- Solvent Influence on the Magnetic Properties of Iron(II) Spin-Crossover Coordination Compounds with 4,4′-Dipyridylethyne as Linker
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New iron(II) coordination polymers with solvent-dependent spin-crossover behaviour have been synthesised by using an N2O2 Schiff base like ligand and 4,4′-dipyridylethyne as the bridging axial ligand in different solvents. The effects of different solvents and preparation methods (temperature, concentration) on the magnetic properties have been investigated. Annealing the coordination polymers prepared by the same method but in different solvents led to the same compound exhibiting the same three-step spin crossover independent of the magnetic properties of the solvated species. The X-ray structures of the axial ligand, an iron(II) dimer and one of the iron(II) coordination polymers are discussed. Powder X-ray diffraction analysis was additionally used for further comparison of the compounds.
- Dankhoff, Katja,Lochenie, Charles,Puchtler, Florian,Weber, Birgit
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- Syntheses, spectroscopic and molecular quadratic nonlinear optical properties of dipolar ruthenium(II) complexes of the ligand 1,2-phenylenebis(dimethylarsine)
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Six new complex salts trans-[RuIICl(pdma)2L][PF 6]n [pdma = 1,2-phenylenebis(dimethylarsine); L = (E,E,E)-1,6-bis(4-pyridyl)hexa-1,3,5-triene (bph), n = 1,5; L = N-methyl-4-[(e)-2-(4-pyridyl)ethenyl]pyridinmm (Mebpe-), n = 2, 7; L = N-methyl-4-[(E,E)-4-(4-pyridyl)buta-1,3-dienyl]pyridinium (Mebpb+), n = 2, 8; L = N-methyl-4-{(E,E,E)-6-(4-pyridyl)hexa1,3,5-trienyl}pyridinium (Mebph+), n = 2,9; L = bis(4-pyridyl)acetylene (bpa), n = 1, 10; L = N-methyl-4-[2-(4-pyridyl)-ethynyl]pyridinium (Mebph+), n = 2, 11] have been prepared. The electronic absorption spectra of 5 and 7-11 display intense, visible metal-to-ligand charge-transfer (MLCT) bands, with λmax values in the range 434-492 nm in acetonitrile. Cyclic voltammetric studies reveal reversible RuIII/II waves with E1/2 values in the range 1.06-1.15 V vs. Ag-AgCl, Natogether with irreversible L-based reduction processes. Along with a number of previously reported related compounds (B. J. Coe et al., J. Chem. Soc., Dalton Trans., 1996, 3917; 1997, 591; 2000, 797), salts 5 and 7-11 have been investigated by using Stark (electroabsorption) spectroscopy in butyronitrile glasses at 77 K. These studies have afforded dipole moment changes Δμ12 for the MLCT transitions which have been used to calculate molecular static first hyperpolarizabilities β0 according to the two-state equation β0 = 3Δμ12(μ12) 2/(Emax)2(μ12= transition dipole moment, Emax = MLCT energy). MLCT absorption and electrochemical data show that a trans-{RuIICl(pdma)2}+ centre is considerably less electron-rich than a {RuII(NH3) 5}2- unit. Although the β0 responses of the pdma complexes are only a little smaller than those of their {Ru II(NH3)5}2- analogues, this result is partly attributable to unexpected changes in the relative π12 values on freezing. Thus, substantial increases in μ12 for the arsine compounds act to partially offset the β0-decreasing influence of their higher Emax values when compared with the analogous pentaammine species. Single crystal X-ray structures have been obtained for the salts 1-2.5MeCN, 4·2MeCN, 7 and 11, but only 1-2.5MeCN adopts a non-centrosymmetric space group (Fdd2) such as may show bulk NLO effects.
- Coe, Benjamin J.,Harries, Josephine L.,Harris, James A.,Brunschwig, Bruce S.,Coles, Simon J.,Light, Mark E.,Hursthouse, Michael B.
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- Carborane viologen derivative as well as metal supramolecular polymer, synthesis method and application
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The invention discloses a carborane viologen derivative, a metal supramolecular polymer, a synthesis method and application. Viologen is used as a central core structure, 1,2-bis(4-pyridyl)acetylene is synthesized through a Sonagashira coupling reaction, and then alkynyl is attacked by decaborane to synthesize a carborane viologen precursor A; or alkynyl in bis(4-bromophenyl)acetylene is attackedwith decaborane to synthesize bis(4-bromophenyl)carborane, then a carborane viologen precursor B is synthesized through a Still coupling reaction, and finally the carborane viologen derivative is further obtained through the carborane viologen precursor A or the carborane viologen precursor B. Then, viologen is used as a central core structure, the carborane viologen derivative, ruthenium trichloride, cobalt dichloride or ferrous acetate are used as reaction raw materials, acetic acid is used as a solvent for reflux reaction, and finally, a product in reaction liquid is separated and dried tosynthesize the carborane viologen metal supramolecular polymer.
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Paragraph 0091-0092
(2021/01/24)
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- Electrochemical investigation of structurally varied azinium scaffolds
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Inspired by the successful utilization of aziniums as anolytes in redox-flow batteries, we have designed and prepared a systematically extended series of (di)azinium compounds based on pyrazine, bipyridine, 1,5-naphthyridine, 3,8-phenanthroline, (E)-4,4′-
- Bure?, Filip,Bure?ová, Zuzana,Klikar, Milan,Kví?ala, Jaroslav,Mazúr, Petr,Mike?ová, Michaela,Rak, Kamil
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p. 8830 - 8839
(2021/10/22)
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- The Covalent and Coordination Co-Driven Assembly of Supramolecular Octahedral Cages with Controllable Degree of Distortion
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Discovering and constructing novel and fancy structures is the goal of many supramolecular chemists. In this work, we propose an assembly strategy based on the synergistic effect of coordination and covalent interactions to construct a set of octahedral s
- Bao, Shu-Jin,Xu, Ze-Ming,Ju, Yun,Song, Ying-Lin,Wang, Heng,Niu, Zheng,Li, Xiaopeng,Braunstein, Pierre,Lang, Jian-Ping
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supporting information
p. 13356 - 13361
(2020/09/03)
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- Photoinduced direct hydration of dipyridylacetylenes in acidic aqueous solution
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Photoinduced direct hydration of dipyridylacetylenes (DPAs) in acidic aqueous solution was achieved upon UV irradiation at room temperature. This is a catalyst-free reaction with moderate-to-good yields, and asymmetric dipyridylacetylenes afford the corresponding Markovnikov addition products.
- Hao, Haijun,Li, Ya,Su, Zimu,Zhuang, Junpeng
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supporting information
p. 7669 - 7672
(2020/08/25)
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- Single-molecule conductance of functionalized oligoynes: Length dependence and junction evolution
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We report a combined experimental and theoretical investigation of the length dependence and anchor group dependence of the electrical conductance of a series of oligoyne molecular wires in single-molecule junctions with gold contacts. Experimentally, we focus on the synthesis and properties of diaryloligoynes with n = 1, 2, and 4 triple bonds and the anchor dihydrobenzo[b]thiophene (BT). For comparison, we also explored the aurophilic anchor group cyano (CN), amino (NH2), thiol (SH), and 4-pyridyl (PY). Scanning tunneling microscopy break junction (STM-BJ) and mechanically controllable break junction (MCBJ) techniques are employed to investigate single-molecule conductance characteristics. The BT moiety is superior as compared to traditional anchoring groups investigated so far. BT-terminated oligoynes display a 100% probability of junction formation and possess conductance values which are the highest of the oligoynes studied and, moreover, are higher than other conjugated molecular wires of similar length. Density functional theory (DFT)-based calculations are reported for oligoynes with n = 1-4 triple bonds. Complete conductance traces and conductance distributions are computed for each family of molecules. The sliding of the anchor groups leads to oscillations in both the electrical conductance and the binding energies of the studied molecular wires. In agreement with experimental results, BT-terminated oligoynes are predicted to have a high electrical conductance. The experimental attenuation constants βH range between 1.7 nm-1 (CN) and 3.2 nm-1 (SH) and show the following trend: β H(CN) H(NH2) H(BT) H(PY) ≈ βH(SH). DFT-based calculations yield lower values, which range between 0.4 nm -1 (CN) and 2.2 nm-1 (PY).
- Moreno-Garcia, Pavel,Gulcur, Murat,Manrique, David Zsolt,Pope, Thomas,Hong, Wenjing,Kaliginedi, Veerabhadrarao,Huang, Cancan,Batsanov, Andrei S.,Bryce, Martin R.,Lambert, Colin,Wandlowski, Thomas
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supporting information
p. 12228 - 12240
(2013/09/23)
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- A metal-organic framework constructed of 1,2-Di(pyridin-4-yl)ethyne, terephthalic acid, and zinc(II) nitrate
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A metal-organic framework (MOF) was prepared from 1,2-di(pyridin-4-yl) ethyne, terephthalic acid and zinc(II) nitrate in dimethylformamide, water and ethanol at 80 °C. The cavities of the MOF are occupied by disordered molecules of dimethylformamide. The crystals are monoclinic, space group P21/c with Z = 4.
- Albrecht, Marcel,Nieger, Martin,Schmidt, Andreas
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experimental part
p. 103 - 106
(2012/05/20)
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- Pd-catalyzed [2+2+1] coupling of alkynes and arenes: Phenol diazonium salts as mechanistic trapdoors
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Alkynes and phenol diazonium salts undergo a Pd-catalyzed [2+2+1] cyclization reaction to spiro[4,5]decatetraene-7-ones. This structure was confirmed for one example by X-ray single-crystal structure analysis. The reaction is believed to proceed through oxidative addition of the phenol diazonium cation to Pd0, subsequent insertion of two alkynes, followed by irreversible spirocyclization. Copyright
- Schmidt, Bernd,Berger, Rene,Kelling, Alexandra,Schilde, Uwe
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supporting information; experimental part
p. 7032 - 7040
(2011/07/30)
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- Syntheses of novel 2,3-diaryl-substituted 5-cyano-4-azaindoles exhibiting c-Met inhibition activity
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Herein we report the syntheses of 2,3-diaryl-substituted pyrrolo[3,2-b]pyridine-5-carbonitriles via a one-pot 5-endo-dig-cyclization/protection reaction followed by palladium catalyzed arylation. In addition, a complementary synthesis route employing Laro
- Koolman, Hannes,Heinrich, Timo,Boettcher, Henning,Rautenberg, Wilfried,Reggelin, Michael
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scheme or table
p. 1879 - 1882
(2009/11/30)
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- An improved preparation of 4-ethynylpyridine and its application to the synthesis of linear bipyridyl ligands
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A convenient synthesis of 4-ethynylpyridine, 5, starting from 4- vinylpyridine has been developed. Compound 5 reacts readily with pyridyl- and aryl-iodides to give the linear bidentate ligands 7, 9, and 11 in excellent yields.
- Champness, Neil R.,Khlobystov, Andrei N.,Majuga, Alexander G.,Schroeder, Martin,Zyk, Nikolai V.
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p. 5413 - 5416
(2007/10/03)
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- Octatetrayne-linked porphyrins: "stretched" cyclis dimers and trimers with very spacious cavities
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Synthesis are described for two octatetrayne-linked cyclic porphyrin oligomers with extremely spacious cavities.These hosts bind strongly to complementary multidentate guests.Thus, the octatetrayne-linked dimer binds bifunctional ligand bis(4-pyridyl)ethy
- Anderson, Harry L.,Walter, Christopher J.,Vidal-Ferran, Anton,Hay, Robert A.,Lowden, Philip A.,Sanders, Jeremy K. M.
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p. 2275 - 2280
(2007/10/02)
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- Intramolecular Electron Transfer from Pentacyanoferrate(II) to Pentaaminecobalt(III) with 3,3'-Dimethyl-4,4'-bipyridine, 4,4'-Bipyridylacetylene, 1,4-Bis(4-pyridyl)butadiyne, 2,7-Diazapyrene, and 3,8-Phenanthroline as Bridging Ligands: Adiabaticity and th
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Rate constants for intramolecular electron transfer from iron to cobalt in (NH3)5CO(III)LFe(II)(CN)5 (L=3,3'-dimethyl-4,4'-bipyridine, 4,4'-bipyridylacetylene, 1,4-bis(4-pyridyl)butadiyne, 2,7-diazapyrene, and 3,8-phenanthroline) have been measured at 25
- Lee, Gyu-Hwan,Ciana, Leopoldo Della,Haim, Albert
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p. 2535 - 2541
(2007/10/02)
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