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1.
Precise structural design of large hetero-multinuclear metal-oxo clusters is crucial for controlling their large spin ground states and multielectron redox properties for application as a single-molecule magnet (SMM), molecular magnetic refrigeration, and efficient redox catalyst. However, it is difficult to synthesize large hetero-multinuclear metal oxo clusters as designed because the final structures are unpredictable when employing conventional one-step condensation reaction of metal cations and ligands. Herein, we report a “cationic metal glue strategy” for increasing the size and nuclearity of hetero-multinuclear metal-oxo clusters by using lacunary-type anionic molecular metal oxides (polyoxometalates, POMs) as rigid multidentate ligands. The employed method enabled the synthesis of {(FeMn4)Mn2Ln2(FeMn4)} oxo clusters (Ln=Gd, Tb, Dy, and Lu), which are the largest among previously reported paramagnetic hetero-multinuclear metal-oxo clusters in POMs and showed unique SMM properties. These clusters were synthesized by conjugating {FeMn4} oxo clusters with Mn and Ln cations as glues in a predictable way, indicating that the “cationic metal glue strategy” would be a powerful tool to construct desired large hetero-multinuclear metal clusters precisely and effectively.  相似文献   

2.
Two new polyoxometalate (POM)‐based hybrid monomers (Bu4N)5(H)[P2V3W15O59{(OCH2)3CNHCO(CH3)C?CH2}] ( 2 ) and (S(CH3)2C6H4OCOC(CH3)=CH2)6[PVMo10O40] ( 5 ) were developed by grafting polymerizable organic units covalently or electrostatically onto Wells–Dawson and Keggin‐type clusters and were characterized by analytical and spectroscopic techniques including ESI‐MS and/or single‐crystal X‐ray diffraction analyses. Radical initiated polymerization of 2 and 5 with organic monomers (methacryloyloxy)phenyldimethylsulfonium triflate (MAPDST) and/or methylmethacrylate (MMA) yielded a new series of POM/polymer hybrids that were characterized by 1H, 31P NMR and IR spectroscopic techniques, gel‐permeation chromatography as well as thermal analyses. Preliminary tests were conducted on these POM/polymer hybrids to evaluate their properties as photoresists using electron beam (E‐beam)/extreme ultraviolet (EUV) lithographic techniques. It was observed that the POM/polymer hybrid of 2 with MAPDST exhibited improved sensitivity under EUV lithographic conditions in comparison to the MAPDST homopolymer resist possibly due to the efficient photon harvesting by the POM clusters from the EUV source.  相似文献   

3.
Using metal–organic cages (MOCs) as preformed supermolecular building-blocks (SBBs) is a powerful strategy to design functional metal–organic frameworks (MOFs) with control over the pore architecture and connectivity. However, introducing chemical complexity into the network via this route is limited as most methodologies focus on only one type of MOC as the building-block. Herein we present the pairwise linking of MOCs as a design approach to introduce defined chemical complexity into porous materials. Our methodology exploits preferential Rh-aniline coordination and stoichiometric control to rationally link Cu4L4 and Rh4L4 MOCs into chemically complex, yet extremely well-defined crystalline solids. This strategy is expected to open up significant new possibilities to design bespoke multi-functional materials with atomistic control over the location and ordering of chemical functionalities.

A new strategy to design atomically precise multivariate metal–organic frameworks is presented. This is achieved by linking two preformed metal–organic cages via a precisely tuned Rh–aniline interaction.  相似文献   

4.
Herein, we report the stepwise assembly and reversible transformation of atomically precise ligated titanium coated bismuth-oxide core nanostructures. The soluble and stable Bi38O45@Ti6-oxo clusters with weakly coordinated surface salicylate ligands were first prepared as precursors. Owing to the high surface reactivity of the Bi38O45 inner core, its shell composition and morphology could be systemically modified by assembly with various Ti ions and auxiliary ligands (L), especially those with different flexibility, bridging ability and steric hindrance. As a result, a series of new core–shell Bi38O44/45@TixL-oxo (x = 14, 16, 18 or 20) clusters containing gradually increasing shell Ti atoms were successfully synthesized. Among them, the Bi38Ti20-oxo cluster is the largest one in the family of heterometallic Bi/Ti-oxo clusters to date. In addition, the sensitized titanium outer shell can effectively improve the photocurrent response under visible light irradiation. More remarkably, the obtained core–shell Bi38O44/45@TixL-oxo clusters can serve as stable and efficient catalysts for CO2 cycloaddition with epoxides under ambient conditions, whose activity was significantly influenced by the outer ligated titanium shell structure. This work provides a new insight into the construction of atomically precise heterometallic core–shell nanostructures and also an interesting shell engineering strategy for tuning their physicochemical properties.

Core–shell Bi38O44/45@TixL-oxo clusters were prepared by the stepwise assembly from soluble Bi38O45@Ti6 precursors to show modifiable shell and reversible structure transformation, which further changed their chemical fixation activities of CO2.  相似文献   

5.
Trinuclear heterometallic complexes containing the {M2Ln(Piv)6(NO3)} (MII = Ni, Cu; LnIII = Nd, Pr, Sm, Eu, Gd; Piv? is the anion of pivalic acid) and {Cu2Ln(Piv)8)]? (LnIII = Eu, Gd) metal cores were synthesized, their structures and magnetic properties were studied. For the most compounds, it was shown that their magnetic properties can be interpreted taking no interaction of the 3d-metal ions and a lanthanide into account. Ferromagnetic exchange interactions were found to exist between the unpaired electrons of the paramagnetic centers in the exchange clusters of the gadolinium-containing heterometallic complexes {M-Gd-M} (M = Ni or Cu).  相似文献   

6.
The synthesis of a series of hydrosilylboronates via the selective iridium- or nickel-catalyzed monoborylation of dihydrosilane Si–H bonds is described. The synthesized silylboronates, which bear a single Si–H bond, can be used as novel silicon nucleophiles in the presence of transition-metal catalysts or bases. The first 29Si{1H} NMR spectroscopic evidence for the formation of (t-Bu)2HSiLi, generated by the reaction of (t-Bu)2HSi–B(pin) with MeLi, is reported as the first example of a dialkylhydorosilyl lithium species.

Monoborylation of a dihydrosilane Si–H bond can be achieved in the presence of iridium- or nickel-based catalysts, yielding novel hydrosilylboronates that bear a hydrogen atom at the silicon center.  相似文献   

7.
Lithium reagents have long played important roles in synthetic chemistry. However, unsaturated organosilicon lithium reagents are few in number. Herein, we describe the first isolation of a 1,2-dilithiodisilene: [(boryl)SiLi]2 (2) was prepared in 73% yield by the reduction of (boryl)tribromosilane (1, boryl = (HCArN)2B, Ar = 2,6-iPr2C6H3) with lithium in Et2O. The salt elimination reaction of 2 with dihaloboranes RBX2 afforded disilaborirenes [(boryl)Si]2BR (3a–c), whereas the reaction with two equivalents of B-bromocatecholborane ((cat)BBr) yielded the first tetraboryldisilene [(boryl)(cat)BSi]2 (4). X-ray diffraction analysis and density functional theory calculations indicated that the disilene 2 and tetraboryldisilene 4 feature an almost planar geometry and disilaborirenes 3a–c are aromatic with a silicon–boron hybrid 2π-electron delocalized structure. The results indicate that 1,2-dilithiodisilene 2 is a powerful synthetic reagent for the construction of novel silicon multiply bonded species with unique electronic structures and that the boryl substituents have significant electronic effects on the structure of silicon multiple bonding.

Dianionic disilyne: reduction of boryltribromosilane yielded the 1,2-dilithio-disilene 2, which is a powerful transfer reagent for the synthesis of a novel 2π aromatic system and the first tetraboryldisilene.  相似文献   

8.
Polyoxometalates (POMs) are anionic molecular metal oxides with expansive diversity in terms of their composition, structure, nuclearity and charge. Within this vast collection of compounds are dominant structural motifs (POM platforms), that are amenable to significant chemical tuning with minimal perturbation of the inorganic oxide molecular structure. Consequently, this enables the systematic investigation of these compounds as inorganic additives within materials whereby structure and charge can be tuned independently i.e. [PW12O40]3−vs. [SiW12O40]4− while also investigating the impact of varying the charge balancing cations on self-assembly. The rich surface chemistry of POMs also supports their functionalisation by organic components to yield so-called inorganic–organic hybrids which will be the key focus of this perspective. We will introduce the modifications possible for each POM platform, as well as discussing the range of nanoparticles, microparticles and surfaces that have been developed using both surfactant and polymer building blocks. We will also illustrate important examples of POM-hybrids alongside their potential utility in applications such as imaging, therapeutic delivery and energy storage.

Polyoxometalates are anionic molecular metal oxides with diversity in composition, structure, nuclearity and charge. Their adaptable chemistry leads to potential for self-assembly with other building blocks into a variety of hybrid structures.  相似文献   

9.
Two modes of reactivity of N-silylphosphoranimines have been utilized to prepare the title compounds containing either B–N=P or Si–N=P–N–B linkages. First, silicon-nitrogen bond cleavage reactions of the N-silylphosphoranimines, Me3SiN=PMe(R)OCH2CF3 (1: R=Me, 2: R=Ph), with various chloroboranes gave the new N-borylphosphoranimines, Ph(Me2N)B–N=PMe2OCH2CF3 (2) and [(Me3Si)2N](Cl)B–N=PMe2OCH2CF3 (10). In other cases, however, the expected B–N=P products were unstable and cyclic phosphazenes [Me(R)P=N]3,4 were obtained. Second, deprotonation-substitution reactions of the aminophosphoranimines, Me3SiN=P(R)Me–N(R)H, were used to prepare a series of novel (borylamino)-phosphoranimines, Me3SiN=P(R)(Me)–N(R)–B(NMe2)2 (18: R=Me, R=t-Bu; 19: R=R=Me; 20: R=Ph, R=t-Bu; 21: R=Ph, R=Me) and Me3SiN=PMe2–N(t-Bu)–B(Ph)X (22: X=NMe2, 23: X=OCH2CF3). All of the new boron–nitrogen–phosphorus products were fully characterized by multinuclear NMR (1H, 13C, and 31P) spectroscopy and elemental analysis.  相似文献   

10.
Multiply-bonded main group metal compounds are of interest as a new class of reactive species able to activate and functionalize a wide range of substrates. The aluminium sulfido compound K[Al(NONDipp)(S)] (NONDipp = [O(SiMe2NDipp)2]2−, Dipp = 2,6-iPr2C6H3), completing the series of [Al(NONDipp)(E)] anions containing Al–E{16} multiple bonds (E{16} = O, S, Se, Te), was accessed via desulfurisation of K[Al(NONDipp)(S4)] using triphenylphosphane. The crystal structure showed a tetrameric aggregate joined by multiple K⋯S and K⋯π(arene) interactions that were disrupted by the addition of 2.2.2-cryptand to form the separated ion pair, [K(2.2.2-crypt)][Al(NONDipp)(S)]. Analysis of the anion using density functional theory (DFT) confirmed multiple-bond character in the Al–S group. The reaction of the sulfido and selenido anions K[Al(NONDipp)(E)] (E = S, Se) with CO2 afforded K[Al(NONDipp)(κ2E,O-EC{O}O)] containing the thio- and seleno-carbonate groups respectively, consistent with a [2 + 2]-cycloaddition reaction and C–E bond formation. An analogous cycloaddition reaction took place with benzophenone affording compounds containing the diphenylsulfido- and diphenylselenido-methanolate ligands, [κ2E,O-EC{O}Ph2]2−. In contrast, when K[Al(NONDipp)(E)] (E = S, Se) was reacted with benzaldehyde, two equivalents of substrate were incorporated into the product accompanied by formation of a second C–E bond and complete cleavage of the Al–E{16} bonds. The products contained the hitherto unknown κ2O,O-thio- and κ2O,O-seleno-bis(phenylmethanolate) ligands, which were exclusively isolated as the cis-stereoisomers. The mechanisms of these cycloaddition reactions were investigated using DFT methods.

Reaction of Al–E (E = S, Se) multiple bonds with C Created by potrace 1.16, written by Peter Selinger 2001-2019 O functionalities generates new C–E bonds.  相似文献   

11.
The properties of metal nanoclusters depend on both their structures and electronic states. However, in contrast to the significant advances achieved in the synthesis of structurally well-defined metal nanoclusters, systematic control of their electronic states is still challenging. In particular, stimuli-responsive and reversible control of the electronic states of metal nanoclusters is attractive from the viewpoint of their practical applications. Recently, we developed a synthesis method for atomically precise Ag nanoclusters using polyoxometalates (POMs) as inorganic ligands. Herein, we exploited the acid/base nature of POMs to reversibly change the electronic states of an atomically precise {Ag27} nanocluster via protonation/deprotonation of the surrounding POM ligands. We succeeded in systematically controlling the electronic states of the {Ag27} nanocluster by adding an acid or a base (0–6 equivalents), which was accompanied by drastic changes in the ultraviolet-visible absorption spectra of the nanocluster solutions. These results demonstrate the great potential of Ag nanoclusters for unprecedented applications in various fields such as sensing, biolabeling, electronics, and catalysis.

The electronic states of Ag nanoclusters were reversibly controlled driven by protonation/deprotonation of polyoxometalate ligands.  相似文献   

12.
The first series of niobium–tungsten–lanthanide (Nb‐W‐Ln) heterometallic polyoxometalates {Ln12W12O36(H2O)24(Nb6O19)12} (Ln=Y, La, Sm, Eu, Yb) have been obtained, which are comprised of giant cluster‐in‐cluster‐like ({Ln12W12}‐in‐{Nb72}) structures built from 12 hexaniobate {Nb6O19} clusters gathered together by a rare 24‐nuclearity sodalite‐type heterometal–oxide cage {Ln12W12O36(H2O)24}. The Nb‐W‐Ln clusters present the largest multi‐metal polyoxoniobates and a series of rare high‐nuclearity 4d‐5d‐4f multicomponent clusters. Furthermore, the giant Nb‐W‐Ln clusters may be isolated as discrete inorganic alkali salts and can be used as building blocks to form high‐dimensional inorganic–organic hybrid frameworks.  相似文献   

13.
Multiferroic materials have attracted great interest because of their underlying new science and promising applications in data storage and mutual control devices. However, they are still very rare and highly imperative to be developed. Here, we report an organic–inorganic hybrid perovskite trimethylchloromethylammonium chromium chloride (TMCM–CrCl3), showing the coexistence of magnetic and electric orderings. It displays a paraelectric–ferroelectric phase transition at 397 K with an Aizu notation of 6/mFm, and spin-canted antiferromagnetic ordering with a Néel temperature of 4.8 K. The ferroelectricity originates from the orientational ordering of TMCM cations, and the magnetism is from the [CrCl3] framework. Remarkably, TMCM–CrCl3 is the first experimentally confirmed divalent Cr2+-based multiferroic material as far as we know. A new category of hybrid multiferroic materials is pointed out in this work, and more Cr2+-based multiferroic materials will be expectedly developed in the future.

An organic–inorganic hybrid perovskite Trimethylchloromethylammonium chromium(ii) chloride (TMCM–CrCl3) can simultaneously show excellent ferroelectricity and antiferromagnetism, which is the first experimentally confirmed Cr2+-based multiferroic material.  相似文献   

14.
The early-late heterometallic complexes [TiCp((OCH2)2Py)(μ-O)M(COD)] (M = Rh, Ir) behave as four-electron donor ligands yielding the polynuclear cationic complexes [TiCp(OCH2)2 Py(μ-O){M(COD)}2]OTf (M = Rh (1), Ir (2)). The molecular structure of complex 1 has been established through an X-ray diffraction study.  相似文献   

15.
Two series of new divalent organolanthanide complexes with the general formula [η51-{1-R-3-(C5H9OCH2)C9H5}]2LnII (R = H, Ln = Yb (3); R = Me3Si, Ln = Yb (4); R = H, Ln = Eu (5); R = Me3Si, Ln = Eu (6)) were prepared by reactions of 2 equiv. of 1-R-3-(C5H9OCH2)C9H6 (R = H (1), R = Me3Si (2)) with the lanthanide(III) amides [(Me3Si)2N]3Ln(μ-Cl)Li(THF)3 (Ln = Yb, Eu) via a one-electron reductive elimination process. Recrystallization of 6 from n-hexane afforded [η51-(C5H9OCH2C9H5SiMe3)]2EuII · (C6H14)0.5 (7). All compounds were fully characterized by elemental analyses, and spectroscopic methods. The structures of complexes 4 and 7 were additionally determined by single-crystal X-ray analyses. The catalytic activity of the complexes on methyl methacrylate and ε-caprolactone polymerization was studied, and the temperatures, substituents on the indenyl ring, and solvents effects on the catalytic activity of the complexes were examined.  相似文献   

16.
The strategy of aggregation-induced emission enhancement (AIEE) has been proven to be efficient in wide areas and has recently been adopted in the field of metal nanoclusters. However, the relationship between atomically precise clusters and AIEE is still unclear. Herein, we have successfully obtained two few-atom heterometallic gold–silver hepta-/decanuclear clusters, denoted Au6Ag and Au9Ag, and determined their structures by X-ray diffraction and mass spectrometry. The nature of the AuI⋯AgI interactions thereof is demonstrated through energy decomposition analysis to be far-beyond typical closed-shell metal–metal interaction dominated by dispersion interaction. Furthermore, a positive correlation has been established between the particle size of the nanoaggregates and the photoluminescence quantum yield for Au6Ag, manifesting AIEE control upon varying the stoichiometric ratio of Au : Ag in atomically-precise clusters.

The strategy of aggregation-induced emission enhancement (AIEE) has been proven to be efficient in wide areas and has recently been adopted in the field of metal nanoclusters.  相似文献   

17.
A series of polyoxometalates (POMs) that incorporate the highest‐nuclearity Ln clusters that have been observed in such structures to date (Ln26 , Ln=La and Ce) are described, which exhibit giant multishell configurations (Ln⊂W6⊂Ln26⊂W100). Their structures are remarkably different from known giant POMs that feature multiple Ln ions. In particular, the incorporated Ln–O clusters with a nuclearity of 26 are significantly larger than known high‐nuclearity (≤10) Ln–O clusters in POM chemistry. Furthermore, they also contain the largest number of La and Ce centers for any POM reported to date and represent a new kind of rare giant POMs with more than 100 W atoms. Interestingly, the La26‐containing POM can undergo a single‐crystal to single‐crystal structural transformation in the presence of various transition‐metal ions, such as Cu2+, Co2+, and Ni2+, from an inorganic molecular nanocluster into an inorganic–organic hybrid extended framework that is built from POM building blocks with even higher‐nuclearity La28 clusters bridged by transition‐metal complexes.  相似文献   

18.
Solvatothermal syntheses have been exploited to effect the isolation of three novel polyoxoalkoxometalate clusters, [{Fe(OH)(CH3CN)2} Fe6OCl6{(OCH2)3CCH2OH}4] (1), [Fe10O2Cl8{(OCH2)3CCH2CH3}6] (2), and [(VO)2Fe8O2Cl6{(OCH2)3CCH2CH3}6] (3). The structure of 1 may be described as a hexametalate core {Fe6OCl6}10+, consisting of a octahedral arrangement of chloride ligands encasing an octahedron of six Fe(III) sites, with a central oxo group. The remaining four coordination sites at each octahedral iron center are occupied by doubly bridging oxygen donors from the trisalkoxo ligands. One triangular face of this substructure, defined by three oxygen atoms, from three adjacent trisalkoxo ligands, is capped by the {Fe(OH)(CH3CN)2}2+ subunit. The structure of 2 is based on the decametalate core of edge-sharing octahedra. The eight peripheral Fe(III) sites of the cluster bond to four oxygen donors from the trisalkoxo ligands, a terminal Cl ligand, and one of the 6-oxo groups. The two central iron sites are linked to four oxygen donors from the trisalkoxo ligands and to both of the 6-oxo groups. Cluster 3 is structurally related to 2 with two {FeCl}2+ units replaced by {VO}2+ groups.  相似文献   

19.
The hydrazino complex {methoxo[4-phenylbutane-2,4-dione(p-nitrobenzoyl)hydrazonato(2-)]oxovanadium(V)}, VO(p-NO2bhbzac)OCH3, (1), has been prepared by the direct reaction of bis(benzoylacetonato) oxovanadium(IV), VO(bza)2, with p-NO2-C6H4C(O)NHNH2, p-NO2bh, in CH3OH. The resulting compound contains benzoylacetone-(p-NO2)benzoyl hydrazone as tridentate Schiff base-type ligand and OCH3 group as Lewis base, both ligated to vanadium. The crystals are orthorhombic, with Z = 8, space group Pbca, a = 11.699(5) Å, b = 14.035(5) Å, c = 22.564(5) Å, R1 = 0.0756 and wR2 = 0.1302. The crystal structure demonstrated the square-pyramidal geometry of the VOoxo(ONO)O coordination sphere with the oxo ligand at the apical position. The electronic absorption spectra revealed a ligand-to-metal charge-transfer (LMCT) band in the near UV region at max = 23,700 cm–1 (B = 5640 dm3 mol–1 cm–1) in CH3CN, max = 23,420 cm–1 (B = 5550 dm3 mol–1 cm–1) in DMSO, and max near 26,950 (sh) cm–1 (B = 10,550 dm3 mol–1 cm–1) in CH2Cl2. The FT-IR spectra of (1) show the characteristic strong (V = O) stretching vibration at 993 cm–1 and support the view that the oxovanadium complex is pentacoordinated and monomeric.  相似文献   

20.
The development of rational synthetic routes to inorganic arsenide compounds is an important goal because these materials are finding applications in many areas of materials science. In this paper, we show that the binary crown clusters [M@As8]3− (M = Nb, Ta) can be used as synthetic precursors which, when combined with ZnMes2, generate ternary intermetalloid clusters with 12-vertex cages, {M@[As8(ZnMes)4]}3− (M = Nb, Ta). Structural studies are complemented by mass spectrometry and an analysis of the electronic structure using DFT. The synthesis of these clusters presents new opportunities for the construction of As-based nanomaterials.

Two ternary intermetalloid clusters were constructed through binary intermetalloid clusters with a low valent group 12 metal salt. These clusters represent the first example of the structural transformation for intermetalloid clusters.  相似文献   

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