首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 720 毫秒
1.
A new molecular magnet, [NO2BrBzPyCH3][Ni(mnt)2] ( 1 ) ([NO2BrBzPyCH3]+ = 1‐(2′‐bromo‐4′‐nitrobenzyl)‐2‐methylpyridinium, and mnt2– = maleonitriledithiolate), has been prepared and characterized by single crystal X‐ray diffraction and magnetic measurements. The Ni(III) ions of 1 form a quasi‐one‐dimensional alternating zig‐zag magnetic chain within a Ni(mnt)2 column by intermolecular Ni···S, Ni···Ni or π···π interactions, and the [NO2BrBzPyCH3]+ cations stack into a column via weak Br···O interaction, p···π stacking interactions and C‐H···O hydrogen bonds between the cations. Magnetic susceptibility measurements in the temperature range 1.8‐300 K show that 1 exhibits a spin‐gap transition around 180 K, and an antiferromagnetic interaction in the high‐temperature phase (HT) and spin gap behavior in the low‐temperature phase (LT). The transition for 1 is a second‐order phase transition as determined by DSC analyses.  相似文献   

2.
The complex [Mg(1, 10‐phenanthroline)3(NO3)2]·9H2O has been synthesized. It forms crystals having the shape of sheaves with very thin filaments. The compound has been characterized by UV, IR, NMR and mass spectra. The UV and mass spectra are indicative of an electron density transfer from NO3 to Mg2+. On the base of the spectroscopic studies a model of the crystal structure has been proposed.  相似文献   

3.
The reaction of 2‐aldehyde‐8‐hydroxyquinoline, histamine, and YbX3 · 6H2O (X = NO3, ClO4) affords two ytterbium complexes [Yb(nma)2] · ClO4 · 2CH2Cl2 ( 1 ) and [Yb(nma)(NO3)2(DMSO)] · CH3OH ( 2 ) (Hnma = N‐(2‐(8‐hydroxylquinolinyl)methane(2‐(4‐imidazolyl)ethanamine))). The crystal structures were determined by X‐ray diffraction and it has been revealed that the anions have played important role in the assembly. In the case of 1 , the Yb3+ ions are completely encapsulated by two nma ligands with uncoordinated perchlorate anion balancing the positive charge. In the case of 2 , the Yb3+ ions are ligated by the ligand, oxygen atoms of the nitrate ion, and DMSO. Both complexes exhibit essential NIR luminescence of Yb3+ ions.  相似文献   

4.
Two luminescent metal‐organic frameworks (LMOFs), namely, [Cd2(DDCPB) · (DMF)2 · H2O]n (CHD‐ 1 ) and [Zn2(DDCPB) · (DMA)2]n · n(DMA) (CHD‐ 2 ), were solvothermally constructed, which present structural diversity. Single crystal X‐ray diffraction analysis indicates that they consist of [Cd2(μ2‐O)2(κ‐O)2] building units (for CHD‐ 1 ), [Zn2(κ‐O)6] building units (for CHD‐ 2 ), which are further linked by multicarboxylate H4DDCPB to construct microporous frameworks. Remarkably, both CHD‐ 1 and 2 exhibit highly efficient luminescent sensing for environmentally relevant Cu2+ ions through luminescence quenching. Theoretical and experimental calculations indicate that the luminescent quenching can be attributes to the donor‐acceptor electron transfer between the MOFs and analytes. This work indicates that CHD‐ 1 and 2 could be taken as a potential candidate for developing multifunctional luminescence sensors.  相似文献   

5.
Three 1H‐benzimidazole‐5‐carboxylate (Hbic)‐based coordination polymers, {[Ni(H2O)(Hbic)2] · 2H2O}n ( 1 ), {[Ni(H2O)2(Hbic)2] · 3H2O}n ( 2 ), and {[Co2(H2O)4(Hbic)4] · 4DMF · 3H2O}n ( 3 ) were obtained by reactions of the ligand H2bic and NiII or CoII salts in the presence of different structure directing molecules. They were structurally characterized by single‐crystal X‐ray diffraction, IR spectra, elemental analysis, thermal stability, luminescent, and magnetic measurements. Structural analysis suggests that the three polymers exhibit a 2D (4, 4) layer for 1 and 1D linear double chains for both 2 and 3 due to the variable binding modes and the specific spatial orientation of the Hbic ligand towards the different paramagnetic metal ions, which were further aggregated into different 3D supramolecular architectures by popular hydrogen‐bonding interactions. Weak and comparable antiferromagnetic couplings mediating by Hbic bridge are observed between the neighboring spin carriers for 2 and 3 , respectively. Additionally, complexes 1 – 3 also display different luminescence emissions at room temperature due to the ligand‐to‐metal charge transfer.  相似文献   

6.
A new two‐dimensional metal‐organic coordination polymer [Cd2(2,3,2′,3′‐sdpa)(H2O)3] · 2H2O ( 1 ) were hydro(solvo)thermally synthesized by the reaction of 2,3,2′,3′‐sulfonyldiphthalic acid (2,3,2′,3′‐H4sdpa) with Cd(NO3)2 · 4H2O and characterized by elemental analysis, thermogravimetry, IR and luminescence spectroscopy, and X‐ray diffraction. In complex 1 , two kinds of cadmium atoms are linked together by anionic sdpa4– ligands to form a 2D metal‐organic network. The adjacent 2D layers further interact with each other through hydrogen bonds and π ··· π interactions to form a 3D supramolecular structure. The luminescence spectra and thermal properties of 1 were also investigated.  相似文献   

7.
A mononuclear complex [Cu(HL · S)2(NO3)2] ( 1 ) and a one‐ dimensional coordination polymer [Cu(HL · S)Cl2]n ( 2 ) [HL · S = 4‐(pyridin‐2‐ylmethyl)tetrahydro‐2H‐thiopyran‐4‐ol] showcase the structure‐directing role of the counterions in their formation reaction: monodentate ligation of NO3 and Cl induces an octahedral (with two HL · S per Cu in 1 ) or trigonal‐bipyramidal (with one HL · S per Cu in 2 ) CuII coordination environment. In contrast to 1 exhibiting no coordinative metal–sulfur bonds in the crystal lattice (space group P21/c), 2 (P21/c) features intermolecular Cu–S contacts of 2.3188(7) Å. The coordination compounds are thermally stable up to ca. 160 °C. Whereas 1 demonstrates the spin‐like behavior of an isolated central CuII ion, compound 2 exhibits weak antiferromagnetic intra‐chain coupling with J ≈ –2.1 cm–1 between neighboring CuII ions.  相似文献   

8.
Different kinds of counterions (such as NO3, ClO4, and Cl) play a special role in controlling the framework of coordination compounds. Using this strategy, 5‐aminotetrazole‐1‐propionic acid (Hatzp) was selected to react with praseodymium(III) nitrate or perchlorate in the same solvent system, producing two different coordination compounds, [Pr2(atzp)4(H2O)8] · 2NO3 · 2H2O ( 1 ) and [Pr2(atzp)6(H2O)2] · H2O ( 2 ). These compounds were structurally characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. X‐ray diffraction analysis revealed that compound 1 displays a dinuclear structure, whereas 2 shows a one dimensional zigzag chain framework. Furthermore, the luminescence properties of compounds 1 and 2 were investigated at room temperature in the solid state.  相似文献   

9.
Two discrete lanthanide complexes with bulky aromatic mixed‐ligands, {[La2(na)6(phen)2]·[La2(na)6(phen)2]} ( 1 ) and [La2(na)6(2,2′‐bipy)2] ( 2 ) (Hna = 1‐naphthoic acid, phen = 1,10‐phenanthroline, and 2,2′‐bipy = 2,2′‐bipyridine), have been synthesized under hydrothermal conditions and fully characterized by single‐crystal X‐ray crystallography, IR, elemental analysis, TG‐DTA and fluorescence spectra. Structure determination reveals that 1 contains two separate binuclear [La2(na)6(phen)2] units, in which both crystallographically LaIII ions are nine‐coordinated with tricapped trigonal prism polyhedron for La1 and a distorted monocapped square antiprism arrangement for La2; whereas 2 has a binuclear structure bridged by carboxylate groups of four na anions. Due to the introduction of bulky aromatic ligands, non‐classical C–H···O H–bonds and π – involved stacking interactions become the dominantly driving forces for the supramolecular structure. The two solid complexes exhibit intense fluorescent emissions at room temperature resulted from the ligand‐to‐metal charge transfer.  相似文献   

10.
Three complexes of bifunctional 5‐substituted tetrazolatecarboxylate ligands [2‐(5‐(pyrazin‐2‐yl)‐2H‐tetrazol‐2‐yl)acetic acid (Hpztza), 3‐(5‐amino‐2H‐tetrazol‐1(5H)‐yl)propanoic acid (Hatzp), and N,N′‐bis(tetrazol‐5‐yl)anime‐N2,N2′‐diacetic acid (H2datza)], namely a mononuclear structure [La(pztza)2(H2O)5] · 4H2O · pztza ( 1 ), a 1D polymeric chain structure [La2(atzp)4(H2O)8] · 2NO3 · 2H2O ( 2 ), and a 2D layer network [La(datza)(H2O)3] · 4H2O ( 3 ) were prepared and structurally characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. The structures of these complexes are controlled not only by the number and different coordination modes of the tetrazole‐carboxylate ligands but also the different 5‐substituents of the tetrazole ring. The complexes show ligand‐centered luminescence at room temperature in the solid state. The obvious enhancements in luminescence make these complexes to be the potential materials for optical use.  相似文献   

11.
Three mononuclear copper(II) complexes of copper nitrate with 2, 6‐bis(pyrazol‐1‐yl)pyridine ( bPzPy ) and 2, 6‐bis(3′,5′‐dimethylpyrazol‐1‐yl)pyridine ( bdmPzPy ), [Cu(bPzPy)(NO3)2] ( 1 ), [Cu(bPzPy)(H2O)(NO3)2] ( 2 ) and [Cu(bdmPzPy)(NO3)2] ( 3 ) were synthesized by the reaction of copper nitrate with the ligand in ethanol solution. The complexes have been characterized through analytical, spectroscopic and EPR measurements. Single crystal X‐ray structure analysis of complexes 1 and 2 revealed a five‐coordinate copper atom in 1 , whereas 2 contains a six‐coordinate (4+2) CuII ion with molecular units acting as supramolecular nodes. These neutral nodes are connected through O–H ··· O(nitrate) hydrogen bonds to give couples of parallel linear strips assembled in 1D‐chains in a zipper‐like motif.  相似文献   

12.
Blue crystals of metal nitratocuprates(II), M3[Cu(NO3)4](NO3) (M = K ( I ), NH4 ( II ), Rb ( III )) and Cs2[Cu(NO3)4] ( IV ) were synthesized from Cu(NO3)2 · 3 H2O and MNO3 by heating at 100–140 °C during 3–12 h. X-ray single crystal structures for isotypic I and II reveal the presence of the [Cu(NO3)4]2– and NO3 anions and M+ cations. Structure IV contains [Cu(NO3)4]2– and Cs+. In structures I , II , and IV , Cu atoms have a square-planar coordination [CuO4] with short Cu–O distances of 1.92–2.00 Å, the oxygen atoms belonging to four different NO3 groups. Each coordinated NO3 group is a nonsymmetrical bidentate ligand with the second, longer Cu–O distance from 2.38 to 2.74 Å. Rubidium derivative III was shown to be isotypic to I on the basis of unit cell dimensions and symmetry. Eight-coordinate metal(II) environment in tetranitrates is compared for transition metals with different electronic configurations.  相似文献   

13.
Two MOFs of [SrII(5‐NO2‐BDC)(H2O)6] ( 1 ) and [BaII(5‐NO2‐BDC)(H2O)6] ( 2 ) have been synthesized in water using alkaline earth metal salts and the rigid organic ligand 5‐NO2‐H2BDC. The compounds were characterized by elemental analysis, infrared spectrum, thermal analysis, and X‐ray crystallography. Crystal structure analyses have shown that the two complexes are isostructural as evidenced by IR spectra and TG‐DTA. Both compounds present three‐dimensional frameworks built up from infinite chains of edge‐sharing twelve‐membered rings through O–H···O hydrogen bonds. The specific heat capacities of the title complexes have been determined by an improved RD496‐III microcalorimeter with the values of (109.29 ± 0.693) J mol−1 K−1 and (81.162 ± 0.858) J mol−1 K−1 at 298.15 K, and the molar enthalpy changes of the formation reactions of complexes at 298.15 K were calculated as (4.897 ± 0.008) kJ mol−1 and (2.617 ± 0.009) kJ mol−1, respectively.  相似文献   

14.
A new 3D metal‐organic framework {[Ag4(btc)(bix)2] · H2O}n ( 1 ) [H4btc = biphenyl‐2, 2′,4, 4′‐tetracarboxylic acid, bix = 1, 4‐bis(imidazol‐1‐ylmethyl)benzene] was synthesized under hydrothermal conditions and characterized by single‐crystal X‐ray diffraction, infrared (IR) spectroscopy, thermal gravimetric analysis (TGA), and luminescence studies. The most remarkable structural feature of 1 is that the 1D chain and 2D network interpenetrated structures are further linked by parallel aligned 1D AgI chains to generate 3D metal‐organic framework.  相似文献   

15.
The coordination polymers, {[Co(bbim)2(H2O)2](tcbdc) · 2H2O}n ( 1 ), {[Ni(tcbdc)(bbim)(H2O)2] · 2DMF}n ( 2 ), and {[Cu2(tcbdc)2(bbim)4] · 4H2O}n ( 3 ) [bbim = 1,1′‐(1,4‐butanediyl)bis(imidazole) and tcbdc2– = tetrachlorobenzene‐1,4‐dicarboxylate] were synthesized and characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, luminescence, and single‐crystal X‐ray diffraction analysis. Complex 1 has a double‐stranded chain structure through doubly bridged [Co(bbim)2] units. Complex 2 exhibits two‐dimensional square grid, whereas complex 3 has a three‐dimensional porous network structure with an unprecedented 44 · 611 topological structure through interpenetrating square grid. The water molecules in complex 3 occupy the vacancy through three kinds of hydrogen bond interactions. Upon excitation at 370 nm, complexes 1 – 3 present solid‐state luminescence at room temperature.  相似文献   

16.
The fundamental properties and extraction capability of an ionic liquid (IL), trioctylammonium nitrate ([HTOA][NO3]), for PdII and PtIV, are investigated. At room temperature, [HTOA][NO3] is a solid (melting point: 30.7 °C), but it becomes a liquid (melting point: 16.7 °C) when saturated with water. Water-saturated [HTOA][NO3] exhibits a viscosity of 267.1 mPa·s and an aqueous solubility of 2.821?×?10?4 mol·dm?3 at 25 °C, and can be used as an extraction solvent without dilution. [HTOA][NO3] exhibits an extremely high extraction capability for PdII and PtIV in dilute hydrochloric acid (0.1–2 mol·dm?3 HCl); the distribution ratio reaches 3 × 104 for both the metals. From electrospray ionization mass spectrometry analysis, the species extracted in the IL phase are [PdCl3]? and [PdCl2(NO3)]? for PdII and [PtCl6]2? and [PtCl5]? for PtIV. A majority of the other transition metals are considerably less or marginally extracted into [HTOA][NO3] from a 0.1 mol·dm?3 hydrochloric acid solution. The extraction capacity of [HTOA][NO3] is greater than that of other hydrophobic ILs such as [HTOA]Cl and bis(trifluoromethanesulfonyl)imide-based ILs. The metals extracted into the IL phase are quantitatively back-extracted using an aqueous solution containing thiourea and nitric acid. By controlling the thiourea concentration and shaking time, PdII and PtIV are mutually separated to some extent in the back extraction process. The IL phase used for the back extraction can be reused for the forward extraction of these metals after scrubbing it with an aqueous nitric acid solution.  相似文献   

17.
Trinuclear silver(I) thiolate and silver(I) thiocarboxylate complexes [Ag3(μ‐dppm)3n‐SR)2](ClO4) [n = 2, R = C6H4Cl‐4 ( 1 ) and C{O}Ph ( 2 ); n = 3, R = tBu ( 3 )], pentanuclear silver(I) thiolate complex [Ag5(μ‐dppm)43‐SC6H4NO2‐4)4](PF6) ( 4 ), and hexanuclear silver(I) thiolate complexes [Ag6(μ‐dppm)43‐SR)4]Y2 [Y = ClO4, R =C6H4CH3‐4 ( 5 ) and C10H7 (2‐naphthyl) ( 7 ); Y = PF6, R = C6H4OCH3‐4( 6 )], were synthesized [dppm = bis(diphenylphosphanyl)methane] and their crystal structures as well as photophysical properties were studied. In the solid state at 77 K, trinuclear silver(I) thiolate and silver(I) thiocarboxylate complexes 1 and 2 exhibit luminescence at 470–523 nm, tentatively attributed to originate from the 3IL (intraligand) of thiolate or thiocarboxylate ligands, whereas hexanuclaer silver(I) thiolate complexes 5 and 7 produce dual emission, in which high‐energy emission is tentatively attributed to come from the 3IL of thiolate ligands and low‐energy emission is tentatively assigned to come from the admixture of metal ··· metal bond‐to‐ligand charge‐transfer (MMLCT) and metal‐centered (MC) excited states.  相似文献   

18.
The pendant‐armed ligands L1 and L2 were synthesized by N‐alkylation of the four secondary amine groups of the macrocyclic precursor L using o‐nitrobenzylbromide (L1) and p‐nitrobenzylbromide (L2). Nitrates and perchlorates of CuII, NiII and CoII were used to synthesize the metal complexes of both ligands and the complexes were characterized by microanalysis, MS‐FAB, conductivity measurements, IR and UV‐Vis spectroscopy and magnetic studies. The crystal structures of L1, [CuL1](ClO4)2·CH3CN·H2O, [CuL2](ClO4)2·6CH3CN, [CuL2][Cu(NO3)4]·5CH3CN·0.5CH3OH and [NiL2](ClO4)2·3CH3CN·H2O were determined by single crystal X‐ray crystallography. These structural analysis reveal the free ligand L1, three mononuclear endomacrocyclic complexes {[CuL1](ClO4)2·CH3CN·H2O, [CuL2](ClO4)2·6CH3CN and [NiL2](ClO4)2·3CH3CN·H2O} and one binuclear complex {[CuL2][Cu(NO3)4]·5CH3CN·0.5CH3OH} in which one of the metals is in the macrocyclic framework and the other metal is outside the ligand cavity and coordinated to four nitrate ions.  相似文献   

19.
Three new compounds based on H2BDC and PyBImE [H2BDC = 1,4‐benzenedicarboxylatic acid, PyBImE = 2‐(2‐pyridin‐4‐yl‐vinyl)benzimidazole], namely, [Co(PyBImE)(BDC)(H2O)2] ( 1 ), [Co(PyBImE)2(HBDC)(BDC)0.5] ( 2 ), and [(HPyBImE)+ · (BDC)20.5 · (H2BDC)0.5] ( 3 ), were synthesized by hydrothermal methods and characterized by single‐crystal X‐ray diffraction. Compound 1 is a one‐dimensional chain bridged by terephthalate in a bis(monodentate) fashion. In the complex the nitrogen atom from NBIm and the coordination water molecule complete the coordination sphere. In complex 2 , the dinuclear cobalt units are bridged by terephthalate in a bis(bidentate) fashion into a one‐dimensional chain, but different from complex 1 , the nitrogen atom from NPy and the oxygen atom from hydrogenterephthalate complete the coordination sphere. Complex 3 is a co‐crystal with PyBImE and H2BDC in a 1:1 ratio and the transfer of hydrogen atoms leads the complex into a salt. Interesting supramolecular structures are shown due to the hydrogen bonding as well as π ··· π interactions in the three complexes. Thermal and magnetic properties of 1 and 2 were also studied.  相似文献   

20.
Three novel polyoxometalate compounds consisting of Anderson‐type anions and trivalent lanthanide cations, [Ln(H2O)7Cr(OH)6Mo6O18]n·4nH2O (Ln = Ce 1 ; Sm 2 ; Eu 3 ), have been synthesized in aqueous solution and characterized by single crystal X‐ray diffraction, elemental analyses, IR spectra, and TG analyses. Single crystal X‐ray diffractions reveal that the structures of the 1:1 composite compound formed by the heteropolyanion [Cr(OH)6Mo6O18]3? as the building unit and the [Ln(H2O)7]3+ complex fragment as the linker, which exhibit a type of zig‐zag chain with alternating cations and anions through the Mo‐Ot′‐Ln‐Ot′‐Mo linkage in the crystal. The magnetic properties of 1 ? 3 have been studied by measuring their magnetic susceptibility over the temperature range of 2‐300 K. The UV‐vis spectra of 1 give the Mo‐O and CrIII‐O charge transfer transitions at 203 and 543 nm, respectively. In addition, the fluorescent characteristic transition of the Eu3+ ions in compound 3 is reported.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号