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1.
A series of ring‐contracted (14‐crown‐5, 17‐crown‐6) and ring‐enlarged (16‐crown‐5, 17‐crown‐5, 19‐crown‐6, 20‐crown‐6) crown ethers and their complexes with alkali‐metal cations Na+ and K+ had been explored using density functional theory (DFT) at B3LYP/6‐31G* level in order to reveal the effects of the methylene‐chain length in a crown ether. The nucleophilicity of all crown ethers had been investigated by the Fukui functions. The quantum chemistry parameters, such as the energy gap (ΔE), the highest occupied molecular orbital energy (EHOMO) and the lowest unoccupied molecular orbital energy (ELUMO) for less‐symmetrical crown ethers and symmetrical frameworks (15‐crown‐5, 18‐crown‐6) had been calculated. In addition, the thermodynamic energies of complexation reactions had also been studied. The results of the DFT calculations show that the methylene‐chain length plays an important role in determining the structure characters of the crown ethers and also strongly influences the properties of the ethers. Some of the calculated results are in a good agreement with the experimental values. 相似文献
2.
Structures of Alkali Metal Salts of Aromatic, Heterocyclic Amides: Synthesis and Structure of Crown Ether Adducts of the Alkali Metal Indolides The synthesis of five alkali metal indolide crown ether complexes is reported. Lithium‐indolide(12‐crown‐4) ( 1 ) was synthezised from butyllithium, indole, and 12‐crown‐4; sodium‐indolide(15‐crown‐5) ( 2 ) from sodium metal, indole, and 15‐crown‐5; potassium‐indolide(18‐crown‐6) ( 3 ) from potassium hydride, indole, and 18‐crown‐6. Rubidium‐ and cesium‐indolide(18‐crown‐6) ( 4 , 5 ) were made from Rb‐ and Cs‐hexamethyldisilazide, indole, and 18‐crown‐6. The structures of 2 , 4 , and 5 could be determined by X‐ray diffraction. The complexes 2 and 4 are mononuclear, the indolide anion shows an η1(N)‐coordination to the metal cation. Complex 5 is dinuclear with a central [Cs—N—]2‐ring. 相似文献
3.
Salen with two aza‐crown ether pendants H2L1 and its analogues H2L2‐H2L4 were successfully synthesized starting from benzo‐10‐aza‐15crown‐5 (BN15C5) or morpholine. Their structures were characterized by IR, MS, 1H NMR and elemental analysis, and were confirmed by X‐ray diffraction analysis of H2L1. Moreover, the saturated oxygen uptake of their cobalt(II) complexes CoL1‐CoL4 in diethyleneglycol dimethyl ether was determined at different temperature. The oxygenation contants (KO2 ) and thermodynamic parameters (ΔH° and ΔS°) were calculated. The modulation of O2‐binding capabilities by pendant substituents were investigated as compared with the parent Schiff base complex CoL5 (CoSalen). The results indicate that the dioxygen affinities of CoL have been much more enhanced by aza‐crown pendants than that by morpholino pendants, and the O2‐binding capabilities of CoL1 and CoL2 with aza‐crown pendants would also be enhanced by adding alkali metal cations. 相似文献
4.
Davood Nematollahi Leila Mohammadi‐Behzad Saied Saeed Hossainy Davarani 《Electroanalysis》2009,21(9):1099-1106
The electrochemical oxidation of catechols ( 1 ) have been studied in the presence of diaza‐18‐crown‐6 (DA18C6) ( 3a ), diaza‐15‐crown‐5 (DA15C5) ( 3b ), and aza‐15‐crown‐5 (A15C5) ( 3c ) as nucleophiles in aqueous solution, by means of cyclic voltammetry and controlled‐potential coulometry. The results indicate the participation of electrochemically generated o‐benzoquinones ( 2 ) in Michael‐type reaction with aza‐crown ethers ( 3 ) to form the corresponding new o‐benzoquinone‐aza‐crown ether adducts ( 5 ). Based on ECE mechanism, the observed homogeneous rate constants (kobs) of the reaction of o‐bezoquinones ( 2 ) with aza‐crown ethers ( 3 ) were estimated by comparing the experimental cyclic voltammograms with the digital simulated results. The calculated observed homogeneous rate constants (kobs) was found to vary in the order DA18C6>DA15C5>A15C5. 相似文献
5.
Maria G. Babashkina Damir A. Safin Michael Bolte Axel Klein 《Heteroatom Chemistry》2010,21(7):486-491
The reaction of the lithium salts of N‐phosphorylated thioureas RC(S)NHP(O)(OiPr)2 (R = 1‐aza‐15‐crown‐5, HL I ; 1‐aza‐12‐crown‐4, HL II ) with Co(II) or Ni(II) leads to the chelate complexes [ ML I,II 2 ]. The metal center is found in a tetrahedral ([ CoL I,II 2 ]) or square planar ([ NiL I,II 2 ]) O2S2 environment formed by the CS sulfur atoms and the PO oxygen atoms of two deprotonated ligands L . The molecular structure of [ CoL I 2 ] was elucidated by X‐ray diffraction and the extraction properties of HL I,II and [ ML I,II 2 ] toward alkali metal and ammonium picrates were investigated. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:486–491, 2010; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20637 相似文献
6.
Tuncer Hkelek Elif Ece Kaya Zeynel Kl 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(4):o278-o280
The title compound, C22H30N2O2·H2O, is an 18‐membered diaza‐crown ether ligand containing two ether O and two aza N atoms. In the macrocyclic ring, the mean N⋯O distance is 4.526 (4) Å. The macrocyclic inner‐hole size, estimated as twice the mean distance of the donor atoms from their centroid, is ∼2.29 Å. 相似文献
7.
Yoichi Habata Sadatoshi Akabori Xian Xin Zhang Reed M. Izatt Jerald S. Bradshaw 《Journal of heterocyclic chemistry》2001,38(6):1329-1340
A series of monoaza‐15‐crown‐5 ethers (2b‐2h) having 4′‐hydroxy‐3′,5′‐disubstituted benzyl groups have been prepared by the Mannich reaction of 2,6‐disubstituted phenols with the corresponding N‐methoxymethylmonoaza‐crown ethers. Competitive transport through a chloroform membrane by 12‐crown‐4 derivatives (lithium, potassium and cesium) and 15‐crown‐5 derivatives (sodium, potassium and cesium) were measured under basic‐source phase and acidic‐receiving phase conditions. All ligands transported size‐matched alkali‐metal cations. Ligands 1h and 2h with two fluorine atoms in the side arm gave higher metal ion transport rates than those of dimethyl‐ (1a and 2a), diisopropyl‐ (1b and 2b), and butylmethyl‐ (1d and 2d) derivatives. X‐ray crystal structures of six alkali metal complexes with monoaza‐12‐crown‐4‐derivatives ( 1b‐LiSCN, 1b‐KSCN, 1c‐NaSCN, 1d‐LiSCN, 1f‐RbSCN and 1h‐LiSCN ) and three alkali metal complexes with 15‐crown‐5 derivatives ( 2b‐KSCN, 2c‐KSCN , and 2e‐KSCN ) along with crystal structures of some new ligands (1b, 1c, 1d, 1f, and 2c) are also reported. These X‐ray analyses indicate that the crystal structures of the alkali metal ion complexes of these new armed‐crown ethers changed depending on the substituents at the 3′‐ and 5′‐positions of the appended hydroxybenzyl arms. 相似文献
8.
Complexes of trifluoromethanesulfonates (triflates) with alkali metals Na, Rb, Cs have been prepared in the presence of various macrocyclic polyether crowns [(12‐crown‐4), (15‐crown‐5) and (18‐crown‐6)]. Depending on the combination of alkali ion with crown, the complexes include separated ion pairs [Na(12‐crown‐4)2] [SO3CF3] ( 1 ) and contact ion pairs [Na(15‐crown‐5)] [SO3CF3] ( 2 ), [Rb(18‐crown‐6)] [SO3CF3] ( 3 ), and [Cs(18‐crown‐6)] [SO3CF3] ( 4 ), in which the triflate acts as a bidentate ligand. It is shown that the choice of crown ether is of paramount importance in determining the solid‐state structural outcome. The complex resulting from the pairing of crown ether ( 1 ) develops, when the crown ether is too small in relation to the alkali ion radius. When the cavity size of the crown ether is matched with the alkali ion radius, simple monomeric structures are identified in 2 , 3 and 4 . The title compounds crystallize in the monoclinic crystal system: 1 : space group P2/c with a = 9.942(3), b = 11.014(2), c = 10.801(3) Å, β = 97.30(2)°, V = 1173.1(4) Å3, Z = 2, R1 = 0.0812, wR2 = 0.1133: 2 : space group P21/m with a = 7.949(2), b = 12.063(3), c = 9.094(2) Å, β = 105.98(2)°, V = 838.3(4) Å3, Z = 2, R1 = 0.0869, wR2 = 0.1035: 3 : space group P21/c with a = 12.847(5), b = 8.448(2), c = 22.272(6) Å, β = 122.90(3)°, V = 2029.5(1) Å3, Z = 4, R1 = 0.0684, wR2 = 0.1044: 4 : space group P21/n with a = 12.871(3), b = 8.359(1), c = 19.019(4) Å, β = 92.61(2)°, V = 2044.2(6) Å3, Z = 4, R1 = 0.0621, wR2 = 0.0979. 相似文献
9.
Sayuri Yonekawa Aaron M. Goodpaster Benjamin A. Abel Rodney G. Paulin Charles W. Sexton James S. Poole Bruce N. Storhoff Phillip E. Fanwick 《Journal of heterocyclic chemistry》2006,43(3):689-694
10.
Yuan Miao Xueye Wang Xin Jin Ling Yi Cuihuan Ren 《Journal of computational chemistry》2011,32(3):406-415
A classical model of “molecular machine,” which acts as an ON–OFF switch for 2,2′‐bipyridyl‐3,3′‐15‐crown‐5 ( L ), has been theoretically studied. It is highly important to understand the mechanism of this switch. The alkali‐metal cations (Na+ and K+) and W(CO)4 fragment are introduced to coordinate with the different active sites of L , respectively. The density functional theory (DFT) method is used for understanding the stereochemical structural natures and thermodynamic properties of all the target molecules at B3LYP/6‐31G(d) and SDD (Stuttgart–Dresden) level, together with the corresponding effective core potential (ECP) for tungsten (W). The fully optimized geometries have been performed with real frequencies, which indicate the minima states. The nucleophilicity of L has been investigated by the Fukui functions. The natural bond orbital analysis is used to study the intermolecular charge‐transfer interactions and explore the origin of the internal forces of the molecular switch. In addition, the binding energies, enthalpies, Gibbs free energies, and the cation exchange energies have been studied for L , W(CO)4 L , and their corresponding complexes. The properties of the complexes displayed by in presence or absence of the W(CO)4 fragment are also analyzed. The calculated results of allosterism displayed by L are in a good agreement with the experimental results. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2011 相似文献
11.
Ning Su Jerald S. Bradshaw Guoping Xue N. Kent Dalley Xian X. Zhang Paul B. Savage Krzysztof E. Krakowiak Reed M. Izatt 《Journal of heterocyclic chemistry》2000,37(4):711-718
The Mannich aminomethylation reaction of aromatic thiols has been used to produce diaza‐18‐crown‐6 ligands containing thiol‐derived side arms. Thiophenols were attached to the azacrown through N‐CH2‐S linkages even in the presence of hydroxy or acetamido groups. Heteroaromatic thiols containing N=C‐SH (or NH‐C=S) structural fragments were attached to diaza‐18‐crown‐6 by N‐CH2‐N linkages with the thiol becoming a thione function. X‐ray crystal structural analyses show the N‐CH2‐S and N‐CH2‐N linkages for some of the new macrocyclic compounds. Interactions of four of the new diaza‐18‐crown‐6 ligands with Na+, K+, Ba2+, Ag+, Zn2+, Cd2+, Ni2+, and Cu2+ were evaluated by calorimetric titration at 25° in methanol. The results show that these ligands form stable complexes with many of the metal ions studied. 相似文献
12.
A New Water‐Soluble Phosphorus‐Dipyrromethene and Phosphorus‐Azadipyrromethene Dye: PODIPY/aza‐PODIPY
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Dr. Xin‐Dong Jiang Jiuli Zhao Dongmei Xi Haifeng Yu Jian Guan Shuang Li Dr. Chang‐Liang Sun Prof. Dr. Lin‐Jiu Xiao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(16):6079-6082
PODIPY and aza‐PODIPY have been successfully prepared by the treatment of dipyrromethene and azadipyrromethene with POCl3 in the presence of Et3N. The new PODIPY and aza‐PODIPY dyes are found to have photophysical properties. PODIPY and aza‐PODIPY are water‐soluble, and aza‐PODIPY is suited for labeling living Hep‐2 cells for imaging assays in the near‐infrared region. Molecular orbital calculations show that the increase in the HOMO–LUMO band gap for the lowest energy absorption bands is observed in the new phosphorus‐containing aza‐PODIPY, and the HOMO and LUMO energies of aza‐PODIPY are found to be higher than those of aza‐BODIPY. 相似文献
13.
Wolf Peter Fehlhammer Stephan Schrlkamp Michael Hoyer Hans Hartl Wolfgang Beck 《无机化学与普通化学杂志》2005,631(15):3025-3029
Alkali‐isocyanoacetates. Synthesis and Structure of [K(18‐crown‐6)](O2CCH2NC) The alkali isocyanoacetates M+[O2CCH2NC]? (M = Li,Na,K,Cs) ( 1a ‐ d ) are synthesized by reaction of ethyl isocyanoacetate with the respective alkali hydroxides in ethanol and characterized by IR, NMR (1H, 13C), and mass spectrometry (FAB). In alcoholic solution as well as in the gas phase ion pairs and higher aggregated species are observed. In contrast, [K(18‐crown‐6)][O2CCH2NC] ( 2 ) which is obtained from 1c and 18‐crown‐6, turns out to be a 1:1 electrolyte in solution (acetone); in the solid, the isocyanoacetate anion binds to K+ via the two carboxylate oxygen atoms resulting in an O8‐coordinated metal atom. 相似文献
14.
Usha D. Phalgune Kumar Vanka P. R. Rajamohanan 《Magnetic resonance in chemistry : MRC》2013,51(12):767-774
Density functional theory (DFT)/Becke–Lee–Yang–Parr (B3LYP) and gauge‐including atomic orbital (GIAO) calculations were performed on a number of 1,2,4‐triazole derivatives, and the optimized structural parameters were employed to ascertain the nature of their predominant tautomers. 13C and 15N NMR chemical shifts of 3‐substituted 1,2,4‐triazole‐5‐thiones and their propargylated derivatives were calculated via GIAO/DFT approach at the B3LYP level of theory with geometry optimization using a 6‐311++G** basis set. A good agreement between theoretical and experimental 13C and 15N NMR chemical shifts could be found for the systems investigated. The data generated were useful in predicting 15N chemical shifts of all the nitrogen atoms of the triazole ring, some of which could not be obtained in solution state 15N HMBC/HSQC NMR measurements. The energy profile computed for the dipropargylated derivatives was found to follow the product distribution profile of regioisomers formed during propargylation of 1,2,4‐triazole thiones. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
15.
Maria G. Babashkina Elmira R. Shakirova Dr. Damir A. Safin Felix D. Sokolov Axel Klein Łukasz Szyrwiel Maria Kubiak Henryk Kozlowski Dmitriy B. Krivolapov 《无机化学与普通化学杂志》2010,636(15):2626-2632
Reaction of O,O′‐diisopropylthiophosphoric acid isothiocyanate (iPrO)2P(S)NCS with 1,10‐diaza‐18‐crown‐6, 1,7‐diaza‐18‐crown‐6, or 1,7‐diaza‐15‐crown‐5 leads to the N‐thiophosphorylated bis‐thioureas N,N′‐bis[C(S)NHP(S)(OiPr)2]‐1,10‐diaza‐18‐crown‐6 ( H2LI ), N,N′‐bis[C(S)NHP(S)(OiPr)2]‐1,7‐diaza‐18‐crown‐6 ( H2LII ) and N,N′‐bis[C(S)NHP(S)(OiPr)2]‐1,7‐diaza‐15‐crown‐5 ( H2LIII ). Reaction of the potassium salts of H2LI–III with a mixture of CuI and 2,2′‐bipyridine ( bpy ) or 1,10‐phenanthroline ( phen ) in aqueous EtOH/CH2Cl2 leads to the dinuclear complexes [Cu2(bpy)2LI–III] and [Cu2(phen)2LI–III] . The structures of these compounds were investigated by 1H, 31P{1H} NMR spectroscopy, and elemental analysis. The crystal structures of H2LI and [Cu2(phen)2LI] were determined by single‐crystal X‐ray diffraction. Extraction capacities of the obtained compounds in comparison to the related compounds 1,10‐diaza‐18‐crown‐6, N,N′‐bis[C(=CMe2)CH2P(O)(OiPr)2]‐1,10‐diaza‐18‐crown‐6, N,N′‐bis[C(S)NHP(O)(OiPr)2]‐1,10‐diaza‐18‐crown‐6 towards the picrate salts LiPic, NaPic, KPic. and NH4Pic were also studied. 相似文献
16.
Xiaoming He Wai Han Lam Nianyong Zhu Vivian Wing‐Wah Yam 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(35):8842-8851
Two calixarene‐based bis‐alkynyl‐bridged AuI isonitrile complexes with two different crown ether pendants, [{calix[4]arene‐(OCH2CONH‐C6H4C≡C)2}{Au(CNR)}2] (R=benzo[15]crown‐5 ( 1 ); R=benzo[18]crown‐6 ( 2 )), together with their related crown‐free analogue 3 (R=C6H3(OMe)2‐3,4) and a mononuclear gold(I) complex 4 with benzo[15]crown‐5 pendant, have been designed and synthesized, and their photophysical properties have been studied. The X‐ray structure of the ligand, calix[4]arene‐(OCH2CONH‐C6H4C?CH)2 has been determined. The cation‐binding properties of these complexes with various metal ions have been studied using UV/Vis, emission, 1H NMR, and ESI‐MS techniques, and DFT calculations. A new low‐energy emission band associated with Au???Au interaction could be switched on upon formation of the metal ion‐bound adduct in a sandwich fashion. 相似文献
17.
Vira V. Ponomarova Julia A. Rusanova Eduard B. Rusanov Konstantin V. Domasevitch 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(10):867-872
In (1,4,7,10,13,16‐hexaoxacyclooctadecane)rubidium hexachloridoantimonate(V), [Rb(C12H24O6)][SbCl6], (1), and its isomorphous caesium {(1,4,7,10,13,16‐hexaoxacyclooctadecane)caesium hexachloridoantimonate(V), [Cs(C12H24O6)][SbCl6]}, (2), and ammonium {ammonium hexachloridoantimonate(V)–1,4,7,10,13,16‐hexaoxacyclooctadecane (1/1), (NH4)[SbCl6]·C12H24O6}, (3), analogues, the hexachloridoantimonate(V) anions and 18‐crown‐6 molecules reside across axes passing through the Sb atoms and the centroids of the 18‐crown‐6 groups, both of which coincide with centres of inversion. The Rb+ [in (1)], Cs+ [in (2)] and NH4+ [in (3)] cations are situated inside the cavity of the 18‐crown‐6 ring; they are situated on axes and are equally disordered about centres of inversion, deviating from the centroid of the 18‐crown‐6 molecule by 0.4808 (13), 0.9344 (7) and 0.515 (8) Å, respectively. Interaction of the ammonium cation and the 18‐crown‐6 group is supported by three equivalent hydrogen bonds [N...O = 2.928 (3) Å and N—H...O = 162°]. The centrosymmetric structure of [Cs(18‐crown‐6)]+, with the large Cs+ cation approaching the centre of the ligand cavity, is unprecedented and accompanied by unusually short Cs—O bonds [2.939 (2) and 3.091 (2) Å]. For all three compounds, the [M(18‐crown‐6)]+ cations and [SbCl6]− anions afford linear stacks along the c axis, with the cationic complexes embedded between pairs of inversion‐related anions. 相似文献
18.
John A. Schlueter Urs Geiser 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(8):m325-m327
The crystal structure of the title compound, K[Ag(CN)2]·C12H24O6, conventionally denoted K(18‐crown‐6)Ag(CN)2, where 18‐crown‐6 is 1,4,7,10,13,16‐hexaoxacyclooctadecane, is characterized by closely packed linear chains formed by the coordination of the nitrile N atoms of the [Ag(CN)2]− anions to the K+ cations. The K atoms lie on centers of inversion and are additionally bound to the six O atoms of the crown ether. 相似文献
19.
Kiyoshi Matsumoto Hirokazu Iida Yukio Ikemi Akira Shigeta Mitsuo Toda Naoto Hayashi Robert A Bulman 《Journal of heterocyclic chemistry》2005,42(2):191-199
Substitution on the nitrogen atom, where necessary by high‐pressure SNAr reactions, of aza‐18‐crown‐6 ethers linked to heterocyclic aromatics has extended the number of potential host compounds for Ag+. The complexation of Ag+ by the new compounds has been evaluated by liquid membrane ion transport and ion extraction experiments. The nature of the binding sites of these new host compounds for Ag+ has been assessed, in DMF/D2O (4/1), by 13C nmr titration experiments with AgClO4. 相似文献
20.
The unsymmetrical bis‐Schiff base manganese(III) and cobalt(II) complexes with either benzo‐10‐aza‐crown ether pendants (MnL1Cl, MnL2Cl) or morpholino pendant (MnL3Cl, CoL3) have been employed as models for hydrolase by studying the kinetics of their hydrolysis reactions with p‐nitrophenyl picolinate (PNPP). A kinetic model of PNPP cleavage catalyzed by these complexes is proposed. The effects of complex structures and reaction temperature on the rate of PNPP hydrolysis have been examined. All four complexes exhibit high catalytic activity and the rate increases with pH under 25°C. The complexes of ligands containing a crown ether group exhibit higher catalytic activities than the non‐crown analogues. The catalytic activity of the complexes follows the order Mn(III)>Co(II) under the same ligands. 相似文献