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1.
Rosa A. Vzquez García Sylvain Berns Ren Gutirrez Prez Marcos Martínez García 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(10):o619-o620
In 2‐methyl‐1,4,5‐triphenyl‐1H‐imidazole, C22H18N2, the three substituent phenyl groups are not delocalized with the imidazole moiety; the dihedral angles these phenyl groups form with the imidazole ring are in the range 25.90 (5)–63.49 (6)°. 相似文献
2.
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
3.
Evan A. Sarina Marilyn M. Olmstead Dung N. Nguyen Michael P. Groziak 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(2):183-185
The structure of the title compound, C7H6BNO3, a new boron heterocycle, prepared by the condensation of (2‐ethoxycarbonylphenyl)boronic acid and hydroxylamine, reveals the specific mode of intramolecular condensation between a phenylboronic acid and an ortho hydroxamic acid substituent. The crystal structure shows that dehydration occurs to form a planar oxazaborinine ring possessing both phenol‐like B—O—H and lactam functional groups. In the extended structure, intermolecular hydrogen bonding generates a 14‐membered ring. To our knowledge, this is the first crystal structure determination involving a six‐membered ring that exhibits consecutive B—OH, O, NH, and C=O functional groups. 相似文献
4.
All Solid State Chromium(III) Selective Potentiometric Sensor Based on 2‐(1‐(2‐((3‐(2‐Hydroxyphenyl)‐1H‐pyrozol‐1‐yl)methyl)benzyl)‐1H‐pyrazol‐3‐yl)phenol
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Pankaj Kumar Sanjeev Kumar Sapna Jain Bhawna Y. Lamba Girdhar Joshi Shefali Arora 《Electroanalysis》2014,26(10):2161-2167
Highly selective all solid state electrochemical sensor based on a synthesized compound i.e. 2‐(1‐(2‐((3‐(2‐hydroxyphenyl)‐1H‐pyrozol‐1‐yl)methyl)benzyl)‐1H‐pyrazol‐3‐yl)phenol (I) as an ionophore has been prepared and investigated for the selective quantification of chromium(III) ions. The effect of various plasticizers, viz. dibutyl phosphonate (DBP), dibutyl(butyl) phosphonate (DBBP), nitrophenyl octyl ether (NPOE), tris‐(2‐ethylhexyl)phosphonate (TEP), tri‐butyl phosphonate (TBP), dioctyl phthalate (DOP), dioctyl sebacate (DOS), benzyl acetate (BA) and acetophenone (AP) along with anion excluders NaTPB (sodium tetraphenyl borate) and KClTPB (potassium(tetrakis‐4‐chlorophenyl)borate was also studied. The optimum composition of the best performing membrane contained (I):KClTPB:NPOE:PVC in the ratio 15 : 3 : 40 : 42 w/w. The sensor exhibited near Nernstian slope of 20.1±0.2 mV/decade of activity in the working concentration range of 1.2×10?7–1.0×10?1 M, and in a pH range of 3.8–4.5. The sensor exhibited a fast response time of 10 s and could be used for about 5 months without any considerable divergence in potentials. The proposed sensor showed very good selectivity over most of the common cations including Na+, Li+, K+, Cu2+, Sr2+, Ni2+, Co2+, Ba2+, Hg2+, Pb2+, Zn2+, Cs+, Mg2+, Cd2+, Al3+, Fe3+and La3+. The activity of Cr(III) ions was successfully determined in the industrial waste samples by using this sensor. 相似文献
5.
An efficient one‐pot synthesis of 3‐[(4,5‐dihydro‐1H‐pyrrol‐3‐yl)carbonyl]‐2H‐chromen‐2‐one (=3‐[(4,5‐dihydro‐1H‐pyrrol‐3yl)carbonyl]‐2H‐1‐benzopyran‐2‐one) derivatives 4 by a four‐component reaction of a salicylaldehyde 1 , 4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one, a benzylamine 2 , and a diaroylacetylene (=1,4‐diarylbut‐2‐yne‐1,4‐dione) 3 in EtOH is reported. This new protocol has the advantages of high yields (Table), and convenient operation. The structures of these coumarin (=2H‐1‐benzopyran‐2‐one) derivatives, which are important compounds in organic chemistry, were confirmed spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS) and by elemental analyses. A plausible mechanism for this reaction is proposed (Scheme 2). 相似文献
6.
Bertrand Alluis Nathalie Prol Hakima Elhajji Olivier Dangles 《Helvetica chimica acta》2000,83(2):428-443
Water‐soluble derivatives of rutin, a very common glycoside of quercetin (=3,3′,4′,5,7‐pentahydroxyflavone=2‐(3,4‐dihydroxyphenyl)‐3,5,7‐trihydroxy‐4H‐1‐benzopyran‐4‐one) and a potent plant antioxidant from the flavonol family, were synthesized by simple chemical procedures aimed at introducing carboxy or sulfo groups at the sugar moiety (Scheme 1). Such derivatives form stable molecular complexes with malvin, a polyphenolic pigment from the anthocyanin family, and thereby prove to be very effective in the enhancement (hyperchromism) and variation (bathochromism) of natural colours. The H2O‐solubilizing carboxylate and sulfate groups are shown to deeply modify the enthalpy‐entropy balance of the pigment‐flavonol complexation (copigmentation). A molecular interpretation of the complexation‐induced bathochromic shift in the pigment VIS band is proposed. Finally, the H2O‐soluble rutin derivatives are shown to retain the high antioxidant ability of rutin as evidenced by their efficient trapping of the coloured radical DPPH (=2,2‐diphenyl‐1‐(2,4,6‐trinitrophenyl)hydrazyl). 相似文献
7.
Yasushi Kai Jun Sakamoto Takashi Nakagawa Nobuko Kanehisa Masahiro Katsura 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):e596-e597
In the title compound, C14H10N4, all the atoms are close to being coplanar (r.m.s. deviation 0.0098 Å) except for the imino H atoms. The molecule forms a one‐dimensional chain through intermolecular N—H?N hydrogen bonds. 相似文献
8.
Qiuli Yao Prof. Dr. Chengye Yuan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(19):6080-6088
A highly enantioselective synthesis of α‐hydroxyphosphinates was achieved based on the L ‐proline‐catalyzed aldol reaction of α‐acylphosphinates and acetone. Due to the preexisting chirality at the phosphorus center, mixtures of two diastereomers of the α‐hydroxyphosphinates were obtained in moderate to good yields, with simultaneously high enantioselectivity for both diastereomers. The products could be converted into α‐hydroxy‐H‐phosphinates with satisfactory yields. Furthermore, an unprecedented oxidation–reduction reaction of the α‐hydroxyphosphinates or α‐hydroxy‐H‐phosphinates to form phosphonates was observed, and the mechanism involved in such a chemical transformation is discussed. 相似文献
9.
Eberhardt Herdtweck Alexander Zeller Thomas Strassner 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(6):m166-m168
In the crystal structure of the title compound, [CoCl2(C7H12N2)2], molecular units are formed by coordination of the unsubstituted N atoms of two tert‐butyl‐substituted imidazole molecules and two chloride ligands, which distinguishes the complex from structures of imidazolium‐based dications with tetrachloridocobaltate dianions. There are two crystallographically independent molecules in the asymmetric unit, related by a noncrystallographic inversion centre. 相似文献
10.
Jun Luo Xin‐Rong Zhang Li‐Li Cui Wei‐Quan Dai Bao‐Shu Liu 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(12):m614-m616
The two new title complexes, [Mn(C5H3N6)2(H2O)2] and [Zn(C5H3N6)2(H2O)2], are isomorphous. In both compounds, the metal atom is located on an inversion center and is coordinated by four N atoms from two 5‐(pyrazin‐2‐yl)‐1H‐tetrazolate anions in the basal plane and by two O atoms of water ligands in the apical positions to form a distorted octahedral geometry. Intermolecular hydrogen‐bond interactions between the uncoordinated N atoms of the tetrazolate anions and the H atoms of the water molecules lead to the formation of a three‐dimensional network. 相似文献
11.
A novel straightforward synthesis of 3‐(1H‐tetrazol‐5‐yl)coumarins (=3‐(1H‐tetrazol‐5‐yl)‐2H‐1‐benzopyran‐2‐ones) 6 via domino Knoevenagel condensation, Pinner reaction, and 1,3‐dipolar cycloaddition of substituted salicylaldehydes (=2‐hydroxybenzaldehydes), malononitrile (propanedinitrile), and sodium azide in H2O is reported (Scheme 1 and Table 2). This general protocol provides a wide variety of 3‐(1H‐tetrazol‐5‐yl)coumarins in good yields under mild reaction conditions. 相似文献
12.
Hai‐Qiong Yao Li‐Hong Wu Gui‐Xin Chou Qing Liu Zheng‐Tao Wang 《Helvetica chimica acta》2015,98(5):657-662
Two new rare α‐pyrone (=2H‐pyran‐2‐one) derivatives, rhodanthpyrones A and B ( 1 and 2 , resp.), together with fourteen known compounds, 3 – 16 , were isolated from the whole plants of Gentiana rhodantha. The structures of these compounds were elucidated by spectroscopic analyses. This is the first report on the occurrence of α‐pyrone derivatives in the genus Gentiana. 相似文献
13.
Sergey A. Popov Nikita V. Chukanov Galina V. Romanenko Tatjana V. Rybalova Yuri V. Gatilov Vladimir A. Reznikov 《Journal of heterocyclic chemistry》2006,43(2):277-291
14.
Rosa M. Claramunt Dionisia Sanz Concepción López Elena Pinilla M. Rosario Torres José Elguero Pierre Nioche C. S. Raman 《Helvetica chimica acta》2009,92(10):1952-1962
The existence of polymorphism in parent indazolin‐3‐one (=1,2‐dihydro‐3H‐indazol‐3‐one; 1 ) is reported as well as an X‐ray and NMR CPMAS study establishing that its 7‐nitro derivative 2 exists as the 3‐hydroxy tautomer. Absolute shieldings calculated at the GIAO/B3LYP/6‐311++G(d,p) level were used to determine the tautomeric oxo/hydroxy equilibrium in solution, i.e., always the 1H‐indazol‐3‐ol tautomer predominates. 相似文献
15.
M.Manuel Oliveira LuisM. Carvalho Corinne Moustrou Andr Samat Robert Guglielmetti AnaM.F. Oliveira‐Campos 《Helvetica chimica acta》2001,84(5):1163-1171
The synthesis and photochromic properties of new 2,2‐diphenyl‐2H‐1‐benzopyrans, fused to an indole moiety, are described. All compounds exhibit photochromic behaviour in solution at room temperature. The heteroanellation effects are variable and depend on the position and geometry of the fused indole moiety. A general bathochromic shift in the spectra of the open forms is observed. The presence of a N‐methyl group prevents the broadening of the absorption spectra and promotes the instability of some photoinduced forms of compounds with the indole moiety fused at the 5,6 positions of the 2H‐1‐benzopyran skeleton. The enhanced photocolouration efficiency in the near‐UV and the kinetics of thermal bleaching indicate that the novel compounds with an indole moiety fused at the 6,7 positions, particularly those with a linked thiophene moiety, are very interesting molecules for applications in the field of variable optical absorption systems. 相似文献
16.
Alexander S. Lyakhov Dmitry O. Ivashkevich Sergei V. Voitekhovich Pavel N. Gaponik 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(12):m563-m564
The title compound, [CuCl2(C5H11N5)], is the first structurally characterized molecular chelate complex involving an α‐aminoalkyltetrazole. There are two complex molecules in the asymmetric unit. The ligand molecules are bidentate. Both Cu atoms reveal rather distorted square‐planar coordinations. The complex molecules are linked together by van der Waals interactions only. 相似文献
17.
Saeed Balalaie Mohammad Ali Bigdeli Enayatollah Sheikhhosseini Azizollah Habibi Hamed Piri Moghadam Mehrnoush Naderi 《Helvetica chimica acta》2012,95(3):528-535
The novel coumarin‐3‐carboxamides (=2‐oxo‐2H‐1‐benzopyran‐3‐carboxamides) 5a – 5g containing lipophilic spacers were synthesized through the Ugi‐four‐component reaction (Scheme 1). The reactions of aromatic aldehydes 1 , 4,4′‐oxybis[benzenamine] or 4,4′‐methylenebis[benzenamine] as diamine 2 , coumarin‐3‐carboxylic acid (=2‐oxo‐2H‐benzopyran‐3‐carboxylic acid; 3 ), and alkyl isocyanides 4 lead to the desired substituted coumarin‐3‐carboxamides 5a – 5g at room temperature with high bond‐forming efficiency. These novel coumarin derivatives exhibit brilliant fluorescence at 544 nm in CHCl3. 相似文献
18.
Miguel Angel Harvey Sergio Baggio Juan Carlos Muoz Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(7):m283-m285
The structure of [Zn(C19H12N5)2], which is monomeric and consists of neutral Zn(bbip‐H)2 entities [bbip‐H is the anionic form of bis(benzimidazolyl)pyridine, formed by the loss of one H atom], has been solved from a racemic twin. The Zn atom lies at a site with imposed 222 symmetry and the bbip‐H ligand has imposed twofold symmetry. The imidazolyl H atom is disordered over two symmetry‐related positions, thus raising the molecular symmetry as required by the space group. The angle between the planes of the two coordinated bbip‐H ligands is 84.6 (3)°, so defining a distorted octahedral environment around the metal atom. 相似文献
19.
Maciej Kubicki Pawe Wagner 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(8):o509-o511
The only specific interactions that influence the crystal packing of the title compound, C15H17ClN4O2, are weak C—H⋯N and C—H⋯Cl hydrogen bonds, even though there is a possibility of, for example, π–π stacking or halogen bonding. The dihedral angle between the mean planes of the imidazole and benzene rings is 59.82 (5)°. The length of the C—N bond connecting the imidazole and piperidine fragments is correlated with the degree of pyramidalization of the piperidine N atom. 相似文献
20.
Lara C. Spencer Ilia A. Guzei Tebogo V. Segapelo James Darkwa 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(11):m317-m319
The title compound, [PdCl2(C21H17N3)], is a member of a sequence of Pd, Pt and Co dichloride complexes bearing polysubstituted (pyrazol‐1‐ylmethyl)pyridine ligands. It is shown that there is a correlation between the steric bulkiness of the bidentate (pyrazol‐1‐ylmethyl)pyridine ligands and the Pd—Npyrazole distances, i.e. the larger the ligand, the longer the bond. In contrast, no trend is observed between the steric properties of the ligand and the Pd—Npyridine bond lengths. 相似文献