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1.
Attachment of bulky substituents at both thiophene donor (D) and thiazole acceptor (A) heterocycles of a dipolar (μg=10.4 D) D‐π‐A merocyanine dye affords a more than 1 Å expansion of the common antiparallel supramolecular dimer motif in the solid state, enabling very close π‐contacts (3.36 Å) to two other neighbor molecules on each of the two remaining π‐faces. This unusual packing motif leads to three‐dimensional percolation pathways for hole transport and affords thin‐film transistors with mobility up to 0.64 cm2 V?1 s?1.  相似文献   

2.
Design and synthesis of metal–organic polyhedra (MOPs) with targeted geometries from predetermined secondary building units (SBUs) is a long‐standing challenge in chemistry and material science. Theoretical prediction shows that there are 6 possible polyhedra from the 3‐coordinated, 4‐coordinated octahedron ((3,4)‐c octahedron) to (3,5)‐c icosahedron with minimal transitivity (simplest possible). Except for one missing polyhedron ( mtr ) due to the unfavorable angles, we report five MOPs based on these structures, including an octahedral (3,4)‐c VMOP‐ 21 ( rdo ), an icosahedral (3,5)‐c VMOP‐ 25 ( trc ), and three intermediate derived trinodal (3,4,5)‐c VMOP‐ 22 – 24 ( ghm , hmg , xum ). Remarkably, all these MOPs obey the minimal transitivity principle and are consistent with geometrical predictions.  相似文献   

3.
Metal–organic polyhedra (MOPs) or frameworks (MOFs) based on Cr3+ are notoriously difficult to synthesize, especially as crystals large enough to be suitable for characterization of the structure or properties. It is now shown that the co‐existence of In3+ and Cr3+ induces a rapid crystal growth of large single crystals of heterometallic In‐Cr‐MOPs with the [M8L12] (M=In/Cr, L=dinegative 4,5‐imidazole‐dicarboxylate) cubane‐like structure. With a high concentration of protons from 12 carboxyl groups decorating every edge of the cube and an extensive H‐bonded network between cubes and surrounding H2O molecules, the newly synthesized In‐Cr‐MOPs exhibit an exceptionally high proton conductivity (up to 5.8×10?2 S cm?1 at 22.5 °C and 98 % relative humidity, single crystal).  相似文献   

4.
A strategy called ultramicroporous building unit (UBU) is introduced. It allows the creation of hierarchical bi‐porous features that work in tandem to enhance gas uptake capacity and separation. Smaller pores from UBUs promote selectivity, while larger inter‐UBU packing pores increase uptake capacity. The effectiveness of this UBU strategy is shown with a cobalt MOF (denoted SNNU‐45) in which octahedral cages with 4.5 Å pore size serve as UBUs. The C2H2 uptake capacity at 1 atm reaches 193.0 cm3 g?1 (8.6 mmol g?1) at 273 K and 134.0 cm3 g?1 (6.0 mmol g?1) at 298 K. Such high uptake capacity is accompanied by a high C2H2/CO2 selectivity of up to 8.5 at 298 K. Dynamic breakthrough studies at room temperature and 1 atm show a C2H2/CO2 breakthrough time up to 79 min g?1, among top‐performing MOFs. Grand canonical Monte Carlo simulations agree that ultrahigh C2H2/CO2 selectivity is mainly from UBU ultramicropores, while packing pores promote C2H2 uptake capacity.  相似文献   

5.
Motifs of Closest Packings: The Compounds Zn3(PS4)2 and LiZnPS4 The crystal structure of Zn3(PS4)2 was determined by single crystal X‐ray methods. The compound crystallizes tetragonally (Pn2; a = 7.823(1), c = 9.053(1)Å; Z = 2) with a new structure type built up by corner‐sharing ZnS4 tetrahedra, which form two‐dimensional layers. Between them the P atoms are coordinated likewise tetrahedrally by sulfur. The PS4 tetrahedra are arranged according to the motif of the cubic closest packing with zinc in three quarters of the tetrahedral voids. LiZnPS4 (I4¯; a = 5.738(1), c = 8.914(1)Å; Z = 2) was synthesized by heating the elements at 400 °C. In comparison with Zn3(PS4)2 one Zn atom is replaced by two Li atoms. The metal atoms are located in the centres of the sulfur tetrahedra in such a way that the unit cell volume is only about half that of the zinc compound. In this packing of the PS4 units all the tetrahedral voids are occupied by lithium and zinc atoms. Chemical bonding in LiZnPS4 is discussed by means of the electron localization function ELF.  相似文献   

6.
A low‐temperature polymorph of 1,1′:3′,1′′:3′′,1′′′:3′′′,1′′′′‐quinquephenyl (m‐quinquephenyl), C30H22, crystallizes in the space group P21/c with two molecules in the asymmetric unit. The crystal is a three‐component nonmerohedral twin. A previously reported room‐temperature polymorph [Rabideau, Sygula, Dhar & Fronczek (1993). Chem. Commun. pp. 1795–1797] also crystallizes with two molecules in the asymmetric unit in the space group P. The unit‐cell volume for the low‐temperature polymorph is 4120.5 (4) Å3, almost twice that of the room‐temperature polymorph which is 2102.3 (6) Å3. The molecules in both structures adopt a U‐shaped conformation with similar geometric parameters. The structural packing is similar in both compounds, with the molecules lying in layers which stack perpendicular to the longest unit‐cell axis. The molecules pack alternately in the layers and in the stacked columns. In both polymorphs, the only interactions between the molecules which can stabilize the packing are very weak C—H...π interactions.  相似文献   

7.
Dexketoprofen [(2S)‐2‐(3‐benzoylphenyl)propanoic acid], C16H14O3, is the S‐enantiomer of ketoprofen, a nonsteroidal anti‐inflammatory drug (NSAID) that has analgesic, antipyretic and anti‐inflammatory properties, and finds applications for the short‐term treatment of mild to moderate pain. A new crystalline phase of dexketoprofen is reported. Its solid‐state structure was determined by single‐crystal X‐ray diffraction (SCXRD). The molecular structure of the two independent molecules found in the asymmetric unit of this new phase ( DXKP‐β ) were compared to those of the already known crystal form of dexketoprofen ( DXKP‐α ) and with the S‐enantiomer of the racemic compound. The three different conformers of dexketoprofen found in DXKP‐α and DXKP‐β were then investigated by computational methods. The optimized structures are very close to the corresponding starting geometries and do not differ significantly in energy. The crystal packing of DXKP‐β was studied by means of Hirshfeld surface (HS) analysis; interaction energies were also calculated. A comparison with DXKP‐α shows close similarities between the two crystal forms, i.e. in both cases, molecules assemble through the catemer O—H…O synthon of the carboxylic acid stabilized by additional C—H…O contacts and, accordingly, the interaction energies, as well as the contributions to the HS area, are very similar. Finally, the thermal behaviour of the two polymorphs of dexketoprofen was assessed by means of XRD (both from single crystal and microcrystalline powder) and differential scanning calorimetry (DSC); both crystal forms are stable under the experimental conditions adopted (air, 300–350 K for DXKP‐α and 300–340 K DXKP‐β ) and no solid–solid phase transition occurs between the two crystal forms in the investigated temperature range (from 100 K up to ca 350 K).  相似文献   

8.
Dynamic supramolecular systems involving a tetratopic palladium(II) acceptor and three different pyridine‐ and imidazole‐based donors have been used for self‐selection by a synergistic effect of morphological information and coordination ability of ligands through specific coordination interactions. Three different cages were first synthesized by two‐component self‐assembly of individual donor and acceptor. When all four components were allowed to interact in a reaction mixture, only one out of three cages was isolated. The preferential binding affinity towards a particular partner was also established by transforming a non‐preferred cage into a preferred cage by interaction with the appropriate ligand. Computational studies further supported the fact that coordination interaction of imidazole moiety to PdII is enthalpically more preferred compared to pyridine, which drives the selection process. Analysis of crystal packing of both complexes indicated the presence of strong hydrogen bonds between nitrate and water molecules and also H‐bonded 3D networks of water. Both complexes exhibit promising proton conductivity (10?5 to ca. 10?3 S cm?1) at ambient temperature under a relative humidity of circa 98 % with low activation energy.  相似文献   

9.
Synthesis and Crystal Structure of LiHSO4 Single crystals of the new compound LiHSO4 are synthezised from the system Lithiumsulfate/Sulfuric acid. The up to day not determined structure of the title compound is monoclinic, space group P21/c with the lattice constants a = 5.234(2), b = 7.322(1) and c = 8.363(1) Å, b? = 90.02(2)°. The volume of the unit cell has been determined to V = 320.5 Å3, the number of formula units to Z = 4 and the density to Dx = 2.156 g cm?3. There are crystallographically identical SO3(OH)- and LiO4-tetrahedra in the structure. Every tetraheda is linked to four different tetrahedra of the other sort. Two neighboured LiO4 terahedra form a common edge. In that way layers are formed running parallel the yz-plane. These layers are connected over hydrogen bonds.  相似文献   

10.
A discotic liquid‐crystalline (LC) material, consisting of a planarized triphenylborane mesogen, was synthesized. X‐ray diffraction analysis confirmed that this compound forms a hexagonal columnar LC phase with an interfacial distance of 3.57 Å between the discs. At ambient temperature, this boron‐centered discotic liquid crystal exhibited ambipolar carrier transport properties with electron and hole mobility values of approximately 10?3 and 3×10?5 cm2 V?1 s?1, respectively.  相似文献   

11.
Random donor‐acceptor (D‐A) supramolecular comb polymers were formed when hydroxyl functionalized donor and acceptor small molecules based on Oligo(phenylenevinylene) (named OPVCN‐OH ) and Perylenebisimide (named UPBI‐PDP ), respectively, were complexed with Poly(4‐vinyl pyridine) (P4VP). A series of random D‐A supramolecular comb polymers were formed by varying the ratios of UPBI‐PDP and OPVCN‐OH with P4VP. A 100% P4VP‐donor polymer complex [ P4VP(OPV1.00 )] and a 100% P4VP‐acceptor polymer complex [ P4VP(UPBI1.00 )] were also synthesized and characterized. Complex formation was confirmed by FT‐IR and 1H NMR spectroscopy. Solid state structural studies carried out using small angle X‐ray scattering and wide angle X‐ray diffraction experiments revealed altered packing of the D and A molecules in the complexes. Transmission electron microscopy images showed lamellar structures in the < 10 nm scale for the P4VP(OPV1.00 ), P4VP(UPBI1.00 ), and mixed P4VP (D‐A) complexes. The effect of the nanoscopic D‐A self‐assembly on the bulk mobility of the materials was probed using SCLC measurements. The mixed D‐A random complexes exhibited ambipolar charge transport characteristics with higher values for the average bulk hole mobility estimate. P4VP(OPV0.25 + UPBI0.75) exhibited an average hole mobility in the order of 10?2cm2 V?1 s?1 and electron mobility 10?5cmV?1 s?1. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2403–2412  相似文献   

12.
The molecular structure of poly (p-hydroxybenzoic acid) (C6H4COO)x at ambient temperature was determined by x-ray powder diffraction analysis. The diffraction pattern is explained as a mixture of two orthorhombic phases having the same space group Pbc21 with four C6H4COO chemical repeats in the unit cell and the following cell parameters: a = 7.42 Å, b = 5.70 Å, and c = 12.45 Å for phase I (ρcalc = 1.51 g cm?3); and a = 3.83 Å, b = 11.16 Å, and c = 12.56 Å for phase II (ρcalc = 1.48 g cm?3). The chain conformation is the same in both phases, involving two benzoyl rings staggered by ca. 120° along the chain. Disorder has been considered in the packing of phase I by giving equal occupancy to the two molecules oriented up or down along the c chain axis. ©1995 John Wiley & Sons, Inc.  相似文献   

13.
An ionic thermo‐responsive copolymer with multiple lower critical solution temperatures (multi‐LCSTs) has been developed, and the multi‐LCSTs were easily changeable according to the various counter anion types. The multi‐LCST values were achieved by introducing an ionic segment with an imidazolium moiety within the p‐NIPAAm polymer chain to produce poly(NIPAAm‐co‐BVIm) copolymers, [p‐NIBIm]+[Br]?, and changing the counter anion type to produce [p‐NIBIm]+[X]? (X = Cl, AcO, HCO3, BF4, CF3SO3, PF6, SbF6). The as‐prepared temperature‐responsive copolymers were physicochemically characterized via proton nuclear magnetic resonance spectroscopy (1H‐NMR), Fourier‐transform infrared, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. Their various LCST values, micelle sizes, and surface charges were determined using an Ultraviolet‐visible spectrophotometer and a Zeta (ξ) sizer, which were fitted with temperature and stirring control. The copolymers showed a broad LCST spectrum between 39°C and 52°C. The Zeta (ξ) potential values at a pH = 7 decreased from about +9.7 for [p‐NIBIm]+[X]? (X = Cl ≈ Br) to about +2.0 mV for [p‐NIBIm]+[X]? (X = PF6 ≈ SbF6). The micelle size (or volume) of the copolymers with different anionic species gradually increased from 181.2 nm (or 2.49 × 10?17 cm?3) for [p‐NIBIm]+[Br]? to 229.2 nm (or 5.04 × 10?17 cm?3) for [p‐NIBIm]+[CF3SO3]?, showing a clear effect of the anion on the micelle size (or volume) at a constant temperature, such as body temperature. The fact that the most important physicochemical properties for the thermo‐responsive copolymers, such as the LCST value, micelle size (or volume), and surface charge, could be easily controlled only through the anion exchange suggests these are highly applicable as ionic thermo‐responsive copolymers in a drug (or gene, protein) delivery system. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

14.
Potassium Hydrogensulfate Dihydrogensulfate, K(HSO4)(H2SO4) – Synthesis and Crystal Structure Single crystals with the composition KH3(SO4)2 have been synthesized from the system Potassium sulfate/sulfuric acid. The hitherto crystallographically not investigated compound crystallizes in the monoclinic space group P21/c (14) with the unit cell parameters a = 7.654(3), b = 11.473(5) and c = 8.643(3) Å, β = 112.43(3)°, V = 701.6 Å3, Z = 4 and Dx = 2.22 g · cm?3. The structure contains two types of tetrahedra, SO3(OH) and SO2(OH)2. These tetrahedra form tetramers via hydrogen bonds consisting of both, two SO3(OH) and two SO2(OH)2 tetrahedra. The tetramers are linked to each other via hydrogen bonds. Potassium is coordinated by 9 oxygen atoms which belong to both kinds of tetrahedra. These potassium oxygen polyhedra are connected by common faces forming chains running parallel z.  相似文献   

15.
The limited long‐term hydrolytic stability of rapidly emerging 3D‐extended framework materials (MOFs, COFs, MOPs, etc.) is still one of major barriers for their practical applications as new solid‐state electrolytes in fuel cells. To obtain hydrolytically stable materials, two H2PO4?‐exchanged 3D inorganic cationic extended frameworks (CEFs) were successfully prepared by a facile anion‐exchange method. Both anion‐exchanged CEFs (YbO(OH)P and NDTBP) show significantly enhanced proton conductivity when compared with the original materials (YbO(OH)Cl and NDTB) with an increase of up to four orders‐of‐magnitude, reaching 2.36×10?3 and 1.96×10?2 S cm?1 at 98 % RH and 85 °C for YbO(OH)P and NDTBP, respectively. These values are comparable to the most efficient proton‐conducting MOFs. In addition, these two anion‐exchanged materials are stable in boiling water, which originates from the strong electrostatic interaction between the H2PO4? anion and the cationic host framework, showing a clear advance over all the acid‐impregnated materials (H2SO4@MIL‐101, H3PO4@MIL‐101, and H3PO4@Tp‐Azo) as practical solid‐state fuel‐cell electrolytes. This work offers a new general and efficient approach to functionalize 3D‐extended frameworks through an anion‐exchange process and achieves water‐stability with ultra‐high proton conductivity above 10?2 S cm?1.  相似文献   

16.
A C3‐symmetric π‐conjugated macrocycle combined with an appropriate hydrogen bonding module (phenylene triangle) allowed the construction of crystalline supramolecular frameworks with a cavity volume of up to 58 %. The frameworks were obtained through non‐interpenetrated stacking of a hexagonal sheet possessing three kinds of pores with different sizes and shapes. The activated porous material absorbed CO2 up to 96 cm3 g?1 at 195 K under 1 atm.  相似文献   

17.
We report herein a series of tetrablock‐mimic azobenzene‐containing [60]fullerene dyads that form supramolecular liquid crystals (LCs) from phase‐segregated two‐dimensional (2D) crystals. The unique double‐, triple‐, and quadruple‐layer packing structure of fullerenes in the 2D crystals leads to different smectic supramolecular LC phases, and novel LC phase transitions were observed upon changes in the fullerene packing layer number in the 2D crystals. Interestingly, by combining the LC properties with 2D crystals, these materials show excellent electron mobility in the order of 10−3 cm2 V−1 s−1, despite their relatively low fullerene content. Our results provide a novel method to manipulate 2D crystal layer thickness, with promising applications in optoelectronic devices.  相似文献   

18.
The oxidation of 1,5‐dimethyl‐3‐(2′‐pyridyl)‐6‐thiooxotetrazane (SvdH3py) by benzoquinone leads to a 1:1 adduct of 1,5‐dimethyl‐3‐(2′‐pyridyl)‐6‐thiooxoverdazyl radical (Svdpy) with hydroquinone (hq). The single‐crystal X‐ray diffraction of this adduct at room temperature (RT) shows that the radicals exhibit a slight curvature that leads to the formation of alternating head‐to‐tail (antiparallel) stacked 1D chains. Moreover, temperature‐dependent X‐ray measurements at 100, 200, and 303 K reveal that the lateral slippages between the radicals of the stacks |δ1| and |δ2| vary from 0.64 to 0.78 Å and 0.54 to 0.40 Å between 100 and 303 K. Despite the alternation of the inter‐radical distances and lateral slippages, the magnetic susceptibility data can be fitted with excellent agreement using a regular one‐dimensional antiferromagnetic chain model with J=?5.9 cm?1. Wavefunction‐based calculations indicate an alternation of the magnetic interaction parameters correlated with the structural analysis at RT. Moreover, they demonstrate that the thermal slippage of the radicals induces a switching of the physical behavior, since the exchange interaction changes from antiferromagnetic (?0.9 cm?1) at 100 K to ferromagnetic (1.4 cm?1) at 303 K. The theoretical approach thus reveals a much richer magnetic behavior than the analysis of the magnetic susceptibility data and ultimately questions the relevance of a spin‐coupled picture based on temperature‐independent parameters.  相似文献   

19.
Excited states of fluorene‐ethylenedioxythiophene (FEDOT) and fluorene‐S,S‐dioxide‐thiophene (FTSO2) monomers and dimers were studied by the symmetry‐adapted cluster (SAC)‐configuration interaction (CI) method. The absorption and emission peaks observed in the experimental spectra were theoretically assigned. The first three excited states of the optimized conformers, and the conformers of several torsional angles, were computed by SAC‐CI/D95(d). Accurate absorption spectra were simulated by taking the thermal average for the conformers of torsional angles from 0° to 90°. The conformers of torsional angles 0°, 15°, and 30° mainly contributed to the absorption spectra. The full width at half‐maximum of the FEDOT absorption band is 0.60 eV (4839 cm?1), which agrees very well with the experimental value of 0.61 eV (4900 cm?1). The maximum absorption wavelength is located at 303 nm, which is close to those of the experimental band (327 nm). The calculated absorption spectrum of FTSO2 showed two bands in the range of 225–450 nm. This agrees very well with the available experimental spectrum of a polymer of FTSO2, where two bands are detected. The excited‐state geometries were investigated by CIS/6‐31G(d). These showed a quinoid‐type structure which exhibited a shortening of the inter‐ring distance (0.06 Å for FEDOT and 0.04 Å for FTSO2). The calculated emission energy of FEDOT is 3.43 eV, which agrees very well with the available experimental data (3.46 eV). The fwhmE is about 0.49 eV (3952 cm?1), while the experimental fwhm is 0.43 eV (3500 cm?1). For FTSO2, two bands were also found in the emission spectrum. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010  相似文献   

20.
A novel high energetic material, 1‐amino‐1‐methylamino‐2,2‐dinitroethylene (AMFOX‐7), was synthesized through 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) reacting with methylamine in N‐methyl pyrrolidone (NMP) at 80.0°C, and its structure was determined by single crystal X‐ray diffraction. The crystal is monoclinic, space group P21/m with crystal parameters of a=6.361(3) Å, b=7.462(4) Å, c=6.788(3) Å, β=107.367(9)°, V=307.5(3) Å3, Z=2, µ=0.160 mm?1, F(000)=168, Dc=1.751 g·cm?3, R1=0.0463 and wR2=0.1102. Thermal decomposition of AMFOX‐7 was studied, and the enthalpy, apparent activation energy and pre‐exponential constant of the exothermic decomposition reaction are 303.0 kJ·mol?1, 230.7 kJ·mol?1 and 1021.03 s?1, respectively. The critical temperature of thermal explosion is 245.3°C. AMFOX‐7 has higher thermal stability than FOX‐7.  相似文献   

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