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1.
In continuation of our investigation of characteristics and thermodynamic properties of the i‐motif 5′‐d[(CCCTAA)3CCCT)] upon insertion of intercalating nucleotides into the cytosine‐rich oligonucleotide, this article evaluates the stabilities of i‐motif oligonucleotides upon insertion of naphthalimide (1H‐benzo[de]isoquinoline‐1,3(2H)‐dione) as the intercalating nucleic acid. The stabilities of i‐motif structures with inserted naphthalimide intercalating nucleotides were studied using UV melting temperatures (Tm) and circular dichroism spectra at different pH values and conditions (crowding and non‐crowding). This study indicated a positive effect of the naphthalimide intercalating nucleotides on the stabilities of the i‐motif structures compared to the wild‐type structure which is in contrast to a previous observation for a pyrene‐intercalating nucleotide showing a decrease in Tm values.  相似文献   

2.
Two coordination polymers, namely {[Mn(2,4′‐bpdc)(bimb)(H2O)0.5] · 0.5H2O}n ( 1 ) and [Mn(4,4′‐bpdc)(bimb)]n · 2.5H2O ( 2 ) [2,4′‐bpdc = biphenyl‐2,4′‐dicarboxylate, 4,4′‐bpdc = biphenyl‐4,4′‐dicarboxylate, and bimb = 1,4‐bis(1‐imidazol‐yl)‐2,5‐dimethyl benzene], were hydrothermally synthesized by reactions of manganese(II) salt with the rigid ligand 1,4‐bis(1‐imidazol‐yl)‐2,5‐dimethyl benzene and isomeric biphenyl dicarboxylate ligands. Complex 1 has an unusual 6‐connected three‐dimensional (3D) architecture with point symbol (44.611). Complex 2 has also a 3D structure with two‐interpenetrated pcu topology with point symbol (412.63). Structural comparisons show that the positions of the carboxylate groups in the ligand backbone play an important role in governing the structural topologies of these complexes.  相似文献   

3.
A new coordination polymer, [Co2(L)2(4,4′‐bipy)]n·3nH2O ( 1 ) based on 5‐(3‐methyl‐5‐phenyl‐4H‐1,2,4‐triazol‐4‐yl)isophthalic acid (H2 L ) and 4,4′‐bipyridine (4,4′‐bipy) has been hydrothermally synthesized and characterized by single‐crystal X‐ray diffraction, XRPD, IR, and elemental analysis. Temperature‐dependent magnetic susceptibility and thermal degradation for 1 were also studied. The asymmetric unit of compound 1 consists of two crystallographically independent Co(II) ion, two L 2? ligand, one 4,4′‐bipy ligand, and three lattice water molecules. The 2D triangle networks were linked by the bridging 4,4′‐bipy ligand to give rise to a 2‐fold interpenetrated 3D architecture. The simplest cyclic motif of the 2D networks is a triangle ring consisting of three Co(II) cations and three L 2? ligands. So we can define Co(II) ions as 4‐connected nodes and the L 2? ligands as 3‐connected nodes. Thus, the 3D structure can be described as a 2‐fold parallel interpenetrated ins InS 3,4‐conn topology.  相似文献   

4.
A dinucleoside‐3′,5′‐phosphodiester model, 5′‐amino‐4′‐aminomethyl‐5′‐deoxyuridylyl‐3′,5′‐thymidine, incorporating two aminomethyl functions in the 4′‐position of the 3′‐linked nucleoside has been prepared and its hydrolytic reactions studied over a wide pH range. The amino functions were found to accelerate the cleavage and isomerization of the phosphodiester linkage in both protonated and neutral form. When present in protonated form, the cleavage of the 3′,5′‐phosphodiester linkage and its isomerization to a 2′,5′‐linkage are pH‐independent and 50–80 times as fast as the corresponding reactions of uridylyl‐3′,5′‐uridine (3′,5′‐UpU). The cleavage of the resulting 2′,5′‐isomer is also accelerated, albeit less than with the 3′,5′‐isomer, whereas isomerization back to the 3′,5′‐diester is not enhanced. When the amino groups are deprotonated, the cleavage reactions of both isomers are again pH‐independent and up to 1000‐fold faster than the pH‐independent cleavage of UpU. Interestingly, the 2′‐ to 3′‐isomerization is now much faster than its reverse reaction. The mechanisms of these reactions are discussed. The rate accelerations are largely accounted for by electrostatic and hydrogen‐bonding interactions of the protonated amino groups with the phosphorane intermediate.  相似文献   

5.
Four new complexes, [Zn(btca)(2,2′‐bpy)] ( 1 ), [Mn(btca)(2,2′‐bpy)] ( 2 ), [Co(btca)(phen)] ( 3 ), and [Cu(btca)(phen)] ( 4 ), (H2btca=benzotriazole‐5‐carboxylic acid, 2,2′‐bpy=2,2′‐bipyridine, phen=1,10‐phenanthroline), were successfully synthesized and characterized by elemental analysis, single crystal X‐ray diffraction, and IR spectroscopy. Complexes 1 – 4 crystallize in the orthorhombic system with space group of Pbca and show similar 2D layers, which are interlinked to supramolecular networks by π‐π stacking interactions. Furthermore, TGA curves show that complexes 1 – 4 have good thermal stability. Solid‐state fluorescent property of complex 1 was also investigated at room temperature.  相似文献   

6.
Hydrothermal treatment of aqueous mixtures of copper(II) halides and 3,3′‐bipyridine (3,3′‐bpy) has afforded the coordination polymers [CuCl(3,3′‐bpy)]n ( 1 ) and [Cu2Br2(3,3′‐bpy)]n ( 2 ), which were analyzed via single crystal X‐ray diffraction, infrared spectroscopy, and elemental analysis. The structure of 1 consists of two‐dimensional (2‐D) layers constructed from the linkage of castellated one‐dimensional (1‐D) [CuCl]n stepped chains through anti‐conformation 3,3′‐bpy tethers. Compound 2 presents a related 2‐D sheet motif, albeit built from infinite 1‐D [Cu2Br2]n ladders strutted by 3,3′‐bpy ligands in anti conformation. In both cases neighboring 2‐D sheets stack into 3‐D via weak C–H···halogen interactions.  相似文献   

7.
Zinc and cadmium diphenate (dip, biphenyl‐2,2′‐dicarboxylate) coordination polymers containing conformationally flexible dipyridylamide ligands show diverse chain and layer topologies as determined by single‐crystal X‐ray diffraction. [Cd(dipH)2(bdin)]n ( 1 ) [bdin = N,N′‐(butane‐1,3‐diyl)diisonicotinamide] shows a simple 1D zigzag chain structure. {[Cd(dip)(pdin)(H2O)] · 1.25H2O}n ( 2 ) [pdin = N,N′‐(propane‐1,3‐diyl)diisonicotinamide] shows bilayer slabs formed by interleaving of (4,4) rectangular grid layers. {[Zn2(dip)2(3‐pna)2] · 3H2O}n ( 3 ) (3‐pna = 3‐pyridylnicotinamide) manifests a rare 4‐connected 1D ribbon topology. {[Cd(dip)(4‐ppbp)] · 2H2O}n ( 4 ) [4‐ppbp = propane‐1,3‐diylbis(piperidine‐4,1‐diyl)bis(pyridin‐4‐ylmethanone)] shows a 3,5‐connected layer with (426)(42678) 3,5L2 topology. {[Zn4(dip)4(H2O)2(4‐ppbp)2] · 12H2O}n ( 5 ) exhibits 2D 3,6‐connected layers with (43)2(466683) kgd topology featuring embedded R(8)A(2) classification 10‐membered water clusters. Compounds 1 , 4 , and 5 undergo violet or blue‐violet fluorescence upon ultraviolet irradiation. Thermal decomposition behavior of the new phases is also discussed.  相似文献   

8.
Three copper(II) complexes, [Cu2(OAc)4L2] · 2CH3OH ( 1 ), [CuBr2L′2(CH3OH)] · CH3OH ( 2a ), and [CuBr2L′2(DMSO)] · 0.5CH3OH ( 2b ) {L = N‐(9‐anthracenyl)‐N′‐(3‐pyridyl)urea and L′ = N‐[10‐(10‐methoxy‐anthronyl)]‐N′‐(3‐pyridyl)urea} have been synthesized by the reaction of L with the corresponding copper(II) salts. Complex 1 shows a dinuclear structure with a conventional “paddlewheel” motif, in which four acetate units bridge the two CuII ions. In complexes 2a and 2b , the anthracenyl ligand L has been converted to an anthronyl derivative L′, and the central metal ion exhibits a distorted square pyramidal arrangement, with two pyridyl nitrogen atoms and two bromide ions defining the basal plane and the apical position is occupied by a solvent molecule (CH3OH in 2a and DMSO in 2b ).  相似文献   

9.
The arsenic(III) and antimony(III) cyanides M(CN)3 (M=As, Sb) have been prepared in quantitative yields from the corresponding trifluorides through fluoride–cyanide exchange with Me3SiCN in acetonitrile. When the reaction was carried out in the presence of one equivalent of 2,2′‐bipyridine, the adducts [M(CN)3 ? (2,2′‐bipy)] were obtained. The crystal structures of As(CN)3, [As(CN)3 ? (2,2′‐bipy)] and [Sb(CN)3 ? (2,2′‐bipy)] were determined and are surprisingly different. As(CN)3 possesses a polymeric three‐dimensional structure, [As(CN)3 ? (2,2′‐bipy)] exhibits a two‐dimensional sheet structure, and [Sb(CN)3 ? (2,2′‐bipy)] has a chain structure, and none of the structures resembles those found for the corresponding arsenic and antimony triazides.  相似文献   

10.
The complexes [Co(L1)(mpy)] ( 1 ), [Ni(L1)(mpy)] ( 2 ), [Co(L1)(tbpy)] · 2H2O ( 3 ), [Ni2(L1)2(tbpy)2] · 5H2O ( 4 ), [Mn2(L1)2(tbpy)2] · 3H2O ( 5 ), [Mn(L1)(biim‐3)] ( 6 ), [Ni2(L1)2(btb)2(H2O)] · 2H2O ( 7 ), [Cu(L2)(mpy)] · 7H2O ( 8 ), [Co(L2)(tbpy)(H2O)] ( 9 ), [Ni(L2)(tbpy)(H2O)] · H2O ( 10 ), [Cu(L2)(bib)] · 2H2O ( 11 ), and [Cu(L2)(btb)] · 2H2O ( 12 ) [H2L1 = (3‐carboxyl‐phenyl)‐(4‐(2′‐carboxyl‐phenyl)‐benzyl)ether, H2L2 = 3‐carboxy‐1‐(4′‐carboxybenzyl)‐2‐oxidopyridinium, mpy = 2‐(4‐(4′‐methylphenyl)‐6‐(pyrindin‐2‐yl)pyridin‐2‐yl)pyridine), tbpy = 2‐(4‐(4′‐tert‐butylphenyl)‐6‐(pyrindin‐2‐yl)pyridin‐2‐yl)pyridine), biim‐3 = 1,3‐bis(imidazol‐1′‐yl)propane, btb = 1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene, bib = 1,4‐bis(imidazol‐1′‐ylmethyl)benzene] were synthesized. Compounds 1 – 6 have similar 1D chain structures, which are further linked by π–π interactions to generate supramolecular double chains for 1 and 2 , and supramolecular layers for 3 – 6 . Compound 7 displays a 3D 6‐connected framework with (44 · 611) topology. Compound 8 features a monomolecular structure, which is further linked by hydrogen bonds between the lattice water molecules and carboxylate oxygen atoms of L2 anions to form a 2D supramolecular layer. The monomolecular structures of 9 and 10 are connected by hydrogen bonds and π–π interactions simultaneously to generate supramolecular layers. Compounds 11 and 12 show layer structures.  相似文献   

11.
A new class of dye‐sensitized solar cells (DSSCs) using the hemicage cobalt‐based mediator [Co(ttb)]2+/3+ with the highly preorganized hexadentate ligand 5,5′′,5′′′′‐((2,4,6‐triethyl benzene‐1,3,5‐triyl)tris(ethane‐2,1‐diyl))tri‐2,2′‐bipyridine (ttb) has been fully investigated. The performances of DSSCs sensitized with organic D –π–A dyes utilizing either [Co(ttb)]2+/3+ or the conventional [Co(bpy)3]2+/3+ (bpy=2,2′‐bipyridine) redox mediator are comparable under 1000 W m?2 AM 1.5 G illumination. However, the hemicage complexes exhibit exceptional stability under thermal and light stress. In particular, a 120‐hour continuous light illumination stability test for DSSCs using [Co(ttb)]2+/3+ resulted in a 10 % increase in the performance, whereas a 40 % decrease in performance was found for [Co(bpy)3]2+/3+ electrolyte‐based DSSCs under the same conditions. These results demonstrate the great promise of [Co(ttb)]2+/3+ complexes as redox mediators for efficient, cost‐effective, large‐scale DSSC devices.  相似文献   

12.
Complexes [Pd(C6H3XH‐2‐R′‐5)Y(N^N)] (X=O, NH; Y=Br, I; R′=H, NO2; N^N=N,N,N′,N′‐tetramethylethylenediamine (tmeda), 2,2′‐bipyridine (bpy), 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine (dtbbpy)) react with RN?C?E (E=NR, S) or RC≡N (R=alkyl, aryl, NR′′2) and TlOTf (OTf=CF3SO3) to give, respectively, 1) products of the insertion of the C?E group into the C? Pd bond, protonation of the N atom, and coordination of X to Pd, [Pd{κ2X,E‐(XC6H3{EC(NHR)}‐2‐R′‐4)}(N^N)]OTf or [Pd(κ2X,N‐{ZC6H3(NH?CR)‐2‐R′‐4})(N^N)]OTf, or products of the coordination of carbodiimides and OH addition, [Pd{κ2C,N‐(C6H4{OC(NR)}NHR‐2)}(bpy)]OTf; or 2) products of the insertion of the C≡N group to Pd and N‐protonation, [Pd(κ2X,N‐{XC6H3(NH?CR)‐2‐R′‐4})(N^N)]OTf.  相似文献   

13.
Three metal coordination polymers [Zn(bdc)(L)(H2O)]n ( 1 ), [Co(pta)(L)(H2O)2]n ( 2 ), and [Cd(tda)(L)(H2O)]n ( 3 ) [H2bdc = 1,2‐benzene dicarboxylate acid, H2pta = terephthalic acid, H2tda = 2,5‐thiophenedicarboxylic acid, L = 3,5‐bis(imidazole‐1‐yl)pyridine] were synthesized and structurally characterized by IR spectroscopy, elemental analysis, X‐ray powder diffraction, and X‐ray single crystal diffraction. Complex 1 shows a three‐dimensional (3D) structure with cco topology with the symbol 65 · 8, whereas complex 2 features a 3D structure with cds topology with the symbol 65 · 8. Complex 3 has a 2D network constructed by the cadmium atoms bridged through the ligands tda and L. Their X‐ray powder diffraction patterns were compared with the simulated ones. Moreover, their luminescent properties were investigated in the solid state at room temperature, and the thermogravimetric analyses were carried out to study the thermal stability of the 3D networks.  相似文献   

14.
The crystal structure of K[PtCl3(caffeine)] was determined. The coordination geometry around platinum is square-planar formed by N9 of the caffeine ligand and three Cl? ions. The bond lengths and angles of K[PtCl3(caffeine)] were compared with those reported for [PtCl3(caffeine)]? and K[PtCl3(theobromine)]. At the level of the statistical significance of the data we have compared, no differences in the bond distances and angles for any of these compounds were noticed. Weak interactions between K+ and Cl? are responsible for the formation of 1-D polymeric chains in the crystal structure of the complex. The interactions of K[PtCl3(caffeine)] with inosine (Ino) and guanosine-5′-monophosphate (5′-GMP) were studied by 1H NMR spectroscopy at 295 K in D2O in a molar ratio of 1 : 1. The results indicate formation of the reaction product [PtCl3(Nu)] (Nu=Ino or 5′-GMP) with the release of caffeine from the coordination sphere of the starting complex. The higher stability of the bond between the Pt(II) ion and Ino or 5′-GMP compared to the stability of the platinum–caffeine bond is confirmed by density functional theory calculations (B3LYP/LANL2DZp) using as models 9-methylhypoxanthine and 9-methylguanine.  相似文献   

15.
《化学:亚洲杂志》2018,13(15):1915-1919
Metallosupramolecule‐based polymeric platforms with high degrees of hierarchy and tailorable functionalities are of great interests because of their unique morphologies and potential applications. Herein, the controllable synthesis of a highly‐ordered polymeric structure, {[M,P‐Co8(PDA)6(HIP)3(DMF)5(H2O)]3‐[Co(DMF)(H2O)2]} ( 1 ) (PDA=2,6‐pyridinedicarboxylate, HIP=5‐hydroxyisophthalate, DMF=dimethylformamide) with unique topology is reported. The solid‐state structure of 1 reveals that it is alternately and periodically assembled from racemic supramolecular monomers to form a zigzag‐shaped polymeric strand. Discrete racemic supramolecules ( 2 ) with topologies similar to those of monomeric species of 1 are also controllably synthesized in a separate reaction. Formation of intermolecular hydrogen bonds between supramolecules associated with hydroxyl groups of HIPs are critical for the unique solid‐state packing geometries of 1 and 2 .  相似文献   

16.
The novel oligonucleotide analogue 7 , consisting of 1′,4′‐anhydro‐2′,5′‐dideoxy‐2′‐(thymin‐1‐yl)‐D ‐altritol ( 4 ), residues was synthesized by the phosphoramidite approach on an automated DNA synthesizer. The phosphoramidite building block 6 was obtained by phosphitylation of the corresponding isonucleoside 5 . Oligoisonucleotide 7 contains an extended phosphodiester linkage with a higher flexibility. Oligoisonucleotide 7 was studied with respect to hybridization properties, enzymatic stability, and CD spectra. It exhibits a high stability towards snake‐venom phosphodiesterase and an acceptable hybridization to complementary single‐stranded DNA and RNA.  相似文献   

17.
Five new transition metal complexes [Cu(HL)2(H2O)2] ( 1 ), [Cu(HL)2(phen)] ( 2 ), [Cu(HL)2(H2O)]2(4,4′‐bipy) ( 3 ), [Zn(HL)2(H2O)2]·(4,4′‐bipy) ( 4 ), [Ag(HL)(4,4′‐bipy)]n ( 5 ), (H2L=5‐chloro‐1‐phenyl‐1H‐pyrazole‐3,4‐dicarboxylic acid, phen=1,10‐phenanthroline; 4,4′‐bipy=4,4′‐bipyridine) have been synthesized and characterized. Complexes 1 , 2 and 4 exhibit monomeric structures, 3 shows a dinuclear structure, 5 displays 1D chain structure, and all extend to 3D supramolecular network via rich hydrogen bonds. Complexes 1 , 2 , 3 , 5 comprise single helical chains, while complex 4 generates quadruple‐stranded helical chains. Furthermore, the antibacterial activities of the titled complexes against bacterial species, three Gram positive bacteria (Staphylococcus aureus, Bacillus subtilis and Candida albicans) and two Gram negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were studied and compared to the activities of free ligands by using the microdilution method.  相似文献   

18.
By using X‐ray crystallography, we show that the complexes Λ/Δ‐[Ru(TAP)2(11‐CN‐dppz)]2+ (TAP=1,4,5,8‐tetraazaphenanthrene, dppz=dipyridophenazine) bind DNA G‐quadruplex in an enantiospecific manner that parallels the specificity of these complexes with duplex DNA. The Λ complex crystallises with the normally parallel stranded d(TAGGGTTA) tetraplex to give the first such antiparallel strand assembly in which syn‐guanosine is adjacent to the complex at the 5′ end of the quadruplex core. SRCD measurements confirm that the same conformational switch occurs in solution. The Δ enantiomer, by contrast, is present in the structure but stacked at the ends of the assembly. In addition, we report the structure of Λ‐[Ru(phen)2(11‐CN‐dppz)]2+ bound to d(TCGGCGCCGA), a duplex‐forming sequence, and use both structural models to provide insight into the motif‐specific luminescence response of the isostructural phen analogue enantiomers.  相似文献   

19.
Using isothermal-isobaric Monte Carlo simulations we investigate defect topologies due to a spherical colloidal particle immersed in a nematic liquid crystal. Defects arise because of the competition between the preferential orientation at the colloid's surface and the far-field director ?n(0). Considering a chemically homogeneous colloid as a special case we observe the well-known surface and saturn ring defect topologies for weak and strong perpendicular anchoring, respectively; for homogeneous, strong parallel anchoring we find a boojum defect topology that has been seen experimentally [see P. Poulin and D. A. Weitz, Phys. Rev. E 57, 626 (1998)] but not in computer simulations. We also consider a heterogeneous, patchy colloid where the liquid-crystal molecules anchor either preferentially planar or perpendicular at the surface of the colloid. For a patchy colloid we observe a boojum ring defect topology in agreement with recent experimental studies [see M. Conradi, M. Ravnik, M. Bele, M. Zorko, S. Z?umer, and I. Mus?evic?, Soft Matter 5, 3905 (2009)]. We also observe two other novel defect topologies that have not been reported thus far neither experimentally nor theoretically.  相似文献   

20.
The arsenomolybdates [H2As2Mo6O26(H2O)] · (H2biyb)2 · 2H2O ( 1 ) and [H3As2Mo6O26] · (H3pt)2 ( 2 ) [biyb = 1,4‐bis(imidazol‐1‐ylmethyl)benzene, pt = 4′‐(3′′‐pyridyl)‐2,3′:6′3′′‐terpyridine] were synthesized via hydrothermal method. The structures of the compounds were characterized by single‐crystal X‐ray diffraction analyses, elemental analyses, IR spectroscopy, and TG analysis. Compounds 1 and 2 exhibit two isomeric forms of [HxAs2Mo6O26](6–x)–. The structure of 1 is constructed from the B‐type [H2As2Mo6O26(H2O)]4– polyanions and free biyb ligands via weak interactions to form 3D supramolecular framework with a {3 · 4 · 53 · 6}{3 · 43 · 52}{3 · 5 · 6}2{3 · 52}2 topology structure. In compound 2 , the A‐type [H3As2Mo6O26]3– clusters are surrounded by pt ligands through hydrogen bond interactions forming 3D supramolecular framework with a {43 · 63}2{46 · 66 · 83} topology structure. The electrochemical behaviors, electrocatalytic and photocatalytic activities of 1 and 2 are detected.  相似文献   

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