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1.
Kyle A. Powers David K. Geiger 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(3):329-335
The isostructural salts benzene‐1,2‐diaminium bis(pyridine‐2‐carboxylate), 0.5C6H10N22+·C6H4NO2?, (1), and 4,5‐dimethylbenzene‐1,2‐diaminium bis(pyridine‐2‐carboxylate), 0.5C8H14N22+·C6H4NO2?, (2), and the 1:2 benzene‐1,2‐diamine–benzoic acid cocrystal, 0.5C6H8N2·C7H6O2, (3), are reported. All of the compounds exhibit extensive N—H…O hydrogen bonding that results in interconnected rings. O—H…N hydrogen bonding is observed in (3). Additional π–π and C—H…π interactions are found in each compound. Hirshfeld and fingerprint plot analyses reveal the primary intermolecular interactions and density functional theory was used to calculate their strengths. Salt formation by (1) and (2), and cocrystallization by (3) are rationalized by examining pKa differences. The R22(9) hydrogen‐bonding motif is common to each of these structures. 相似文献
2.
Isao Ogino Mingyang Chen Jason Dyer Philip W. Kletnieks James F. Haw Prof. David A. Dixon Prof. Bruce C. Gates Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(25):7427-7436
An essentially molecular ruthenium–benzene complex anchored at the aluminum sites of dealuminated zeolite Y was formed by treating a zeolite‐supported mononuclear ruthenium complex, [Ru(acac)(η2‐C2H4)2]+ (acac=acetylacetonate, C5H7O2?), with 13C6H6 at 413 K. IR, 13C NMR, and extended X‐ray absorption fine structure (EXAFS) spectra of the sample reveal the replacement of two ethene ligands and one acac ligand in the original complex with one 13C6H6 ligand and the formation of adsorbed protonated acac (Hacac). The EXAFS results indicate that the supported [Ru(η6‐C6H6)]2+ incorporates an oxygen atom of the support to balance the charge, being bonded to the zeolite through three Ru? O bonds. The supported ruthenium–benzene complex is analogous to complexes with polyoxometalate ligands, consistent with the high structural uniformity of the zeolite‐supported species, which led to good agreement between the spectra and calculations at the density functional theory level. The calculations show that the interaction of the zeolite with the Hacac formed on treatment of the original complex with 13C6H6 drives the reaction to form the ruthenium–benzene complex. 相似文献
3.
Man Singh 《Surface and interface analysis : SIA》2008,40(2):76-80
Interfacial tension (IFT) (γift, N m?1) of benzene‐water; and surface tensions (γ, N m?1) and viscosities (η, N s m?2) of solvents methanol, ethanol, glycerol, ethyl acetate, n‐hexane, diethyl ether, chloroform, benzene, carbon tetrachloride [CCl4], formic acid, Acetonitril, and dimethylformamide [DMF] were measured with Survismeter‐IFT. The ± 1.1 × 10?5 N m?1, ± 1.3 × 10?5 N m?1, and ± 1.1 × 10?5 N s m?2 deviations in respective values were noted. It has 10 times better accuracy than those of individual methods. The survismeter is inexpensive minimizing 2/3 each of consumables, human efforts, time, and infrastructure, cutting down 80% of the waste disposed the environment. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
4.
Yi Ren Semin Lee Jeffery Bertke Danielle L. Gray Jeffrey S. Moore 《Acta Crystallographica. Section C, Structural Chemistry》2016,72(12):923-931
Radical salts and charge‐transfer complexes (CTCs) containing tetracyanoquinodimethane (TCNQ) display electrical conductivity, which has led to the development of many TCNQ derivatives with enhanced electron‐accepting properties that are applicable toward organic electronics. To expand the family of TCNQ derivatives, we report the synthesis and structures of 11,11,12,12‐tetracyano‐2,6‐diiodo‐9,10‐anthraquinodimethane (abbreviated as DITCAQ), C20H6I2N4, and its charge‐transfer complexes with various electron donors, namely DITCAQ–anthracene (2/1), C20H6I2N4·0.5C14H10, (I), DITCAQ–pyrene (2/1), C20H6I2N4·0.5C16H10, (II), and DITCAQ–tetrathiafulvalene (2/1), C20H6I2N4·0.5C6H4S4, (III). The molecular structure of DITCAQ consists of a 2,6‐diiodo‐9,10‐dihydroanthracene moiety with two malononitrile substituents. DITCAQ possesses a saddle shape, since the malononitrile groups bend significantly up out of the plane of the central ring and the two benzene rings bend down out of the same plane. π–π interactions between DITCAQ and the electron‐donor molecules control the degree of charge transfer in cocrystals (I), (II), and (III), which is reflected in both the dihedral angles between the terminal benzene ring and the central ring on the DITCAQ motifs, and their corresponding IR spectra. 相似文献
5.
Arthur D. Hendsbee Jason D. Masuda Adam Pirko 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(12):m391-m394
In the complex salt [η6‐1‐chloro‐2‐(pyrrolidin‐1‐yl)benzene](η5‐cyclopentadienyl)iron(II) hexafluoridophosphate, [Fe(C5H5)(C10H12ClN)]PF6, (I), the complexed cyclopentadienyl and benzene rings are almost parallel, with a dihedral angle between their planes of 2.3 (3)°. In a related complex salt, (η5‐cyclopentadienyl){2‐[η6‐2‐(pyrrolidin‐1‐yl)phenyl]phenol}iron(II) hexafluoridophosphate, [Fe(C5H5)(C16H17NO)]PF6, (II), the analogous angle is 5.4 (1)°. In both complexes, the aromatic C atom bound to the pyrrolidine N atom is located out of the plane defined by the remaining five ring C atoms. The dihedral angles between the plane of these five ring atoms and a plane defined by the N‐bound aromatic C atom and two neighboring C atoms are 9.7 (8) and 5.6 (2)° for (I) and (II), respectively. 相似文献
6.
En Tang Zhao‐Ji Li Yu‐Mei Dai Yuan‐Gen Yao 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(2):m61-m63
The title compound, [CoII(C10H8O6)(C10H8N2)(H2O)2]n, was obtained by the hydrothermal reaction of CoSO4 with benzene‐1,4‐dioxydiacetate [systematic name: p‐phenylenebis(oxyacetate)] and 4,4′‐bipyridine (4,4′‐bpy). The Co atom lies at an inversion center and the benzene‐1,4‐dioxydiacetate and 4,4′‐bipyridine moieties lie about other inversion centers. The benzene‐1,4‐dioxydiacetate ligands bridge the octahedral CoII coordination centers, forming a one‐dimensional zigzag chain. The chains are further bridged by 4,4′‐bpy ligands, forming a novel two‐dimensional supramolecular architecture. Hydrogen‐bonding interactions between the coordinated water molecules and the carboxylate O atoms lead to the formation of a three‐dimensional network structure. 相似文献
7.
Sean R. Parkin Edward J. Behrman 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(10):o529-o533
On crystallization from CHCl3, CCl4, CH2ClCH2Cl and CHCl2CHCl2, 6‐chloro‐5‐hydroxy‐2‐pyridone, C5H4ClNO2, (I), undergoes a tautomeric rearrangement to 6‐chloro‐2,5‐dihydroxypyridine, (II). The resulting crystals, viz. 6‐chloro‐2,5‐dihydroxypyridine chloroform 0.125‐solvate, C5H4ClNO2·0.125CHCl3, (IIa), 6‐chloro‐2,5‐dihydroxypyridine carbon tetrachloride 0.125‐solvate, C5H4ClNO2.·0.125CCl4, (IIb), 6‐chloro‐2,5‐dihydroxypyridine 1,2‐dichloroethane solvate, C5H4ClNO2·C2H4Cl2, (IIc), and 6‐chloro‐2,5‐dihydroxypyridine 1,1,2,2‐tetrachloroethane solvate, C5H4ClNO2·C2H2Cl4, (IId), have I41/a symmetry, and incorporate extensively disordered solvent in channels that run the length of the c axis. Upon gentle heating to 378 K in vacuo, these crystals sublime to form solvent‐free crystals with P21/n symmetry that are exclusively the pyridone tautomer, (I). In these sublimed pyridone crystals, inversion‐related molecules form R22(8) dimers via pairs of N—H...O hydrogen bonds. The dimers are linked by O—H...O hydrogen bonds into R46(28) motifs, which join to form pleated sheets that stack along the a axis. In the channel‐containing pyridine solvate crystals, viz. (IIa)–(IId), two independent host molecules form an R22(8) dimer via a pair of O—H...N hydrogen bonds. One molecule is further linked by O—H...O hydrogen bonds to two 41 screw‐related equivalents to form a helical motif parallel to the c axis. The other independent molecule is O—H...O hydrogen bonded to two related equivalents to form tetrameric R44(28) rings. The dimers are π–π stacked with inversion‐related dimers, which in turn stack the R44(28) rings along c to form continuous solvent‐accessible channels. CHCl3, CCl4, CH2ClCH2Cl and CHCl2CHCl2 solvent molecules are able to occupy these channels but are disordered by virtue of the site symmetry within the channels. 相似文献
8.
Xiaofan Zhang Shangtao Chen Huayi Li Zhicheng Zhang Yingying Lu Chunhong Wu Youliang Hu 《Journal of polymer science. Part A, Polymer chemistry》2005,43(23):5944-5952
Activated with methylaluminoxane (MAO), phenoxy‐based zirconium complexes bis[(3‐tBu‐C6H3‐2‐O)‐CH?NC6H5]ZrCl2, bis[(3,5‐di‐tBu‐C6H2‐2‐O)‐PhC?NC6H5] ZrCl2, and bis[(3,5‐di‐tBu‐C6H2‐2‐O)‐PhC?N(2‐F‐C6H4)]ZrCl2 for the first time have been used for the copolymerization of ethylene with 10‐undecen‐1‐ol. In comparison with the conventional metallocene, the phenoxy‐based zirconium complexes exhibit much higher catalytic activities [>107 g of polymer (mol of catalyst)?1 h?1]. The incorporation of 10‐undecen‐1‐ol into the copolymers and the properties of the copolymers are strongly affected by the catalyst structure. Among the three catalysts, complex c is the most favorable for preparing higher molecular weight functionalized polyethylene containing a higher content of hydroxyl groups. Studies on the polymerization conditions indicate that the incorporated commoner content in the copolymers mainly depends on the comonomer concentration in the feed. The catalytic activity is slightly affected by the Al(MAO)/Zr molar ratio but decreases greatly with an increase in the polymerization temperature. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5944–5952, 2005 相似文献
9.
Hatem M. Titi Israel Goldberg 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(12):o639-o644
The structure of 1‐benzofuran‐2,3‐dicarboxylic acid (BFDC), C10H6O5, (I), exhibits an intramolecular hydrogen bond between one –COOH group and the other, while the second carboxyl function is involved in intermolecular hydrogen bonding to neighbouring species. The latter results in the formation of flat one‐dimensional hydrogen‐bonded chains in the crystal structure, which are π–π stacked along the normal to the plane of the molecular framework, forming a layered structure. 1:1 Cocrystallization of BFDC with pyridine, phenazine and 1,4‐phenylenediamine is associated with H‐atom transfer from BFDC to the base and charge‐assisted hydrogen bonding between the BFDC− monoanion and the corresponding ammonium species, while preserving, in all cases, the intramolecular hydrogen bond between the carboxyl and carboxylate functions. The pyridinium 2‐carboxylato‐1‐benzofuran‐3‐carboxylic acid, C5H6N+·C10H5O5−, (II), and phenazinium 3‐carboxylato‐1‐benzofuran‐2‐carboxylic acid, C12H9N2+·C10H5O5−, (III), adducts form discrete hydrogen‐bonded ion‐pair entities. In the corresponding crystal structures, the two components are arranged in either segregated or mixed π–π stacks, respectively. On the other hand, the structure of 4‐aminoanilinium 2‐carboxylato‐1‐benzofuran‐3‐carboxylic acid, C6H9N2+·C10H5O5−, (IV), exhibits an intermolecular hydrogen‐bonding network with three‐dimensional connectivity. Moreover, this fourth structure exhibits induction of supramolecular chirality by the extended hydrogen bonding, leading to a helical arrangement of the interacting moieties around 21 screw axes. The significance of this study is that it presents the first crystallographic characterization of pure BFDC, and manifestation of its cocrystallization with a variety of weakly basic amine molecules. It confirms the tendency of BFDC to preserve its intramolecular hydrogen bond and to prefer a monoanionic form in supramolecular association with other components. The aromaticity of the flat benzofuran residue plays an important role in directing either homo‐ or heteromolecular π–π stacking in the first three structures, while the occurrence of a chiral architecture directed by multiple hydrogen bonding is the dominant feature in the fourth. 相似文献
10.
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
11.
Annie Cleetus Gulshan Rani G. B. Dharma Rao Deepak Chopra 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(8):786-794
Methyl 4‐(4‐fluorophenyl)‐6‐methyl‐2‐oxo‐1,2,3,4‐tetrahydropyrimidine‐5‐carboxylate, ( I ), was found to exhibit solvatomorphism. The compound was prepared using a classic Biginelli reaction under mild conditions, without using catalysts and in a solvent‐free environment. Single crystals of two solvatomorphs and one anhydrous form of ( I ) were obtained through various crystallization methods. The anhydrous form, C13H13FN2O3, was found to crystallize in the monoclinic space group C2/c. It showed one molecule in the asymmetric unit. The solvatomorph with included carbon tetrachloride, C13H13FN2O3·0.25CCl4, was found to crystallize in the monoclinic space group P2/n. The asymmetric unit revealed two molecules of ( I ) and one disordered carbon tetrachloride solvent molecule that lies on a twofold axis. A solvatomorph including ethyl acetate, C13H13FN2O3·0.5C4H8O2, was found to crystallize in the triclinic space group P with one molecule of ( I ) and one solvent molecule on an inversion centre in the asymmetric unit. The solvent molecules in the solvatomorphs were found to be disordered, with a unique case of crystallographically induced disorder in ( I ) crystallized with ethyl acetate. Hydrogen‐bonding interactions, for example, N—H…O=C, C—H…O=C, C—H…F and C—H…π, contribute to the crystal packing with the formation of a characteristic dimer through N—H…O=C interactions in all three forms. The solvatomorphs display additional interactions, such as C—F…N and C—Cl…π, which are responsible for their molecular arrangement. The thermal properties of the forms were analysed through differential scanning calorimetry (DSC), hot stage microscopy (HSM) and thermogravimetric analysis (TGA) experiments. 相似文献
12.
Ruthenium trichloride (RuCl3 or RuIII) catalyzed polymerization of methylmethacrylate (MMA) initiated with n‐butylamine (BA) in the presence of carbon tetrachloride (CCl4) by a charge‐transfer mechanism has been investigated in a dimethylsulfoxide (DMSO) medium by employing a dilatometric technique at 60°C. The rate of polymerization (Rp) has been obtained under the conditions [CCl4]/[BA] ? 1 and [CCl4]/[BA] ? 1. The kinetic data indicate the possible participation of the charge‐transfer complex formed between the amine–RuIII complex and CCl4 in the polymerization of MMA. In the absence of either CCl4 or BA, no polymerization of MMA is observed under the present experimental conditions. The rate of polymerization is inhibited by hydroquinone, suggesting a free‐radical initiation. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 43: 70–77, 2011 相似文献
13.
Diversification of ortho‐Fused Cycloocta‐2,5‐dien‐1‐one Cores and Eight‐ to Six‐Ring Conversion by σ Bond C−C Cleavage
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Lee Eccleshare Leticia Lozada‐Rodríguez Phillippa Cooper Dr. Laurence Burroughs John Ritchie Dr. William Lewis Prof. Dr. Simon Woodward 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(35):12542-12547
Sequential treatment of 2‐C6H4Br(CHO) with LiC≡CR1 (R1=SiMe3, tBu), nBuLi, CuBr?SMe2 and HC≡CCHClR2 [R2=Ph, 4‐CF3Ph, 3‐CNPh, 4‐(MeO2C)Ph] at ?50 °C leads to formation of an intermediate carbanion (Z)‐1,2‐C6H4{CA(=O)C≡CBR1}{CH=CH(CH?)R2} ( 4 ). Low temperatures (?50 °C) favour attack at CB leading to kinetic formation of 6,8‐bicycles containing non‐classical C‐carbanion enolates ( 5 ). Higher temperatures (?10 °C to ambient) and electron‐deficient R2 favour retro σ‐bond C?C cleavage regenerating 4 , which subsequently closes on CA providing 6,6‐bicyclic alkoxides ( 6 ). Computational modelling (CBS‐QB3) indicated that both pathways are viable and of similar energies. Reaction of 6 with H+ gave 1,2‐dihydronaphthalen‐1‐ols, or under dehydrating conditions, 2‐aryl‐1‐alkynylnaphthlenes. Enolates 5 react in situ with: H2O, D2O, I2, allylbromide, S2Me2, CO2 and lead to the expected C ‐E derivatives (E=H, D, I, allyl, SMe, CO2H) in 49–64 % yield directly from intermediate 5 . The parents (E=H; R1=SiMe3, tBu; R2=Ph) are versatile starting materials for NaBH4 and Grignard C=O additions, desilylation (when R1=SiMe) and oxime formation. The latter allows formation of 6,9‐bicyclics via Beckmann rearrangement. The 6,8‐ring iodides are suitable Suzuki precursors for Pd‐catalysed C?C coupling (81–87 %), whereas the carboxylic acids readily form amides under T3P® conditions (71–95 %). 相似文献
14.
Alvaro A. A. De Queiroz cio J. Frana Gustavo A. Abraham Julio S. Romn 《Journal of Polymer Science.Polymer Physics》2002,40(8):714-722
The ring‐opening polymerization of ?‐caprolactone (?‐CL) catalyzed by iodine (I2) was studied. The formation of a charge‐transfer complex (CTC) among triiodide, I, and ?‐CL was confirmed with ultraviolet–visible spectroscopy. The monomer ?‐CL was polymerized in bulk using I2 as a catalyst to form the polyester having apparent weight‐average molecular weights of 35,900 and 45,500 at polymerization temperatures of 25 and 70 °C, respectively. The reactivity of both, ?‐CL monomer and ?‐CL:I2 CTC, was interpreted by means of the potential energy surfaces determined by semiempirical computations (MNDO‐d). The results suggest that the formation of the ?‐CL:I2 CTC leads to the ring opening of the ?‐CL structure with the lactone protonation and the formation of a highly polarized polymerization precursor (?‐CL)+. The band gaps approximated from an extrapolation of the oligomeric polycaprolactone (PCL) structures were computed. With semiempirical quantum chemical calculations, geometries and charge distributions of the protonated polymerization precursor (?‐CL)+ were obtained. The calculated band gap (highest occupied molecular orbit/lowest unoccupied molecular orbit differences) agrees with the experiment. The analysis of the oligomeric PCL isosurfaces indicate the existence of a weakly lone pair character of the C?O and C? O bonds suggesting a ?‐CL ring‐opening specificity. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 714–722, 2002 相似文献
15.
Regiodirected Synthesis and Stereochemistry of 2,4,8‐Trialkyl‐3‐thia‐1,5‐diazabicyclo[3.2.1]octanes and α,ω‐Bis(2,4,6‐trialkyl‐1,3,5‐dithiazinane‐5‐yl)alkanes
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Vnira R. Akhmetova Ruslan A. Vagapov Tat'yana V. Tyumkina Guzel R. Khabibullina Zoya A. Starikova Alexander H. Lobov Yuliya V. Nelyubina Raikhana V. Kunakova Usein M. Dzhemilev 《Journal of heterocyclic chemistry》2015,52(4):1037-1045
2,4,8‐Trialkyl‐3‐thia‐1,5‐diazabicyclo[3.2.1]octanes have been obtained by the regioselective and stereoselective cyclocondensation of 1,2‐ethanediamine with aldehydes RCHO (R═Me, Et, Prn, Bun, Pentn) and H2S at molar ratio 1:3:2 at 0°C. The increase in molar ratio of thiomethylation mixture RCHO–H2S (6:4) at 40°C resulted in selective formation of bis‐(2,4,6‐trialkyl‐1,3,5‐dithiazinane‐5‐yl)ethanes. Cyclothiomethylation of aliphatic α,ω‐diamines with aldehydes RCHO (R═Me, Et) and H2S at molar ratio 1:6:4 and at 40°С led to α,ω‐bis(2,4,6‐trialkyl‐1,3,5‐dithiazinane‐5‐yl)alkanes. Stereochemistry of 2,4,8‐trialkyl‐3‐thia‐1,5‐diazabicyclo[3.2.1]octanes have been determined by means of 1H and 13С NMR spectroscopy and further supported by DFT calculations at the B3LYP/6‐31G(d,p) level. The structure of α,ω‐bis(2,4,6‐trialkyl‐1,3,5‐dithiazinane‐5‐yl)alkanes was confirmed by single‐crystal X‐ray diffraction study. 相似文献
16.
Xiang‐Gao Meng Chun‐Shan Zhou Li Wang Chang‐Lin Liu 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(11):o667-o670
5‐Sulfosalicylic acid (5‐SSA) and 3‐aminopyridine (3‐APy) crystallize in the same solvent system, resulting in two kinds of 1:1 proton‐transfer organic adduct, namely 3‐aminopyridinium 3‐carboxy‐4‐hydroxybenzenesulfonate monohydrate, C5H7N2+·C7H5O6S−·H2O or 3‐APy·5‐SSA·H2O, (I), and the anhydrous adduct, C5H7N2+·C7H5O6S− or 3‐APy·5‐SSA, (II). Both compounds have extensively hydrogen‐bonded three‐dimensional layered polymer structures, with interlayer homo‐ and heterogeneous π–π interactions in (I) and (II), respectively. 相似文献
17.
Bong‐Hwan Han Moon‐Gun Choi 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(8):1001-1003
The structure of tetrakis(3,4‐ethylenedioxy‐2‐thienyl)silane carbon tetrachloride solvate, Si(C6H5O2S)4·CCl4, has been determined in the noncentrosymmetric space group I. The Si and C atoms of the CCl4 are located on the fourfold inversion axes. The Si atom has a tetrahedral geometry. The thiophene ring in the 3,4‐ethylenedioxythiophene group is nearly planar to within 0.005 Å, and the ethylenedioxy moiety is in a half‐chair conformation. 相似文献
18.
Bis(β‐diketiminato) lanthanide amides: synthesis,structure and catalysis for the polymerization of l‐lactide and ε‐caprolactone
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Yu Zheng Rui Jiao Xiao‐dong Shen Ming‐qiang Xue Ying‐ming Yao Yong Zhang Qi Shen 《应用有机金属化学》2014,28(6):461-470
Treatment of the chlorides (L2,6‐iPr2Ph)2LnCl (L2,6‐iPr2Ph = [(2,6‐iPr2C6H3)NC(Me)CHC(Me)N(C6H5)]?) with 1 equiv. of NaNH(2,6‐iPr2C6H3) afforded the monoamides (L2,6‐iPr2Ph)2LnNH(2,6‐iPr2C6H3) (Ln = Y ( 1 ), Yb ( 2 )) in good yields. Anhydrous LnCl3 reacted with 2 equiv. of NaL2,6‐iPr2Ph in THF, followed by treatment with 1 equiv. of NaNH(2,6‐iPr2C6H3), giving the analogues (L2,6‐iPr2Ph)2LnNH(2,6‐iPr2C6H3) (Ln = Sm ( 3 ), Nd ( 4 )). Two monoamido complexes stabilized by two L2‐Me ligands, (L2‐Me)2LnNH(2,6‐iPr2C6H3) (L2‐Me = [N(2‐MeC6H4)C(Me)]2CH)?; Ln = Y ( 5 ), Yb ( 6 )), were also synthesized by the latter route. Complexes 1 , 2 , 3 , 4 , 5 , 6 were fully characterized, including X‐ray crystal structure analyses. Complexes 1 , 2 , 3 , 4 , 5 , 6 are isostructural. The central metal in each complex is ligated by two β‐diketiminato ligands and one amido group in a distorted trigonal bipyramid. All the complexes were found to be highly active in the ring‐opening polymerization of L‐lactide (L‐LA) and ε‐caprolactone (ε‐CL) to give polymers with relatively narrow molar mass distributions. The activity depends on both the central metal and the ligand (Yb < Y < Sm ≈ Nd and L2‐Me < L2,6‐iPr2Ph). Remarkably, the binary 3/benzyl alcohol (BnOH) system exhibited a striking ‘immortal’ nature and proved able to quantitatively convert 5000 equiv. of L‐LA with up to 100 equiv. of BnOH per metal initiator. All the resulting PLAs showed monomodal, narrow distributions (Mw/Mn = 1.06 ? 1.08), with molar mass (Mn) decreasing proportionally with an increasing amount of BnOH. The binary 4/BnOH system also exhibited an ‘immortal’ nature in the polymerization of ε‐CL in toluene. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
19.
Chun‐Shan Zhou Li‐Li Ding Hang Zhang Min‐Na Cao Xiang‐Gao Meng 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(2):o51-o53
The two title compounds of 2,2′‐biimidazole (Bim) with 5‐sulfosalicylic acid (5‐H2SSA) and 2,2′‐bibenzimidazole (Bbim) with 5‐H2SSA are 1:2 organic salts, viz. C6H8N42+·2C7H5O6S−, (I), and C14H12N42+·2C7H5O6S−·3H2O, (II). The cation of compound (I) lies on a centre of inversion, whereas that of (II) lies on a twofold axis. Whilst compound (I) is anhydrous, three water molecules are incorporated into the crystal structure of (II). The substitution of imidazole H atoms by other chemical groups may favour the incorporation of water molecules into the crystal structure. In both compounds, the component cations and anions adopt a homogeneous arrangement, forming alternating cation and anion layers which run parallel to the (001) plane in (I) and to the (100) plane in (II). By a combination of N—H...O, O—H...O and C—H...O hydrogen bonds, the ions in both compounds are linked into three‐dimensional networks. In addition, π–π interactions are observed between symmetry‐related benzene rings of Bbim2+ cations in (II). 相似文献
20.
Klaus Merz 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(2):o65-o67
The crystal packing of 1‐iodo‐3‐nitrobenzene, C6H4INO2, is formed by planar molecules which are linked by I⋯I and NO2⋯NO2 interactions. In the case of 1‐iodo‐3,5‐dinitrobenzene, C6H3IN2O4, the NO2 groups are not exactly coplanar with the benzene ring and the molecules form sheets linked by NO2⋯NO2 interactions. In contrast with 4‐iodonitrobenzene, the crystal structures of both title compounds do not form highly symmetrical I⋯NO2 intermolecular interactions. 相似文献