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1.
Polyoxometalate‐Based Entangled Coordination Networks Induced by an Extended Bis(triazole) Ligand 下载免费PDF全文
Dr. Xiu‐Li Hao Yuan‐Yuan Ma Wen‐Zhe Zhou Dr. Hong‐Ying Zang Dr. Yong‐Hui Wang Prof. Yang‐Guang Li 《化学:亚洲杂志》2014,9(12):3633-3640
The introduction of an extended bridging bis(triazole) ligand, that is, 4,4′‐bis(1,2,4‐triazol‐1‐ ylmethyl)biphenyl (BBPTZ), into the hydrothermal reaction system containing transition metal ions and Keggin‐type polyoxometalates (POMs) led to the isolation of three new organic–inorganic hybrid entangled coordination networks, [CuI2CuII(BBPTZ)6][SiW12O40]?12 H2O ( 1 ), [Ni(BBPTZ)2(H2O)][H2SiW12O40]?11 H2O ( 2 ), and [Ni2(BBPTZ)4(H2O)2][SiW12O40]?3 H2O ( 3 ). All three compounds were characterized by elemental analysis, IR spectroscopy, TG analysis, powder X‐ray diffraction, and single‐crystal X‐ray diffraction. Compound 1 contains a 2‐D POM‐based metal–organic layer entangled with 1‐D ladder‐like metal–organic chains. The adjacent 2‐D networks are parallel to each other, further stacking into a 3‐D supramolecular framework with 1‐D channels. Compound 2 exhibits a 1‐D cantilever‐type loop‐containing chain. The Keggin‐type POMs act as the cantilever groups, leading to the adjacent catilever‐type chains interwaving together to form a 3‐D supramolecular open framework with two types of channels. Compound 3 possesses a 3‐D open framework based on 2‐D metal–organic undulated layer and Keggin‐type POM clusters. Three sets of such frameworks further interpenetrate with each other to form an interesting three‐fold interpenetrating framework. The photocatalytic activities of compounds 1–3 for the decomposition of methylene blue (MB) under UV light have been investigated. 相似文献
2.
Hybrid Coordination Networks Constructed from ɛ‐Keggin‐Type Polyoxometalates and Rigid Imidazole‐Based Bridging Ligands as New Carriers for Noble‐Metal Catalysts 下载免费PDF全文
Xiao‐Jian Yang Dr. Meng Sun Prof. Hong‐Ying Zang Dr. Yuan‐Yuan Ma Dr. Xiao‐Jia Feng Dr. Hua‐Qiao Tan Dr. Yong‐Hui Wang Prof. Yang‐Guang Li 《化学:亚洲杂志》2016,11(6):858-867
Three hybrid coordination networks that were constructed from ?‐Keggin polyoxometalate building units and imidazole‐based bridging ligands were prepared under hydrothermal conditions, that is, H[(Hbimb)2(bimb){Zn4PMoV8MoVI4O40}] ? 6 H2O ( 1 ), [Zn(Hbimbp)(bimbp)3{Zn4PMoV8MoVI4O40}] ? DMF ? 3.5 H2O ( 2 ), and H[Zn2(timb)2(bimba)2Cl2{Zn4PMoV8MoVI4O40}] ? 7 H2O ( 3 ) (bimb=1,4‐bis(1‐imidazolyl)benzene, bimbp=4,4′‐bis(imidazolyl)biphenyl, timb=1,3,5‐tris(1‐imidazolyl)benzene, bimba=3,5‐bis(1‐imidazolyl)benzenamine). All three compounds were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single‐crystal X‐ray diffraction. The mixed valence of the Mo centers was analyzed by XPS spectroscopy and bond‐valence sum calculations. In all three compounds, the ?‐Keggin polyoxometalate (POM) units acted as nodes that were connected by rigid imidazole‐based bridging ligands to form hybrid coordination networks. In compound 1 , 1D zigzag chains extended to form a 3D supramolecular architecture through intermolecular hydrogen‐bonding interactions. Compound 2 consisted of 2D curved sheets, whilst compound 3 contained chiral 2D networks. Because of the intrinsic reducing properties of ?‐Keggin POM species, noble‐metal nanoparticles were loaded onto these POM‐based coordination networks. Thus, compounds 1 – 3 were successfully loaded with Ag nanoparticles, and the corresponding composite materials exhibited high catalytic activities for the reduction of 4‐nitrophenol. 相似文献
3.
Synthesis of α‐Dawson‐Type Silicotungstate [α‐Si2W18O62]8− and Protonation and Deprotonation Inside the Aperture through Intramolecular Hydrogen Bonds 下载免费PDF全文
Takuo Minato Dr. Kosuke Suzuki Dr. Keigo Kamata Prof. Dr. Noritaka Mizuno 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(20):5946-5952
The design of structurally well‐defined anionic molecular metal–oxygen clusters, polyoxometalates (POMs), leads to inorganic receptors with unique and tunable properties. Herein, an α‐Dawson‐type silicotungstate, TBA8[α‐Si2W18O62] ? 3 H2O ( II ) that possesses a ?8 charge was successfully synthesized by dimerization of a trivacant lacunary α‐Keggin‐type silicotungstate TBA4H6[α‐SiW9O34] ? 2 H2O ( I ) in an organic solvent. POM II could be reversibly protonated (in the presence of acid) and deprotonated (in the presence of base) inside the aperture by means of intramolecular hydrogen bonds with retention of the POM structure. In contrast, the aperture of phosphorus‐centered POM TBA6[α‐P2W18O62]?H2O ( III ) was not protonated inside the aperture. The density functional theory (DFT) calculations revealed that the basicities and charges of internal μ3‐oxygen atoms were increased by changing the central heteroatoms from P5+ to Si4+, thereby supporting the protonation of II . Additionally, II showed much higher catalytic performance for the Knoevenagel condensation of ethyl cyanoacetate with benzaldehyde than I and III . 相似文献
4.
Xiu‐Li Hao Yuan‐Yuan Ma Dr. Yong‐Hui Wang Long‐Yang Xu Dr. Fu‐Chen Liu Mao‐Mao Zhang Prof. Yang‐Guang Li 《化学:亚洲杂志》2014,9(3):819-829
Investigation into a hydrothermal reaction system with transition‐metal (TM) ions, 1,4‐bis(1,2,4‐triazol‐1‐lmethyl)benzene (BBTZ) and various charge‐tunable Keggin‐type polyoxometalates (POMs) led to the preparation of four new entangled coordination networks, [CoII(HBBTZ)(BBTZ)2.5][PMo12O40] ( 1 ), [CuI(BBTZ)]5[BW12O40] ? H2O ( 2 ), [CuII(BBTZ)]3[AsWV3WVI9O40] ? 10 H2O ( 3 ), and [CuII5(BBTZ)7(H2O)6][P2W22Cu2O77(OH)2] ? 6 H2O ( 4 ). All compounds were characterized by using elemental analysis, IR spectroscopy, thermogravimetric analysis, powder X‐ray diffraction, and single‐crystal X‐ray diffraction. The mixed valence of W centers in compound 3 was further confirmed by using XPS spectroscopy and bond‐valence sum calculations. In the structural analysis, the entangled networks of 1 – 4 demonstrate zipper‐closing packing, 3D polythreading, 3D polycatenation, and 3D self‐penetration, respectively. Moreover, with the enhancement of POM negative charges and the use of different TM types, the number of nodes in the coordination networks of 1 – 4 increased and the basic metal–organic building motifs changed from a 1D zipper‐type chain (in 1 ) to a 2D pseudorotaxane layer (in 2 ) to a 3D diamond‐like framework (in 3 ) and finally to a 3D self‐penetrating framework (in 4 ). The photocatalytic properties of compounds 1 – 4 for the degradation of methylene blue under UV light were also investigated; all compounds showed good catalytic activity and the photocatalytic activity order of Keggin‐type species was initially found to be {XMo12O40}>{XW12O40}>{XW12?nTMnO40}. 相似文献
5.
A Stable Polyoxometalate‐Pillared Metal–Organic Framework for Proton‐Conducting and Colorimetric Biosensing 下载免费PDF全文
Dr. En‐Long Zhou Prof. Chao Qin Dr. Peng Huang Prof. Xin‐Long Wang Dr. Wei‐Chao Chen Dr. Kui‐Zhan Shao Prof. Zhong‐Min Su 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11894-11898
A stable metal–organic framework pillared by Keggin‐type polyoxometalate, Cu6(Trz)10(H2O)4[H2SiW12O40]?8 H2O (Trz=1,2,4‐triazole) ( 1 ), has been prepared under hydrothermal condition. The 2D layer structure with a 22‐member ring was formed by Cu2+ ions, which are connected with each other via the Trz ligands on the ab plane. Thus, the 2D layers are further interconnected through Keggin polyoxoanions to generate a 3D porous network with a small 1D channel. Moreover, the presence of polyoxoanions make it exhibit selective adsorption of water and proton‐conducting properties. Additionally it showed efficient intrinsic peroxidase‐like activity, providing a simple and sensitive colorimetric assay to detect H2O2. 相似文献
6.
Three Keggin‐Type Transition Metal‐Substituted Polyoxometalates as Pure Inorganic Photosensitizers for p‐Type Dye‐Sensitized Solar Cells 下载免费PDF全文
Dr. Xiang‐Wei Guo Dr. Jian‐Sheng Li Dr. Xiao‐Jing Sang Prof. Wei‐Lin Chen Prof. Zhong‐Min Su Prof. En‐Bo Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(10):3234-3238
In light of the serious challenge of severe global energy shortages, p‐type dye‐sensitized solar cells (p‐DSSCs) have attracted increasing levels of interest. The potential of three Keggin‐type transition metal‐substituted polyoxometalates, TBA8Na2[SiW9O37{Co(H2O)3}]? 11 H2O (SiW9Co3), TBA4[(SiO4)W10MnIII2O36H6]?1.5 CH3CN? 2 H2O (SiW10MnIII2), and TBA3.5H5.5[(SiO4)W10MnIII/IV2O36]? 10 H2O?0.5 CH3CN (SiW10MnIII/IV2) has been explored as pure inorganic dye photosensitizers for p‐DSSCs (TBA=(n‐C4H9)4N+). The three dyes show overall conversion efficiencies of 0.038, 0.029, and 0.027 %, respectively, all of which are higher than that of coumarin 343 (0.017 %). These polyoxometalates are the first three pure inorganic dyes reported for use with p‐DSSCs and therefore demonstrate a new strategy for designing efficient dyes, especially pure inorganic dyes. Moreover, they broaden the range of applications for polyoxometalates. 相似文献
7.
Visible‐Light‐Induced Water Oxidation Mediated by a Mononuclear‐Cobalt(II)‐Substituted Silicotungstate 下载免费PDF全文
A mononuclear‐cobalt(II)‐substituted silicotungstate, K10[Co(H2O)2(γ‐SiW10O35)2] ? 23 H2O (POM‐ 1 ), has been evaluated as a light‐driven water‐oxidation catalyst. With in situ photogenerated [Ru(bpy)3]3+ (bpy=2,2′‐bipyridine) as the oxidant, quite high catalytic turnover number (TON; 313), turnover frequency (TOF; 3.2 s?1), and quantum yield (ΦQY; 27 %) for oxygen evolution at pH 9.0 were acquired. Comparison experiments with its structural analogues, namely [Ni(H2O)2(γ‐SiW10O35)2]10? (POM‐ 2 ) and [Mn(H2O)2(γ‐SiW10O35)2]10? (POM‐ 3 ), gave the conclusion that the cobalt center in POM‐ 1 is the active site. The hydrolytic stability of the title polyoxometalate (POM) was confirmed by extensive experiments, including UV/Vis spectroscopy, linear sweep voltammetry (LSV), and cathodic adsorption stripping analysis (CASA). As the [Ru(bpy)3]2+/visible light/sodium persulfate system was introduced, a POM–photosensitizer complex formed within minutes before visible‐light irradiation. It was demonstrated that this complex functioned as the active species, which remained intact after the oxygen‐evolution reaction. Multiple experimental parameters were investigated and the catalytic activity was also compared with the well‐studied POM‐based water‐oxidation catalysts (i.e., [Co4(H2O)2(α‐PW9O34)2]10? (Co4‐POM) and [CoIIICoII(H2O)W11O39]7? (Co2‐POM)) under optimum conditions. 相似文献
8.
Carbon Monoxide Oxidation by Polyoxometalate‐Supported Gold Nanoparticulate Catalysts: Activity,Stability, and Temperature‐ Dependent Activation Properties 下载免费PDF全文
Dr. Takuya Yoshida Prof. Dr. Toru Murayama Prof. Dr. Norihito Sakaguchi Prof. Dr. Mitsutaka Okumura Prof. Dr. Tamao Ishida Prof. Dr. Masatake Haruta 《Angewandte Chemie (International ed. in English)》2018,57(6):1523-1527
Nanoparticulate gold supported on a Keggin‐type polyoxometalate (POM), Cs4[α‐SiW12O40]?n H2O, was prepared by the sol immobilization method. The size of the gold nanoparticles (NPs) was approximately 2 nm, which was almost the same as the size of the gold colloid precursor. Deposition of gold NPs smaller than 2 nm onto POM (Au/POM) was essential for a high catalytic activity for CO oxidation. The temperature for 50 % CO conversion was ?67 °C. The catalyst showed extremely high stability for at least one month at 0 °C with full conversion. The catalytic activity and the reaction mechanism drastically changed at temperatures higher than 40 °C, showing a unique behavior called a U‐shaped curve. It was revealed by IR measurement that Auδ+ was a CO adsorption site and that adsorbed water promoted CO oxidation for the Au/POM catalyst. This is the first report on CO oxidation utilizing Au/POMs catalysts, and there is a potential for expansion to various gas‐phase reactions. 相似文献
9.
The Enhancement on Proton Conductivity of Stable Polyoxometalate‐Based Coordination Polymers by the Synergistic Effect of MultiProton Units 下载免费PDF全文
Dr. Jing Li Dr. Xue‐Li Cao Dr. Yuan‐Yuan Wang Dr. Shu‐Ran Zhang Dr. Dong‐Ying Du Dr. Jun‐Sheng Qin Prof. Shun‐Li Li Prof. Zhong‐Min Su Prof. Ya‐Qian Lan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(27):9299-9304
Two novel polyoxometalate (POM)‐based coordination polymers, namely, [Co(bpz)(Hbpz)][Co(SO4)0.5(H2O)2(bpz)]4 [PMoVI8MoV4VIV4O42]?13 H2O ( NENU‐530 ) and [Ni2(bpz)(Hbpz)3(H2O)2][PMoVI8MoV4VIV4O44]?8 H2O ( NENU‐531 ) (H2bpz=3,3′,5,5′‐tetramethyl‐4,4′‐bipyrazole), were isolated by hydrothermal methods, which represented 3D networks constructed by POM units, the protonated ligand and sulfate group. In contrast with most POM‐based coordination polymers, these two compounds exhibit exceptional excellent chemical and thermal stability. More importantly, NENU‐530 shows a high proton conductivity of 1.5×10?3 S cm?1 at 75 °C and 98 % RH, which is one order of magnitude higher than that of NENU‐531 . Furthermore, structural analysis and functional measurement successfully demonstrated that the introduction of sulfate group is favorable for proton conductivity. Herein, the syntheses, crystal structures, proton conductivity, and the relationship between structure and property are presented. 相似文献
10.
Chunjing Zhang Zhuanfang Zhang Ying Guo Heng Liu Huiyuan Ma Bo Liu Haijun Pang Shaobin Li 《Structural chemistry》2016,27(2):439-447
Three new compounds [Mn(H2O)2(bimb)2(H3SiW12O40)2](bimb)4 (1), [Zn2(bimb)4(H2O)4][SiW12O40] (2), and [Ni2(bimb)4(H2O)4][SiW12O40] (3) (bimb = 1,3-bis(1-imidazoly)benzene) have been synthesized under the same hydrothermal reaction except for tuning the metal cations (Mn2+, Zn2+, and Ni2+). Structural characterizations show that the three compounds possess distinct structural motives. Compound 1 displays a supramolecular one-dimensional (1 D) chain formed by π···π interactions that occur among the almost parallel bimb ligands from adjacent [Mn(H2O)2(bimb)2(SiW12O40)2] dimers. Compound 2 shows a supramolecular two-dimensional (2D) layer achieved by intermolecular (C–H···O) hydrogen bondings between the Zn2(bimb)4 molecular loops and the SiW12 anions. Compound 3 also exhibits a supramolecular 2D layer, but it is different from 2, which is generated by the π···π interactions among adjacent 1D polymeric chains. The distinct structural features of the three compounds suggest that the metal cations should play a significant role in the process of assembly. Additionally, the electrochemical properties of compounds 1–3 have been investigated, and the results indicate that compounds 1–3 possess excellent electrocatalytic activity toward reduction of both iodated and nitrite molecules. 相似文献
11.
Solvent‐Mediated Transformation from Achiral to Chiral Nickel(II) Metal–Organic Frameworks and Reassembly in Solution 下载免费PDF全文
Prof. Xiaoju Li Zhenjiang Yu Prof. Xinxiong Li Xiaofang Guo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(46):16593-16600
Reactions of 5‐nitroisophthalic acid (NO2‐H2ip), 1,4‐bis(imidazol‐1′‐yl)butane (bimb), and Ni(NO3)2 ? 6 H2O gave rise to four metal–organic frameworks (MOFs), [Ni2(NO2‐ip)2(bimb)1.5]n ( 1 ), [Ni4(NO2‐ip)3(bimb)2(OH)2(H2O)]n ? (CH3CH2OH)0.5 n ( 2 ), [Ni(NO2‐ip)(bimb)1.5(H2O)]n ? (H2O)n ? (CH3CH2OH)0.5 n ( 3 ), and [Ni(NO2‐ip) (bimb)(μ‐H2O)]n ? (H2O)n ( 4 ). The metal/ligand ratio, pH value, and solvent exerted a subtle but crucial influence on the formation of complexes 1 – 4 , which possess different visual color and crystal structures. Complex 1 exhibits a twofold interpenetrating 3D pillared bilayer framework composed of binuclear and mononuclear NiII units, whereas complex 2 is a 3D chiral network that consists of asymmetric tetranuclear NiII units. Complexes 3 and 4 are 3D layer‐pillared frameworks that consist of mononuclear NiII ions and a 3D six‐connected network of μ‐water‐bridged dinuclear NiII units, respectively. Interestingly, achiral 4 can be transformed into chiral 2 by using a solvent‐mediated single‐crystal‐to‐single‐crystal process without any chiral auxiliary. Magnetic analyses of 2 and 4 show the occurrence of antiferromagnetic interactions. Complex 3 is difficult to obtain directly as a single solid phase, but it can be homogeneously formed by solvent‐mediated transformations from 1 , 2 , and 4 . 相似文献
12.
Assembly,Structures, and Properties of a Series of Metal‐Organic Coordination Polymers Derived from a Semi‐rigid Bis‐pyridyl‐bis‐amide Ligand 下载免费PDF全文
Xiu‐Li Wang Xiao‐Ting Sha Guo‐Cheng Liu Nai‐Li Chen Chun‐Hua Gong Yun Qu 《无机化学与普通化学杂志》2015,641(7):1274-1281
Four metal‐organic coordination polymers [Cd(4‐bpcb)1.5Cl2(H2O)] ( 1 ), [Cd(4‐bpcb)0.5(mip)(H2O)2] · 3H2O ( 2 ), [Co(4‐bpcb)(oba)(H2O)2] ( 3 ), and [Ni(4‐bpcb)(oba)(H2O)2] ( 4 ) [4‐bpcb = N,N′‐bis(4‐pyridinecarboxamide)‐1, 4‐benzene, H2mip = 5‐methylisophthalic acid, and H2oba = 4, 4′‐oxybis(benzoic acid)] were synthesized under hydrothermal conditions and characterized by single‐crystal X‐ray diffraction, elemental analyses, IR spectroscopy, powder X‐ray diffraction, and TG analysis. In complex 1 , two Cl– anions serve as bridges to connect two Cd‐(μ1‐4‐bpcb) subunits forming a dinuclear unit, which are further linked by μ2‐bridging 4‐bpcb to generate 1D zigzag chain. Complex 2 shows a 2D 63 network constructed by [Cd‐mip]n zigzag chains and μ2‐bridging 4‐bpcb ligands. Complexes 3 and 4 are isostructural 2D (4, 4) grid networks derived from [M‐oba]n (M = Co, Ni) zigzag chains and [M‐(4‐bpcb)]n linear chains. The 1D chains for 1 and the 2D networks for 2 – 4 are finally extended into 3D supramolecular architectures by hydrogen bonding interactions. The roles of dicarboxylates and central metal ions on the assembly and structures of the target compounds were discussed. Moreover, the thermal stabilities, photoluminescent properties, and photocatalytic activities of complexes 1 – 4 and the electrochemical properties of complexes 3 and 4 were investigated. 相似文献
13.
Three unprecedented 2D architectures made up of sandwich‐type tetra‐metal‐substituted polyoxotungstates and transition‐metal complexes, [Cu(dien)(H2O)]2{[Cu(dien)(H2O)]2‐[Cu(dien)(H2O)2]2[Cu4(SiW9O34)2]}? 5H2O ( 1 ; dien=diethylenetriamine), [Zn(enMe)2(H2O)]2{[Zn(enMe)2]2[Zn4‐ (HenMe)2(PW9O34)2]}?8H2O ( 2 ; enMe =1,2‐diaminopropane), and [Zn(enMe)2‐(H2O)]4[Zn(enMe)2]2{(enMe)2{[Zn‐ (enMe)2]2[Zn4(HSiW9O34)2]}{[Zn‐ (enMe)2(H2O)]2[Zn4(HSiW9O34)2]}}? 13H2O ( 3 ) were hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single‐crystal X‐ray diffraction. Compound 1 consists of anions [Cu4(SiW9O34)2]12? linked by copper complexes into a 2D structure, whereas 2 is constructed from novel inorganic–organic hybrid anions [Zn4(HenMe)2(PW9O34)2]8? linked by zinc complexes into a 2D structure. The most interesting is the unique 2D network 3 , which consists of anions [Zn4(PW9O34)2]10? with two types of bridging groups: zinc complexes and enMe ligands. 相似文献
14.
Qihui Chen Feilong Jiang Lian Chen Ming Yang Prof. Maochun Hong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(29):9117-9124
Three new compounds, CuL, CuL′, and Cu2O2L′′2 (H2L=3′‐[(E)‐{[(1S,2S)‐2‐aminocyclohexyl]imino}methyl]‐4′‐hydroxy‐4‐biphenylcarboxlic acid, H2L′=3′‐[(E)‐{[(1S,2S)‐2‐aminocyclohexyl]imino}methyl]‐4′‐hydroxy‐5′‐nitro‐4‐biphenylcarboxlic acid, H2L′′=3′‐(N,N‐dimethylamino methyl)‐4′‐hydroxy‐4‐biphenylcarboxlic acid), were selectively synthesized through a controlled in situ ligand reaction system mediated by copper(II) nitrate and H2L. Selective nitration was achieved by using different solvent mixtures under relatively mild conditions, and an interesting and economical reductive amination system in DMF/EtOH/H2O was also found. All crystal structures were determined by single‐crystal X‐ray diffraction analysis. Both CuL and CuL′ display chiral 1D chain structures, whereas Cu2O2L′′2 possesses a structure with 13×16 Å channels and a free volume of 41.4 %. The possible mechanisms involved in this in situ ligand‐controlled reaction system are discussed in detail. 相似文献
15.
M. Nieves Corella‐Ochoa Dr. Haralampos N. Miras Dr. De‐Liang Long Prof. Leroy Cronin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(43):13743-13754
Five mixed‐metal mixed‐valence Mo/V polyoxoanions, templated by the pyramidal SeO32? heteroanion have been isolated: K10[MoVI12VV10O58(SeO3)8]?18 H2O ( 1 ), K7[MoVI11VV5VIV2O52(SeO3)]?31 H2O ( 2 ), (NH4)7K3[MoVI11VV5VIV2O52(SeO3)(MoV6VV‐ O22)]?40 H2O ( 3 ), (NH4)19K3[MoVI20VV12VIV4O99(SeO3)10]?36 H2O ( 4 ) and [Na3(H2O)5{Mo18?xVxO52(SeO3)} {Mo9?yVyO24(SeO3)4}] ( 5 ). All five compounds were characterised by single‐crystal X‐ray structure analysis, TGA, UV/Vis and FT‐IR spectroscopy, redox titrations, and elemental and flame atomic absorption spectroscopy (FAAS) analysis. X‐ray studies revealed two novel coordination modes for the selenite anion in compounds 1 and 4 showing η,μ and μ,μ coordination motifs. Compounds 1 and 2 were characterised in solution by using high‐resolution ESI‐MS. The ESI‐MS spectra of these compounds revealed characteristic patterns showing distribution envelopes corresponding to 2? and 3? anionic charge states. Also, the isolation of these compounds shows that it may be possible to direct the self‐assembly process of the mixed‐metal systems by controlling the interplay between the cation “shrink‐wrapping” effect, the non‐conventional geometry of the selenite anion and fine adjustment of the experimental variables. Also a detailed IR spectroscopic analysis unveiled a simple way to identify the type of coordination mode of the selenite anions present in POM‐based architectures. 相似文献
16.
Two 3d‐4f Heterometallic Coordination Polymers of Macrocyclic Oxamide with Benzotriazole‐5‐carboxylate Co‐ligand: Syntheses,Crystal Structures and Magnetic Properties 下载免费PDF全文
Two heterometallic 3d–4f coordination polymers, [Gd(CuL)2(Hbtca)(btca)(H2O)] · 2H2O ( 1 ) and [Er(CuL)2(Hbtca)(btca)(H2O)] · H2O · CH3OH ( 2 ) (CuL, H2L = 2,3‐dioxo‐5,6,14,15‐dibenzo‐1,4,8,12‐tetraazacyclo‐pentadeca‐7,13‐dien; H2btca = benzotriazole‐5‐carboxylic acid) were synthesized by solvothermal methods and characterized by single‐crystal X‐ray diffraction. Complexes 1 and 2 exhibit a double‐strand meso‐helical chain structures formed by [LnIIICuII2] (LnIII = Gd, Er) units by oxamide and benzotriazole‐5‐carboxylate bridges. They are isomorphic except that one free water molecule of 1 is replaced by a methanol molecule. All 1D chains are further interlinked by hydrogen bonds resulting in a 3D supramolecular architecture. The magnetic properties of the compound 1 and 2 are also discussed. 相似文献
17.
Two Vanadium‐substituted Keggin‐type polyoxometalates, K3H2[α‐SiVW11O40]?6H2O (SiVW11) and K4H2[γ(1, 2)‐SiV2W10O40]?4H2O (SiV2W10) were first successfully immobilized on 4‐aminobenzoic acid modified glass carbon electrodes respectively by layer‐by‐layer assembly with poly (ethylenimine) (PEI) as counterions. The regular growth processes were monitored by cyclic voltammetry (CV), and it was proved that the multilayer films were uniform and stable. The cyclic voltammetry results indicated that the electrochemical behavior of two multilayer films was similar, and their redox couples are pH‐ and scan rate‐dependent. The multilayer films show favorable electrocatalytic active toward the reduction of NO2?, IO3? and H2O2. 相似文献
18.
Four Gadolinium Coordination Compounds Derived from Various Tetrazole‐Containing Carboxylic Acids 下载免费PDF全文
Lei Shen Yu‐Ting Min Xue Bai Jing Wang Qi Wu Jie Yang Hong‐Jian Chen Fei Geng Gao‐Wen Yang Qiao‐Yun Li 《无机化学与普通化学杂志》2016,642(19):1112-1119
Reactions of four different tetrazole‐containing carboxylic acids with GdCl3 · 6H2O, produced the coordination compounds, [Gd4(pytza)5(H2O)10(μ‐O) Cl] · 4H2O · 2Cl ( 1 ) [pytza = 2‐(5‐(pyridine‐4‐yl)‐2H‐tetrazole‐2‐yl)acetato], [Gd(pztza)2(H2O)6] · pztza · 3H2O ( 2 ), [pztza = 2‐(5‐(pyrazin‐2‐yl)‐2H‐tetrazol‐2‐yl) acetato], [Gd(pmtza)2(H2O)6]Cl · 2H2O ( 3 ), [pmtza = 2‐(5‐(pyrimidyl‐2‐yl)‐2H‐tetrazol‐2‐yl) acetato], and Gd(tzpya)2(H2O)5]Cl · 4H2O ( 4 ) [tzpya = 2‐(4‐(5H‐tetrazol‐5‐yl)pyridin‐1(4H)‐yl) acetato]. The compounds were structurally characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray diffraction. X‐ray diffraction analysis reveals that compound 1 displays a 2D single layered network and compounds 2 – 4 are mononuclear. Compounds 1 – 4 are self‐assembled to form 3D networks by hydrogen bonding interactions. Furthermore, the luminescent properties in the solid state at room temperature were investigated. 相似文献
19.
The First 3‐Connected SrSi2‐Type 3D Chiral Framework Constructed from {Ni6PW9} Building Units 下载免费PDF全文
Dr. Xin‐Xiong Li Dr. Wei‐Hui Fang Dr. Jun‐Wei Zhao Prof. Dr. Guo‐Yu Yang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(6):2315-2318
A novel 3‐connected SrSi2‐type 3D chiral framework constructed from hexa‐NiII‐cluster‐substituted polyoxometalate (POM) units [Ni(enMe)2]3[WO4]3[Ni6(enMe)3(OH)3PW9O34]2?9H2O ( 1 ) (enMe=1,2‐diaminopropane) has been made from a hydrothermal synthetic method. This POM represents the first 3D framework based on {Ni6PW9} units and {WO4} connectors. 相似文献
20.
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