Deprotonation-Induced and Ion-Pairing-Modulated Diradical Properties of Partially Conjugated Pyrrole-Quinone Conjunction.

Quinoidal molecules based on dipyrrolyldiketone boron complexes (QPBs), in which pyrrole units were connected by a partially conjugated system as a singlet spin coupler, were synthesized. QPB, which was stabilized by the introduction of a benzo unit at the pyrrole β-positions, formed a closed-shell tautomer conformation that showed near-infrared absorption. The deprotonated species, monoanion QPB- and dianion QPB2-, showing over 1000 nm absorption, were formed by the addition of bases, providing ion pairs in combination with countercations. Diradical properties were observed in QPB2-, whose hyperfine coupling constants were modulated by ion-pairing with π-electronic and aliphatic cations, demonstrating cation-dependent diradical properties. VT NMR and ESR along with a theoretical study revealed that the singlet diradical was more stable than the triplet diradical.

[1]  Yoichi Kobayashi,et al.  π-Stacked Ion Pairs: Tightly Associated Charged Porphyrins in Ordered Arrangement Enabling Radical-Pair Formation. , 2022, Journal of the American Chemical Society.

[2]  Jishan Wu,et al.  Hückel- and Baird-type 3D Global Aromaticity in a Fully Conjugated Molecular Cage. , 2021, Angewandte Chemie.

[3]  Xiaoqi Sun,et al.  A high capacity small molecule quinone cathode for rechargeable aqueous zinc-organic batteries , 2021, Nature Communications.

[4]  H. Maeda,et al.  Pyrrole-bridged quinones: π-electronic systems that modulate electronic structures by tautomerism and deprotonation. , 2021, Chemical communications.

[5]  Y. Shigeta,et al.  Ion-pairing π-electronic systems: ordered arrangement and noncovalent interactions of negatively charged porphyrins† , 2021, Chemical science.

[6]  Takuya Yamada,et al.  Boron-Doped Polycyclic π-Electron Systems with an Antiaromatic Borole Substructure That Forms Photoresponsive B-P Lewis Adducts. , 2021, Journal of the American Chemical Society.

[7]  Y. Haketa,et al.  First decade of π-electronic ion-pairing assemblies , 2020, Molecular Systems Design & Engineering.

[8]  A. Dreuw,et al.  Quinoidal Azaacenes: 99 % Diradical Character , 2020, Angewandte Chemie.

[9]  Yongqian Shi,et al.  Stable Organic Diradicals Based on Fused Quinoidal Oligothiophene Imides with High Electrical Conductivity. , 2020, Journal of the American Chemical Society.

[10]  Baohua Li,et al.  Organic quinones towards advanced electrochemical energy storage: recent advances and challenges , 2019, Journal of Materials Chemistry A.

[11]  K. Müllen,et al.  Heteroatom-Doped Nanographenes with Structural Precision , 2019, Accounts of chemical research.

[12]  Yoichi Kobayashi,et al.  Multiply aryl-substituted dipyrrolyldiketone boron complexes exhibiting anion-responsive emissive properties. , 2019, Chemical communications.

[13]  U. Bunz,et al.  True Blue Through Oxidation-A Thiaazulenic Heterophenoquinone as Electrochrome. , 2019, Chemistry.

[14]  M. Dolenc,et al.  Chemicals and Drugs Forming Reactive Quinone and Quinone Imine Metabolites. , 2018, Chemical research in toxicology.

[15]  C. Zhong,et al.  Multichannel Strategies to Produce Stabilized Azaphenalene Diradicals: A Predictable Model to Generate Self‐Doped Cathode Interfacial Layers for Organic Photovoltaics , 2018, Advanced Functional Materials.

[16]  Y. Haketa,et al.  Dimension-Controlled π-Electronic Ion-Pairing Assemblies , 2018 .

[17]  Li-Ya Niu,et al.  Difluoroboron β-diketonate dyes: Spectroscopic properties and applications , 2017 .

[18]  T. Herng,et al.  Radical and Diradical Formation in Naphthalene Diimides through Simple Chemical Oxidation. , 2017, Chemphyschem : a European journal of chemical physics and physical chemistry.

[19]  David A. Nicewicz,et al.  Organic Photoredox Catalysis. , 2016, Chemical reviews.

[20]  S. Jang,et al.  First-Principles Density Functional Theory Modeling of Li Binding: Thermodynamics and Redox Properties of Quinone Derivatives for Lithium-Ion Batteries. , 2016, Journal of the American Chemical Society.

[21]  Alison E Wendlandt,et al.  Quinone-Catalyzed Selective Oxidation of Organic Molecules. , 2015, Angewandte Chemie.

[22]  Wei Huang,et al.  Heteroatom-doped graphene materials: syntheses, properties and applications. , 2014, Chemical Society reviews.

[23]  J. Abe,et al.  Remarkable solvatochromic color change via proton tautomerism of a phenol-linked imidazole derivative. , 2014, The journal of physical chemistry. A.

[24]  K. Nakashima,et al.  DFT studies of ESR parameters for NO centered radicals, N‐alkoxyaminyl and aminoxyl radicals , 2011, Magnetic resonance in chemistry : MRC.

[25]  T. Kawai,et al.  Chemical-stimuli-controllable circularly polarized luminescence from anion-responsive π-conjugated molecules. , 2011, Journal of the American Chemical Society.

[26]  H. Takezoe,et al.  Oriented salts: dimension-controlled charge-by-charge assemblies from planar receptor-anion complexes. , 2010, Angewandte Chemie.

[27]  C. Moriyoshi,et al.  Extremely High Resolution Single Crystal Diffractometory for Orbital Resolution using High Energy Synchrotron Radiation at SPring‐8 , 2010 .

[28]  M. Takata,et al.  Submicrometer Single Crystal Diffractometry for Highly Accurate Structure Determination , 2010 .

[29]  Shinsuke Nishida,et al.  Three-dimensional intramolecular exchange interaction in a curved and nonalternant pi-conjugated system: corannulene with two phenoxyl radicals. , 2010, Angewandte Chemie.

[30]  W. C. Lineberger,et al.  The lowest singlet and triplet States of the oxyallyl diradical. , 2009, Angewandte Chemie.

[31]  Kenichi Kato,et al.  X-ray diffractometry for the structure determination of a submicrometre single powder grain , 2009, Journal of synchrotron radiation.

[32]  Anilesh Kumar,et al.  The guanine cation radical: investigation of deprotonation states by ESR and DFT. , 2006, The journal of physical chemistry. B.

[33]  Hyoyoung Lee,et al.  Singlet-triplet gap in triplet ground-state biradicals is modulated by substituent effects. , 2002, Journal of the American Chemical Society.

[34]  K. Oyaizu,et al.  Electrochemical and ferromagnetic couplings in 4,4',4' '-(1,3,5-benzenetriyl)tris(phenoxyl) radical formation. , 2001, The Journal of organic chemistry.

[35]  Krebs,et al.  Synthesis of a Triazatriangulenium Salt. , 2000, Angewandte Chemie.

[36]  D. Shultz,et al.  EFFECT OF ALIPHATIC AMINE BASES ON THE AGGREGATION OF ALKALI METAL SALTS OF 3,5-DI-TERT-BUTYLSEMIQUINONE (3,5-DBSQ) , 1998 .

[37]  M. Murcko,et al.  The effects of heteroatom substitution on the singlet–triplet energy differences in diradicals—ab initio calculations of ΔEST in meta-benzoquinomethane and in 1,3-naphthoquinomethane , 1998 .

[38]  A. Ichimura,et al.  Semiempirical study of electron exchange interaction in organic high-spin .pi.-systems. Classifying structural effects in organic magnetic molecules , 1991 .

[39]  M. B. Coolidge,et al.  Ab initio MCSCF and CI calculations of the singlet-triplet energy differences in oxyallyl and in dimethyloxyallyl , 1990 .

[40]  K. Mukai,et al.  ESR Studies of a New Stable π-Conjugated Bisaryloxyl Biradical , 1979 .

[41]  L. Salem.  Diradicals , 1973 .

[42]  K. Bowers,et al.  Anomalous paramagnetism of copper acetate , 1952, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.