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1.
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
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.
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
4.
M. Sc. Sven Herrmann M. Sc. Monika Kostrzewa Prof. Dr. Andreas Wierschem Prof. Dr. Carsten Streb 《Angewandte Chemie (International ed. in English)》2014,53(49):13596-13599
Corrosion is a global problem for any metallic structure or material. Herein we show how metals can easily be protected against acid corrosion using hydrophobic polyoxometalate‐based ionic liquids (POM‐ILs). Copper metal disks were coated with room‐temperature POM‐ILs composed of transition‐metal functionalized Keggin anions [SiW11O39TM(H2O)]n? (TM=CuII, FeIII) and quaternary alkylammonium cations (CnH2 n+1)4N+ (n=7–8). The corrosion resistance against acetic acid vapors and simulated “acid rain” was significantly improved compared with commercial ionic liquids or solid polyoxometalate coatings. Mechanical damage to the POM‐IL coating is self‐repaired in less than one minute with full retention of the acid protection properties. The coating can easily be removed and recovered by rinsing with organic solvents. 相似文献
5.
A polyoxometalate‐based inorganic–organic hybrid compound [CoII(2, 2′‐bpy)2]2[Mo8O26] ( 1 ) was synthesized by hydrothermal methods and structurally characterized by IR spectrum, TG analysis and X‐ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n, a = 10.0681(2), b = 16.4467(2), c = 15.7838(3) Å, β = 100.046(1)°, V = 2573.52(8) Å3, Z = 2. The structure of 1 is built up from β‐[Mo8O26]4? subunits covalently linked via [CoII(2, 2′‐bpy)2]2+ fragments into a infinite 1D {[CoII(2, 2′‐bpy)2]2[Mo8O26]}∞ polymer. 相似文献
6.
Morteza Tahmasebi Masoud Mirzaei Hossein Eshtiagh-Hosseini Joel T. Mague Antonio Bauz Antonio Frontera 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(4):469-477
A new inorganic–organic hybrid based on an aspartate functionalized polyoxomolybdate, [pentaaquacobalt(II)]‐μ‐aspartate‐[γ‐octamolybdate]‐μ‐aspartate‐[pentaaquacobalt(II)] tetrahydrate, [Co2(C4H6NO4)2(γ‐Mo8O26)(H2O)10]·4H2O ( 1 ), has been synthesized under hydrothermal conditions from the reaction of an Evans–Showell‐type polyoxometalate, (NH4)6[Co2Mo10H4O38], and l ‐aspartic acid. The complex exhibits a supramolecular three‐dimensional framework structure in the crystal lattice. Compound 1 was structurally characterized by elemental analyses, IR and UV–Vis (diffuse reflectance) spectroscopy and single‐crystal X‐ray diffraction. In this compound, aspartic acid acts as a bridge between the two Co atoms and the Mo centres, with the –CH2COOH side chain directly linked to the Mo centre in γ‐[Mo8O26]4? and the α‐carboxylate side chain bound to the Co centre. Commonly, the binding of transition‐metal complexes to POMs involves coordination of the metal to a terminal O atom of the POM so that 1 , with a bridging ligand between Mo and Co atoms, belongs to a separate class of hybrid materials. While the starting materials are both chiral and one might expect them to form a chiral hybrid, the decomposition of the chiral Evans–Showell‐type POM and its conversion to the centrosymmetric γ‐octamolybdate POM, plus the presence of two aspartate ligands centrosymmetrically placed on either side of the POM, leads to the formation of an achiral hybrid. We have studied energetically by means of density functional theory (DFT) calculations and using the Bader's `atoms‐in‐molecules' analysis the electrostatically enhanced hydrogen bonds (EEHBs) observed in the solid state of 1 , which are crucial for the formation of one‐dimensional supramolecular assemblies. 相似文献
7.
Time‐Resolved Assembly of Cluster‐in‐Cluster {Ag12}‐in‐{W76} Polyoxometalates under Supramolecular Control 下载免费PDF全文
Caihong Zhan Jamie M. Cameron Jing Gao Jamie W. Purcell De‐Liang Long Leroy Cronin 《Angewandte Chemie (International ed. in English)》2014,53(39):10362-10366
We report the time‐resolved supramolecular assembly of a series of nanoscale polyoxometalate clusters (from the same one‐pot reaction) of the form: [H(10+m)Ag18Cl(Te3W38O134)2]n, where n=1 and m=0 for compound 1 (after 4 days), n=2 and m=3 for compound 2 (after 10 days), and n=∞ and m=5 for compound 3 (after 14 days). The reaction is based upon the self‐organization of two {Te3W38} units around a single chloride template and the formation of a {Ag12} cluster, giving a {Ag12}‐in‐{W76} cluster‐in‐cluster in compound 1 , which further aggregates to cluster compounds 2 and 3 by supramolecular Ag‐POM interactions. The proposed mechanism for the formation of the clusters has been studied by ESI‐MS. Further, control experiments demonstrate the crucial role that TeO32?, Cl?, and Ag+ play in the self‐assembly of compounds 1 – 3 . 相似文献
8.
Takuo Minato Dr. Kosuke Suzuki Dr. Kazuya Yamaguchi Prof. Dr. Noritaka Mizuno 《Angewandte Chemie (International ed. in English)》2016,55(33):9630-9633
The disassembly and reassembly of giant molecules are essential processes in controlling the structure and function of biological and artificial systems. In this work, the disassembly and reassembly of a giant ring‐shaped polyoxometalate (POM) without isomerization of the monomeric units is reported. The reaction of a hexavacant lacunary POM that is soluble in organic solvents, [P2W12O48]14?, with manganese cations gave the giant ring‐shaped POM [{γ‐P2W12O48Mn4(C5H7O2)2(CH3CO2)}6]42?. This POM is a hexamer of manganese‐substituted {P2W12O48Mn4} units, and its inner cavity was larger than any of those previously reported for ring‐shaped polyoxotungstates. It was disassembled into monomeric units in acetonitrile, and the removal of the capping organic ligands on the manganese cations led to reassembly into a tetrameric ring‐shaped POM, [{γ‐P2W12O48Mn4(H2O)6}4(H2O)4]24?. 相似文献
9.
Sequential Synthesis of 3 d–3 d, 3 d–4 d,and 3 d–5 d Hybrid Polyoxometalates and Application to the Electrocatalytic Oxygen Reduction Reactions 下载免费PDF全文
Dr. Guillaume Rousseau Shuangshuang Zhang Dr. Olivier Oms Dr. Anne Dolbecq Dr. Jérôme Marrot Dr. Rongji Liu Xinke Shang Prof. Guangjin Zhang Prof. Pierre Mialane 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(34):12153-12160
The Co7(AlePy)2 polyoxometalate, which encloses a {(PW9)2CoII7} core covalently bound to two free aminopyridine groups through bisphosphonate ligands ( AlePy ), has been isolated. It can be used as a precursor, allowing the synthesis of heterometallic hybrid compounds, as illustrated by the characterization of cobalt/zinc ( Co7(AlePyZn)2 ), cobalt/palladium ( Co7(AlePyPd)2 ), and cobalt/platinum ( Co7(AlePyPt)2 ) species. A composite based on the water‐insoluble precious metal‐free Co7(AlePyZn)2 compound and the low‐cost carbon material Vulcan XC‐72 has been selected as a cathode material ( Co7Zn/C ) for oxygen reduction reaction studies. The electrocatalytic performances of the Co7Zn/C hybrids were assessed at neutral and basic pH, showing that Co7Zn/C exhibits high selectivity for the four‐electron reduction of O2. Moreover, its durability is superior to that of a commercial Pt/C catalyst with 20 % loading. Also, comparative studies performed in the presence of methanol have indicated that Co7Zn/C has a much better tolerance to the crossover effect than Pt/C . Altogether, these results indicate for the first time that, even in neutral media, polyoxometalate/carbon composites can represent low‐cost oxygen reduction catalysts that can function stably, for a long time, and with high performance. 相似文献
10.
Structural Characterization of the Complex between Hen Egg‐White Lysozyme and ZrIV‐Substituted Keggin Polyoxometalate as Artificial Protease 下载免费PDF全文
Annelies Sap Elke De Zitter Prof. Luc Van Meervelt Prof. Tatjana N. Parac‐Vogt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11692-11695
Successful co‐crystallization of a noncovalent complex between hen egg‐white lysozyme (HEWL) and the monomeric ZrIV‐substituted Keggin polyoxometalate (POM) (Zr1 K1), (Et2NH2)3[Zr(PW11O39)] ( 1 ), has been achieved, and its single‐crystal X‐ray structure has been determined. The dimeric ZrIV‐substituted Keggin‐type polyoxometalate (Zr1 K2), (Et2NH2)10[Zr(PW11O39)2] ( 2 ), has been previously shown to exhibit remarkable selectivity towards HEWL hydrolysis. The reported X‐ray structure shows that the hydrolytically active ZrIV‐substituted Keggin POM exists as a monomeric species. Prior to hydrolysis, this monomer interacts with HEWL in the vicinity of the previously identified cleavage sites found at Trp28‐Val29 and Asn44‐Arg45, through water‐mediated H‐bonding and electrostatic interactions. Three binding sites are observed at the interface of the negatively charged Keggin POM and the positively charged regions of HEWL at: 1) Gly16, Tyr20, and Arg21; 2) Asn44, Arg45, and Asn46; and 3) Arg128. 相似文献
11.
Meng Wen Zu‐Ping Xiao Chun‐Ya Wang Xi‐He Huang 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(2):136-139
The title compound, {[Zn4(C8H4O4)3(OH)2(C12H6N2O2)2]·2H2O}n, has been prepared hydrothermally by the reaction of Zn(NO3)2·6H2O with benzene‐1,4‐dicarboxylic acid (H2bdc) and 1,10‐phenanthroline‐5,6‐dione (pdon) in H2O. In the crystal structure, a tetranuclear Zn4(OH)2 fragment is located on a crystallographic inversion centre which relates two subunits, each containing a [ZnN2O4] octahedron and a [ZnO4] tetrahedron bridged by a μ3‐OH group. The pdon ligand chelates to zinc through its two N atoms to form part of the [ZnN2O4] octahedron. The two crystallographically independent bdc2− ligands are fully deprotonated and adopt μ3‐κO:κO′:κO′′ and μ4‐κO:κO′:κO′′:κO′′′ coordination modes, bridging three or four ZnII cations, respectively, from two Zn4(OH)2 units. The Zn4(OH)2 fragment connects six neighbouring tetranuclear units through four μ3‐bdc2− and two μ4‐bdc2− ligands, forming a three‐dimensional framework with uninodal 6‐connected α‐Po topology, in which the tetranuclear Zn4(OH)2 units are considered as 6‐connected nodes and the bdc2− ligands act as linkers. The uncoordinated water molecules are located on opposite sides of the Zn4(OH)2 unit and are connected to it through hydrogen‐bonding interactions involving hydroxide and carboxylate groups. The structure is further stabilized by extensive π–π interactions between the pdon and μ4‐bdc2− ligands. 相似文献
12.
Reactions of the oxorhenium(V) complexes [ReOX3(PPh3)2] (X = Cl, Br) with the N‐heterocyclic carbene (NHC) 1,3,4‐triphenyl‐1,2,4‐triazol‐5‐ylidene (LPh) under mild conditions and in the presence of MeOH or water give [ReOX2(Y)(PPh3)(LPh)] complexes (X = Cl, Br; Y = OMe, OH). Attempted reactions of the carbene precursor 5‐methoxy‐1,3,4‐triphenyl‐4,5‐dihydro‐1H‐1,2,4‐triazole ( 1 ) with [ReOCl3(PPh3)2] or [NBu4][ReOCl4] in boiling xylene resulted in protonation of the intermediately formed carbene and decomposition products such as [HLPh][ReOCl4(OPPh3)], [HLPh][ReOCl4(OH2)] or [HLPh][ReO4] were isolated. The neutral [ReOX2(Y)(PPh3)(HLPh)] complexes are purple, airstable solids. The bulky NHC ligands coordinate monodentate and in cis‐position to PPh3. The relatively long Re–C bond lengths of approximate 2.1Å indicate metal‐carbon single bonds. 相似文献
13.
Anna Giusti Dr. Gaëlle Charron Dr. Sandra Mazerat Jean‐Daniel Compain Pierre Mialane Prof. Anne Dolbecq Dr. Eric Rivière Dr. Wolfgang Wernsdorfer Dr. Rosa Ngo Biboum Bineta Keita Dr. Louis Nadjo Prof. Arianna Filoramo Dr. Jean‐Philippe Bourgoin Dr. Talal Mallah Prof. 《Angewandte Chemie (International ed. in English)》2009,48(27):4949-4952
A POM to remember : Hexanuclear FeIII polyoxometalate (POM) single‐molecule magnets (see structure) can be noncovalently assembled on the surface of single‐wall carbon nanotubes. Complementary characterization techniques (see TEM image and magnetic hysteresis loops) demonstrate the integrity and bistability of the individual molecules, which could be used to construct single‐molecule memory devices.
14.
Joaquim Li Inga Huth Lise‐Marie Chamoreau Dr. Bernold Hasenknopf Dr. Emmanuel Lacôte Dr. Serge Thorimbert Dr. Max Malacria Prof. 《Angewandte Chemie (International ed. in English)》2009,48(11):2035-2038
POM alert : The incorporation of an amide oxygen atom into the framework of the Dawson‐type polyoxometalate (POM) cluster [P2V3W15O62]9? (see picture) allows the communication of electronic effects between the organic and the inorganic parts of the molecule, including fine‐tuning of the redox properties of the entire hybrid POM by the organic components, and transmission of the POM's electron‐attracting properties to the organic moiety.
15.
The polynuclear copper(II) complex [Cu2(Hdpa)2(μ‐ClDHBQ)(ClO4)2]n, 1 is bridged by ClDHBQ?2 (2,5‐dichloro‐3,6‐dihydroxy‐1,4‐benzoquinone dianionic) and 2,2′‐dipyridylamine (Hdpa). In the axial position, Cu is connected with the oxygen atom of ClO. The perchlorate anion may be envisaged as a monodentate O‐bound ligand. Through the bond bridge of O–Cu … O–Cl, the binuclear compound [Cu2(Hdpa)2(μ‐ClDHBQ)(ClO4)2] is strung together into a long chain compound. Tetrachlorocatechol underwent partial oxidation/hydrolysis/dechlorination processes to produce ClDHBQ?2. The other mononuclear complex [Cu(Hdpa)(TeCQ)](DMF), 2 , in which tetrachloroquinone (TeCQ) was produced by oxidation of tetrachlorocatechol (TeCC), therefore complex 2 is in the quinone form. The magnetic susceptibility measurements show antiferromagnetic coupling with J = ?11.9 cm?1, θ = 2.6 K, and g = 2.05 for complex 1. Complex 2 exhibits the typical paramagnetic behavior of s = 1/2. 相似文献
16.
Dr. Min‐Xia Yao Qi Zheng Kang Qian Prof. Dr. You Song Prof. Dr. Song Gao Prof. Dr. Jing‐Lin Zuo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(1):294-303
By using the node‐and‐spacer approach in suitable solvents, four new heterotrimetallic 1D chain‐like compounds (that is, containing 3d–3d′–4f metal ions), {[Ni(L)Ln(NO3)2(H2O)Fe(Tp*)(CN)3] ? 2 CH3CN ? CH3OH}n (H2L=N,N′‐bis(3‐methoxysalicylidene)‐1,3‐diaminopropane, Tp*=hydridotris(3,5‐dimethylpyrazol‐1‐yl)borate; Ln=Gd ( 1 ), Dy ( 2 ), Tb ( 3 ), Nd ( 4 )), have been synthesized and structurally characterized. All of these compounds are made up of a neutral cyanide‐ and phenolate‐bridged heterotrimetallic chain, with a {? Fe? C?N? Ni(? O? Ln)? N?C? }n repeat unit. Within these chains, each [(Tp*)Fe(CN)3]? entity binds to the NiII ion of the [Ni(L)Ln(NO3)2(H2O)]+ motif through two of its three cyanide groups in a cis mode, whereas each [Ni(L)Ln(NO3)2(H2O)]+ unit is linked to two [(Tp*)Fe(CN)3]? ions through the NiII ion in a trans mode. In the [Ni(L)Ln(NO3)2(H2O)]+ unit, the NiII and LnIII ions are bridged to one other through two phenolic oxygen atoms of the ligand (L). Compounds 1 – 4 are rare examples of 1D cyanide‐ and phenolate‐bridged 3d–3d′–4f helical chain compounds. As expected, strong ferromagnetic interactions are observed between neighboring FeIII and NiII ions through a cyanide bridge and between neighboring NiII and LnIII (except for NdIII) ions through two phenolate bridges. Further magnetic studies show that all of these compounds exhibit single‐chain magnetic behavior. Compound 2 exhibits the highest effective energy barrier (58.2 K) for the reversal of magnetization in 3d/4d/5d–4f heterotrimetallic single‐chain magnets. 相似文献
17.
Yu-Kun Lu Ya-Ping Li Ling-Yu Yang Wen-Hong Wang Yuan Pan Wen-Fu Yan Yun-Qi Liu 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(10):1344-1352
A novel modified polyoxometalate, {PMo12O40[Cu(2,2′‐bpy)]}[Cu(2,2′‐bpy)(en)(H2O)]2 [2,2′‐bpy is 2,2′‐bipyridyl (C10H8N2) and en is ethylenediamine (C2H8N2)], has been synthesized hydrothermally and structurally characterized by elemental analysis, TG, IR, XPS and single‐crystal X‐ray diffraction. The structural analysis reveals that the compound contains the reduced Keggin polyanion [PMo12O40]6? as the parent unit, which is monocapped by [Cu(2,2′‐bpy)]2+ fragments via four bridging O atoms on an {Mo4O4} pit and bi‐supported by two [Cu(2,2′‐bpy)(en)(H2O)]2+ coordination cations simultaneously. There exist strong intramolecular π–π stacking between the capping and supporting units, which play a stabilizing role during the crystallization of the compound. Adjacent POM clusters are further aggregated to form a three‐dimensional supramolecular network through noncovalent forces, hydrogen bonding and π–π stacking interactions. In addition, the photocatalytic properties were investigated in detail, and the results indicated that the compound can be used as a photocatalyst towards the decomposition of the organic pollutant methylene blue (MB). 相似文献
18.
[{Ni4(OH)3AsO4}4(B‐α‐PW9O34)4]28−: A New Polyoxometalate Structural Family with Catalytic Hydrogen Evolution Activity 下载免费PDF全文
Hongjin Lv Dr. Yingnan Chi Jan van Leusen Prof. Paul Kögerler Dr. Zheyuan Chen Dr. John Bacsa Dr. Yurii V. Geletii Weiwei Guo Prof. Tianquan Lian Prof. Craig L. Hill 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(48):17363-17370
A new structural polyoxometalate motif, [{Ni4(OH)3AsO4}4(B‐α‐PW9O34)4]28?, which contains the highest nuclearity structurally characterized multi‐nickel‐containing polyanion to date, has been synthesized and characterized by single‐crystal X‐ray diffraction, temperature‐dependent magnetism and several other techniques. The unique central {Ni16(OH)12O4(AsO4)4} core shows dominant ferromagnetic exchange interactions, with maximum χmT of 69.21 cm3 K mol?1 at 3.4 K. Significantly, this structurally unprecedented complex is an efficient, water‐compatible, noble‐metal‐free catalyst for H2 production upon visible light irradiation (photosensitizer=[Ir(ppy)2(dtbbpy)][PF6]; sacrificial electron donor=triethylamine or triethanolamine). The highest turnover number of approximately 580, corresponding to a best quantum yield of approximately 4.07 %, is achieved when using triethylamine as electron donor in the presence of water. The mechanism of this photodriven process has been probed by time‐solved luminescence and by static emission quenching. 相似文献
19.
The amino substituted bidentate chelating ligand 2‐amino‐5‐(2‐pyridyl)‐1,3,4‐thiadiazole (H2 L ) was used to prepare 3:1‐type coordination compounds of iron(II), cobalt(II) and nickel(II). In the iron(II) perchlorate complex [FeII(H2 L )3](ClO4)2·0.6MeOH·0.9H2O a 1:1 mixture of mer and fac isomers is present whereas [FeII(H2 L )3](BF4)2·MeOH·H2O, [CoII(H2 L )3](ClO4)2·2H2O and [NiII(H2 L )3](ClO4)2·MeOH·H2O feature merely mer derivatives. Moessbauer spectroscopy and variable temperature magnetic measurements revealed the [FeII(H2 L )3]2+ complex core to exist in the low‐spin state, whereas the [CoII(H2 L )3]2+ complex core resides in its high‐spin state, even at very low temperatures. 相似文献
20.
Reactions of copper(I) halides (Cl, Br, I) with 1‐methyl‐1, 3‐imidazoline‐2‐thione (mimzSH) in 1 : 2 molar ratio yielded sulfur‐bridged dinuclear [Cu2X2(μ‐S‐mimzSH)2(η1‐S‐mimzSH)2] (X = I, 1 , Br, 2 ; Cl, 3 ) complexes. Copper(I) iodide with 1,3‐imidazoline‐2‐thione (imzSH2) and Ph3P in 1 : 1 : 1 molar ratio has also formed a sulfur‐bridged dinuclear [Cu2I2(μ‐S‐imzSH2)2(PPh3)2] ( 4 ) complex. The central Cu(μ‐S)2Cu cores form parallelograms with unequal Cu–S bond distances {2.324(2), 2.454(3) Å} ( 1 ); {2.3118(6), 2.5098(6) Å} ( 2 ); {2.3075(4), 2.5218(4) Å} ( 3 ); {2.3711(8), 2.4473(8) Å} ( 4 ). The Cu···Cu separations, 2.759–2.877Å in complexes 1 – 3 are much shorter than 3.3446Å in complex 4 . The weak intermolecular interactions {H2CH···S# ( 2 ); CH···Cl# ( 3 ); NH···I# ( 4 )} between dimeric units in complexes 2 – 4 lead to the formation of linear 1D polymers. 相似文献