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1.
The design and synthesis of new organic lgands is important to the rapid development of coordination polymers (CPs). However, CPs based on asymmetric ligands are still rare, mainly because such ligands are usually expensive and more difficult to synthesize. The new asymmetric ligand 4‐[4‐(1H‐imidazol‐1‐yl)phenyl]pyridine (IPP) has been used to construct the title one‐dimensional coordination polymer, catena‐poly[[[aqua{4‐[4‐(1H‐imidazol‐1‐yl‐κN3)phenyl]pyridine}cadmium(II)]‐μ‐5‐hydroxybenzene‐1,3‐dicarboxylato‐κ3O1,O1′:O3] monohydrate], {[Cd(C8H4O5)(C14H11N3)2(H2O)]·H2O}n, under hydrothermal reaction of IPP with CdII in the presence of 5‐hydroxyisophthalic acid (5‐OH‐H2bdc). The CdII cation is coordinated by two N atoms from two distinct IPP ligands, three carboxylate O atoms from two different 5‐OH‐bdc2− dianionic ligands and one water O atom in a distorted octahedral geometry. The cationic [Cd(IPP)2]2+ nodes are linked by 5‐OH‐bdc2− ligands to generate a one‐dimensional chain. These chains are extended into a two‐dimensional layer structure via O—H…O and O—H…N hydrogen bonds and π–π interactions.  相似文献   

2.
The structures of five compounds consisting of (prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine complexed with copper in both the CuI and CuII oxidation states are presented, namely chlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ3N,N′,N′′}copper(I) 0.18‐hydrate, [CuCl(C15H17N3)]·0.18H2O, (1), catena‐poly[[copper(I)‐μ2‐(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ5N,N′,N′′:C2,C3] perchlorate acetonitrile monosolvate], {[Cu(C15H17N3)]ClO4·CH3CN}n, (2), dichlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ3N,N′,N′′}copper(II) dichloromethane monosolvate, [CuCl2(C15H17N3)]·CH2Cl2, (3), chlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ3N,N′,N′′}copper(II) perchlorate, [CuCl(C15H17N3)]ClO4, (4), and di‐μ‐chlorido‐bis({(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ3N,N′,N′′}copper(II)) bis(tetraphenylborate), [Cu2Cl2(C15H17N3)2][(C6H5)4B]2, (5). Systematic variation of the anion from a coordinating chloride to a noncoordinating perchlorate for two CuI complexes results in either a discrete molecular species, as in (1), or a one‐dimensional chain structure, as in (2). In complex (1), there are two crystallographically independent molecules in the asymmetric unit. Complex (2) consists of the CuI atom coordinated by the amine and pyridyl N atoms of one ligand and by the vinyl moiety of another unit related by the crystallographic screw axis, yielding a one‐dimensional chain parallel to the crystallographic b axis. Three complexes with CuII show that varying the anion composition from two chlorides, to a chloride and a perchlorate to a chloride and a tetraphenylborate results in discrete molecular species, as in (3) and (4), or a bridged bis‐μ‐chlorido complex, as in (5). Complex (3) shows two strongly bound Cl atoms, while complex (4) has one strongly bound Cl atom and a weaker coordination by one perchlorate O atom. The large noncoordinating tetraphenylborate anion in complex (5) results in the core‐bridged Cu2Cl2 moiety.  相似文献   

3.
The reaction of 2‐cyanopyridine with N‐phenylthiosemicarbazide afforded 2‐[amino(pyridin‐2‐yl)methylidene]‐N‐phenylhydrazine‐1‐carbothioamide (Ham4ph) and crystals of 4‐phenyl‐5‐(pyridin‐2‐yl)‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thione (pyph3NS, 1 , C13H10N4S). Crystals of methyl 2‐{[4‐phenyl‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐3‐yl]sulfanyl}acetate (phpy2NS, 2 , C16H14N4O2S), derived from 1 , were obtained by the reaction of Ham4ph with chloroacetic acid, followed by the acid‐catalyzed esterification of the carboxylic acid with methyl alcohol. Crystals of bis(methanol‐κO)bis(methyl 2‐{[4‐phenyl‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐3‐yl‐κ2N1,N5]sulfanyl}acetato)zinc(II)/cadmium(II) hexabromidocadmate(II), [Zn0.76Cd0.24(C16H14N4O2S)2(CH3OH)2][Cd2Br6] or [Zn0.76Cd0.24(phpy2NS)2(MeOH)2][Cd2Br6], 3 , and dichlorido(methyl 2‐{[4‐phenyl‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐3‐yl‐κ2N1,N5]sulfanyl}acetato)mercury(II), [HgCl2(C16H14N4O2S)] or [Hg(phpy2NS)Cl2], 4 , were synthesized using ligand 2 and CdBr2 or HgCl2, respectively. The molecular and supramolecular structures of the compounds were studied by X‐ray diffractometry. The asymmetric unit of 3 is formed from CdBr3 and M(phpy2NS)(MeOH) units, where the metal centre M has a 76% occupancy of ZnII and 24% of CdII. The M2+ centre of the cation, located on a crystallographic inversion centre, is hexacoordinated and appears as a slightly distorted octahedral [MN4O2]2+ cation. The Cd centre of the anion is coordinated by two terminal bromide ligands and two bridging bromide ligands that generate [Cd2Br6]2? cadmium–bromide clusters. These clusters display crystallographic inversion symmetry forming two edge‐shared tetrahedra and serve as agents that direct the structure in the formation of supramolecular assemblies. In mononuclear complex 4 , the coordination geometry around the Hg2+ ion is distorted tetrahedral and comprises two chloride ligands and two N‐atom donors from the phpy2NS ligand, viz. one pyridine N atom and the other from triazole. In the crystal packing, all four compounds exhibit weak intermolecular interactions, which facilitate the formation of three‐dimensional architectures. Along with the noncovalent interactions, the structural diversity in the complexes can be attributed to the metal centre and to the coordination geometry, as well as to its ionic or neutral character.  相似文献   

4.
Iron is of interest as a catalyst because of its established use in the Haber–Bosch process and because of its high abundance and low toxicity. Nitrogen‐heterocyclic carbenes (NHC) are important ligands in homogeneous catalysis and iron–NHC complexes have attracted increasing attention in recent years but still face problems in terms of stability under oxidative conditions. The structure of the iron(II) complex [1,1′‐bis(pyridin‐2‐yl)‐2,2‐bi(1H‐imidazole)‐κN3][3,3′‐bis(pyridin‐2‐yl‐κN)‐1,1′‐methanediylbi(1H‐imidazol‐2‐yl‐κC2)](trimethylphosphane‐κP)iron(II) bis(hexafluoridophosphate), [Fe(C17H14N6)(C16H12N6)(C3H9P)](PF6)2, features coordination by an organic decomposition product of a tetradentate NHC ligand in an axial position. The decomposition product, a C—C‐coupled biimidazole, is trapped by coordination to still‐intact iron(II) complexes. Insights into the structural features of the organic decomposition products might help to improve the stability of oxidation catalysts under harsh conditions.  相似文献   

5.
In the title mononuclear complex, [Cu(C5H9N3)(C10H15N5)](ClO4)2, the CuII centre is surrounded by two N‐donor ligands, which impose a square‐pyramidal environment on the metal. The new tridentate ligand [2‐(imidazol‐4‐yl)­ethyl]­[(1‐methyl­imidazol‐2‐yl)­methyl]­amine (HISMIMA) lies in the basal plane, while the hist­amine ligand occupies the apical and one of the basal positions around the CuII ion.  相似文献   

6.
In the title compound, [Pb(C12H8NO2)2]n, the Pb atom sits on a crystallographic C2 axis and is six‐coordinate, ligated by two chelating carboxylate groups from two 3‐(pyridin‐4‐yl)benzoate (L) ligands and by two N atoms from another two ligands. Each ligand bridges two PbII centres, extending the structure into a corrugated two‐dimensional (4,4) net. The ligand L is conformationally chiral, with a torsion angle of 27.9 (12)° between the planes of its two rings. The torsion angle has the same sense throughout the structure, so that the extended two‐dimensional polymer is homochiral. Investigation of the thermal stability shows that the network is stable up to 613 K. In the absence of any stereoselective factor in the preparation of the compound, the enantiomeric purity of the crystal studied, based only on the torsional conformation of the ligand, implies that the bulk sample is a racemic conglomerate.  相似文献   

7.
The title salt, C15H18NO2+·Br·H2O, is an analogue of the antidepressant drug agomelatine. The cation is protonated at the carbonyl O atom of its amide group. The side chain at the 1‐position adopts an extended conformation, with all non‐H atoms lying in the same plane as the naphthalene ring. This is in contrast with the crystal structures known for three agomelatine polymorphs, and also with two known cocrystals containing agomelatine. The structure displays three types of hydrogen bond, namely C=O—H...O, N—H...Br and O—H...Br, which define a two‐dimensional network parallel to the (100) plane. The naphthalene rings interdigitate in a `zipper‐like' fashion between these hydrogen‐bonded networks, forming an offset arrangement. Direct face‐to‐face π–π contacts between naphthalene rings are not present in the structure.  相似文献   

8.
The title compound, [Cd3(C8H10O4)3(C12H9N3)2(H2O)2]n or [Cd3(chdc)3(4‐PyBIm)2(H2O)2]n, was synthesized hydrothermally from the reaction of Cd(CH3COO)2·2H2O with 2‐(pyridin‐4‐yl)‐1H‐benzimidazole (4‐PyBIm) and cyclohexane‐1,4‐dicarboxylic acid (1,4‐chdcH2). The asymmetric unit consists of one and a half CdII cations, one 4‐PyBIm ligand, one and a half 1,4‐chdc2− ligands and one coordinated water molecule. The central CdII cation, located on an inversion centre, is coordinated by six carboxylate O atoms from six 1,4‐chdc2− ligands to complete an elongated octahedral coordination geometry. The two terminal rotationally symmetric CdII cations each exhibits a distorted pentagonal–bipyramidal geometry, coordinated by one N atom from 4‐PyBIm, five O atoms from three 1,4‐chdc2− ligands and one O atom from an aqua ligand. The 1,4‐chdc2− ligands possess two conformations, i.e.e,etrans‐chdc2− and e,acis‐chdc2−. The cis‐1,4‐chdc2− ligands bridge the CdII cations to form a trinuclear {Cd3}‐based chain along the b axis, while the trans‐1,4‐chdc2− ligands further link adjacent one‐dimensional chains to construct an interesting two‐dimensional network.  相似文献   

9.
The new asymmetrical organic ligand 2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole ( L , C17H13N5O), containing pyridine and imidazole terminal groups, as well as potential oxdiazole coordination sites, was designed and synthesized. The coordination chemistry of L with soft AgI, CuI and CdII metal ions was investigated and three new coordination polymers (CPs), namely, catena‐poly[[silver(I)‐μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole] hexafluoridophosphate], {[Ag( L )]PF6}n, catena‐poly[[copper(I)‐di‐μ‐iodido‐copper(I)‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)] 1,4‐dioxane monosolvate], {[Cu2I2( L )2]·C4H8O2}n, and catena‐poly[[[dinitratocopper(II)]‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)]–methanol–water (1/1/0.65)], {[Cd( L )2(NO3)2]·2CH4O·0.65H2O}n, were obtained. The experimental results show that ligand L coordinates easily with linear AgI, tetrahedral CuI and octahedral CdII metal atoms to form one‐dimensional polymeric structures. The intermediate oxadiazole ring does not participate in the coordination interactions with the metal ions. In all three CPs, weak π–π interactions between the nearly coplanar pyridine, oxadiazole and benzene rings play an important role in the packing of the polymeric chains.  相似文献   

10.
The zinc(II) atom in the centrosymmetric complex is in a distorted N6 octahedral geometry defined by two tridentate ligands. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

11.
The coordination polymer catena‐poly[[(dimethylformamide‐κO)[μ3‐5‐(1,3‐dioxo‐4,5,6,7‐tetraphenylisoindolin‐2‐yl)isophthalato‐κ4O1,O1′:O3:O3′](methanol‐κO)manganese(III)] dimethylformamide monosolvate], {[Mn(C40H23NO6)(CH3OH)(C3H7NO)]·C3H7NO}n, has been synthesized from the reaction of 5‐(1,3‐dioxo‐4,5,6,7‐tetraphenylisoindolin‐2‐yl)isophthalic acid and manganese(II) acetate tetrahydrate in a glass tube at room temperature by solvent diffusion. The MnII centre is hexacoordinated by two O atoms from one chelating carboxylate group, by two O atoms from two monodentate carboxylate groups and by one O atom each from a methanol and a dimethylformamide (DMF) ligand. The single‐crystal structure crystallizes in the triclinic space group P. Moreover, the coordination polymer shows one‐dimensional 2‐connected {0} uninodal chain networks, and free DMF molecules are connected to the chains by O—H...O hydrogen bonds. The thermogravimetric and photoluminescent properties of the compound have also been investigated.  相似文献   

12.
The title CdII compound, {[Cd2(C13H7NO4)2(H2O)4]·5H2O}n, was synthesized by the hydrothermal reaction of Cd(NO3)2·4H2O and 5‐(pyridin‐4‐yl)isophthalic acid (H2L). The asymmetric unit contains two crystallographically independent CdII cations, two deprotonated L2− ligands, four coordinated water molecules and five isolated water molecules. One of the CdII cations adopts a six‐coordinate octahedral coordination geometry involving three O atoms from one bidentate chelating and one monodentate carboxylate group of two different L2− ligands, one N atom of another L2− ligand and two coordinated water molecules. The second CdII cation adopts a seven‐coordinate pentagonal–bipyramidal coordination geometry involving four O atoms from two bidentate chelating carboxylate groups of two different L2− ligands, one N atom of another L2− ligand and two coordinated water molecules. Each L2− ligand bridges three CdII cations and, likewise, each CdII cation connects to three L2− ligands, giving rise to a two‐dimensional graphite‐like 63 layer structure. These two‐dimensional layers are further linked by O—H...O hydrogen‐bonding interactions to form a three‐dimensional supramolecular architecture. The photoluminescence properties of the title compound were also investigated.  相似文献   

13.
The unsymmetric precursor ethyl 6-acetylpyridine-2-carboxylate (4) was synthesized from 2,6-dimethylpyridine (1). On the basis of this precursor, a new mono(imino)pyridine ligand (5) and the corresponding Co(Ⅱ) complex {2-carbethoxy-6-[1-[(2,6-diethylphenyl)imino]ethyl]pyridine}CoCl2 (6) were prepared. The crystal structure of complex indicates that the 2-carbethoxy-6-iminopyridine is coordinated to the cobalt as a tridentate ligand using [N, N, O] atoms, and the coordination geometry of the central cobalt is a distorted trigonal bipyramid, with the pyridyl nitrogen atom and the two chlorine atoms forming the equatorial plane. Being applied to the ethylene oligomedzation, this cobalt complex shows catalytic activity of 1.820× 10^4 g/mol-Cooh at 101325 Pa of ethylene at 15.5℃ for 1 h, when 1000 equiv, of methylaluminoxane (MAO) is employed as the cocatalyst.  相似文献   

14.
The mononuclear complex, [NiCl2 (trzCH2CH2COPh)4]·6H2O (trz =1,2,4‐triazole), was synthesized and its structure was determined by single crystal X‐ray determination. It crystallizes in the monoclinic system, space group P21/c, with lattice parameters: a = 0.80391(2) nm, b = 1.08215(2) tun, c = 2.90133(2) nm, β = 94.792 (1)° and Z = 2. Each nickel atom is coordinated by four N atoms of triazole from four β‐(1,2,4‐triazole‐1‐yl)propiophenone ligands and two chloride anions in trans arrangement with octahedral coordination geometry. In addition to the coordinating nickel complex, there are six uncoordinated water molecules. The Ni‐Cl distance is 0.24865(8) nm and the Ni‐N distances are in the range of 0.2072(2) to 0.2099(2) nm, respectively. In the solid state, the title compound forms three dimensional network structure through hydrogen bonds. The intermolecular hydrogen bonds connect the [NiCl2(C2H2N3CH2CH2COPh)4] and H2O moieties. The deep green crystals were also examined by elemental analysis, FT‐IR and UV spectra, which are in agreement with the structural data.  相似文献   

15.
In the coordination polymer catena‐poly[[[diaqua[5‐carboxy‐2‐(pyridin‐3‐yl)‐1H‐imidazole‐4‐carboxylato‐κ2N3,O4]lead(II)]‐μ‐5‐carboxy‐2‐(pyridin‐3‐yl)‐1H‐imidazole‐4‐carboxylato‐κ3N3,O4:N2] dihydrate], {[Pb(C10H6N3O4)(H2O)2]·2H2O}n, the two 5‐carboxy‐2‐(pyridin‐3‐yl)‐1H‐imidazole‐4‐carboxylate ligands have different coordination modes, one being terminal and the other bridging. The bridging ligand links PbII cations into one‐dimensional coordination polymer chains. The structure is also stabilized by intra‐ and interchain π–π stacking interactions between the pyridine rings, resulting in the formation of a two‐dimensional network. Extensive hydrogen‐bonding interactions lead to the formation of a three‐dimensional supramolecular network.  相似文献   

16.
Crystals of poly[[aqua[μ3‐4‐carboxy‐1‐(4‐carboxylatobenzyl)‐2‐propyl‐1H‐imidazole‐5‐carboxylato‐κ5O1O1′:N3,O4:O5][μ4‐1‐(4‐carboxylatobenzyl)‐2‐propyl‐1H‐imidazole‐4‐carboxylato‐κ7N3,O4:O4,O4′:O1,O1′:O1]cadmium(II)] monohydrate], {[Cd2(C15H14N2O4)(C16H14N2O6)(H2O)]·H2O}n or {[Cd2(Hcpimda)(cpima)(H2O)]·H2O}n, (I), were obtained from 1‐(4‐carboxybenzyl)‐2‐propyl‐1H‐imidazole‐4,5‐dicarboxylic acid (H3cpimda) and cadmium(II) chloride under hydrothermal conditions. The structure indicates that in‐situ decarboxylation of H3cpimda occurred during the synthesis process. The asymmetric unit consists of two Cd2+ centres, one 4‐carboxy‐1‐(4‐carboxylatobenzyl)‐2‐propyl‐1H‐imidazole‐5‐carboxylate (Hcpimda2−) anion, one 1‐(4‐carboxylatobenzyl)‐2‐propyl‐1H‐imidazole‐4‐carboxylate (cpima2−) anion, one coordinated water molecule and one lattice water molecule. One Cd2+ centre, i.e. Cd1, is hexacoordinated and displays a slightly distorted octahedral CdN2O4 geometry. The other Cd centre, i.e. Cd2, is coordinated by seven O atoms originating from one Hcpimda2− ligand and three cpima2− ligands. This Cd2+ centre can be described as having a distorted capped octahedral coordination geometry. Two carboxylate groups of the benzoate moieties of two cpima2− ligands bridge between Cd2 centres to generate [Cd2O2] units, which are further linked by two cpima2− ligands to produce one‐dimensional (1D) infinite chains based around large 26‐membered rings. Meanwhile, adjacent Cd1 centres are linked by Hcpimda2− ligands to generate 1D zigzag chains. The two types of chains are linked through a μ2‐η2 bidentate bridging mode from an O atom of an imidazole carboxylate unit of cpima2− to give a two‐dimensional (2D) coordination polymer. The simplified 2D net structure can be described as a 3,6‐coordinated net which has a (43)2(46.66.83) topology. Furthermore, the FT–IR spectroscopic properties, photoluminescence properties, powder X‐ray diffraction (PXRD) pattern and thermogravimetric behaviour of the polymer have been investigated.  相似文献   

17.
The N‐heterocyclic ligand 2‐[(1H‐imidazol‐1‐yl)methyl]‐1H‐benzimidazole (imb) has a rich variety of coordination modes and can lead to polymers with intriguing structures and interesting properties. In the coordination polymer catena‐poly[[cadmium(II)‐bis[μ‐benzene‐1,2‐dicarboxylato‐κ4O1,O1′:O2,O2′]‐cadmium(II)‐bis{μ‐2‐[(1H‐imidazol‐1‐yl)methyl]‐1H‐benzimidazole}‐κ2N2:N32N3:N2] dimethylformamide disolvate], {[Cd(C8H4O4)(C11H10N4)]·C3H7NO}n, (I), each CdII ion exhibits an irregular octahedral CdO4N2 coordination geometry and is coordinated by four O atoms from two symmetry‐related benzene‐1,2‐dicarboxylate (1,2‐bdic2−) ligands and two N atoms from two symmetry‐related imb ligands. Two CdII ions are connected by two benzene‐1,2‐dicarboxylate ligands to generate a binuclear [Cd2(1,2‐bdic)2] unit. The binuclear units are further connected into a one‐dimensional chain by pairs of bridging imb ligands. These one‐dimensional chains are further connected through N—H…O hydrogen bonds and π–π interactions, leading to a two‐dimensional layered structure. The dimethylformamide solvent molecules are organized in dimeric pairs via weak interactions. In addition, the title polymer exhibits good fluorescence properties in the solid state at room temperature.  相似文献   

18.
Multidentate N‐heterocyclic compounds form a variety of metal complexes with many intriguing structures and interesting properties. The title coordination polymer, catena‐poly[zinc(II)‐bis{μ‐2‐[(1H‐imidazol‐1‐yl)methyl]‐1H‐benzimidazole}‐κ2N3:N3′;N3′:N3‐zinc(II)‐bis(μ‐benzene‐1,2‐dicarboxylato)‐κ2O1:O23O1,O1′:O2], [Zn2(C8H4O4)2(C11H10N4)2]n, has been synthesized by the reaction of Zn(NO3)2 with 2‐[(1H‐imidazol‐1‐yl)methyl]‐1H‐benzimidazole (imb) and benzene‐1,2‐dicarboxylic acid (H2bdic) under hydrothermal conditions. There are two crystallographically distinct imb ligands [imb(A) and imb(B)] in the structure which adopt very similar coordination geometries. The imb(A) ligand bridges two symmetry‐related Zn1 ions, yielding a binuclear [(Zn1)2{imb(A)}2] unit, and the imb(B) ligand bridges two symmetry‐related Zn2 ions resulting in a binuclear [(Zn2)2{imb(B)}2] unit. The above‐mentioned binuclear units are further connected alternately by pairs of bridging bdic2− ligands, forming an infinite one‐dimensional chain. These one‐dimensional chains are further connected through N—H...O hydrogen bonds, leading to a two‐dimensional layered structure. In addition, the title polymer exhibits good fluorescence properties in the solid state at room temperature.  相似文献   

19.
The 2‐amine derivatives of 5‐arylidene‐3H‐imidazol‐4(5H )‐one are a new class of bacterial efflux pump inhibitors, the chemical compounds that are able to restore antibiotic efficacy against multidrug resistant bacteria. 5‐Arylidene‐3H‐imidazol‐4(5H )‐ones with a piperazine ring at position 2 reverse the mechanisms of multidrug resistance (MDR) of the particularly dangerous Gram‐negative bacteria E. coli by inhibition of the efflux pump AcrA/AcrB/TolC (a main multidrug resistance mechanism in Gram‐negative bacteria, consisting of a membrane fusion protein, AcrA, a Resistant‐Nodulation‐Division protein, AcrB, and an outer membrane factor, TolC). In order to study the influence of the environment on the conformation of (Z )‐5‐(4‐chlorobenzylidene)‐2‐[4‐(2‐hydroxyethyl)piperazin‐1‐yl]‐3H‐imidazol‐4(5H )‐one, ( 3 ), two different salts were prepared, namely with picolinic acid {systematic name: 4‐[(Z )‐4‐(4‐chlorobenzylidene)‐5‐oxo‐3,4‐dihydro‐1H‐imidazol‐2‐yl]‐1‐(2‐hydroxyethyl)piperazin‐1‐ium pyridine‐2‐carboxylate, C16H20ClN4O2+·C6H4NO2, ( 3 a )} and 4‐nitrophenylacetic acid {systematic name: 4‐[(Z )‐4‐(4‐chlorobenzylidene)‐5‐oxo‐3,4‐dihydro‐1H‐imidazol‐2‐yl]‐1‐(2‐hydroxyethyl)piperazin‐1‐ium 2‐(4‐nitrophenyl)acetate, C16H20ClN4O2+·C8H6NO4, ( 3 b )}. The crystal structures of the new salts were determined by X‐ray diffraction. In both crystal structures, the molecule of ( 3 ) is protonated at an N atom of the piperazine ring by proton transfer from the corresponding acid. The carboxylate group of picolinate engages in hydrogen bonds with three molecules of the cation of ( 3 ), whereas the carboxylate group of 4‐nitrophenylacetate engages in hydrogen bonds with only two molecules of ( 3 ). As a consequence of these interactions, different orientations of the hydroxyethyl group of ( 3 ) are observed. The crystal structures are additionally stabilized by both C—H…N [in ( 3 a )] and C—H…O [in ( 3 a ) and ( 3 b )] intermolecular interactions. The geometry of the imidazolone fragment was compared with other crystal structures possessing this moiety. The tautomer observed in the crystal structures presented here, namely 3H‐imidazol‐4(5H )‐one [systematic name: 1H‐imidazol‐5(4H )‐one], is also that most frequently observed in other structures containing this heterocycle.  相似文献   

20.
The synthesis and crystal structures of two new rhenium(I) complexes obtained utilizing benzhydroxamic acid (BHAH) and 3‐hydroxyflavone (2‐phenylchromen‐4‐one, FlavH) as bidentate ligands, namely tetraethylammonium fac‐(benzhydroxamato‐κ2O,O′)bromidotricarbonylrhenate(I), (C8H20N)[ReBr(C7H6NO2)(CO)3], 1 , and fac‐aquatricarbonyl(4‐oxo‐2‐phenylchromen‐3‐olato‐κ2O,O′)rhenium(I)–3‐hydroxyflavone (1/1), [Re(C15H9O3)(CO)3(H2O)]·C15H10O3, 3 , are reported. Furthermore, the crystal structure of free 3‐hydroxyflavone, C15H10O3, 4 , was redetermined at 100 K in order to compare the packing trends and solid‐state NMR spectroscopy with that of the solvate flavone molecule in 3 . The compounds were characterized in solution by 1H and 13C NMR spectroscopy, and in the solid state by 13C NMR spectroscopy using the cross‐polarization magic angle spinning (CP/MAS) technique. Compounds 1 and 3 both crystallize in the triclinic space group P with one molecule in the asymmetric unit, while 4 crystallizes in the orthorhombic space group P212121. Molecules of 1 and 3 generate one‐dimensional chains formed through intermolecular interactions. A comparison of the coordinated 3‐hydroxyflavone ligand with the uncoordinated solvate molecule and free molecule 4 shows that the last two are virtually completely planar due to hydrogen‐bonding interactions, as opposed to the former, which is able to rotate more freely. The differences between the solid‐ and solution‐state 13C NMR spectra of 3 and 4 are ascribed to inter‐ and intramolecular interactions. The study also investigated the potential labelling of both bidentate ligands with the corresponding fac99mTc‐tricarbonyl synthon. All attempts were unsuccessful and reasons for this are provided.  相似文献   

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