Tatu Kumpulainen, Vladimir Chukharev, Nikolai V Tkachenko, Helge Lemmetyinen, Soji Shimizu, Nagao Kobayashi, Daisuke Sakamaki, Akihiro Ito, Kazuyoshi Tanaka, Hiroshi Imahori

  Journal of the American Chemical Society. 12/2011; 134(3):1825-39.

  5-(Diphenylphosphanyl)-10,15,20-triarylporphyrins (meso-phosphanylporphyrins) underwent complexations with palladium(II) and platinum(II) salts to afford phosphapalladacycle- and5-(Diphenylphosphanyl)-10,15,20-triarylporphyrins (meso-phosphanylporphyrins) underwent complexations with palladium(II) and platinum(II) salts to afford phosphapalladacycle- and phosphaplatinacycle-fused coplanar porphyrin dimers, respectively, via regioselective peripheral β-C-H activation of the meso-phosphanylporphyrin ligands. The optical and electrochemical properties of these metal-linked porphyrin dimers as well as their porphyrin monomer/dimer references were investigated by means of steady-state UV-vis absorption/fluorescence spectroscopy, cyclic and differential pulse voltammetry, time-resolved spectroscopy (fluorescence and transient absorption lifetimes and spectra), and magnetic circular dichroism spectroscopy. All the observed data clearly show that the palladium(II) and platinum(II) linkers play crucial roles in the electronic communication between two porphyrin chromophores at the one-electron oxidized state and in the singlet-triplet intersystem-crossing process at the excited state. It has also been revealed that the C-Pt-C linkage makes more significant impacts on these fundamental properties than the C-Pd-C linkage. Furthermore, density functional theory calculations on the metal-linked porphyrin dimers have suggested that the antibonding dπ-pπ orbital interaction between the peripherally attached metal and adjacent pyrrolic β-carbon atoms destabilizes the highest occupied molecular orbitals of the porphyrin π-systems and accounts for the observed unique absorption properties. On the basis of these experimental and theoretical results, it can be concluded that the linear carbon-metal-carbon linkages weakly but definitely perturb the optical, photophysical, and electrochemical properties of the phosphametallacycle-linked coplanar porphyrin dimers.

• Segregated donor-acceptor columns in liquid crystals that exhibit highly efficient ambipolar charge transport.

  Authors: Hironobu Hayashi, Wataru Nihashi, Tomokazu Umeyama, Yoshihiro Matano, Shu Seki, Yo Shimizu, Hiroshi Imahori

  Journal of the American Chemical Society. 06/2011; 133(28):10736-9.

  Liquid crystalline donor (i.e., phthalocyanine) was covalently linked to acceptor (i.e, fullerene) to achieve efficient charge-transport properties in a liquid crystalline phase. The columnarLiquid crystalline donor (i.e., phthalocyanine) was covalently linked to acceptor (i.e, fullerene) to achieve efficient charge-transport properties in a liquid crystalline phase. The columnar structure exhibited highly efficient ambipolar charge-transport character, demonstrating the potential utility of the strategy in organic electronics.

• Fusion of Phosphole and 1,1'-Biacenaphthene: Phosphorus(V)-Containing Extended π-Systems with High Electron Affinity and Electron Mobility.

  Authors: Yoshihiro Matano, Arihiro Saito, Tatsuya Fukushima, Yasuaki Tokudome, Furitsu Suzuki, Daisuke Sakamaki, Hironori Kaji, Akihiro Ito, Kazuyoshi Tanaka, Hiroshi Imahori

  Angewandte Chemie (International ed. in English). 06/2011;

• Bisquinoxaline-fused porphyrins for dye-sensitized solar cells.

  Authors: Hiroshi Imahori, Hiroaki Iijima, Hironobu Hayashi, Yuuki Toude, Tomokazu Umeyama, Yoshihiro Matano, Seigo Ito

  ChemSusChem. 06/2011; 4(6):797-805.

  5,10,15,20-Tetrakis(2,4,6-trimethylphenyl)-6'-carboxylquinoxalino[2,3-b]quinoxalino[12,13-b']porphyrinatozinc(II) (ZnPBQ) is synthesized to evaluate the effects of π elongation of quinoxaline-fused5,10,15,20-Tetrakis(2,4,6-trimethylphenyl)-6'-carboxylquinoxalino[2,3-b]quinoxalino[12,13-b']porphyrinatozinc(II) (ZnPBQ) is synthesized to evaluate the effects of π elongation of quinoxaline-fused porphyrins on the optical, electrochemical, and photovoltaic properties. ZnPBQ showed an intensified Soret band as well as red-shifted Soret and Q bands relative to 5,10,15,20-tetrakis(2,4,6-trimethylphenyl)-6'-carboxylquinoxalino[2,3-b]porphyrinatozinc(II) (ZnPQ), demonstrating the improved light-harvesting property of ZnPBQ. The optical and electrochemical HOMO-LUMO gaps were consistent with those estimated by DFT calculations. The photovoltaic properties were compared under optimized conditions, in which a sealed device structure with TiCl(4) -treated, TiO(2) double layers was used. The ZnPBQ cell exhibited a relatively high power conversion efficiency (η) of 4.7%, which was smaller than that of the ZnPQ cell (η=6.3%). The weaker electronic coupling between the LUMO of ZnPBQ and conduction band (CB) of TiO(2) or more tilted geometry of ZnPBQ on the TiO(2) surface may result in the low electron injection/charge collection efficiency as well as the low incident photon-to-current efficiency (IPCE) for the ZnPBQ cell (maximum IPCE=56%) relative to the ZnPQ cell (maximum IPCE=75%), leading to the lower η value of the ZnPBQ cell than that of the ZnPQ cell. In addition, the open-circuit potential of the ZnPBQ cell also slightly decreased with the effect of charge recombination from the electrons injected into the CB of TiO(2) to I(3)(-).

• Pentavalent organobismuth reagents in organic synthesis: alkylation, alcohol oxidation and cationic photopolymerization.

  Authors: Yoshihiro Matano

  Topics in current chemistry. 05/2011; 311:19-44.

  Organic transformations using organobismuth(V) reagents developed by my group are reviewed. The characteristic properties of bismuth, such as the inert pair effect, small bond dissociation energy,Organic transformations using organobismuth(V) reagents developed by my group are reviewed. The characteristic properties of bismuth, such as the inert pair effect, small bond dissociation energy, and polarized bonding are strongly related to the reactivity of pentavalent organobismuth compounds. The Bi(V) reagents discussed in this chapter include tetraorganylbismuthonium salts ([Ar(3)RBi(+)][X(-)]), triarylbismuth ylides (Ar(3)Bi=CHCOR), triarylbismuth imides (Ar(3)Bi=NCOR), triarylbismuth oxides (Ar(3)Bi=O), and triarylbismuth dichlorides (Ar(3)BiCl(2)). These organobismuth(V) compounds are readily accessible in a few steps from triarylbismuthanes (Ar(3)Bi). New and efficient carbon-carbon bond forming reactions, carbon-heteroatom bond forming reactions, alcohol oxidation, and photoinduced cationic polymerization have been investigated using these reagents. In all these reactions, the good leaving ability as well as the high nucleofugality of the triarylbismuthonio group plays a crucial role in bond-forming and bond-breaking steps.

• Carbon nanotube wiring of donor-acceptor nanograins by self-assembly and efficient charge transport.

  Authors: Tomokazu Umeyama, Noriyasu Tezuka, Fumiaki Kawashima, Shu Seki, Yoshihiro Matano, Yoshihide Nakao, Tetsuya Shishido, Masayuki Nishi, Kazuyuki Hirao, Heli Lehtivuori, Nikolai V Tkachenko, Helge Lemmetyinen, Hiroshi Imahori

  Angewandte Chemie (International ed. in English). 05/2011; 50(20):4615-9.

• J-aggregation of a sulfonated amphiphilic porphyrin at the air-water interface as a function of pH.

  Authors: Gustavo de Miguel, Kohei Hosomizu, Tomokazu Umeyama, Yoshihiro Matano, Hiroshi Imahori, Marta Pérez-Morales, María T Martín-Romero, Luis Camacho

  Journal of colloid and interface science. 01/2011; 356(2):775-82.

  π-A isotherms, ellipsometric measurements, Brewster angle microscopy (BAM) and reflection spectroscopy have been utilized to characterize the films of an amphiphilic porphyrin ((OD)(3)TPPS(3)) at theπ-A isotherms, ellipsometric measurements, Brewster angle microscopy (BAM) and reflection spectroscopy have been utilized to characterize the films of an amphiphilic porphyrin ((OD)(3)TPPS(3)) at the air-water interface as a function of pH. This porphyrin forms stable mono-molecular layers at such interfaces, and exhibits different J-aggregation as a function of pH. The J-aggregation of (OD)(3)TPPS(3) on neutral pH subphases is notable considering that the nitrogen atoms at the central macrocycle have a pK(a)≈4.9. The type of aggregates at neutral pH is like those detected at pH<4, because the central porphyrin ring is already protonated. However at basic pH the aggregation happens without protonation of the central ring but can be instead controlled by application of the surface pressure. At the air-water interface, (OD)(3)TPPS(3) shows two bands, a red component and a blue component, which have characteristics of non-degenerate linear oscillators being perpendicularly polarized between each other. The spectral behavior observed on subphases at different pHs is qualitatively interpreted by means of exciton coupling theory, assuming that the degenerate transitions attributed to the Soret band are split. Additionally, highly oriented molecular films of these J-aggregates were deposited onto transparent quartz slides.

• Dispersion of carbon nanotubes by photo- and thermal-responsive polymers containing azobenzene unit in the backbone.

  Authors: Tomokazu Umeyama, Kazuhiro Kawabata, Noriyasu Tezuka, Yoshihiro Matano, Yuji Miyato, Kazumi Matsushige, Masahiko Tsujimoto, Seiji Isoda, Mikio Takano, Hiroshi Imahori

  Chemical communications (Cambridge, England). 08/2010; 46(32):5969-71.

  Photo- and thermal-responsive polymers containing azobenzene units in the main chain have been utilized as removable dispersants for single-walled carbon nanotubes (SWNTs) in organic solvents.Photo- and thermal-responsive polymers containing azobenzene units in the main chain have been utilized as removable dispersants for single-walled carbon nanotubes (SWNTs) in organic solvents. Intermolecular interactions between SWNTs and the polymers are reversibly controllable by tuning the trans-cis composition.

• Synthesis of alpha,alpha'-linked oligophospholes and polyphospholes by using Pd-CuI-promoted Stille-type coupling.

  Authors: Arihiro Saito, Yoshihiro Matano, Hiroshi Imahori

  Organic letters. 06/2010; 12(11):2675-7.

  Palladium-copper-promoted Stille-type cross-coupling reactions between alpha-stannylphospholes and alpha-iodophospholes afforded alpha,alpha'-linked oligophospholes and polyphosphole efficiently. ItPalladium-copper-promoted Stille-type cross-coupling reactions between alpha-stannylphospholes and alpha-iodophospholes afforded alpha,alpha'-linked oligophospholes and polyphosphole efficiently. It has been revealed that the polyphosphole P-oxide possesses an extremely narrow band gap and a high electron-accepting ability as compared to polythiophene.

• Selective formation and efficient photocurrent generation of [70]fullerene-single-walled carbon nanotube composites.

  Authors: Tomokazu Umeyama, Noriyasu Tezuka, Shu Seki, Yoshihiro Matano, Masayuki Nishi, Kazuyuki Hirao, Heli Lehtivuori, Nikolai V Tkachenko, Helge Lemmetyinen, Yoshihide Nakao, Shigeyoshi Sakaki, Hiroshi Imahori

  Advanced materials (Deerfield Beach, Fla.). 04/2010; 22(15):1767-70.

• Remarkable effects of P-perfluorophenyl group on the synthesis of core-modified phosphaporphyrinoids and phosphadithiasapphyrin.

  Authors: Takashi Nakabuchi, Yoshihiro Matano, Hiroshi Imahori

  Organic letters. 02/2010; 12(5):1112-5.

  P,X,N(2)-type phosphaporphyrins and phosphacalixphyrins (X = N, S) bearing a perfluorophenyl (C(6)F(5)) group at the core phosphorus atom were prepared in high overall yield fromP,X,N(2)-type phosphaporphyrins and phosphacalixphyrins (X = N, S) bearing a perfluorophenyl (C(6)F(5)) group at the core phosphorus atom were prepared in high overall yield from 1-perfluorophenyl-2,5-di(ethoxycarbonyl)phosphole as a common starting material. In addition, P-C(6)F(5) P,S(2),N(2)-type sapphyrin was successfully prepared as the first example of ring-expanded phosphorus-containing porphyrin.

• Good solvent effects of C70 cluster formations and their electron-transporting and photoelectrochemical properties.

  Authors: Noriyasu Tezuka, Tomokazu Umeyama, Yoshihiro Matano, Tetsuya Shishido, Mitsuo Kawasaki, Masayuki Nishi, Kazuyuki Hirao, Heli Lehtivuori, Nikolai V Tkachenko, Helge Lemmetyinen, Yoshihito Honsho, Shu Seki, Hiroshi Imahori

  The journal of physical chemistry. B. 02/2010; 114(45):14287-97.

  Good solvent effects of C(70) cluster formations and their electron-transporting and photoelectrochemical properties have been systematically examined for the first time. Nano-to-micrometer scaleGood solvent effects of C(70) cluster formations and their electron-transporting and photoelectrochemical properties have been systematically examined for the first time. Nano-to-micrometer scale assemblies of C(70) with different morphologies were prepared by rapidly injecting poor solvent (i.e., acetonitrile) into a solution of C(70) dissolved in various good solvents (i.e., benzene, toluene, chlorobenzene, etc). The cluster morphology engineering was successfully achieved by changing the good solvent, yielding the spherical, rodlike, or platelike clusters in the mixed solvents. The clusters of C(70) were electrophoretically deposited onto a nanostructured SnO(2) electrode to examine the photoelectrochemical properties under the white light or monochromatic light illumination. The maximum incident photon-to-current efficiency (IPCE) varied from 0.8 to 10% depending on the combinations of the poor-good solvents. The differences in the IPCE values are discussed in terms of the surface area, thickness, and electron mobility of the deposited cluster films. The electron mobility is found to be the most predominant factor for the IPCE, indicating the importance of the electron-transporting process in the overall photocurrent generation. In addition, the electron mobility is closely correlated with the underlying molecular alignment and the resultant cluster structure. Thus, these results will provide basic clue for the design of C(70)-based molecular devices including the organic photovoltaics.

• Synthesis and Reactions of Phosphaporphyrins: Reconstruction of pi-Skeleton Triggered by Oxygenation of a Core Phosphorus Atom.

  Authors: Takashi Nakabuchi, Makoto Nakashima, Shinya Fujishige, Haruyuki Nakano, Yoshihiro Matano, Hiroshi Imahori

  The Journal of organic chemistry. 12/2009;

  The synthesis, structures, optical and redox properties, and reactivity of phosphaporphyrins are reported. The 21-phosphaporphyrin (P,N(3)-porphyrin) and 23-phospha-21-thiaporphyrinThe synthesis, structures, optical and redox properties, and reactivity of phosphaporphyrins are reported. The 21-phosphaporphyrin (P,N(3)-porphyrin) and 23-phospha-21-thiaporphyrin (P,S,N(2)-porphyrin) were prepared via acid-promoted dehydrative condensation between a phosphatripyrrane and the corresponding 2,5-bis[hydroxy(phenyl)methyl]heteroles followed by 2,3-dichloro-5,6-dicyanobenzoquinone oxidation. Experimental (NMR, UV-vis, and X-ray analyses) and theoretical (DFT calculations) results suggest that the 18pi aromaticity inherent in regular N(4)-porphyrins was maintained in these phosphaporphyrins. X-ray crystallography revealed a slightly distorted 18pi aromatic ring for the P,N(3)-porphyrin with the phosphole and three pyrrole rings tilted from the 24-atoms mean plane by 9.6 degrees and 3.8-15.4 degrees , respectively. DFT calculations on model compounds showed that the P,X,N(2)-porphyrins (X = N, S) possess considerably small HOMO-LUMO gaps as compared with N(4)- and S,N(3)-porphyrins, which is reflected in the red-shifted absorptions, low oxidation potentials, and high reduction potentials of the phosphaporphyrins. The P-oxygenation of the P,X,N(2)-porphyrins with H(2)O(2) has been found to lead to the formation of different types of products. The 18pi P,N(3)-porphyrin was transformed into the 22pi aromatic P(O),N(3)-porphyrin accompanied by the pi extension at the peripheral C(3) bridge, whereas the 18pi P,S,N(2)-porphyrin was converted to the isophlorin-type 20pi antiaromatic P(O),S,N(2)-porphyrin. In both of the reactions, simple P-oxygenated 18pi P(O),X,N(2)-porphyrins were formed as the initial products, which were subsequently transformed into the 22pi or 20pi porphyrins. The two reaction courses from 18pi to 20pi/22pi are apparently determined by the combination of the core heteroatoms (i.e., P,N(3) or P,S,N(2)) and the structure of the peripherally fused carbocycles. The present results demonstrate that the incorporation of a phosphorus atom into the core is not only a highly promising way to modify the fundamental properties of the porphyrin 18pi system but also a reliable tool to stabilize uncommon 22pi and 20pi systems through the chemical modifications at the core phosphorus atom.

• Syntheses, Structures, and Coordination Chemistry of Phosphole-Containing Hybrid Calixphyrins: Promising Macrocyclic P,N(2),X-Mixed Donor Ligands for Designing Reactive Transition Metal Complexes.

  Authors: Yoshihiro Matano, Tooru Miyajima, Noriaki Ochi, Takashi Nakabuchi, Motoo Shiro, Yoshihide Nakao, Shigeyoshi Sakaki, Hiroshi Imahori

  Journal of the American Chemical Society. 09/2009;

• Acenaphtho[1, 2-c]phosphole P-Oxide: A Phosphole-Naphthalene pi-Conjugated System with High Electron Mobility.

  Authors: Arihiro Saito, Tooru Miyajima, Makoto Nakashima, Tatsuya Fukushima, Hironori Kaji, Yoshihiro Matano, Hiroshi Imahori

  Chemistry (Weinheim an der Bergstrasse, Germany). 09/2009;

• New Palladium(II) Complex of P,S-Containing Hybrid Calixphyrin. Theoretical Study of Electronic Structure and Reactivity for Oxidative Addition.

  Authors: Noriaki Ochi, Yoshihide Nakao, Hirofumi Sato, Yoshihiro Matano, Hiroshi Imahori, Shigeyoshi Sakaki

  Journal of the American Chemical Society. 08/2009;

  The palladium complex of P,S-containing hybrid calixphyrin 1 was investigated with the DFT method. There are two kinds of valence tautomer in 1: one is a Pd(II) form in which the calixphyrin moietyThe palladium complex of P,S-containing hybrid calixphyrin 1 was investigated with the DFT method. There are two kinds of valence tautomer in 1: one is a Pd(II) form in which the calixphyrin moiety possesses -2 charges and the Pd center takes +2 oxidation state, and the other is a Pd(0) form in which the calixphyrin is neutral and the Pd center takes zero oxidation state. Complex 1 takes the Pd(II) form in the ground state. Though the Pd center takes +2 oxidation state, DFT computations clearly show that the oxidative addition of phenyl bromide (PhBr) to 1 occurs with moderate activation enthalpy, as experimentally proposed. The first step of the oxidative addition is the coordination of PhBr with the Pd center to form intermediate 1INTa, in which the Pd center and the calixphyrin moiety are neutral; in other words, the valence tautomerization from the Pd(II) form to the Pd(0) form occurs in the palladium calixphyrin moiety. The activation enthalpy is 22.5 kcal/mol, and the enthalpy change of reaction is 20.3 kcal/mol. The next step is the C-Br sigma-bond cleavage of PhBr, which occurs with activation enthalpy of 2.0 kcal/mol relative to 1INTa. On the other hand, the oxidative additions of PhBr to palladium complex of P,S-containing hybrid porphyrin 2 and that of conventional porphyrin 3 need much larger activation enthalpies of 49.1 and 74.4 kcal/mol, respectively. The differences in the reactivity among 1, 2, and 3 were theoretically investigated; in 1, the valence tautomerization occurs with moderate activation enthalpy to afford the Pd(0) form which is reactive for the oxidative addition. In 2, the tautomerization from the Pd(II) form to the Pd(0) form needs very large activation enthalpy (43.3 kcal/mol). In 3, such valence tautomerization does not occur at all, indicating that the Pd(II) must change to the Pd(IV) in the oxidative addition of PhBr to 3, which is a very difficult process. These differences are interpreted in terms of the pi* orbital energies of P,S-containing hybrid calixphyrin, hybrid porphyrin, and conventional porphyrin and the flexibility of their frameworks.

• Phosphole-Triazole Hybrids: A Facile Synthesis and Complexation with Pd(II) and Pt(II) Salts.

  Authors: Yoshihiro Matano, Makoto Nakashima, Arihiro Saito, Hiroshi Imahori

  Organic letters. 08/2009;

  The copper-promoted Huisgen reaction of alpha-ethynylphosphole P-oxides with aryl azides affords alpha-(1-aryl-1,2,3-triazol-4-yl)phospholes in high yield. TheThe copper-promoted Huisgen reaction of alpha-ethynylphosphole P-oxides with aryl azides affords alpha-(1-aryl-1,2,3-triazol-4-yl)phospholes in high yield. The alpha-(1-phenyl-1,2,3-triazol-4-yl)phosphole exhibits different coordination behavior in the complexation with MCl(2)(cod) (M = Pd, Pt). It has been revealed that P,N-coordination to PdCl(2) dramatically changes the optical properties of the newly constructed phosphole-triazole hybrid pi-system.

• Phosphole-Containing Calixpyrroles, Calixphyrins, and Porphyrins: Synthesis and Coordination Chemistry.

  Authors: Yoshihiro Matano, Hiroshi Imahori

  Accounts of chemical research. 07/2009;

  Porphyrins are large heterocyclic macrocycles that bind metals to form complexes such as heme and chlorophyll. Porphyrinogens are related macrocycles in which the meso-carbons, the carbon atomsPorphyrins are large heterocyclic macrocycles that bind metals to form complexes such as heme and chlorophyll. Porphyrinogens are related macrocycles in which the meso-carbons, the carbon atoms connecting the pyrroles or the related five-atom heterocycles, are all or partially reduced to methylene, disrupting the pi-electron conjugation. Both porphyrins and porphyrinogens are important components of natural and synthetic systems, and they have completely different coordination behavior. Consequently, the coordination chemistry of the entire porphyrin family, including regular porphyrins, porphyrinogens, and their expanded analogs, has been extensively investigated. Core modification, namely, replacing one or more pyrrole rings with other heterocyclic or carbocyclic rings, is a highly promising approach for creating unprecedented coordination properties in the porphyrin family. The size, shape, charge, and binding ability of the core-modified porphyrin platforms are readily tunable by variation of the heterole subunits. Until recently, however, the only atoms that could be incorporated into the core were carbon and chalcogens (the oxygen family). Phosphole, the phosphorus isologue of pyrrole, is considered a nonaromatic heterole because of insufficient pi-conjugation between the cis-dienic pi-system and the lone electron pair of the phosphorus atom. As a consequence, phospholes behave not only as efficient pi-conjugative frameworks but also as ordinary phosphine ligands for transition metals. With this in mind, we started a research project on core-modified porphyrins in which the phosphole subunit plays a crucial role in providing characteristic coordination environments. In this Account, we describe our efforts to explore the utility of phosphole-containing porphyrins and porphyrinogens as macrocyclic, mixed-donor ligands. We have established convenient methods for the synthesis of calixpyrroles, calixphyrins, and porphyrins with P and either O or S substitutions, that is, P,X,N(2)-hybrids, as well as the phosphatripyrrane precursors. We also have investigated the effects of varying the combination of core heteroatoms (P, N, S, and O) on the coordination properties of the hybrid macrocycles. Our recent investigations have shown that (1) the P,S,N(2)-calixpyrroles behave as monophosphine ligands while maintaining the hosting functions that originate from the pyrrole subunits, (2) the P,X,N(2)-calixphyrins behave as neutral, monoanionic, or dianionic tetradentate ligands with electronic structures that vary widely depending on the combination of heterole subunits, and (3) the P,S,N(2)-porphyrin behaves as a redox-active pi-ligand for group 10 (the Ni family) metals, affording a novel class of core-modified isophlorin complexes. As a whole, the incorporation of the phosphole subunit into the macrocyclic framework provides unprecedented coordinating properties for the porphyrin family, affording exceptional synthetic control over the behavior of these important macrocycles.