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1.
Jan W. Bats Peter Schell Joachim W. Engels 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(5):529-533
Crystal structures are reported for three substituted 1H‐imidazole‐4,5‐dicarbonitrile compounds used as catalysts for the coupling reaction of nucleoside methyl phosphonamidites, namely 2‐(3′,5′‐dimethylbiphenyl‐2‐yl)‐1H‐imidazole‐4,5‐dicarbonitrile, C19H14N4, (I), 2‐(2′,4′,6′‐trimethylbiphenyl‐2‐yl)‐1H‐imidazole‐4,5‐dicarbonitrile, C20H16N4, (II), and 2‐[8‐(3,5‐dimethylphenyl)naphthalen‐1‐yl]‐1H‐imidazole‐4,5‐dicarbonitrile, C23H16N4, (III). The asymmetric unit of (I) contains two independent molecules with similar conformations. There is steric repulsion between the imidazole group and the terminal phenyl group in all three compounds, resulting in the nonplanarity of the molecules. The naphthalene group of (III) shows significant deviation from planarity. The C—N bond lengths in the imidazole rings range from 1.325 (2) to 1.377 (2) Å. The molecules are connected into zigzag chains by intermolecular N—H...Nimidazole [for (I)] or N—H...·Ncyano [for (II) and (III)] hydrogen bonds. 相似文献
2.
Maciej Kubicki Teresa Borowiak Jerzy Suwiński Paweł Wagner 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(1):106-108
Crystalline 4-nitro-1-phenylimidazole, C9H7N3O2, (I), and 4′-nitro-1-phenyl-4,1′-biiimidazole, C12H9N5O2, (II), contain C—H⃛O and C—H⃛N hydrogen bonds, connecting the molecules into infinite chains. The aromatic fragments in both compounds are nearly planar. The dihedral angles between the benzene and imidazole rings are 26.78 (5)° in (I) and 29.36 (8)° in (II). 相似文献
3.
Fen Sun Yan‐Tuan Li Zhi‐Yong Wu Yu‐Lan Song Man Jiang 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(12):m584-m586
The structure of the title compound, [Cu2(C12H24N4O2)(C3H4N2)2(CH4O)2](ClO4)2 or [Cu2(dmoxpn)(HIm)2(CH3OH)2](ClO4)2, where dmoxpn is the dianion of N,N′‐bis[3‐(dimethylamino)propyl]oxamide and HIm is imidazole, consists of a centrosymmetric trans‐oxamidate‐bridged copper(II) binuclear cation, having an inversion centre at the mid‐point of the central C—C bond, and two perchlorate anions. The CuII atom has square‐pyramidal coordination geometry involving two N atoms and an O atom from the dmoxpn ligand, an N atom from an imidazole ring, and an O atom from a methanol molecule. The crystal structure is stabilized by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds and imidazole π–π stacking interactions to form a three‐dimensional supramolecular array. 相似文献
4.
Halis
lmez Cengiz Arc Okan Zafer Yeilel 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(6):m240-m242
In the title complex, mer‐diaqua[2,6‐dioxo‐1,2,3,6‐tetrahydropyrimidine‐4‐carboxylato(2−)]bis(1H‐imidazole‐κN3)cobalt(II), [Co(C5H2N2O4)(C3H4N2)2(H2O)2], the CoII ion is coordinated by a deprotonated N atom and the carboxylate O atom of the orotate ligand, two imidazole N atoms and two aqua ligands in a distorted octahedral geometry. The title complex exists as discrete doubly hydrogen‐bonded dimers, and a three‐dimensional network of O—H...O and N—H...O hydrogen bonds and weak π–π interactions is responsible for crystal stabilization. 相似文献
5.
Diana Yanover Menahem Kaftory 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(8):o365-o370
The lophine derivative 2‐(2‐nitrophenyl)‐4,5‐diphenyl‐1H‐imidazole, C21H15N3O2, (I), crystallized from ethanol as a solvent‐free crystal and from acetonitrile as the monosolvate, C21H15N3O2·C2H3N, (II). Crystallization of 2‐(4‐nitrophenyl)‐4,5‐diphenyl‐1H‐imidazole from methanol yielded the methanol monosolvate, C21H15N3O2·CH4O, (III). Three lophine derivatives of methylated imidazole, namely, 1‐methyl‐2‐(2‐nitrophenyl)‐4,5‐diphenyl‐1H‐imidazole methanol solvate, C22H17N3O2·CH4O, (IV), 1‐methyl‐2‐(3‐nitrophenyl)‐4,5‐diphenyl‐1H‐imidazole, C22H17N3O2, (V), and 1‐methyl‐2‐(4‐nitrophenyl)‐4,5‐diphenyl‐1H‐imidazole, C22H17N3O2, (VI), were recrystallized from methanol, acetonitrile and ethanol, respectively, but only (IV) produced a solvate. Compounds (III) and (IV) each crystallize with two independent molecules in the asymmetric unit. Five imidazole molecules in the six crystals differ in their molecular conformations by rotation of the aromatic rings with respect to the central imidazole ring. In the absence of a methyl group on the imidazole [compounds (I)–(III)], the rotation angles are not strongly affected by the position of the nitro group [44.8 (2) and 45.5 (1)° in (I) and (II), respectively, and 15.7 (2) and 31.5 (1)° in the two molecules of (III)]. However, the rotation angle is strongly affected by the presence of a methyl group on the imidazole [compounds (IV)–(VI)], and the position of the nitro group (ortho, meta or para) on a neighbouring benzene ring; values of the rotation angle range from 26.0 (1) [in (VI)] to 85.2 (1)° [in (IV)]. This group repulsion also affects the outer N—C—N bond angle. The packing of the molecules in (I), (II) and (III) is determined by hydrogen bonding. In (I) and (II), molecules form extended chains through N—H...N hydrogen bonds [with an N...N distance of 2.944 (5) Å in (I) and 2.920 (3) Å in (II)], while in (III) the chain is formed with a methanol solvent molecule as the mediator between two imidazole rings, with O...N distances of 2.788 (4)–2.819 (4) Å. In the absence of the imidazole N—H H‐atom donor, the packing of molecules (IV)–(VI) is determined by weaker intermolecular interactions. The methanol solvent molecule in (IV) is hydrogen bonded to imidazole [O...N = 2.823 (4) Å] but has no effect on the packing of molecules in the unit cell. 相似文献
6.
Miguel A. Huertos Julio Pérez Dr. Lucía Riera Dr. Jesús Díaz Dr. Ramón López Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(28):8495-8507
Complexes [Re(CO)3(N‐RIm)3]OTf (N‐RIm=N‐alkylimidazole, OTf=trifluoromethanesulfonate; 1 a – d ) have been straightforwardly synthesised from [Re(OTf)(CO)5] and the appropriate N‐alkylimidazole. The reaction of compounds 1 a – d with the strong base KN(SiMe3)2 led to deprotonation of a central C? H group of an imidazole ligand, thus affording very highly reactive derivatives. The latter can evolve through two different pathways, depending on the nature of the substituents of the imidazole ligands. Compound 1 a contains three N‐MeIm ligands, and its product 2 a features a C‐bound imidazol‐2‐yl ligand. When 2 a is treated with HOTf or MeOTf, rhenium N‐heterocyclic carbenes (NHCs) 3 a or 4 a are afforded as a result of the protonation or methylation, respectively, of the non‐coordinated N atom. The reaction of 2 a with [AuCl(PPh3)] led to the heterobimetallic compound 5 , in which the N‐heterocyclic ligand is once again N‐bound to the Re atom and C‐coordinated to the gold fragment. For compounds 1 b – d , with at least one N‐arylimidazole ligand, deprotonation led to an unprecedented reactivity pattern: the carbanion generated by the deprotonation of the C2? H group of an imidazole ligand attacks a central C? H group of a neighbouring N‐RIm ligand, thus affording the product of C? C coupling and ring‐opening of the imidazole moiety that has been attacked ( 2 c , d ). The new complexes featured an amido‐type N atom that can be protonated or methylated, thus obtaining compounds 3 c , d or 4 c , d , respectively. The latter reaction forces a change in the disposition of the olefinic unit generated by the ring‐opening of the N‐RIm ligand from a cisoid to a transoid geometry. Theoretical calculations help to rationalise the experimental observation of ring‐opening (when at least one of the substituents of the imidazole ligands is an aryl group) or tautomerisation of the N‐heterocyclic ligand to afford the imidazol‐2‐yl product. 相似文献
7.
Carmen R. Maldonado Miguel Quirs Juan M. Salas 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(8):o489-o491
The title compound, C5H5N5OS·H2O, crystallizes as the monohydrate. Disorder of the H atoms that participate in the hydrogen bonds implies that two different tautomers are present in the crystal structure, one of them with both acidic H atoms attached to the imidazole ring and the other with one acidic H atom on each ring. 相似文献
8.
Fengli Bei Fangfang Jian Xujie Yang Lude Lu Xin Wang S. Shanmuga Sundara Raj Hoong‐Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):718-719
The title compound, C20H14N4, lies about an inversion centre and the benzimidazole moiety and the phenyl ring are twisted by 30.9 (1)°. The benzimidazole moiety is completely planar, with a maximum deviation of 0.009 (2) Å. Intermolecular N—H?N hydrogen bonds give rise to a layered structure, with the layers stacked by van der Waals interactions. 相似文献
9.
Zuoxiang Wang Yurong Zhang Ibrahim Abdul Razak S. Shanmuga Sundara Raj Hoong‐Kun Fun Fengsheng Li Hongchang Song 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(2):161-162
In the title complex of [Ni(C3H4N2)6](C8H7O3)2, the Ni atom is in an octahedral environment formed by the tertiary N atom of the imidazole moieties. The methoxybenzoate moieties act as a bridge connecting two hexakis(imidazole)nickel(II) molecules through N—H?O hydrogen bonds. 相似文献
10.
David J. Nielsen Claudio Pettinari Brian W. Skelton Allan H. White 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(8):o542-o544
Low‐temperature studies of the simple variously substituted imidazole types 4‐phenyl‐1H‐imidazole, C9H8N2, 1‐benzyl‐1H‐imidazole, C10H10N2, and 1‐mesityl‐1H‐imidazole, C12H14N2, extend comparisons between parent imidazole species and their derivatives, the pronounced double‐bond localization opposite the substituted N atom common to simple neutral species being redistributed aromatically on protonation. 相似文献
11.
《Journal of Coordination Chemistry》2012,65(1):97-107
The complexes [{(η 6-arene)Ru(μ-Cl)Cl}2] (arene?=?p-cymene (1), hexamethylbenzene reacts at low temperature with the arylazoimidazole (RaaiR′) ligands 2-(phenylazo)imidazole (Phai-H), 1-methyl-2-(phenylazo)imidazole (Phai-Me), 1-ethyl-2-(phenylazo)imidazole (Phai-Et), 2-(tolylazo)imidazole (Tai-H), 1-methyl-2-(tolylazo)imidazole (Tai-Me) and 1-ethyl-2-(tolylazo)imidazole (Tai-Et) to give complexes of the type [(η 6-arene)RuCl(RaaiR′)]+. The complexes were characterized by FTIR and 1H NMR and 13C {1H} NMR spectroscopy. The molecular structure of [(η 6-p-cymene)RuCl(Me-C6H4-N=N-C3H2N2-1-CH3)]PF6 was established by single-crystal X-ray diffraction methods. 相似文献
12.
Carbon-13?proton coupling constants in N-substituted imidazoles. A 13C NMR study and MO calculations
The 13C NMR data of imidazole, and N-methyl-, N-acetyl-, N-trifluoroacetyl-, N-heptafluorobutyryl- and 2-methyl-imidazoles, were obtained from proton-noise decoupled and single frequency NOE 13C NMR spectra. The considerable changes in the directly-bonded (C, H) coupling constants upon N-acetylation of the imidazole ring, which are comparable to those noted when going from the neutral to the cationic form of imidazole, are primarily due to the large π-electron transfer ability of the N-acetyl- and N-trifluoroacetyl-substituents. The differences in magnitude of the three-bond (C, H) coupling constants along different paths in the imidazole ring may be attributed to the larger π-contributions across a pyridine-like nitrogen than along a pyrrole-like nitrogen. 相似文献
13.
O. Tapia R. Crdenas Y. G. Smeyers A. Hernndez-Laguna J. J. Rndez F. J. Rndez 《International journal of quantum chemistry》1990,38(5):727-740
The potential energy hypersurface of the histamine monocation is determined by ab initio methods at the STO -4G level using analytical gradient techniques. Three transition states and two minima have been found for the Nτ? H tautomer. One of the transition states connects the trans conformational region with a minimum gauche structure, where the proton of the ammonium group is approximately halfway between the Nπ of the imidazole group and the N of the ammonium group, but nearer to the Nπ. This minimum connects the potential energy surface of the Nτ? H tautomer with the imidazolium one. In the latter region, three transition states and two minima have been found. Critical points are discussed in relation with experimental data and histamine H2 receptor models. 相似文献
14.
Miroslav Bo
a Duan Valigura Ingrid Svoboda Hartmut Fuess Wolfgang Linert 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(7):838-839
The title compound, C19H14N5+·ClO4?·H2O, contains planar C19H14N5+ cations, perchlorate anions and water molecules. The two closest parallel cations (plane‐to‐plane distance of 3.41 Å), together with two neighbouring perchlorate anions and two water molecules, form an electrically neutral quasi‐dimeric unit. Two acidic H atoms of the cation, both H atoms of the water molecule, the N atoms of the imidazole rings and three of the four O atoms of the perchlorate anion are involved in the hydrogen‐bonding network within the dimeric unit. The remaining third acidic H atom of the imidazole rings and the water molecules complete a two‐dimensional network of hydrogen bonds, thus forming puckered layers of dimers. The angle between the planes of two neighbouring dimeric units in the same layer is 33.25 (3)°. 相似文献
15.
Ana María Atria Piedad Corts María Teresa Garland Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(10):m396-m398
The structures of aquadichlorobis(1H‐imidazole)cobalt(II), [CoCl2(Him)2(H2O)2] (Him is 1H‐imidazole, C3H4N2), (I), and aquadichlorobis(1H‐imidazole)nickel(II), [NiCl2(Him)2(H2O)2], (II), are isomorphous and consist of monomers with inversion symmetry. The three monodentate ligands (imidazole, chlorine and aqua), together with their symmetry equivalents, define almost perfect octahedra. Hydrogen‐bonding interactions via the imidazole and aqua H atoms lead to a three‐dimensional network. 相似文献
16.
brahim Uar Ahmet Bulut Okan Zafer Yeilel Halis
lmez Orhan Büyükgüngr 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(11):m563-m566
The title mononuclear complex, [Ni(C5H2N2O4)(C3H4N2)2(H2O)2] or [Ni(HOr)(im)2(H2O)2] (im is imidazole and H3Or is orotic acid, or 2,6‐dioxo‐1,2,3,6‐tetrahydropyrimidine‐4‐carboxylic acid), has been synthesized and the crystal structure determination is reported. The NiII ion in the complex has a distorted octahedral coordination geometry comprised of one deprotonated pyrimidine N atom and the adjacent carboxylate O atom of the orotate ligand, two tertiary imidazole N atoms and two aqua ligands. An extensive three‐dimensional network of OW—H⋯O and N—H⋯O hydrogen bonds, and π–π and π–ring interactions are responsible for crystal stabilization. 相似文献
17.
The synthetic utility of N-triflylimidazole as an in situ reagent for facile, high yielding, synthesis of various aliphatic, aromatic, and heteroaromatic nitriles from the corresponding aldoximes has been demonstrated. With benzaldoximes, in the presence of certain substitutents (2-F; 2-OMe; 3-CF3; 2-Me-5-F) a different course of reaction was observed, leading instead to novel 1:1 aldoxime-bis(N-triflyl)imidazole covalent adducts, in which the aldoxime oxygen atom is bonded to the imidazole C-2 ring carbon. For these aldoximes, conversion to nitrile could be effected by reaction with Tf2O in the absence of imidazole. The molecular structure of the adduct formed from 2-methyl-5-fluoro-benzaldoxime was confirmed by X-ray analysis. Plausible mechanisms for the formation of 1:1 covalent adducts have been considered. Various attempts to isolate such adducts via the reaction of an authentic sample of bis(N-triflyl)imidazolium trifate with aldoxime were unsuccessful. Remarkably, whereas isolated benzaldoxime adducts undergo deprotonation/methylation with NaH/MeI, an authentic sample of bis(N-triflyl)imidazolium triflate did not undergo H/Me exchange under these conditions. These transformations are discussed. 相似文献
18.
John F. Gallagher Keith Hanlon Joshua Howarth 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(12):1410-1414
The title compounds, 1-ferrocenylmethyl-2-(4-methoxyphenyl)-1H-benzimidazole, [Fe(C5H5)(C20H17N2O)], (I), and 2-(3,4-dimethoxyphenyl)-1-ferrocenylmethyl-1H-benzimidazole, [Fe(C5H5)(C21H19N2O2)], (II), are model electroactive compounds for anion sensor and antimalarial applications. Distortions from the ideal 120° angle about the MeO—C—C groups are evident, with angles of 115.1 (2) and 125.0 (2)° in (I), and 115.9 (2) and 124.6 (2)°, and 115.7 (2) and 125.1 (2)° in (II). The main intermolecular hydrogen bonds in (I) comprise C—H⋯N and C—H⋯π(C5H5) interactions, while in (II), only weak C—H⋯π(imidazole) and C—H⋯π(arene) interactions are present. 相似文献
19.
The 15N NMR frequencies for imidazole nitrogens undergo significant shifts when imidazole or 1-methyl imidazole is taken from aqueous to CH2Cl2 solution. This shift is probably primarily due to strong hydrogen-bonding between 15N3 of imidazole and H2O protons in aqueous solution. 相似文献
20.
We have studied, by conductivity measurements, the formation of hydrogenbonded complexes between imidazoles and ions in the three systems triethylammonium picrate (Et3NHPic)+imidazole (Im), triethylammonium bromide (Et3NHBr)+Im, and Et3NHPic+1-methylimidazole (1-MeIm) in nitrobenzene in order to specify the importance of the two functions of the imidazole molecule, the tertiary nitrogen N3, and the imino group N1-H. While 1-MelIm forms only a single complex with the cationic species Et3NH+, imidazole enters into specific interactions as well with the cations through its basic site N3 and with the anions through its imino group. The complexing of the anions by imidazole, always weaker than the complexing of the cations, is more effective for Br– than for Pic–. Moreover, if imidazole is used as ligand, a 1:2 complex is formed between the cation and the imidazole, in which the second molecule of imidazole is bonded to the N-H group of the first by a hydrogen bond at the tertiary N atom. We did not observe a correlation between the equilibrium constants K
1
+
for the complexing of the cation Et3NH+ by imidazole and pyridines (k
1
+
for pyridine, 3–4 dimethylpyridine, and imidazole are 8, 24, and 165, respectively) and the pK
a
values of these ligands due to the fundamental difference in the structure of the imidazole and pyridine molecules, although both are considered as aromatic nitrogen bases. 相似文献