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1.
In‐Won Park Dr. Jaeduk Yoo Dr. Suman Adhikari Jung Su Park Prof. Jonathan L. Sessler Prof. Chang‐Hee Lee 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(47):15073-15078
A new ditopic ion‐pair receptor 1 was designed, synthesized, and characterized. Detailed binding studies served to confirm that this receptor binds fluoride and chloride ions (studied as their tetraalkylammonium salts) and forms stable 1:1 complexes in CDCl3. Treatment of the halide‐ion complexes of 1 with Group I and II metal ions (Li+, Na+, K+, Cs+, Mg2+, and Ca2+; studied as their perchlorate salts in CD3CN) revealed unique interactions that were found to depend on both the choice of the added cation and the precomplexed anion. In the case of the fluoride complex [ 1? F]? (preformed as the tetrabutylammonium (TBA+) complex), little evidence of interaction with the K+ ion was seen. In contrast, when this same complex (i.e., [ 1? F]? as the TBA+ salt) was treated with the Li+ or Na+ ions, complete decomplexation of the receptor‐bound fluoride ion was observed. In sharp contrast to what was seen with Li+, Na+, and K+, treating complex [ 1? F]? with the Cs+ ion gave rise to a stable, receptor‐bound ion‐pair complex [Cs ?1? F] that contains the Cs+ ion complexed within the cup‐like cavity of the calix[4]pyrrole, which in turn was stabilized in its cone conformation. Different complexation behavior was observed in the case of the chloride complex [ 1? Cl]?. In this case, no appreciable interaction was observed with Na+ or K+. In addition, treating [ 1? Cl]? with Li+ produces a tightly hydrated dimeric ion‐pair complex [ 1? LiCl(H2O)]2 in which two Li+ ions are bound to the crown moiety of the two receptors. In analogy to what was seen in the case of [ 1? F]?, exposure of [ 1? Cl]? to the Cs+ ion gives rise to an ion‐pair complex [Cs ?1? Cl] in which the cation is bound within the cup of the calix[4]pyrrole. Different complexation modes were also observed when the binding of the fluoride ion was studied by using the tetramethylammonium and tetraethylammonium salts. 相似文献
2.
Soichiro Nakatsuka Yusuke Watanabe Yoshinobu Kamakura Satoshi Horike Daisuke Tanaka Takuji Hatakeyama 《Angewandte Chemie (International ed. in English)》2020,59(4):1435-1439
A triphosphaazatriangulene (H3L) was synthesized through an intramolecular triple phospha‐Friedel–Crafts reaction. The H3L triangulene contains three phosphinate groups and an extended π‐conjugated framework, which enables the stimuli‐responsive reversible transformation of [Cu(HL)(DMSO)?(MeOH)]n, a 3D‐MOF that exhibits reversible sorption characteristics, into (H3L?0.5 [Cu2(OH)4?6 H2O] ?4 H2O), a 1D‐columnar assembled proton‐conducting material. The hydrophilic nature of the latter resulted in a proton conductivity of 5.5×10?3 S cm?1 at 95 % relative humidity and 60 °C. 相似文献
3.
Binod Nepal Prof. Steve Scheiner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(4):1474-1481
CF3H as a proton donor was paired with a variety of anions, and its properties were assessed by MP2/aug‐cc‐pVDZ calculations. The binding energy of monoanions halide, NO3?, formate, acetate, HSO4?, and H2PO4? lie in the 12–17 kcal mol?1 range, although F? is more strongly bound, by 26 kcal mol?1. Dianions SO42? and HPO42? are bound by 27 kcal mol?1, and trianion PO43? by 45 kcal mol?1. When two O atoms are available on the anion, the CH???O? H‐bond (HB) is usually bifurcated, although asymmetrically. The CH bond is elongated and its stretching frequency redshifted in these ionic HBs, but the shift is reduced in the bifurcated structures. Slightly more than half of the binding energy is attributed to Coulombic attraction, with smaller contributions from induction and dispersion. The amount of charge transfer from the anions to the σ*(CH) orbital correlates with many of the other indicators of bond strength, such as binding energy, CH bond stretch, CH redshift, downfield NMR spectroscopic chemical shift of the bridging proton, and density at bond critical points. 相似文献
4.
Soumava Biswas Himanshu Sekhar Jena Suresh Sanda Prof. Dr. Sanjit Konar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(39):13793-13801
Three isostructural lanthanide‐based two‐ dimensional coordination polymers (CPs) {[Ln2(L)3(H2O)2]n ? 2n CH3OH) ? 2n H2O} (Ln=Gd3+ ( 1 ), Tb3+ ( 2 ), Dy3+ ( 3 ); H2L=cyclobutane‐1,1‐dicarboxylic acid) were synthesized by using a low molecular weight dicarboxylate ligand and characterized. Single‐crystal structure analysis showed that in complexes 1 – 3 lanthanide centers are connected by μ3‐bridging cyclobutanedicarboxylate ligands along the c axis to form a rod‐shaped infinite 1D coordination chain, which is further linked with nearby chains by μ4‐connected cyclobutanedicarboxylate ligands to form 2D CPs in the bc plane. Viewing the packing of the complexes down the b axis reveals that the lattice methanol molecules are located in the interlayer space between the adjacent 2D layers and form H‐bonds with lattice and coordinated water molecules to form 1D chains. Magnetic properties of complexes 1 – 3 were thoroughly investigated. Complex 1 exhibits dominant ferromagnetic interaction between two nearby gadolinium centers and also acts as a cryogenic magnetic refrigerant having a significant magnetic entropy change of ?ΔSm=32.8 J kg?1 K?1 for ΔH=7 T at 4 K (calculated from isothermal magnetization data). Complex 3 shows slow relaxation of magnetization below 10 K. Impedance analysis revealed that the complexes show humidity‐dependent proton conductivity (σ=1.5×10?5 S cm?1 for 1 , σ=2.07×10?4 S cm?1 for 2 , and σ=1.1×10?3 S cm?1 for 3 ) at elevated temperature (>75 °C). They retain the conductivity for up to 10 h at high temperature and high humidity. Furthermore, the proton conductivity results were correlated with the number of water molecules from the water‐vapor adsorption measurements. Water‐vapor adsorption studies showed hysteretic and two‐step water vapor adsorption (182000 μL g?1 for 1 , 184000 μL g?1 for 2 , and 1874000 μL g?1 for 3 ) in the experimental pressure range. Simulation of water‐vapor adsorption by the Monte Carlo method (for 1 ) confirmed the high density of adsorbed water molecules, preferentially in the interlayer space between the 2D layers. 相似文献
5.
Sabine Devautour‐Vinot Eriyakkadan S. Sanil Amine Geneste Vanessa Ortiz Pascal G. Yot Jong‐San Chang Guillaume Maurin 《化学:亚洲杂志》2019,14(20):3561-3565
Post‐synthesis modification of MIL‐101(Cr)‐NO2 was explored in order to decorate the organic backbone by propyl‐sulfonic groups, with the aim to incorporate mobile and acidic protons for solid‐state proton electrolyte applications. The resulting solid switched from insulating towards proton superconductive behavior under humidity, while the conductivity recorded at 363 K and 95 % relative humidity reached 4.8×10?3 S cm?1. Propitiously, the impregnation of the material by strong acidic molecules (H2SO4) further boosted the proton conductivity performances up to the remarkable σ value of 1.3×10?1 S cm?1 at 363 K/95 % RH, which reaches the performances of the best proton conductive MOF reported so far. 相似文献
6.
Pressure effects on the two‐site jumping of sodium and potassium cations in a 2,5‐di‐tert‐butyl‐1,4‐benzoquinone ion pair have been studied using a high‐pressure EPR technique. The rate constants of the intramolecular and intermolecular migrations for Na+ and K+ were determined from an EPR spectral simulation. The migration rates were found to be accelerated by increasing the external pressure. Using the pressure dependence of the migration rates, we estimated the activation volumes of the intramolecular (ΔV1?) and intermolecular (ΔV2?) processes for the Na+ and K+ migrations: ΔV1? = ?5.3 cm3 mol?1 and ΔV2? = ?29 cm3 mol?1 for Na+, and ΔV1? = ?8.3 cm3 mol?1 and ΔV2? = ?0.85 cm3 mol?1 for K+. Based on the results, the mechanisms for the two‐site jumping of Na+ and K+ are discussed in terms of volume. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 397–401, 2001 相似文献
7.
Bio‐Inspired Transition Metal–Organic Hydride Conjugates for Catalysis of Transfer Hydrogenation: Experiment and Theory
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Alex McSkimming Dr. Bun Chan Dr. Mohan M. Bhadbhade Dr. Graham E. Ball Prof. Stephen B. Colbran 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):2821-2834
Taking inspiration from yeast alcohol dehydrogenase (yADH), a benzimidazolium (BI+) organic hydride‐acceptor domain has been coupled with a 1,10‐phenanthroline (phen) metal‐binding domain to afford a novel multifunctional ligand ( L BI+) with hydride‐carrier capacity ( L BI++H?? L BIH). Complexes of the type [Cp*M( L BI)Cl][PF6]2 (M=Rh, Ir) have been made and fully characterised by cyclic voltammetry, UV/Vis spectroelectrochemistry, and, for the IrIII congener, X‐ray crystallography. [Cp*Rh( L BI)Cl][PF6]2 catalyses the transfer hydrogenation of imines by formate ion in very goods yield under conditions where the corresponding [Cp*Ir( L BI)Cl][PF6] and [Cp*M(phen)Cl][PF6] (M=Rh, Ir) complexes are almost inert as catalysts. Possible alternatives for the catalysis pathway are canvassed, and the free energies of intermediates and transition states determined by DFT calculations. The DFT study supports a mechanism involving formate‐driven Rh?H formation (90 kJ mol?1 free‐energy barrier), transfer of hydride between the Rh and BI+ centres to generate a tethered benzimidazoline (BIH) hydride donor, binding of imine substrate at Rh, back‐transfer of hydride from the BIH organic hydride donor to the Rh‐activated imine substrate (89 kJ mol?1 barrier), and exergonic protonation of the metal‐bound amide by formic acid with release of amine product to close the catalytic cycle. Parallels with the mechanism of biological hydride transfer in yADH are discussed. 相似文献
8.
Seung Kyu Min Dr. Mina Park Prof. N. Jiten Singh Prof. Han Myoung Lee Dr. Eun Cheol Lee Prof. Dr. Kwang S. Kim Dr. Anita Lagutschenkov Prof. Dr. Gereon Niedner‐Schatteburg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(34):10373-10379
Protonated and deprotonated adipic acids (PAA: HOOC? (CH2)4? COOH2+ and DAA: HOOC? (CH2)4? COO?) have a charged hydrogen bond under the influence of steric constraint due to the molecular skeleton of a circular ring. Despite the similarity between PAA and DAA, it is surprising that the lowest energy structure of PAA is predicted to have (H2O???H???OH2)+ Zundel‐like symmetric hydrogen bonding, whereas that of DAA has H3O+ Eigen‐like asymmetric hydrogen bonding. The energy profiles show that direct proton transfer between mirror image structures is unfavorable. Instead, the chiral transformation is possible by subsequent backbone twistings through stepwise proton transfer along multistep intermediate structures, which are Zundel‐like ions for PAA and Eigen‐like ions for DAA. This type of chiral transformation by multistep intramolecular proton transfers is unprecedented. Several prominent OH???O short hydrogen‐bond stretching peaks are predicted in the range of 1000–1700 cm?1 in the Car–Parrinello molecular dynamics (CPMD) simulations, which show distinctive signatures different from ordinary hydrogen‐bond peaks. The O? H? O stretching peaks in the range of 1800–2700 cm?1 become insignificant above around 150 K and are almost washed out at about 300 K. 相似文献
9.
Proton Order–Disorder Phenomena in a Hydrogen‐Bonded Rhodium–η5‐Semiquinone Complex: A Possible Dielectric Response Mechanism
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Dr. Minoru Mitsumi Kazunari Ezaki Yuuki Komatsu Prof. Dr. Koshiro Toriumi Dr. Tatsuya Miyatou Prof. Dr. Motohiro Mizuno Nobuaki Azuma Prof. Dr. Yuji Miyazaki Prof. Dr. Motohiro Nakano Prof. Dr. Yasutaka Kitagawa Dr. Takayasu Hanashima Dr. Ryoji Kiyanagi Dr. Takashi Ohhara Prof. Dr. Kazuhiro Nakasuji 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(27):9682-9696
A newly synthesized one‐dimensional (1D) hydrogen‐bonded (H‐bonded) rhodium(II)–η5‐semiquinone complex, [Cp*Rh(η5‐p‐HSQ‐Me4)]PF6 ([ 1 ]PF6; Cp*=1,2,3,4,5‐pentamethylcyclopentadienyl; HSQ=semiquinone) exhibits a paraelectric–antiferroelectric second‐order phase transition at 237.1 K. Neutron and X‐ray crystal structure analyses reveal that the H‐bonded proton is disordered over two sites in the room‐temperature (RT) phase. The phase transition would arise from this proton disorder together with rotation or libration of the Cp* ring and PF6? ion. The relative permittivity εb′ along the H‐bonded chains reaches relatively high values (ca., 130) in the RT phase. The temperature dependence of 13C CP/MAS NMR spectra demonstrates that the proton is dynamically disordered in the RT phase and that the proton exchange has already occurred in the low‐temperature (LT) phase. Rate constants for the proton exchange are estimated to be 10?4–10?6 s in the temperature range of 240–270 K. DFT calculations predict that the protonation/deprotonation of [ 1 ]+ leads to interesting hapticity changes of the semiquinone ligand accompanied by reduction/oxidation by the π‐bonded rhodium fragment, producing the stable η6‐hydroquinone complex, [Cp*Rh3+(η6‐p‐H2Q‐Me4)]2+ ([ 2 ]2+), and η4‐benzoquinone complex, [Cp*Rh+(η4‐p‐BQ‐Me4)] ([ 3 ]), respectively. Possible mechanisms leading to the dielectric response are discussed on the basis of the migration of the protonic solitons comprising of [ 2 ]2+ and [ 3 ], which would be generated in the H‐bonded chain. 相似文献
10.
Three lanthanide‐based two‐dimensional (2D) coordination polymers (CPs), [Ln(L)(H2O)2]n, {H3L=(HO)2P(O)CH2CO2H; Ln=Dy3+ (CP 1 ), Er3+ (CP 2 )} and [{Gd2(L)2(H2O)3}.H2O]n, (CP 3 ) were hydrothermally synthesized using phosphonoacetic acid as a linker. Structural features revealed that the dinuclear Ln3+ nodes were present in the 2D sheet of CP 1 and CP 2 while in the case of CP 3 , nodes were further connected to each other forming a chain‐type arrangement throughout the network. The magnetic studies show field‐induced slow magnetic relaxation property in CP 1 and CP 2 with Ueff values of 72 K (relaxation time, τ0=3.05×10?7 s) and 38.42 K (relaxation time, τ0=4.60×10?8 s) respectively. Ab‐initio calculations suggest that the g tensor of Kramers doublet of the lanthanide ion (Dy3+ and Er3+) is strongly axial in nature which reflects in the slow magnetic relaxation behavior of both CPs. CP 3 exhibits a significant magnetocaloric effect with ?ΔSm=49.29 J kg?1 K?1, one of the highest value among the reported 2D CPs. Moreover, impedance analysis of all the CPs show high proton conductivity with values of 1.13×10?6 S cm?1, 2.73×10?3 S cm?1 and 2, 6.27×10?6 S cm?1 for CPs 1 – 3 , respectively, at high temperature (>75 °C) and maximum 95 % relative humidity (RH). 相似文献
11.
Supramolecular Formation of Li+@PCBM Fullerene with Sulfonated Porphyrins and Long‐Lived Charge Separation
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Yuki Kawashima Dr. Kei Ohkubo Dr. Hiroshi Okada Prof. Dr. Yutaka Matsuo Prof. Dr. Shunichi Fukuzumi 《Chemphyschem》2014,15(17):3782-3790
Lithium‐ion‐encapsulated [6,6]‐phenyl‐C61‐butyric acid methyl ester fullerene (Li+@PCBM) was utilized to construct supramolecules with sulfonated meso‐tetraphenylporphyrins (MTPPS4?; M=Zn, H2) in polar benzonitrile. The association constants were determined to be 1.8×105 M ?1 for ZnTPPS4?/Li+@PCBM and 6.2×104 M ?1 for H2TPPS4?/Li+@PCBM. From the electrochemical analyses, the energies of the charge‐separated (CS) states were estimated to be 0.69 eV for ZnTPPS4?/Li+@PCBM and 1.00 eV for H2TPPS4?/Li+@PCBM. Upon photoexcitation of the porphyrin moieties of MTPPS4?/Li+@PCBM, photoinduced electron transfer occurred to produce the CS states. The lifetimes of the CS states were 560 μs for ZnTPPS4?/Li+@PCBM and 450 μs for H2TPPS4?/Li+@PCBM. The spin states of the CS states were determined to be triplet by electron paramagnetic resonance spectroscopy measurements at 4 K. The reorganization energies (λ) and electronic coupling term (V) for back electron transfer (BET) were determined from the temperature dependence of kBET to be λ=0.36 eV and V=8.5×10?3 cm?1 for ZnTPPS4?/Li+@PCBM and λ=0.62 eV and V=7.9×10?3 cm?1 for H2TPPS4?/Li+@PCBM based on the Marcus theory of nonadiabatic electron transfer. Such small V values are the result of a small orbital interaction between the MTPPS4? and Li+@PCBM moieties. These small V values and spin‐forbidden charge recombination afford a long‐lived CS state. 相似文献
12.
The acidity constants of twofold protonated guanosine 5′‐diphosphate, H2(GDP)?, and the stability constants of the [Cu(H;GDP)] and [Cu(GDP)]? complexes were determined in H2O as well as in 30 or 50% (v/v) 1,4‐dioxane/H2O by potentiometric pH titrations (25°; I=0.1M , NaNO3). The results showed that in H2O one of the two protons of H2(GDP)? is located mainly at the N(7) site and the other one at the terminal β‐phosphate group. In contrast, for 50% 1,4‐dioxane/H2O solutions, a micro acidity‐constant evaluation evidenced that ca. 75% of the H2(GDP)? species have both protons phosphate‐bound, because the basicity of pyridine‐type N sites decreases with decreasing solvent polarity whereas the one of phosphate groups increases. In the [Cu(H;GDP)] complex, the proton and the metal ion are in all three solvents overwhelmingly phosphate‐bound, and the release of this proton is inhibited by decreasing polarity of the solvent. Based on previously determined straight‐line plots of log K vs. pK (where R represents a non‐interacting residue in simple diphosphate monoesters ROP(O?)(?O)? O? P(?O)(O?)2, R? DP3?), which were now extended to mixed solvents (based on analogies), it is concluded that, in all three solvents, the [Cu(GDP)]? complex is more stable than expected based on the basicity of the diphosphate residue. This increased stability is attributed to macrochelate formation of the phosphate‐coordinated Cu2+ with N(7) of the guanine residue. The formation degree of this macrochelate amounts in aqueous solution to ca. 75% (being thus higher than that of the Cu2+ complex of adenosine 5′‐diphosphate) and in 50% (v/v) 1,4‐dioxane/H2O to ca. 60%, i.e., the formation degree of the macrochelate is only relatively little affected by the change in solvent, though it needs to be emphasized that the overall stability of the [Cu(GDP)]? complex increases with decreasing solvent polarity. By including previously studied systems in the considerations, the biological implications are shortly discussed, and it is concluded that Nature has here a tool to alter the structure of complexes by shifting them on a protein surface from a polar to an apolar region and vice versa. 相似文献
13.
Won Ju Phang Woo Ram Lee Kicheon Yoo Dae Won Ryu Dr. BongSoo Kim Prof. Chang Seop Hong 《Angewandte Chemie (International ed. in English)》2014,53(32):8383-8387
A porous metal–organic framework (MOF), [Ni2(dobdc)(H2O)2]?6 H2O (Ni2(dobdc) or Ni‐MOF‐74; dobdc4?=2,5‐dioxido‐1,4‐benzenedicarboxylate) with hexagonal channels was synthesized using a microwave‐assisted solvothermal reaction. Soaking Ni2(dobdc) in sulfuric acid solutions at different pH values afforded new proton‐conducting frameworks, H+@Ni2(dobdc). At pH 1.8, the acidified MOF shows proton conductivity of 2.2×10?2 S cm?1 at 80 °C and 95 % relative humidity (RH), approaching the highest values reported for MOFs. Proton conduction occurs via the Grotthuss mechanism with a significantly low activation energy as compared to other proton‐conducting MOFs. Protonated water clusters within the pores of H+@Ni2(dobdc) play an important role in the conduction process. 相似文献
14.
Ruding Zhang Jiajia Huang Wenzhuo Deng Jingze Bao Yilong Pan Shuping Huang Chuan‐Fu Sun 《Angewandte Chemie (International ed. in English)》2019,58(46):16474-16479
A key challenge for potassium‐ion batteries is to explore low‐cost electrode materials that allow fast and reversible insertion of large‐ionic‐size K+. Here, we report an inorganic‐open‐framework anode (KTiOPO4), which achieves a reversible capacity of up to 102 mAh g?1 (307 mAh cm?3), flat voltage plateaus at a safe average potential of 0.82 V (vs. K/K+), a long lifespan of over 200 cycles, and K+‐transport kinetics ≈10 times faster than those of Na‐superionic conductors. Combined experimental analysis and first‐principles calculations reveal a charge storage mechanism involving biphasic and solid solution reactions and a cell volume change (9.5 %) even smaller than that for Li+‐insertion into graphite (≈10 %). KTiOPO4 exhibits quasi‐3D lattice expansion on K+ intercalation, enabling the disintegration of small lattice strain and thus high structural stability. The inorganic open‐frameworks may open a new avenue for exploring low‐cost, stable and fast‐kinetic battery chemistry. 相似文献
15.
Ruding Zhang Jiajia Huang Wenzhuo Deng Jingze Bao Yilong Pan Shuping Huang Chuan‐Fu Sun 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(46):16626-16631
A key challenge for potassium‐ion batteries is to explore low‐cost electrode materials that allow fast and reversible insertion of large‐ionic‐size K+. Here, we report an inorganic‐open‐framework anode (KTiOPO4), which achieves a reversible capacity of up to 102 mAh g?1 (307 mAh cm?3), flat voltage plateaus at a safe average potential of 0.82 V (vs. K/K+), a long lifespan of over 200 cycles, and K+‐transport kinetics ≈10 times faster than those of Na‐superionic conductors. Combined experimental analysis and first‐principles calculations reveal a charge storage mechanism involving biphasic and solid solution reactions and a cell volume change (9.5 %) even smaller than that for Li+‐insertion into graphite (≈10 %). KTiOPO4 exhibits quasi‐3D lattice expansion on K+ intercalation, enabling the disintegration of small lattice strain and thus high structural stability. The inorganic open‐frameworks may open a new avenue for exploring low‐cost, stable and fast‐kinetic battery chemistry. 相似文献
16.
Dual Role of the 1,2,3‐Triazolium Ring as a Hydrogen‐Bond Donor and Anion–π Receptor in Anion‐Recognition Processes
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Dr. Fabiola Zapata Lidia Gonzalez Dr. Antonio Caballero Prof. Ibón Alkorta Prof. Jose Elguero Prof. Pedro Molina 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(27):9797-9808
Several bis(triazolium)‐based receptors have been synthesized as chemosensors for anion recognition. The central naphthalene core features two aryltriazolium side‐arms. NMR experiments revealed differences between the binding modes of the two triazolium rings: one triazolium ring acts as a hydrogen‐bond donor, the other as an anion–π receptor. Receptors 92+?2BF4 ? (C6H5), 112+?2BF4 ? (4‐NO2?C6H4), and 132+?2BF4? (ferrocenyl) bind HP2O73? anions in a mixed‐binding mode that features a combination of hydrogen‐bonding and anion–π interactions and results in strong binding. On the other hand, receptor 102+?2 BF4 ? (4‐CH3O?C6H4) only displays combined Csp2?H/anion–π interactions between the two arms of the receptors and the bound anion rather than triazolium (CH)+???anion hydrogen bonding. All receptors undergo a downfield shift of the triazolium protons, as well as the inner naphthalene protons, in the presence of H2PO4? anions. That suggests that only hydrogen‐bonding interactions exist between the binding site and the bound anion, and involve a combination of cationic (triazolium) and neutral (naphthalene) C?H donor interactions. Theoretical calculations relate the electronic structure of the substituent on the aromatic group with the interaction energies and provide a minimum‐energy conformation for all the complexes that explains their measured properties. 相似文献
17.
Ion‐Pairing Assemblies Based on Pentacyano‐Substituted Cyclopentadienide as a π‐Electronic Anion
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Dr. Yuya Bando Dr. Yohei Haketa Dr. Tsuneaki Sakurai Dr. Wakana Matsuda Prof. Shu Seki Prof. Hikaru Takaya Prof. Hiromitsu Maeda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(23):7843-7850
Pentacyanocyclopentadienide (PCCp?), a stable π‐electronic anion, provided various ion‐pairing assemblies in combination with various cations. PCCp?‐based assemblies exist as single crystals and mesophases owing to interionic interactions with π‐electronic and aliphatic cations with a variety of geometries, substituents, and electronic structures. Single‐crystal X‐ray analysis revealed that PCCp? formed cation‐dependent arrangements with contributions from charge‐by‐charge and charge‐segregated assembly modes for ion pairs with π‐electronic and aliphatic cations, respectively. Furthermore, some aliphatic cations gave dimension‐controlled organized structures with PCCp?, as observed in the mesophases, for which synchrotron XRD analysis suggested the formation of charge‐segregated modes. Noncontact evaluation of conductivity for (C12H25)3MeN+ ? PCCp? films revealed potential hole‐transporting properties, yielding a local‐scale hole mobility of 0.4 cm2 V?1 s?1 at semiconductor–insulator interfaces. 相似文献
18.
Jie Han Dr. Shuang‐Quan Zang Dr. Thomas C. W. Mak Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(17):5078-5088
A series of five complexes that incorporate the guanidinium ion and various deprotonated forms of Kemp’s triacid (H3KTA) have been synthesized and characterized by single‐crystal X‐ray analysis. The complex [C(NH2)3+] ? [H2KTA?] ( 1 ) exhibits a sinusoidal layer structure with a centrosymmetric pseudo‐rosette motif composed of two ion pairs. The fully deprotonated Kemp’s triacid moiety in 3 [C(NH2)3+] ? [KTA3?] ( 2 ) forms a record number of eighteen acceptor hydrogen bonds, thus leading to a closely knit three‐dimensional network. The KTA3? anion adopts an uncommon twist conformation in [(CH3)4N+] ? 2 [C(NH2)3+] ? [KTA3?] ? 2 H2O ( 3 ). The crystal structure of [(nC3H7)4N+] ? 2 [C(NH2)3+] ? [KTA3?] ( 4 ) features a tetrahedral aggregate of four guanidinium ions stabilized by an outer shell that comprises six equatorial carboxylate groups that belong to separate [KTA3?] anions. In 3 [(C2H5)4N+] ? 20 [C(NH2)3+] ? 11 [HKTA2?] ? [H2KTA?] ? 17 H2O ( 5 ), an even larger centrosymmetric inner core composed of eight guanidinium ions and six bridging water molecules is enclosed by a crust composed of eighteen axial carboxyl/carboxylate groups from six HKTA2? anions. 相似文献
19.
SergeyA. Katsyuba PaulJ. Dyson ElenaE. Vandyukova AllaV. Chernova Ana Vidi 《Helvetica chimica acta》2004,87(10):2556-2565
The IR and Raman spectra and conformations of the ionic liquid 1‐ethyl‐3‐methyl‐1H‐imidazolium tetrafluoroborate, [EMIM] [BF4] ( 6 ), were analyzed within the framework of scaled quantum mechanics (SQM). It was shown that SQM successfully reproduced the spectra of the ionic liquid. The computations revealed that normal modes of the EMIM+?BF ion pair closely resemble those of the isolated ions EMIM+ and BF , except for the antisymmetric BF stretching vibrations of the anion, and the out‐of‐plane and stretching vibrations of the H? C(2) moiety of the cation. The most plausible explanation for the pronounced changes of the latter vibrations upon ion‐pair formation is the H‐bonding between H? C(2) and BF . However, these weak H‐bonds are of minor importance compared with the Coulomb interactions between the ions that keep them closely associated even in dilute CD2Cl2 solutions. According to the ‘gas‐phase’ computations, in these associates, the BF anion is positioned over the imidazolium ring of the EMIM+ cation and has short contacts not only with the H? C(2) of the latter, but also with a proton of the Me? N(3) group. 相似文献
20.
Anomalous Enhancement of Proton Conductivity for Water Molecular Clusters Stabilized in Interstitial Spaces of Porous Molecular Crystals
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Prof. Makoto Tadokoro Yuki Ohhata Yuriko Shimazaki Prof. Shin'ichi Ishimaru Prof. Teppei Yamada Prof. Yuki Nagao Dr. Tomoaki Sugaya Dr. Kyosuke Isoda Yuta Suzuki Prof. Hiroshi Kitagawa Prof. Hiroshi Matsui 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(42):13698-13709
In an investigation into the proton conductivity of crystallized water clusters confined within low‐dimensional nanoporous materials, we have found that water‐stable nanoporous crystals are formed by complementary hydrogen bonding between [CoIII(H2bim)3]3+ (H2bim: 2,2′‐biimidazole) and TATC3? (1,3,5‐ tricarboxyl‐2,4,6‐triazinate); the O atoms in the ?COO? groups of TATC3? in the porous outer wall are strongly hydrogen bonded with H2O, forming two types of WMCs (water molecular clusters): a spirocyclic tetramer chain (SCTC) that forms infinite open 1D channels, and an isolated cyclic tetramer (ICT) present in the void space. The ICT is constructed from four H2O molecules as a novel C2‐type WMC, which are hydrogen bonded with four‐, three‐, and two‐coordination spheres, respectively. The largest structural fluctuation is observed at elevated temperatures from the two‐coordinated H2O molecules, which begin to rapidly and isotropically fluctuate on heating. This behavior can be rationalized by a simple model for the elucidation of pre‐melting phenomena, similar to those in ice surfaces as the temperature increases. Moreover, high proton conductivity of SCTCs (ca. 10?5 S cm?1 at 300 K with an activation energy of 0.30 eV) through a proton‐hole mechanism was observed for pellet samples using the alternating impedance method. The proton conductivity exhibits a slight enhancement of about 0.1×10?5 S cm?1 at 274 K due to a structural transition upon approaching this temperature that elongates the unit cell along the b‐axis. The proton‐transfer route can be predicted in WMCs, as O(4) of an H2O molecule at the center of an SCTC shows a motion that rotates the dipole in the b‐axis direction, but not the c‐axis; the thermal ellipsoids of O(4) based on anisotropic temperature factors obtained by X‐ray crystallography reflect a structural fluctuation along the b‐axis direction induced by [CoIII(H2bim)3]3+. 相似文献