Unsaturated bi-heterometal clusters in metal-vacancy sites of 2D MoS2 for efficient hydrogen evolution

The valence states and coordination structures of doped heterometal atoms in two-dimensional(2D)nanomaterials lack predictable regulation strategies.Hence,a robust method is proposed to form unsaturated heteroatom clusters via the metal-vacancy restraint mechanism,which can precisely regulate the bonding and valence state of heterometal atoms doped in 2D molybdenum disulfide.The unsaturated valence state of heterometal Pt and Ru cluster atoms form a spatial coordination structure with Pt–S and Ru–O–S as catalytically active sites.Among them,the strong binding energy of negatively charged suspended S and O sites for H+,as well as the weak adsorption of positively charged unsaturated heterometal atoms for H*,reduces the energy barrier of the hydrogen evolution reaction proved by theoretical calculation.Whereupon,the electrocatalytic hydrogen evolution performance is markedly improved by the ensemble effect of unsaturated heterometal atoms and highlighted with an overpotential of 84 mV and Tafel slope of 68.5 mV dec^(−1).In brief,this metal vacancy-induced valence state regulation of heterometal can manipulate the coordination structure and catalytic activity of heterometal atoms doped in the 2D atomic lattice but not limited to 2D nanomaterials.

Parallelogram 3d-4f-5d heterometallic clusters based on trilacunary tungstoantimonates with excellent proton conductivity

Two 3d-4f-5d heterometallic cluster-containing polyoxometalates,formulated as Na_(22){(SbW_(9)O_(33))_(4)[La_(3)W_(6)MO_(18)(H_(2)O)_(8)(CH_(3)COO)_(4)]_(2)}·nH_(2)O(abbreviated as La_(6)M_(2),M=Co/Mn)were synthesized and structurally characterized.Single-crystal X-ray diffraction analyses reveal that the polyanions of La_(6)Co_(2)and La_(6)Mn_(2)consist of the uncommon 3d-4f-5d clusters{La_(6)W_(12)Co_(2)}and{La_(6)W_(12)Mn_(2)},which are encapsulated by four trilacunary Keggin tungstoantimonates to form the parallelogram-shaped title compounds.Additionally,the polyanions can be extended into a two-dimensional(2D)frame by the linkage of peripheral Na+ions.The inner space of the 2D layer was filled with water molecules and thus an H-bonded network was formed,which is expected to exhibit a fascinating proton conductivity.The study of water-assisted proton conduction demonstrated that La_(6)Co_(2)and La_(6)Mn_(2)were temperature-and humiditydependent proton conductors,respectively,and the proton conductivities could reach 1.3×10^(-2)and 2.3×10^(-2)S/cm at 65℃and 90%RH conditions.

Synthesis and Characterization of a Tetranuclear [Sm_2Co_2] Heterometallic Compound

A new tetranuclear square compound （H3O）[Sm2Co2（CDTA）2（DMF）2 （μ4-O） （H2O）6]ClO4 was synthesized through the assembly reaction of Co2＋ , Sm3＋ and trans-1,2-cclohexylenedinitrilotetraacetic acid （H4CDTA） in aqueous solution. X-ray crystal structural analysis shows that the compound belongs to the monoclinic C2/c space group, with a=27.213（2）, b=10.5574（9）, c=19.4923（17）,β=98.799（1）°, V=5534.1（8）3 , C34H65ClCo2N6O30Sm2 , Mr=1491.93, Dc=1.791g/cm-3 , F（000）=2984,=2.820 mm-1 and Z=4. In the compound, Co2＋ is 7-coordianted while Sm3＋ is 9-coordinated. With the help of a central O2- and 8 carboxylate oxygen atoms, two Co2＋ and two Sm3＋ ions are linked into a square with the side length of 3.45 . Magnetic property was investigated.

Design and Synthesis of Al_(7)Ni_(2) Heterometallic Clusters Based on Metal Substitution and Ligands Protection Strategies

The synthesis of heterometallic aluminum-based materials is challenging yet attractive,due to their potential applications in optics,catalysis,magnetism and semiconductor device.We have now successfully synthesized two Al,Niz heterometallic clusters bearing different peripheral alkoxide ligands through a heterometal substitution strategy.

Synthesis, Structural Characterization and Magnetocaloric Effect of a Butterfly [CoⅡ2GdⅢ2] Cluster

2-(2,3-Dihydroxpropyliminomethyl)6-methoxyphenol(H3L), trimethylacetic acid(Hpiv), Gd(NO3)3·6 H2O and Co(NO3)2·6 H2O were reacted in Me OH to obtain a heterometallic tetranuclear cluster [Gd2Co2(L)2(μ3-OH)2(piv)6]·2 Hpiv·2 CH3OH(1). X-ray crystallographic analysis reveals that compound 1 was found to be a butterfly heterometallic tetranuclear cluster. The crystal(C64H108Co2Gd2N2O28, Mr = 1785.88) belongs to the triclinic crystal system, space group P1 with a =11.9798(6), b = 12.0877(5), c = 15.0367(7) A, α = 67.320(4)°, β = 81.583(4)°, γ = 75.201(4)°, V =1939.62(18) A3, Z = 1, T = 293.15 K, R = 0.048 and w R = 0.144 for 16299 observed reflections with I > 2σ(I). In magnetization study, heterometallic 1 exhibits magnetocaloric effect(MCE) of 14.75 J·kg-1·K-1 at 2 K for ΔH = 5 T, while it does not show non-linear response of the ac-susceptibilities.

Structural Characterization of Chiral Sulfido Cluster(η~5-C_5H_5) WFeCo(CO)_8 (μ_3-S)

The chiral sulfido cluster (η5-C5H5)WFeCo(CO)8(μ3--S) was synthesized by refluxing a solution of HFe2Co(CO)9 (μ3,--S) and (η5-C5H5)Fe(CO)3Cl in tetrahydrofuran. It was characterized by elemental analysis, IR and 1H/13C--NMR. Theproposal concerning mechanism was discussed herewith and the structure was reportedas well. Crystallographic data: Mr= 563. 85, monoclinicl P21/n(# 14); a= 8. 009(2), b= 17. 600(5), c=12. 003(4) A; β=95. 91(2)°; V= 1683. 0 (9) A3; Z=4;Dc=2. 22 g. cm-3; F(000) = 1048, μ=89. 27 cm-1 ; final R=0. 039 and Rw=0. 049for 2121 observable reflections with (I≥3. cσ(I) ). The crystal structure determinationshows that S atom coordinates to all three metal (W,Fe,Co) atoms in a μ3,-fashion,thetitle cluster core has the tetrahedral skeleton.

Synthesis,structure and magnetism of a novel Cu4^ⅡTi5^Ⅳ heterometallic cluster

A nonanuclear Cu4^ⅡTi5^Ⅳheterometallic cluster,[Ti5 Cu4 O6(ba)(16)](1,Hba=benzoic acid)was synthesized in one-pot reaction under the solvothermal condition.The metallic skeleton 1 contains a Ti5 core constructed from two vertex-shared Ti3 triangles and four separated Cu atoms outside which are connected together byμ3-O^2- ions.Total 16 ba ligands adoptμ2-η^1:η^1 coordination mode to protect the overall hetero metallic co re.Due to the unique d-d transitions of Cu^Ⅱion,the reflectance spectrum of 1 displays broad and strong absorption towards visible light extending to the near-infrared region.Moreover,1 shows almost purely paramagnetic behavior with the presence of weak antiferromagnetic interactions at low temperatures.

Acylation of nitriles to β-ketonitriles catalyzed by a heterometallic alkoxide cluster of neodymium and sodium:NdNa_8(O^tBu)_(10)(OH)

Catalytic acylation of nitriles with esters in the presence of 10 mol% NdNa8(OtBu)10(OH) is developed.The procedure is suitable for both enolizable and nonenolizable esters and affords β-ketonitriles in moderate to high yields.The heterometallic alkoxide cluster NdNa8(OtBu)10(OH) is structurally characterized by X-ray diffraction,and a mechanism for the production of β-ketonitriles using the cluster is proposed and verified.

Heterometallic Trinuclear Carbonyl Sulfido Clusters and the Tetranuclear Intermediate via Electrophilic Addition-Elimination Reaction

The reaction of HFe2Co（CO）9（μ3-S）with（η5-C5H4CH3）Mo（CO）3CI has been carried outin refluxing tetrahydrofuran（THF）to give out heterometallic trinuclear clusters（η5-C5H4CH3）MoFeCo-（CO）8（μ3-S）and（η5-C5H4CH3）2Mo2Fe（CO）7（μ3-S）by electrophilic addition-elimination reaction.Howev-er,（η5-C5H4CH3）Fe（CO）2Cl reacted with HFe2Co（CO）9（μ3-S）at room temperature to yield a tetranuclearcluster（η5-C5H4CH3）Fe3Co（CO）11（μ4-S）.The μ4-S cluster could be used as an intermediate in confirmationof the mechanism of the electrophilic addition-elimination reaction.The syntheses,characterizations andX-ray crystal structures of these clusters are reported herein as well as the discussion on the reaction mecha-nism.

Unraveling the condensation reactions of heterometallic {BiNb_(4)} moieties into hybrid Bi_(x)Nb_(y)-oxo clusters with mass spectrometry

The most effective methodologies for the construction of polynuclear complexes usually take advantage of preorganized building blocks.Herein,we successfully developed a new versatile heterometallic{BiNb_(4)}moiety,which can be applied for the assembly of less explored organic-inorganic hybrid polyoxoniobates.Through controlled condensation reactions,three{BiNb_(4)}moieties can be assembled into a pair of isomeric Bi_(3)Nb_(18)clusters at different temperatures;whilst four{BiNb_(4)}moieties can be combined into two unique Bi_(4)Nb_(16)and Bi_(4)Nb_(18)tetramers in different solvents.Interestingly,we have used mass spectrometry to probe the above condensation reactions,which clearly confirmed a stepwise bottom-up assembly process by capturing the presence of bismuth subsalicylate precursors,salicylate coordinated intermediates,Nb incorporated{BiNb_(4)}moieties and the final Bi_(x)Nb_(y)-oxo clusters,respectively.Moreover,the packing modes of the{BiNb_(4)}units induce different solution behaviors,and the{BiNb_(4)}units in Bi4Nb16can be recombined by post-synthetic recrystallization in acetonitrile to produce a new tetramer Bi_(4)Nb_(18)-R.Therefore,this work provides not only a useful{BiNb_(4)}building unit but also the mechanism for their condensation,both of which will promote the future development of metal-oxo clusters.

Mixed transition-metal oxides@carbon core-shell nanostructures derived from heterometallic clusters for enhanced lithium storage

Multicomponent binary metal oxide-involved hybrid structures with unique physicochemical properties have received extensive attention due to their fascinating electrochemical performance.Herein,a flexible strategy,which involves the preparation of dual-functional heterometallic Fe_(2)M clusters and their subsequent sintering treatment,is developed to engineer novel 3D hierarchical porous structures assembled with MFe_(2)O_(4)(M=Co,Mn,Ni and Zn)nanoparticles confined within carbon outer shell(denoted as MFe_(2)O_(4)@C HPSs).In this intriguing construction,it can be observed that MFe_(2)O_(4)@C HPSs comprised of carbon coated secondary MFe_(2)O_(4)nanoparticles with an interconnected carbon network.The as-prepared MFe_(2)O_(4)@C HPSs possess combined advantages of high capacity of MFe_(2)O_(4)and high conductivity of carbon.As expected,the MFe_(2)O_(4)@C HPSs offer a high reversible capacity,high cycling stability and superior rate performance.The interconnected conductive carbon shells facilitates fast ion and electron transport and accommodates the mechanical strain.In addition,nanosized MFe_(2)O_(4)particles,which shorten the ion-transport path and provide extra electroactive sites,also improve the reaction kinetics.Moreover,these MFe_(2)O_(4)@C HPSs exhibit good structural integrity during repeated charging and discharging.The research perspective and strategy reported here are highly versatile and shed new light on the synthesis of other advanced electrode for various applications.

[VS_4-Cu_n](n=3-6)簇合物成簇反应的^(51)V NMR研究

在核磁管内模拟反应体系 (NH4) 3VS4/Et4NBr/CuBr/PPh3在CH2 Cl2 溶液中生成[VS4 Cun](n =3 6 )簇合物的过程 .利用 51 VNMR技术对反应过程进行准原位的实时监测 ,研究 [VS4 Cun](n =3 6 )簇合物的成簇条件和机理以及配体对成簇过程的影响 .本文还详细讨论了反应溶液中不同浓度的PPh3对 [VS4 Cu4]簇合物的51 VNMR化学位移的影响 .

三维Y(Ⅲ)-Ag(Ⅰ)异金属配位聚合物的合成、晶体结构与性质研究

以异烟酸(Hina)和2-磺基苯甲酸(H2L)为配体,在水热条件下与Y(Ⅲ)和Ag(Ⅰ)离子进行协同配位,合成了一个异金属配位聚合物[Y2Ag2L2(ina)4(H2O)2]n(1)。通过X-射线衍射、热重分析、元素分析和红外光谱对其进行表征。X-射线单晶衍射测定其结构为单斜晶系,P21/n空间群,晶胞参数a=0.914 43(3)nm,b=1.378 39(5)nm,c=1.760 76(5)nm,β=102.315(3)°,V=2.168 27(12)nm3,Z=4。它含有一个以羧基O原子桥连的中心对称的四核异金属原子簇[Y2Ag2L2],相邻的原子簇之间通过异烟酸配体相互连接成三维金属有机骨架结构。

系列异金属类立方烷原子簇化合物的振动光谱

通过振动光谱和X 射线结构分析数据的结合 ,归属了系列具有 [M3 YS3 M′](M =Mo ,W ;Y =O ,S ;M′=Cu ,Sn ,Sb ,Pb ,Bi)簇芯的异金属四核类立方烷原子簇化合物的主要振动谱峰。讨论了五种结构类型的光谱特征和成键状态。M′的加入使νM— (μ3—Y) 和νM S 频率下降。当M′为过渡金属 ,例如Cu时 ,Cu与[M3 YS3 ]结合紧密造成了与Cu—S共价键相当的νCu—S振动频率。而当M′为主族金属时 ,νM′—S远小于相应共价键的振动频率值。文中还对νM—M 振动进行若干论述。

含硫杂核原子簇CpWFeCo(CO)_8(μ_3-S)和(CpW)_2Fe(CO)_7(μ_3-S)的合成及结构研究

本文利用过渡金属的亲硫性，通过Ｃｐ＊－Ｗ（ＣＯ）３Ｃｌ（Ｃｐ＊＝Ｃ５Ｈ５，Ｃ５Ｈ４ＣＨ３）与ＨＦｅ２Ｃｏ（ＣＯ）９（μ３－Ｓ）反应，得到四种含硫异核金属羰基原子簇化合物Ｃｐ＊ＷＦｅＣｏ（ＣＯ）８（μ３－Ｓ）（Ｃｐ＊＝Ｃ５Ｈ５，Ⅰ－ａ；Ｃｐ＊＝Ｃ５Ｈ４ＣＨ３，Ⅱ－ａ），（Ｃｐ＊Ｗ）２Ｆｅ（ＣＯ）７（μ３－Ｓ）（Ｃｐ＊＝Ｃ５Ｈ５，Ⅰ－ｂ；Ｃｐ＊＝Ｃ５Ｈ４ＣＨ３，Ⅱ－ｂ）。对合成的簇合物进行了ＩＲ，１Ｈ／１３Ｃ－ＮＭＲ，Ｃ／Ｈ及金属分析，并对Ⅰ－ａ进行了Ｘ－射线单晶结构分析。

具有高稳定性以及光催化产氢活性的奇数环状异金属钛氧纳米团簇

利用太阳能是解决当前能源危机和环境问题的有效途径.二氧化钛是一种稳定性高、环境友好的新型光催化剂.近年来,具有精确结构信息的晶态钛氧团簇(PTCs)作为TiO_(2)的分子结构模型受到广泛关注.目前大多数PTCs含有烷氧基,在空气中易发生水解.这在很大程度上限制了对其光催化性能的研究.在无机钛氧簇的外围修饰大量的共轭有机配体是一种有效提升PTCs稳定性的方法.此外,异金属的嵌入有助于修饰微观电子结构,从而也将影响光催化性能.铝是地球上最丰富的金属元素,其水解产物也大量存在于地壳表面.因此,Ti和Al的水解和光催化研究引起了我们的兴趣.目前,只有少数几例低核的Al掺杂PTCs晶态材料被报道,且其制备过程都需要多步反应.因此,合成高核的包含Al的PTCs材料是一项有趣且充满挑战的工作.本文利用有机配体的保护和异金属离子的掺杂成功地提高了PTCs晶体材料的稳定性.通过研究Ti和Al离子的水解,制备了一例核-壳型的纳米轮簇[Al_(7)Ti_(14)(μ2-O)_(7)(μ3-O)_(14)(L)_(35)]·2CH_(3)CN(1;L=苯甲酸).该轮簇中包含罕见的奇数环状结构,是目前核数最高的包含Al的PTC.借助单晶X射线衍射可以清晰观察到无机{Al_(7)Ti_(14)}核与有机保护配体之间的配位模式.此外,利用红外光谱、热重和漫反射光谱对该化合物进行了进一步表征.有机配体层和Al^(3+)占据了T_(i)^(4+)周围的烷氧基位点,使得该化合物呈现较高的空气、热以及酸碱稳定性.在已报道的PTCs晶态材料中,该化合物也展现出较高的光催化产氢速率(402.88μmol g^(-1)h^(-1)).借助催化过程中的光致变色现象、电子顺磁共振谱、荧光光谱以及光电流响应,我们推测了该化合物催化水分解产氢机理.该项工作不仅为制备稳定的PTCs材料提供了基础,也为新型光催化剂的设计提供了新的思路.

Ruthenium-mediated assembly and enhanced stability of heterometallic polystannides[Ru_(2)Sn_(19)]^(4−)and[Ru_(2)Sn_(20)]^(6−)

In this work,we report the synthesis and characterization of two novel Ru-containing Zintl clusters:[Sn_(19){Ru(COD)(en)}_(2)]^(4−)and[Sn_(20){Ru(COD)}_(2)]^(6−).The synthesized compounds not only expand the family of Ru-Sn cluster systems but also shed light on the structure of heterometallic complexes in a previously unknown range of tin atoms.The single-crystal X-ray diffraction(XRD)analysis reveals the dimeric nature of the clusters.Two different assembly patterns of the formal[Sn(η^(3)-Sn_(9))]monomer were observed:the dimerization through the vertex fusion process and the direct dimerization through the formation of 2c–2e Sn–Snσbond.For both clusters,the density functional theory calculations reveal the locallyσ-aromatic nature of the[Sn(η^(3)-Sn_(9))]monomer resulting in two independent magnetic shielding cones.We believe that our findings will help the community to further explore the fascinating chemistry of polystannide clusters.

Syntheses and Characterizations of （η^5—C5H5）MoFeCo（CO）8（μ3—S）and （

ＳｙｎｔｈｅｓｅｓａｎｄＣｈａｒａｃｔｅｒｉｚａｔｉｏｎｓｏｆ（η~５－Ｃ_５Ｈ_５）ＭｏＦｅＣｏ（ＣＯ）_８（μ_３－Ｓ）ａｎｄ（η~５－Ｃ_５Ｈ_５）_２Ｍｏ_２Ｆｅ（ＣＯ）_７（μ_３－Ｓ）：Ｘ－ｒａｙＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ（η~５－Ｃ_５Ｈ_...

SYNTHESIS, STRUCTURE AND ELECTROCHEMICAL STUDIES ON SINGLE MoFe_3S_4 AND WFe_3S_4 CUBANE-TYPE CLUSTER COMPOUNDS*

Single cubane-like clusters, MFe3S4（R2dtc）5 （M=Mo, R2=—（CH2）4—, Bz2; M=W, R2=Me2, —（CH2）4—; dtc=dialkyldithiocarbamate） were synthesized by assembly reaction of （NH4）2MS4 （M=Mo, W）, FeCl2 with R2dtcNa （or NH4） in DMF. The structure, IR, EPR and cyclic voltammogram are described and discussed. MoFe3S4（C4H8dtc）5 was also obtained from the conversion of linear cluster Fe（DMF）6[（FeCl2）2MoS4] in the presence of C4H8dtc NH4. Both clusters MoFe3S4（C4H8dtc）4·2C2H5CN and WFe3S4（C4H8dtc）5·2DMF crystallize in the monoclinic space group C2/c with a=12.544（2）, （Mo-cluster）, 12.533（4） （W-cluster）; b=20.478（4）, 20.121（6）; c=19.582（7）, 19.659（2）;β=102.82（2）, 102.96（3）°; and Z=4, 4. Their structures were refined to R=0.057 and 0.064 with use of 2690 and 2179 reflections （ι】3Q（I））, respectively. Many similarities in structure for Mo and W clusters indicate that both Mo and W play a very similar role in the clusters.

STUDIES ON SYNTHESES OF MoFe_3S_4 CUBANE-LIKE CLUSTER COMPOUNDS

The features of synthetic processes are described on the basis of the studies of the syntheses of MoFe3S4 cubane-like cluster compounds either by self-assembly reactions or by the conversion of linear clusters. The redox properties and the structure of ligands as well as the stoichiometry of reactants have obvious effects upon the core oxidation state and the structure of products. It is indicated that the self-assembly reaction may pass through a combination process oflinear cluster intermediates having structural unit （M,M’=Mo） Fe).