Nucleobase-Functionalized 1,6-Dithiapyrene-Type Electron-Donors: Supramolecular Assemblies by Complementary Hydrogen-Bonds and π‑Stacks

Synthesis, crystal structures and redox properties of 1,6-dithiapyrene (DTPY)-type electron-donors functionalized with nucleobases (uracil, cytosine and adenine) were investigated. The electrochemical measurements showed that the uracil-substituted derivatives were slightly stronger electron-donors than DTPY, and the cytosine- and adenine-substitution caused a slight weakening of the electron-donating ability. In the crystal structures, DTPY-nucleobases constructed multidimensional assemblies by complementary hydrogen-bonds on the nucleobase moieties and π-stacks and S···S interactions on the DTPY skeleton. The uracil derivative formed two kinds of hydrogen-bonded pairs with different H-bonding modes (Watson–Crick and reverse Watson–Crick types), both of which were further linked through π-stacks on the DTPY skeleton to construct one-dimensional alternating columns. In the CH₂Cl₂ solvated crystal, the uracil derivative built up a two-dimensional π-layer by the complementary hydrogen-bonds and π-stacks. In the cytosine derivative, the complementary hydrogen-bonded pair assembled by the π-stacks and S···S interactions of the DTPY skeleton constructed a two-dimensional network. The adenine derivative formed a channel structure by the one-dimensional π-stack of complementary hydrogen-bonded pairs, where crystalline water molecules with a ladder-like hydrogen-bonded chain were included. Charge-transfer complexes of DTPY-nucleobases with tetracyanoquinodimethane possessed a neutral ground state and exhibited semiconductive behaviors with room temperature conductivities of 10^–6 to 10^–7 S cm^–1

Nucleobase-Functionalized 1,6-Dithiapyrene-Type Electron-Donors: Supramolecular Assemblies by Complementary Hydrogen-Bonds and π‑Stacks

Synthesis, crystal structures and redox properties of 1,6-dithiapyrene (DTPY)-type electron-donors functionalized with nucleobases (uracil, cytosine and adenine) were investigated. The electrochemical measurements showed that the uracil-substituted derivatives were slightly stronger electron-donors than DTPY, and the cytosine- and adenine-substitution caused a slight weakening of the electron-donating ability. In the crystal structures, DTPY-nucleobases constructed multidimensional assemblies by complementary hydrogen-bonds on the nucleobase moieties and π-stacks and S···S interactions on the DTPY skeleton. The uracil derivative formed two kinds of hydrogen-bonded pairs with different H-bonding modes (Watson–Crick and reverse Watson–Crick types), both of which were further linked through π-stacks on the DTPY skeleton to construct one-dimensional alternating columns. In the CH₂Cl₂ solvated crystal, the uracil derivative built up a two-dimensional π-layer by the complementary hydrogen-bonds and π-stacks. In the cytosine derivative, the complementary hydrogen-bonded pair assembled by the π-stacks and S···S interactions of the DTPY skeleton constructed a two-dimensional network. The adenine derivative formed a channel structure by the one-dimensional π-stack of complementary hydrogen-bonded pairs, where crystalline water molecules with a ladder-like hydrogen-bonded chain were included. Charge-transfer complexes of DTPY-nucleobases with tetracyanoquinodimethane possessed a neutral ground state and exhibited semiconductive behaviors with room temperature conductivities of 10^–6 to 10^–7 S cm^–1

Nucleobase-Functionalized 1,6-Dithiapyrene-Type Electron-Donors: Supramolecular Assemblies by Complementary Hydrogen-Bonds and π‑Stacks

Synthesis, crystal structures and redox properties of 1,6-dithiapyrene (DTPY)-type electron-donors functionalized with nucleobases (uracil, cytosine and adenine) were investigated. The electrochemical measurements showed that the uracil-substituted derivatives were slightly stronger electron-donors than DTPY, and the cytosine- and adenine-substitution caused a slight weakening of the electron-donating ability. In the crystal structures, DTPY-nucleobases constructed multidimensional assemblies by complementary hydrogen-bonds on the nucleobase moieties and π-stacks and S···S interactions on the DTPY skeleton. The uracil derivative formed two kinds of hydrogen-bonded pairs with different H-bonding modes (Watson–Crick and reverse Watson–Crick types), both of which were further linked through π-stacks on the DTPY skeleton to construct one-dimensional alternating columns. In the CH₂Cl₂ solvated crystal, the uracil derivative built up a two-dimensional π-layer by the complementary hydrogen-bonds and π-stacks. In the cytosine derivative, the complementary hydrogen-bonded pair assembled by the π-stacks and S···S interactions of the DTPY skeleton constructed a two-dimensional network. The adenine derivative formed a channel structure by the one-dimensional π-stack of complementary hydrogen-bonded pairs, where crystalline water molecules with a ladder-like hydrogen-bonded chain were included. Charge-transfer complexes of DTPY-nucleobases with tetracyanoquinodimethane possessed a neutral ground state and exhibited semiconductive behaviors with room temperature conductivities of 10^–6 to 10^–7 S cm^–1

Nucleobase-Functionalized 1,6-Dithiapyrene-Type Electron-Donors: Supramolecular Assemblies by Complementary Hydrogen-Bonds and π‑Stacks

Synthesis, crystal structures and redox properties of 1,6-dithiapyrene (DTPY)-type electron-donors functionalized with nucleobases (uracil, cytosine and adenine) were investigated. The electrochemical measurements showed that the uracil-substituted derivatives were slightly stronger electron-donors than DTPY, and the cytosine- and adenine-substitution caused a slight weakening of the electron-donating ability. In the crystal structures, DTPY-nucleobases constructed multidimensional assemblies by complementary hydrogen-bonds on the nucleobase moieties and π-stacks and S···S interactions on the DTPY skeleton. The uracil derivative formed two kinds of hydrogen-bonded pairs with different H-bonding modes (Watson–Crick and reverse Watson–Crick types), both of which were further linked through π-stacks on the DTPY skeleton to construct one-dimensional alternating columns. In the CH₂Cl₂ solvated crystal, the uracil derivative built up a two-dimensional π-layer by the complementary hydrogen-bonds and π-stacks. In the cytosine derivative, the complementary hydrogen-bonded pair assembled by the π-stacks and S···S interactions of the DTPY skeleton constructed a two-dimensional network. The adenine derivative formed a channel structure by the one-dimensional π-stack of complementary hydrogen-bonded pairs, where crystalline water molecules with a ladder-like hydrogen-bonded chain were included. Charge-transfer complexes of DTPY-nucleobases with tetracyanoquinodimethane possessed a neutral ground state and exhibited semiconductive behaviors with room temperature conductivities of 10^–6 to 10^–7 S cm^–1

Nucleobase-Functionalized 1,6-Dithiapyrene-Type Electron-Donors: Supramolecular Assemblies by Complementary Hydrogen-Bonds and π‑Stacks

Synthesis, crystal structures and redox properties of 1,6-dithiapyrene (DTPY)-type electron-donors functionalized with nucleobases (uracil, cytosine and adenine) were investigated. The electrochemical measurements showed that the uracil-substituted derivatives were slightly stronger electron-donors than DTPY, and the cytosine- and adenine-substitution caused a slight weakening of the electron-donating ability. In the crystal structures, DTPY-nucleobases constructed multidimensional assemblies by complementary hydrogen-bonds on the nucleobase moieties and π-stacks and S···S interactions on the DTPY skeleton. The uracil derivative formed two kinds of hydrogen-bonded pairs with different H-bonding modes (Watson–Crick and reverse Watson–Crick types), both of which were further linked through π-stacks on the DTPY skeleton to construct one-dimensional alternating columns. In the CH₂Cl₂ solvated crystal, the uracil derivative built up a two-dimensional π-layer by the complementary hydrogen-bonds and π-stacks. In the cytosine derivative, the complementary hydrogen-bonded pair assembled by the π-stacks and S···S interactions of the DTPY skeleton constructed a two-dimensional network. The adenine derivative formed a channel structure by the one-dimensional π-stack of complementary hydrogen-bonded pairs, where crystalline water molecules with a ladder-like hydrogen-bonded chain were included. Charge-transfer complexes of DTPY-nucleobases with tetracyanoquinodimethane possessed a neutral ground state and exhibited semiconductive behaviors with room temperature conductivities of 10^–6 to 10^–7 S cm^–1

Intermolecular Hydrogen-Bond Networks and Physical Properties of BF₄^– and TCNQ^{<b>•</b>–} Salts of Three-Fold Symmetric Tris(alkylamino)phenalenyliums

Synthesis, redox properties, and crystal structures of tris­(alkylamino)­phenalenyliums (TAP) having alkyl groups (<i>n</i>-Pr, <i>i</i>-Pr, <i>t</i>-Bu) and their charge-transfer salts with tetracyanoquinodimethane radical anion (TCNQ^{<b>•</b>–}) were investigated. The electrochemical measurements revealed that TAP exhibits two irreversible reduction processes to neutral radical and anion species. The introduction of an alkylamino group caused a large negative shift of the first reduction potential and a significant decrease of the on-site Coulomb repulsion because of the electron-donating nature of amino groups and the extension of the π-electronic system. In the crystal structures of the BF₄^– salts, the TAP skeleton possesses a nearly 3-fold symmetric molecular plane indicating the delocalization of positive charge. The face-to-face stack of TAP formed π-dimer or columnar structures, which were connected through intermolecular N–H···F hydrogen bonds with BF₄^– to construct multidimensional network structures. The TCNQ^{<b>•</b>–} salts prepared by the metathesis method were characterized as fully ionic salts with a 1:1 component ratio. In the crystal structures, both TAP and TCNQ^{<b>•</b>–} molecules formed π-dimers, and the intermolecular hydrogen bonds between TAP and TCNQ^{<b>•</b>–} constructed a two-dimensional sheet

Intermolecular Hydrogen-Bond Networks and Physical Properties of BF₄^– and TCNQ^{<b>•</b>–} Salts of Three-Fold Symmetric Tris(alkylamino)phenalenyliums

Synthesis, redox properties, and crystal structures of tris­(alkylamino)­phenalenyliums (TAP) having alkyl groups (<i>n</i>-Pr, <i>i</i>-Pr, <i>t</i>-Bu) and their charge-transfer salts with tetracyanoquinodimethane radical anion (TCNQ^{<b>•</b>–}) were investigated. The electrochemical measurements revealed that TAP exhibits two irreversible reduction processes to neutral radical and anion species. The introduction of an alkylamino group caused a large negative shift of the first reduction potential and a significant decrease of the on-site Coulomb repulsion because of the electron-donating nature of amino groups and the extension of the π-electronic system. In the crystal structures of the BF₄^– salts, the TAP skeleton possesses a nearly 3-fold symmetric molecular plane indicating the delocalization of positive charge. The face-to-face stack of TAP formed π-dimer or columnar structures, which were connected through intermolecular N–H···F hydrogen bonds with BF₄^– to construct multidimensional network structures. The TCNQ^{<b>•</b>–} salts prepared by the metathesis method were characterized as fully ionic salts with a 1:1 component ratio. In the crystal structures, both TAP and TCNQ^{<b>•</b>–} molecules formed π-dimers, and the intermolecular hydrogen bonds between TAP and TCNQ^{<b>•</b>–} constructed a two-dimensional sheet

Changes in fetal baroreceptor sensitivity during intrauterine inflammation in preterm fetal sheep

Baroreflex is a regulatory mechanism that slows the fetal heart rate. This study aimed to investigate the effects of lipopolysaccharide (LPS)-induced endotoxemia on fetal baroreceptor sensitivity in preterm fetal sheep. The changes in fetal baroreceptor sensitivity were measured in seven chronically instrumented preterm fetal sheep. Fetal baroreceptor sensitivity was measured in three phases: (A) control phase, defined as the 24 h before the first injection of LPS; (B) acute phase, defined as the 24 h between the first and second injections of LPS; and (C) fetal acidosis phase, defined as the time from the second LPS injection until intrauterine fetal death. Histological examinations of the fetal membrane and umbilical cord were also conducted. Each fetus developed metabolic acidosis after the second injection of LPS. The fetuses died 24.7 (SD = 6.1) hours after the second injection of LPS. Both the umbilical cord and fetal membranes showed histological evidence of severe inflammation. In total, 163 fetal baroreceptor measurements were performed in this experiment (A, n = 77 times; B, n = 60 times; C, n = 26 times). Fetal baroreceptor sensitivity showed significant differences in all three phases (A: 2.7 [SD = 0.2]; B: 2.5 [SD = 0.2]; and C: 1.5 [SD = 0.2]). Post hoc tests showed that baroreceptor sensitivity in the acidosis phase had decreased significantly compared to that in the control and acute phases (pp=.002, respectively). Fetal baroreceptor sensitivity decreased during fetal acidosis induced by LPSs.</p

Exploration of Charge-Transfer Solids Utilizing Nucleobases: Nanoarchitectures by Hydrogen-Bonds in the Ionic Assemblies of Guanine and TCNQ Derivatives

We studied formation and structural characteristics of charge-transfer solids of 9-<i>n</i>-butylguanine (<b>BuG</b>) with fluorinated tetracyanoquinodimethane derivatives (F_<i>n</i>TCNQ, <i>n</i> = 4, 2, and 1). Complex formation in a methanol (MeOH)-containing solvent generated two types of salts composed of either a methoxy-substituted anion or a fully ionic anion radical of F_<i>n</i>TCNQ. In all anion radical salts, <b>BuG</b> existed as a protonated or a hemiprotonated species, <b>BuGH</b>^<b>+</b> or (<b>BuG</b>)­(<b>BuGH</b>^<b>+</b>), respectively, and formed hydrogen-bonded (H-bonded) assemblies. In these <b>BuGH</b>^<b>+</b> assemblies, F_<i>n</i>TCNQ^•– molecules were fixed and aligned periodically, providing H-bonded polycationic templates. In (<b>BuGH</b>^<b>+</b>)­(F₄TCNQ^•–), <b>BuGH</b>^<b>+</b> dimers by complementary H-bonds formed a two-dimensional (2D) polycationic sheet. The F₄TCNQ^•– face-to-face dimers formed a one-dimensional (1D) segregated column aided by formation of H-bonds with <b>BuGH</b>^<b>+</b>. In (<b>BuGH</b>^<b>+</b>)­(F₂TCNQ^•–)­(MeOH), <b>BuGH</b>^<b>+</b> dimers by complementary double H-bonds formed a 1D polycationic ribbon supported by MeOH-mediated H-bonds. A 1D mixed stack column of (<b>BuGH</b>^<b>+</b>)₂ and (F₂TCNQ^•–)₂ dimers was formed owing to their complementary geometry and size. In (<b>BuG</b>)­(<b>BuGH</b>^<b>+</b>)­(F₁TCNQ^•–), a new type of <b>BuG</b>–<b>BuGH</b>^<b>+</b> pair formed a 1D ribbon supported by complementary H-bonds, and F₁TCNQ^•– dimers were aligned by H-bonds with the <b>BuG</b>–<b>BuGH</b>^<b>+</b> ribbon

Exploration of Charge-Transfer Solids Utilizing Nucleobases: Nanoarchitectures by Hydrogen-Bonds in the Ionic Assemblies of Guanine and TCNQ Derivatives

We studied formation and structural characteristics of charge-transfer solids of 9-<i>n</i>-butylguanine (<b>BuG</b>) with fluorinated tetracyanoquinodimethane derivatives (F_<i>n</i>TCNQ, <i>n</i> = 4, 2, and 1). Complex formation in a methanol (MeOH)-containing solvent generated two types of salts composed of either a methoxy-substituted anion or a fully ionic anion radical of F_<i>n</i>TCNQ. In all anion radical salts, <b>BuG</b> existed as a protonated or a hemiprotonated species, <b>BuGH</b>^<b>+</b> or (<b>BuG</b>)­(<b>BuGH</b>^<b>+</b>), respectively, and formed hydrogen-bonded (H-bonded) assemblies. In these <b>BuGH</b>^<b>+</b> assemblies, F_<i>n</i>TCNQ^•– molecules were fixed and aligned periodically, providing H-bonded polycationic templates. In (<b>BuGH</b>^<b>+</b>)­(F₄TCNQ^•–), <b>BuGH</b>^<b>+</b> dimers by complementary H-bonds formed a two-dimensional (2D) polycationic sheet. The F₄TCNQ^•– face-to-face dimers formed a one-dimensional (1D) segregated column aided by formation of H-bonds with <b>BuGH</b>^<b>+</b>. In (<b>BuGH</b>^<b>+</b>)­(F₂TCNQ^•–)­(MeOH), <b>BuGH</b>^<b>+</b> dimers by complementary double H-bonds formed a 1D polycationic ribbon supported by MeOH-mediated H-bonds. A 1D mixed stack column of (<b>BuGH</b>^<b>+</b>)₂ and (F₂TCNQ^•–)₂ dimers was formed owing to their complementary geometry and size. In (<b>BuG</b>)­(<b>BuGH</b>^<b>+</b>)­(F₁TCNQ^•–), a new type of <b>BuG</b>–<b>BuGH</b>^<b>+</b> pair formed a 1D ribbon supported by complementary H-bonds, and F₁TCNQ^•– dimers were aligned by H-bonds with the <b>BuG</b>–<b>BuGH</b>^<b>+</b> ribbon