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1.
The crystal structures of the title compounds, [Cu(C15H11N2O2)2(C14H15N)2] and [Cu(C15H11N2O2)2(C14H15N)2]·2CHCl3, respectively, have been determined. The red disolvate complex affords a square‐planar CuN4 coordination environment in which the CuII atom lies on a centre of symmetry. The blue solvent‐free complex affords a distorted square‐pyramidal CuN4O coordination environment and adjacent mol­ecules form centrosymmetric dimers. A comparison of the different crystal structures focuses on the role of the solvent mol­ecules in supramolecular assemblies of the copper(II) complexes.  相似文献   

2.
The synthesis and structures of three isoxazole‐containing Schiff bases are reported, namely, (E)‐2‐{[(isoxazol‐3‐yl)imino]methyl}phenol, C10H8N2O2, (E)‐2‐{[(5‐methylisoxazol‐3‐yl)imino]methyl}phenol, C11H10N2O2, and (E)‐2,4‐di‐tert‐butyl‐6‐{[(isoxazol‐3‐yl)imino]methyl}phenol, C18H24N2O2. All three structures contain an intramolecular O—H…N hydrogen bond, alongside weaker intermolecular C—H…N and C—H…O contacts. The C—O(H) and imine C=N bond lengths were consistent with structures existing in the enol rather than the keto form. Despite having dihedral angles <25°, none of the compounds were observed to be strongly thermochromic, unlike their anil counterparts; however, all three compounds showed a visible colour change upon irradiation with UV light.  相似文献   

3.
Reactions of isopropoxides of praseodymium, neodymium and samarium with bifunctional tridentate and tetradentate schiff bases (i.e. salicylidene-O-aminophenol and bis-salicylaldehyde ethylenediamine) have been carried out in benzene in different stoichiometric ratios resulting in the formation of products with the formula M(OPri)(C11H9NO2), M(C13H9NO2)(C13H10NO2). M2(C13H9NO2) M(OPri)(C15H14N2O2), M(C16H14N2O2)(C16H15N2O2) and M2(C16H14N2O2)3 (where M stands for Pr, Nd and Sm). The products were found to be yellow to orange solids soluble in benzene and alcohol. The absorption spectra of these complexes were also recorded in methanol.  相似文献   

4.
Structures are reported for eight Schiff bases derived from various salicylaldehydes: five are newly synthesized and re‐investigations are reported for three previously reported structures, leading, in each case, to some revision of previous conclusions. In (E)‐N‐(3,4‐dimethylisoxazol‐5‐yl)‐4‐[(2‐hydroxybenzylidene)amino]benzenesulfonamide, C18H17N3O4S, (I), and (E)‐4‐[(5‐bromo‐2‐hydroxy‐3‐methoxybenzylidene)amino]‐N‐(3,4‐dimethylisoxazol‐5‐yl)benzenesulfonamide. C19H18BrN3O5S, (II), the isoxazole rings adopt different orientations relative to the rest of the molecules, despite the additional substituents in (II) being in the aryl ring remote from the isoxazole unit. The molecules of both (E)‐4‐bromo‐2‐[(2‐hydroxyphenylimino)methyl]‐6‐methoxyphenol, C14H12BrNO3, (III), and (E)‐4‐bromo‐2‐methoxy‐6‐[(2‐methoxyphenylimino)methyl]phenol, C15H14BrNO3, (IV), are both effectively planar; while (III) adopts the phenol–imine constitution, (IV) adopts the keto–amine constitution. (E)‐2‐Methoxy‐6‐[(2‐methoxyphenylimino)methyl]phenol, C15H15NO3, (V), which was determined previously using powder X‐ray data assuming the phenol–imine constitution, has now been refined from single‐crystal X‐ray data, confirming the phenol–imine constitution. In (E)‐3‐benzoyl‐2‐[(5‐fluoro‐2‐hydroxybenzylidene)amino]‐4,5,6,7‐tetrahydrobenzo[b]thiophene, C22H18FNO2S, (VI), the fused carbocyclic ring exhibits conformational disorder; both disorder components, having populations of 0.705 (4) and 0.295 (4), adopt half‐chair conformations. The isostructural (E)‐3‐benzoyl‐2‐[(2‐hydroxybenzylidene)amino)]‐4,5,6,7‐tetrahydrobenzo[b]thiophene, C22H19NO2S, (VII), which was originally reported as having a fully ordered structure [Kaur et al. (2014). Acta Cryst. E 70 , o476–o477], has been rerefined using the original data set and found to exhibit the same type of disorder as found in (VI), with disordered populations having occupancies of 0.851 (3) and 0.149 (3). The triclinic polymorph of (E)‐[(2‐hydroxyphenylimino)methyl]phenol, C13H11NO2, (VIII), which crystallizes with Z′ = 2 in the space group P, has been described variously as occurring as the keto–amine tautomer [Maciejewska et al. (1999). J. Phys. Org. Chem. 12 , 875–880] and as the phenol–imine tautomer [Tunç et al. (2009). J. Chem. Crystallogr. 39 , 672–676]. Rerefinement of this structure using one of the original data sets shows that both of the independent molecules exist in the keto–amine form. In the structures of compounds (I), (VI), (VII) and (VIII), hydrogen bonds generate simple chains, while a chain of rings is formed in (V). Sheets are formed by hydrogen bonds in both (II) and (III), while in (IV), the sheet structure is built from aromatic π–π stacking interactions.  相似文献   

5.
The X‐ray crystal structures are reported of four novel and potentially O,N,S‐tridentate donor ligands that demonstrate antitumour activity. These ligands are 1‐[(4‐methyl­thio­semicarbazono)methyl]‐2‐naphthol, C13H13N3OS, (III), 1‐[(4‐ethylthio­semicarbazono)­methyl]‐2‐naphthol, C14H15N3OS, (IV), 1‐[(4‐phenyl­thio­semicarbazono)­methyl]‐2‐naphthol, C18H15N3OS, (V), and 1‐[(4,4‐di­methyl­thio­semicarbazono)­methyl]‐2‐naphthol di­methyl sulfoxide solvate, C14H15N3OS·C2H6OS, (VI). These chelators are N4‐substituted thio­semicarbazones, each based on the same parent aldehyde, namely 2‐­zhydroxynaphthalene‐1‐carboxaldehyde isonicotinoylhydrazone. Conformational variations within this series are discussed in relation to the optimum conformation for metal‐ion binding.  相似文献   

6.
The cycloadducts of isoquinolinium N‐phenyl imide 2 with C=C bonds are derivatives of 2‐amino‐1,2‐dihydroisoquinoline. Their Nβ‐vinylphenylhydrazine system is amenable to an acid‐catalyzed [3,3]‐sigmatropic shift; the formation of pentacyclic aminals is exemplified by 6 → 8 . The dimethyl maleate adduct 11 , C21H20N2O4, is exceptional by being converted on treatment with acid to bright‐yellow crystals, C24H22N2O6 (additional C3H2O2). X‐Ray crystal‐structure analysis and NMR spectra reveal structure 13 , and mechanistic studies indicated an initial β‐elimination at the N−N bond of 11 to yield 18 ; this step is followed by a retro‐Mannich‐type cleavage that gives methyl isoquinoline‐1‐acetate ( 14 ) and methyl 2‐(phenylimino)acetate ( 15 ), according to the sequence C21H20N2O4 ( 11 )→ 18 →C12H11NO2 ( 14 )+C9H9NO2 ( 15 ). In the second act of the drama, electrophilic attack by 15 ‐H+ on the ene‐hydrazine group of a second molecule of 11 furnishes 13 by a polystep intramolecular redox reaction. All rate constants must be fine‐tuned in this reaction cascade to give 13 in yields of up to 78% with an overall stoichiometry: 2 C21H20N2O4 ( 11 )→C24H22N2O6 ( 13 )+C12H11NO2 ( 14 )+aniline. Interception and model experiments confirmed the above pathway. A by‐product, C33H31N3O6 ( 62 ), arises from an acid‐catalyzed dimerization of 11 and subsequent elimination of 15 .  相似文献   

7.
The room‐temperature crystal structures of four new thio derivatives of N‐methylphenobarbital [systematic name: 5‐ethyl‐1‐methyl‐5‐phenylpyrimidine‐2,4,6(1H,3H,5H)‐trione], C13H14N2O3, are compared with the structure of the parent compound. The sulfur substituents in N‐methyl‐2‐thiophenobarbital [5‐ethyl‐1‐methyl‐5‐phenyl‐2‐thioxo‐1,2‐dihydropyrimidine‐4,6(3H,5H)‐dione], C13H14N2O2S, N‐methyl‐4‐thiophenobarbital [5‐ethyl‐1‐methyl‐5‐phenyl‐4‐thioxo‐3,4‐dihydropyrimidine‐2,6(1H,5H)‐dione], C13H14N2O2S, and N‐methyl‐2,4,6‐trithiophenobarbital [5‐ethyl‐1‐methyl‐5‐phenylpyrimidine‐2,4,6(1H,3H,5H)‐trithione], C13H14N2S3, preserve the heterocyclic ring puckering observed for N‐methylphenobarbital (a half‐chair conformation), whereas in N‐methyl‐2,4‐dithiophenobarbital [5‐ethyl‐1‐methyl‐5‐phenyl‐2,4‐dithioxo‐1,2,3,4‐tetrahydropyrimidine‐6(5H)‐one], C13H14N2OS2, significant flattening of the ring was detected. The number and positions of the sulfur substituents influence the packing and hydrogen‐bonding patterns of the derivatives. In the cases of the 2‐thio, 4‐thio and 2,4,6‐trithio derivatives, there is a preference for the formation of a ring motif of the R22(8) type, which is also a characteristic of N‐methylphenobarbital, whereas a C(6) chain forms in the 2,4‐dithio derivative. The preferences for hydrogen‐bond formation, which follow the sequence of acceptor position 4 > 2 > 6, confirm the differences in the nucleophilic properties of the C atoms of the heterocyclic ring and are consistent with the course of N‐methylphenobarbital thionation reactions.  相似文献   

8.
The slow evaporation of analytical NMR samples resulted in the formation of crystals of (E)‐2‐({[4‐(dimethylamino)phenyl]imino}methyl)‐4‐nitrophenol, C15H15N3O3, (I), and (E)‐2‐({[4‐(diethylamino)phenyl]imino}methyl)‐4‐nitrophenol, C17H19N3O3, (II). Despite the small structural difference between these two N‐salicylideneaniline derivatives, they show different space groups and diverse molecular packing. The molecules of both compounds are close to being planar due to an intramolecular O—H...N hydrogen bond. The 4‐alkylamino‐substituted benzene ring is inclined at an angle of 13.44 (19)° in (I) and 2.57 (8)° in (II) with respect to the 4‐nitro‐substituted phenol ring. Only very weak intermolecular π–π stacking and C—H...O interactions were found in these structures.  相似文献   

9.
The title compounds, (E)‐2‐[(2‐bromo­phenyl)imino­methyl]‐4‐methoxy­phenol, C14H12BrNO2, (I), (E)‐2‐[(3‐bromo­phenyl)­imino­methyl]‐4‐methoxy­phenol, C14H12BrNO2, (II), and (E)‐2‐[(4‐bromo­phenyl)imino­methyl]‐4‐methoxy­phenol, C14H12BrNO2, (III), adopt the phenol–imine tautomeric form. In all three structures, there are strong intra­molecular O—H⋯N hydrogen bonds. Compound (I) has strong inter­molecular hydrogen bonds, while compound (III) has weak inter­molecular hydrogen bonds. In addition to these inter­molecular inter­actions, C—H⋯π inter­actions in (I) and (III), and π–π inter­actions in (I), play roles in the crystal packing. The dihedral angles between the aromatic rings are 15.34 (12), 6.1 (3) and 39.2 (14)° for (I), (II) and (III), respectively.  相似文献   

10.
Red non‐solvate crystals of the title compound from ethanol, C23H19N3O4, orange solvate crystals from tert‐butanol, C23H19N3O4·C4H10O, yellow solvate crystals from dioxane–water, C23H19N3O4·0.5C4H8O2, and intense yellow solvate crystals from benzene–N,N′‐dimethylformamide, C23H19N3O4·C6H6, differ from each other in their molecular conformation and hydrogen‐bonding scheme. The bathochromic shifts of the crystal color are explained by the molecular planarity and charge‐transfer effect among the imidazole mol­ecules.  相似文献   

11.
Three related compounds containing a pyrazole moiety with vicinal phenyl rings featuring a methyl­sulfonyl substituent are described, namely 3‐methyl‐1‐[4‐(methyl­sulfonyl)­phenyl]‐5‐phenyl‐1H‐pyrazole, C17H16N2O2S, ethyl 1‐[4‐(methyl­sul­fonyl)­phenyl]‐5‐phenyl‐1H‐pyrazole‐3‐carboxyl­ate, C19H18N2O4S, and 1‐[4‐(methyl­sulfonyl)­phenyl]‐3‐[3‐(morpholino)­phenoxy­methyl]‐5‐phenyl‐1H‐pyrazole, C27H27N3O4S. The design of these compounds was based on celecoxib, a selective cyclo­oxy­genase‐2 (COX‐2) inhibitor, in order to study the influence of various substituents on COX‐2 and 5‐lipoxy­genase (5‐LOX) inhibition.  相似文献   

12.
A novel two‐dimensional CoII coordination framework, namely poly[(μ2‐biphenyl‐4,4′‐diyldicarboxylato‐κ2O4:O4′){μ2‐bis[4‐(2‐methyl‐1H‐imidazol‐1‐yl)phenyl] ether‐κ2N3:N3′}cobalt(II)], [Co(C14H8O4)(C20H18N4O)]n, has been prepared and characterized by IR, elemental analysis, thermal analysis and single‐crystal X‐ray diffraction. The crystal structure reveals that the compound has an achiral two‐dimensional layered structure based on opposite‐handed helical chains. In addition, it exhibits significant photocatalytic degradation activity for the degradation of methylene blue.  相似文献   

13.
Four derivatives of 2,6‐bis­(hydroxy­methyl)­phenol, with various para substituents, have been investigated; these are 2,6‐bis­(hydroxy­methyl)‐4‐methyl­phenol, C9H12O3, (I), 2,6‐bis­(hydroxy­methyl)‐4‐methoxy­phenol, C9H12O4, (II), 2,6‐bis­(hydroxy­methyl)‐4‐phenoxy­phenol, C14H14O4, (III), and 2,6‐bis­(hydroxy­methyl)‐4‐[1‐(4‐methoxy­phenyl)‐1‐methyl­ethyl]­phenol, C18H22O4, (IV). All four structures display hydrogen‐bonding networks resulting in sheets, with possible weak inter‐sheet π–π interactions in one case. In all the structures but one, the mol­ecules form centrosymmetric dimeric subunits held together by two hydrogen bonds between the hydroxy­methyl groups and, in two cases, by probable π–π interactions.  相似文献   

14.
Fluorescence quenching of [Ru(bpy)3]2+ by a series of organic dyes has been investigated by using the steady state fluorescence technique in aqueous medium. The dyes used are anthraquinone dyes: uniblue, acid blue 129, alizarin, alizarin red S and the azo dyes: congo red, sunset yellow, methyl orange, tartrazine, acid orange 63, methyl red and erichrome black T. The quenching of [Ru(bpy)3]2+ was found to obey the Stern-Volmer equation and the corresponding Stern-Volmer plots were linear indicating dynamic quenching. The quenching rate constants (k q) were calculated from the fluorescence data. The mechanism of quenching was discussed on the basis of the quenching rate constants as well as the reduction potential of dyes. The electron transfer mechanism has been proved by the calculation of Gibbs energy changes (ΔG et) by applying the Rehm-Weller equation.  相似文献   

15.
The crystal structures of 4‐methyl‐2‐[N‐(3,4‐methyl­ene­dioxybenzyl­idene)hydrazino]­thia­zole, C12H11N3O2S, and its reduction product 4‐methyl‐2‐[N‐(3,4‐methyl­ene­dioxybenzyl­idene)hydrazono]‐4,5‐di­hydro­thia­zole, C12H13N3O2S, have been determined and compared. In the reduction product, the tautomer observed bears an H atom on the exocyclic N atom. Both compounds form hydrogen‐bonded dimers over centers of inversion.  相似文献   

16.
Bendroflumethiazide, or 3‐benzyl‐6‐(trifluoromethyl)‐3,4‐dihydro‐2H‐1,2,4‐benzothiadiazine‐7‐sulfonamide 1,1‐dioxide, is reported to crystallize as 1:1 solvates with acetone, C15H14F3N3O4S2·C3H6O, and N,N‐dimethylformamide, C15H14F3N3O4S2·C3H7NO. A detailed investigation of the crystal packing and intermolecular interactions is presented by means of Hirshfeld surface analysis. This analysis confirms the atomic positions of methyl H atoms of the solvent molecules that were inferred from the X‐ray data and provides a useful tool for structure validation.  相似文献   

17.
The compounds N′‐benzylidene‐N‐methylpyrazine‐2‐carbohydrazide, C13H12N4O, (IIa), N′‐(2‐methoxybenzylidene)‐N‐methylpyrazine‐2‐carbohydrazide, C14H14N4O2, (IIb), N′‐(4‐cyanobenzylidene)‐N‐methylpyrazine‐2‐carbohydrazide dihydrate, C14H11N5O·2H2O, (IIc), N‐methyl‐N′‐(2‐nitrobenzylidene)pyrazine‐2‐carbohydrazide, C13H11N5O3, (IId), and N‐methyl‐N′‐(4‐nitrobenzylidene)pyrazine‐2‐carbohydrazide, C13H11N5O3, (IIe), have dihedral angles between the pyrazine rings and the benzene rings in the range 55–78°. These methylated pyrazine‐2‐carbohydrazides have supramolecular structures which are formed by weak C—H...O/N hydrogen bonds, with the exception of (IIc) which is hydrated. There are π–π stacking interactions in all five compounds. Three of these structures are compared with their nonmethylated counterparts, which have dihedral angles between the pyrazine rings and the benzene rings in the range 0–6°.  相似文献   

18.
Molecular clip 1 remains monomeric in water and engages in host–guest recognition processes with suitable guests. We report the Ka values for 32 1? guest complexes measured by 1H NMR, UV/Vis, and fluorescence titrations. The cavity of 1 is shaped by aromatic surfaces of negative electrostatic potential and therefore displays high affinity and selectivity for planar and cationic aromatic guests that distinguishes it from CB[n] receptors that prefer aliphatic over aromatic guests. Electrostatic effects play a dominant role in the recognition process whereby ion–dipole interactions may occur between ammonium ions and the C=O groups of 1 , between the SO3? groups of 1 and pendant cationic groups on the guest, and within the cavity of 1 by cation–π interactions. Host 1 displays a high affinity toward dicationic guests with large planar aromatic surfaces (e.g. naphthalene diimide NDI+ and perylene diimide PDI+) and cationic dyes derived from acridine (e.g. methylene blue and azure A). The critical importance of cation–π interactions was ascertained by a comparison of analogous neutral and cationic guests (e.g. methylene violet vs. methylene blue; quinoline vs. N‐methylquinolinium; acridine vs. N‐methylacridinium; neutral red vs. neutral red H+) the affinities of which differ by up to 380‐fold. We demonstrate that the high affinity of 1 toward methylene blue (Ka=3.92×107 m ?1; Kd=25 nm ) allows for the selective sequestration and destaining of U87 cells stained with methylene blue.  相似文献   

19.
The structures of two conformationally similar 1,4‐di­hydro­pyrimidines with a novel carbamoyl substitution, viz. 6‐methyl‐5‐(N‐methyl­carbamoyl)‐4‐phenyl‐1,2,3,4‐tetrahydro­py­rimidine‐2‐thione monohydrate, C13H15N3OS·H2O, (I), and 4‐(4‐chloro­phenyl)‐6‐methyl‐5‐(N‐methyl­carbamoyl)‐1,2,3,4‐tetra­hydro­pyrimidine‐2‐thione monohydrate, C13H14ClN3OS·H2O, (II), exhibit the structural features of 1,4‐di­hydro­pyridine calcium channel blockers. In both structures, the pyrimidine ring adopts a flattened boat conformation and the carbamoyl side chain is in an extended conformation with an anticlinal orientation. The phenyl ring occupies a pseudo‐axial position with respect to the pyrimidine ring in these structures. Both compounds crystallize with one mol­ecule of water, which participates in a two‐dimensional hydrogen‐bonding network. The mol­ecules are linked into dimers by N—H·S hydrogen bonds in both structures.  相似文献   

20.
The photocatalytic activity of graphite‐like carbon nitride (g‐C3N4) could be enhanced by heterojunction strategies through increasing the charge‐separation efficiency. As a surface‐based process, the heterogeneous photocatalytic process would become more efficient if a larger contact region existed in the heterojunction interface. In this work, ultrathin g‐C3N4 nanosheets (g‐C3N4‐NS) with much larger specific surface areas are employed instead of bulk g‐C3N4 (g‐C3N4‐B) to prepare AgIO3/g‐C3N4‐NS nanocomposite photocatalysts. By taking advantage of this feature, the as‐prepared composites exhibit remarkable performances for photocatalytic wastewater treatment under visible‐light irradiation. Notably, the optimum photocatalytic activity of AgIO3/g‐C3N4‐NS composites is almost 80.59 and 55.09 times higher than that of pure g‐C3N4‐B towards the degradation of rhodamine B and methyl orange pollutants, respectively. Finally, the stability and possible photocatalytic mechanism of the AgIO3/g‐C3N4‐NS system are also investigated.  相似文献   

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