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1.
Jose G. Trujillo‐Ferrara Itzia I. Padilla‐Martínez Herbert Hpfl Francisco J. Martínez‐Martínez Norberto Farfan‐García Efrn V. García‐Bez 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(10):o723-o726
The carboxylic acid group and the double bond are coplanar in (E)‐3‐(benzoxazol‐2‐yl)prop‐2‐enoic acid, C10H7NO3, whereas in isomeric (Z)‐3‐(benzoxazol‐2‐yl)prop‐2‐enoic acid, also C10H7NO3, they are almost orthogonal. In both isomers, a strong O—H⋯N hydrogen bond, with the carboxylic acid group as a donor and the pyridine‐like N atom as an acceptor, and weak C—H⋯O interactions contribute to the observed supramolecular structures, which are completed by π–π stacking interactions between oxazole and benzenoid rings. 相似文献
2.
A Highly Efficient Near‐Infrared‐Emissive Copolymer with a N=N Double‐Bond π‐Conjugated System Based on a Fused Azobenzene–Boron Complex 下载免费PDF全文
Masayuki Gon Kazuo Tanaka Yoshiki Chujo 《Angewandte Chemie (International ed. in English)》2018,57(22):6546-6551
Fused azobenzene–boron complexes (BAzs) show highly efficient near‐infrared (NIR) emission from the nitrogen–nitrogen double bond (N=N) containing π‐conjugated copolymer. Optical measurements showed that BAz worked as a strong electron acceptor because of the intrinsic electron deficiency of the N=N double bond and the boron–nitrogen (B?N) coordination which dramatically lowered the energy of the lowest unoccupied molecular orbital (LUMO) of the azobenzene ligand. The simple donor–acceptor (D–A) type copolymer of bithiophene (BT) and BAz exhibited intense photoluminescence (PL) in the NIR region both in the dilute solution (λPL=751 nm, ΦPL=0.25) and in the film (λPL=821 nm, ΦPL=0.038). The BAz monomer showed slight PL in the dilute solution, and aggregation‐induced emission (AIE) was detected. We proposed that N=N double bonds should be attractive and functional building blocks for designing π‐conjugated materials. 相似文献
3.
Makoto Eishima Shigeru Ohba Masumi Suzuki Chiaki Nagasawa Takeshi Sugai 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):1391-1393
In the racemic crystals of (1S,2R)‐ or (1R,2S)‐1‐[N‐(chloroacetyl)carbamoylamino]‐2,3‐dihydro‐1H‐inden‐2‐yl chloroacetate, C14H14Cl2N2O4, (I), the enantiomeric molecules form a dimeric structure via the N—H?O cyclic hydrogen bond of the carbamoyl moieties. In the chiral crystals of (—)‐(1S,2R)‐1‐[N‐(chloroacetyl)carbamoylamino]‐2,3‐dihydro‐1H‐inden‐2‐yl chloroacetate, C14H14Cl2N2O4, (II), the N—H?O intermolecular hydrogen bond forms a zigzag chain around the twofold screw axis. The melting points and calculated densities of (I) and (II) are 446 and 396 K, and 1.481 and 1.445 Mg m?3, respectively. 相似文献
4.
5.
Andrey B. Lysenko 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(10):m291-m294
5‐[4‐(1,2,4‐Triazol‐4‐yl)phenyl]‐1H‐tetrazole, C9H7N7, (I), an asymmetric heterobifunctional organic ligand containing triazole (tr) and tetrazole (tz) termini linked directly through a 1,4‐phenylene spacer, crystallizes in the polar space group Pc. The heterocyclic functions, serving as single hydrogen‐bond donor (tz) or acceptor (tr) units, afford hydrogen‐bonded zigzag chains with no crystallographic centre of inversion. In the structure of catena‐poly[[diaquacadmium(II)]bis{μ2‐5‐[4‐(1,2,4‐triazol‐4‐yl)phenyl]tetrazol‐1‐ido‐κ2N1:N1′}], [Cd(C9H6N7)2(H2O)2]n, (II), the CdII dication resides on a centre of inversion in an octahedral {N4O2} environment. In the equatorial plane, the CdII polyhedron is built up from four N atoms of two kinds, namely of trans‐coordinating tr and tz fragments [Cd—N = 2.2926 (17) and 2.3603 (18) Å], and the coordinating aqua ligands occupy the two apical sites. The metal centres are separated at a distance of 11.1006 (7) Å by means of the double‐bridging tetrazolate anion, L−, forming a chain structure. The water ligands and tz fragments interact with one another, like a double hydrogen‐bond donor–acceptor synthon, leading to a hydrogen‐bonded three‐dimensional array. 相似文献
6.
《中国化学》2017,35(10):1559-1568
The donor‐π‐conjugated‐acceptor (D‐π‐A) structure is an important design for the luminescent materials because of its diversity in the selections of donor, π‐bridge and acceptor groups. Herein, we demonstrate two examples of D‐π‐A structures capable to finely modulate the excited state properties and arrangement of energy levels, TPA‐AN‐BP and CZP‐AN‐BP , which possess the same acceptor and π‐bridge but different donor. The investigation of their photophysical properties and DFT calculation revealed that the D‐π‐A structure with proper donor, π‐bridge and acceptor can result in separation of frontier molecular orbitals on the corresponding donor and acceptor with an obvious overlap on the π‐bridge, resulting in a hybridized local and charge‐transfer (HLCT ) excited state with high photoluminescent (PL ) efficiencies. Meanwhile, their singlet and triplet states are arranged on corresponding moieties with large energy gap between T2 and T1 , and a small energy gap between S1 and T2 , which favor the reverse intersystem crossing (RISC ) from high‐lying triplet levels to singlet levels. As a result, the sky‐blue emission non‐doped OLED based on the TPA‐AN‐BP reached maximum external quantum efficiency (EQE ) of 4.39% and a high exciton utilization efficiency (EUE ) of 77%. This study demonstrates a new strategy to construct highly efficient OLED materials. 相似文献
7.
Vladimir A. Basiuk Vadim A. Soloshonok Luc Van Meervelt Elena V. Basiuk 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(5):598-599
The title compound, C12H19N3O2, is an unusual product of silica‐catalyzed intermolecular condensation of α‐aminoisobutyric acid. The molecule has three types of C—N bonds: a double bond, a cis‐amide bond and single bonds, two of which are typical and two having intermediate lengths due to π‐electron delocalization between C=N and C=O groups. The cis‐amide moieties interact to form dimers via hydrogen bonds which stack in parallel layers. 相似文献
8.
Lingping Cheng Jianfeng Cai Qing Fu Yanxiong Ke 《Journal of separation science》2019,42(15):2482-2490
6‐(4‐Aminophenyl)‐5‐methyl‐4,5‐dihydro‐3(2H)‐pyridazinone is a key synthetic intermediate for cardiotonic agent levosimendan. Very few studies address the use of chiral stationary phases in chromatography for the enantioseparation of this intermediate. This study presents two efficient preparative methods for the isolation of (R)(?)‐6‐(4‐aminophenyl)‐5‐methyl‐4,5‐dihydro‐3(2H)‐pyridazinone in polar organic solvent chromatography and supercritical fluid chromatography using polysaccharide‐based chiral stationary phases and volatile organic mobile phases without additives in isocratic mode. Under optimum conditions, Chiralcel OJ column showed the best performance (α = 1.71, Rs = 5.47) in polar organic solvent chromatography, while Chiralpak AS column exhibited remarkable separations (α = 1.81 and Rs = 6.51) in supercritical fluid chromatography with an opposite enantiomer elution order. Considering the sample solubility, runtime and solvent cost, the preparations were carried out on Chiralcel OJ column and Chiralpak AS column (250 × 20 mm i.d.; 10 µm) in polar organic mode and supercritical fluid chromatography mode with methanol and CO2/methanol as mobile phases, respectively. By utilizing the advantages of chromatographic techniques and polysaccharide‐based chiral stationary phases, this work provides two methods for the fast and economic preparation of (R)(?)‐6‐(4‐aminophenyl)‐5‐methyl‐4,5‐dihydro‐3(2H)‐pyridazinone, which are suitable for the pharmaceutical industry. 相似文献
9.
Gerson Lpez L. Marina Jaramillo Rodrigo Abonia Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(4):o168-o173
The molecules of N‐(3‐tert‐butyl‐1‐phenyl‐1H‐pyrazol‐5‐yl)‐2‐chloro‐N‐(4‐methoxybenzyl)acetamide, C23H26ClN3O2, are linked into a chain of edge‐fused centrosymmetric rings by a combination of one C—H...O hydrogen bond and one C—H...π(arene) hydrogen bond. In N‐(3‐tert‐butyl‐1‐phenyl‐1H‐pyrazol‐5‐yl)‐2‐chloro‐N‐(4‐chlorobenzyl)acetamide, C22H23Cl2N3O, a combination of one C—H...O hydrogen bond and two C—H...π(arene) hydrogen bonds, which utilize different aryl rings as the acceptors, link the molecules into sheets. The molecules of S‐[N‐(3‐tert‐butyl‐1‐phenyl‐1H‐pyrazol‐5‐yl)‐N‐(4‐methylbenzyl)carbamoyl]methyl O‐ethyl carbonodithioate, C26H31N3O2S2, are also linked into sheets, now by a combination of two C—H...O hydrogen bonds, both of which utilize the amide O atom as the acceptor, and two C—H...π(arene) hydrogen bonds, which utilize different aryl groups as the acceptors. 相似文献
10.
Antonija Hergold‐Brundi Gordana Pavlovi Ana Dunja Mance Kreimir Jakop
i 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):e520-e521
The title compound, C15H14N2O3, is the first example of a structurally determined tertiary amine with both N‐5‐nitrofurfuryl and N‐prop‐2‐ynyl moieties. The molecule is not planar, i.e. the furan ring is inclined at an angle of 84.35 (4)° to the phenyl ring. The crystal structure is dominated by van der Waals forces. The terminal alkynyl group as the strongest C—H hydrogen‐bond donor is not involved in hydrogen‐bond formation. 相似文献
11.
Andreas Kolmer Lukas Kaltschnee Volker Schmidts Lars H. Peeck Herbert Plenio Christina M. Thiele 《Magnetic resonance in chemistry : MRC》2013,51(11):695-700
There has been much debate about the σ‐donor and π‐acceptor properties of N‐heterocyclic carbenes (NHCs). While a lot of synthetic modifications have been performed with the goal of optimizing properties of the catalyst to tune reactivity in various transformations (e.g. metathesis), direct methods to characterize σ‐donor and π‐acceptor properties are still few. We believe that dynamic NMR spectroscopy can improve understanding of this aspect. Thus, we investigated the intramolecular dynamics of metathesis precatalysts bearing two NHCs. We chose four systems with one identical NHC ligand (N,N′‐Bis(2,4,6‐trimethylphenyl)‐imidazolinylidene (SIMes) in all four cases) and NHCewg ligands bearing four different electron‐withdrawing groups (ewg). Both rotational barriers of the respective Ru‐NHC‐bonds change significantly when the electron density of one of the NHCs (NHCewg) is modified. Although it is certainly not possible to fully dissect σ‐donor and π‐acceptor portions of the bonding situations in the respective Ru‐NHC‐bond via dynamic NMR spectroscopy, our studies nevertheless show that the analysis of the rotation around the Ru‐SIMes‐bond can be used as a spectroscopic parameter complementary to cyclic voltammetry. Surprisingly, we observed that the rotation around the Ru‐NHCewg‐bond shows the same trend as the initiation rate of a ring‐closing metathesis of the four investigated bis‐NHC‐complexes. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
12.
Christos P. Constantinides Dr. Panayiotis A. Koutentis Prof. Jeremy M. Rawson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(23):7109-7116
X‐ray studies show that 1,3‐diphenyl‐7‐(thien‐2‐yl)‐1,4‐dihydro‐1,2,4‐benzotriazin‐4‐yl ( 6 ) adopts a distorted, slipped π‐stacked structure of centrosymmetric dimers with alternate short and long interplanar distances (3.48 and 3.52 Å). Cyclic voltammograms of 7‐(thien‐2‐yl)benzotriazin‐4‐yl 6 show two fully reversible waves that correspond to the ?1/0 and 0/+1 processes. EPR and DFT studies on radical 6 indicate that the spin density is mainly delocalized over the triazinyl fragment. Magnetic susceptibility measurements show that radical 6 obeys Curie–Weiss behavior in the 5–300 K region with C=0.378 emu K mol?1 and θ=+4.72 K, which is consistent with ferromagnetic interactions between S=1/2 radicals. Fitting the magnetic susceptibility revealed the behavior is consistent with an alternating ferromagnetic chain (g=2.0071, J1=+7.12 cm?1, J2=+1.28 cm?1). 相似文献
13.
De‐Qiang Qi Gui‐Ge Hou Jian‐Ping Ma Ru‐Qi Huang Yu‐Bin Dong 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(3):o85-o87
A novel three‐dimensional framework of 2‐[(1H‐imidazol‐1‐yl)methyl]‐1H‐benzimidazole dihydrate, C11H10N4·2H2O or L·2H2O, (I), in which L acts as both hydrogen‐bond acceptor and donor in the supramolecular construction with water, has been obtained by self‐assembly reaction of L with H2O. The two independent water molecules are hydrogen bonded alternately with each other to form a one‐dimensional infinite zigzag water chain. These water chains are linked by the benzimidazole molecules into a three‐dimensional framework, in which each organic molecule is hydrogen bonded by three water molecules. This study shows that the diversity of hydrogen‐bonded patterns plays a crucial role in the formation of the three‐dimensional framework. More significantly, as water molecules are important in contributing to the conformation, stability, function and dynamics of biomacromolecules, the infinite chains of hydrogen‐bonded water molecules seen in (I) may be a useful model for water in other chemical and biological processes. 相似文献
14.
Haozhe Yang Simone Budow‐Busse Henning Eickmeier Hans Reuter Frank Seela 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(12):1116-1120
The title compound {systematic name: 4‐amino‐5‐cyclopropyl‐7‐(2‐deoxy‐β‐D‐erythro‐pentofuranosyl)‐7H‐pyrrolo[2,3‐d]pyrimidine}, C14H18N4O3, exhibits an anti glycosylic bond conformation, with the torsion angle χ = −108.7 (2)°. The furanose group shows a twisted C1′‐exo sugar pucker (S‐type), with P = 120.0 (2)° and τm = 40.4 (1)°. The orientation of the exocyclic C4′—C5′ bond is ‐ap (trans), with the torsion angle γ = −167.1 (2)°. The cyclopropyl substituent points away from the nucleobase (anti orientation). Within the three‐dimensional extended crystal structure, the individual molecules are stacked and arranged into layers, which are highly ordered and stabilized by hydrogen bonding. The O atom of the exocyclic 5′‐hydroxy group of the sugar residue acts as an acceptor, forming a bifurcated hydrogen bond to the amino groups of two different neighbouring molecules. By this means, four neighbouring molecules form a rhomboidal arrangement of two bifurcated hydrogen bonds involving two amino groups and two O5′ atoms of the sugar residues. 相似文献
15.
F. L. Oliveira P. C. Huber W. P. Almeida J. R. Sabino R. Aparicio 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(2):119-122
The ZnII center in the dicationic complex of the title compound, [Zn(C10H7N3S)3](NO3)2·0.5C2H5OH·H2O, is in a distorted octahedral environment with imperfect noncrystallographic C3 symmetry. Each 2‐(1,3‐thiazol‐2‐yl)‐1H‐benzimidazole ligand coordinates in a bidentate manner, with the Zn—N(imidazole) bond lengths approximately 0.14 Å shorter than the Zn—N(thiazole) bond lengths. Charge‐assisted hydrogen bonds connect cations, anions and water molecules. A lattice void is occupied by an ethanol solvent molecule disordered about a crystallographic inversion center and π‐stacking is observed between one type of symmetry‐related benzene rings. 相似文献
16.
Raymond E. Borg Maryam Hatamimoslehabadi Stephanie Bellinger Jeffrey La Farha Mithila Chandra Yelleswarapu Jonathan Rochford 《Photochemistry and photobiology》2019,95(1):280-292
The synthesis, photophysical and photoacoustic characterization for a series of nine π‐extended quadrupolar curcumin dyes is presented. A systematic evaluation of the π‐bridging unit including the p‐phenyl, naphth‐4‐yl, thien‐2‐yl and hybrid 4‐naphthathien‐2‐yl groups is presented. Furthermore, evaluation of the strongly donating donor‐π‐acceptor‐π‐donor quadrupolar dimethylamino terminated derivatives is also included. Select dyes exhibit excited state absorption at increased laser fluence which translates to the production of a nonlinear enhanced photoacoustic response. In particular, the bis‐4‐dimethylaminonaphtha‐2‐thien‐5‐yl curcuminBF2 contrast agent DMA‐5 exhibits an excellent molar photoacoustics (PA) emission at both low (9.4 × 103 V M?1) and high (1.47 × 105 V M?1) laser fluence which is confirmed by its strong contrast by photoacoustic tomography (PAT). In summary, the strong absorbance and enhanced photoacoustic properties of naphthyl and thienyl curcuminoids here presented provides great promise for future photoacoustic imaging applications as demonstrated by preliminary PAT studies. 相似文献
17.
Qiao‐Sheng Hu Xiu‐Zhi Zhang Shu‐Fen Luo Yu‐Hui Sun Zi‐Yi Du 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(6):o195-o197
Two polymorphs of (2‐carboxyethyl)(phenyl)phosphinic acid, C9H11O4P, crystallize in the chiral P212121 space group with similar unit‐cell parameters. They feature an essentially similar hydrogen‐bonding motif but differ slightly in their detailed geometric parameters. For both polymorphs, the unequivocal location of the hydroxy H atoms together with the expected differences in the P—O bond lengths establish unequivocally that both forms contain the S isomer; the protonated phosphinic acid and carboxy O atoms serve as hydrogen‐bond donors, while the second phosphinic acid O atom acts as a double hydrogen‐bond acceptor and the remaining carboxy O atom is not involved in hydrogen bonding. Thus, an undulating two‐dimensional supramolecular layer aggregate is formed based on an R43(20) ring unit. Such polymorphism derives from the rotation of the C—C single bonds between the two hydrogen‐bond‐involved carboxy and phosphinic acid moieties. 相似文献
18.
Katharine F. Bowes Christopher Glidewell John N. Low Manuel Melguizo Antonio Quesada 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(1):o4-o8
Crystallization of 2‐amino‐4‐chloro‐6‐morpholinopyrimidine, C8H11ClN4O, (I), yields two polymorphs, both with space group P21/c, having Z′ = 1 (from diethyl ether solution) and Z′ = 2 (from dichloromethane solution), denoted (Ia) and (Ib), respectively. In polymorph (Ia), the molecules are linked by an N—H⋯O and an N—H⋯N hydrogen bond into sheets built from alternating R(8) and R(40) rings. In polymorph (Ib), one molecule acts as a triple acceptor of hydrogen bonds and the other acts as a single acceptor; one N—H⋯O and three N—H⋯N hydrogen bonds link the molecules in a complex chain containing two types of R(8) and one type of R(18) ring. 2‐Amino‐4‐chloro‐6‐piperidinopyrimidine, C9H13ClN4, (II), which is isomorphous with polymorph (Ib), also has Z′ = 2 in P21/c, and the molecules are linked by three N—H⋯N hydrogen bonds into a centrosymmetric four‐molecule aggregate containing three R(8) rings. 相似文献
19.
Alexander S. Filatov Marina A. Petrukhina 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(3):o193-o194
The rod‐like molecule of the title hydrocarbon, C24H18, is centrosymmetric, with the centroid of the central benzene ring residing on an inversion center. The molecules display a planar conformation of the benzene rings and aggregate into stacks along the [010] direction via Csp3—H⋯π(arene) interactions, thus forming a stair‐like pseudo‐two‐dimensional network. Each molecule acts as both a C—H hydrogen donor and a π‐arene acceptor, forming four hydrogen bonds per molecule. 相似文献
20.
Haijun Bin Lu Xiao Yong Liu Ping Shen Yongfang Li 《Journal of polymer science. Part A, Polymer chemistry》2014,52(14):1929-1940
A series of donor‐π‐acceptor (D‐π‐A) conjugated copolymers ( PBDT‐AT, PDTS‐AT, PBDT‐TT , and PDTS‐TT ), based on benzo[1,2‐b:4,5‐c']dithiophene‐4,8‐dione (BDD) acceptor unit with benzodithiophene (BDT) or dithienosilole (DTS) as donor unit, alkylthiophene (AT) or thieno[3,2‐b]thiophene (TT) as conjugated π‐bridge, were designed and synthesized for application as donor materials in polymer solar cells (PSCs). Effects of the donor unit and π‐bridge on the optical and electrochemical properties, hole mobilities, and photovoltaic performance of the D‐π‐A copolymers were investigated. PSCs with the polymers as donor and PC70BM as acceptor exhibit an initial power conversion efficiency (PCE) of 5.46% for PBDT‐AT , 2.62% for PDTS‐AT , 0.82% for PBDT‐TT , and 2.38% for PDTS‐TT . After methanol treatment, the PCE was increased up to 5.91%, 3.06%, 1.45%, and 2.45% for PBDT‐AT, PDTS‐AT, PBDT‐TT , and PDTS‐TT , respectively, with significantly increased FF. The effects of methanol treatment on the photovoltaic performance of the PSCs can be ascribed to the increased and balanced carrier transport and the formation of better nanoscaled interpenetrating network in the active layer. The results indicate that both donor unit and π‐bridge are crucial in designing a D‐π‐A copolymer for high‐performance photovoltaic materials. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1929–1940 相似文献