Synthesis and Crystal Structures of Novel Keggin and Dawson Polyoxometalates Containing Amantadine

Heteropolyoxometalates are a large family of potent medicines due to their excellent antiviral and antitumor activity 1-4, while their application in clinic meets great difficulties for their toxicity 5. How to synthesize heteropolyoxometalate medicines possessing high activity and low toxicity has become the focus in heteropolyoxometalate medicine research. Previously reported polyoxometalates showing medical activities are all salts simple Na+, K+ or NH4+ etc. inorganic cations, in which o…     

Novel charge transfer supramolecular assemblies with Keggin anions and 2-amino-5-nitropyridine

Several novel compounds with the non-linear optical chromophore 2-amino-5-nitropyridine (2A5NP) and Keggin polyoxoanions (alpha-isomers), having the general formula (2A5NP)(m)H(n)[XM12O40].xH2O, M = Mo, W, were synthesised. Compounds were obtained with X = P, n = 3, m = 3 and 4 and X = Si, n = m = 4 (x = 2-6). Thus, for each of the anions [PMo12O40]3- and [PW12O40]3- two different compounds were obtained, with the same anion and organic counterpart but with a different stoichiometric ratio. These presented different charge transfer properties and thermal stability. All compounds were characterised by spectroscopic and analytical techniques. The single crystal X-ray diffraction structure of (2A5NP)4H3[PMo12O40].2.5H2O.0.5C2H5OH showed that the water solvent molecules and the organic chromophores are assembled via infinite one-dimensional chains of hydrogen bonds with formation of open channels, which accommodate [PMo12O40]3- and ethanol solvent molecules.     

Tetravalent metal complexation by Keggin and lacunary phosphomolybdate anions

We report the synthesis, spectroscopic and structural characterization, and computational analysis of a series of phosphomolybdate complexes with tetravalent metal cations. The reaction between Ce (IV) and Th (IV) with phosphomolybdate at the optimum pH for the stabilization of the lacunary heteropolyoxometalate anion, [PMo 11O 39] (7-), results in the formation of compounds containing the anions [Ce(PMo 11O 39) 2] (10-) and [Th(PMo 11O 39) 2] (10-), respectively. Single crystal X-ray diffraction analysis was performed on salts of both species, Cs 10[Ce(PMo 11O 39) 2].20H 2O and (NH 4) 10[Th(PMo 11O 39) 2].22H 2O. In both anionic complexes the f-block metal cation is coordinated to the four unsaturated terminal lacunary site oxygens of each [PMo 11O 39] (7-) anion, yielding 8 coordinate sandwich complexes, analogous to previously prepared related complexes. Spectroscopic characterization points to the stability of these complexes in solution over a reasonably wide pH range. Density functional analysis suggests that the Ce-O bond strength in [Ce(PMo 11O 39) 2] (10-) is greater than the Th-O bond strength in [Th(PMo 11O 39) 2] (10-), with the dominant bonding interaction being ionic in both cases. In contrast, under similar reaction conditions, the dominant solid state Zr (IV) and Hf (IV) complexes formed contain the anions [Zr(PMo 12O 40)(PMo 11O 39)] (6-) and [Hf(PMo 12O 40)(PMo 11O 39)] (6-), respectively. In these complexes the central Group 4 d-block metal cations are coordinated to the four unsaturated terminal lacunary site oxygens of the [PMo 11O 39] (7-) ligand and to four bridging oxygens of a plenary Keggin anion, [PMo 12O 40] (3-). In addition, (NH 4) 5{Hf[PMo 12O 40][(NH 4)PMo 11O 39]}.23.5H 2O can be crystallized as a minor product. The structure of the anion, {Hf[PMo 12O 40][(NH 4)PMo 11O 39]} (5-), reveals coordination of the central Hf (IV) cation via four bridging oxygens on both the coordinated [PMo 11O 39] (7-) and [PMo 12O 40] (3-) anions. Unusually, the highly charged lacunary site remains uncoordinated to the Hf metal center but instead interacts with an ammonium cation. (31)P NMR indicates that complexation of the Keggin anion, [PMo 12O 40] (3-), to Hf (IV) and Zr (IV) will stabilize the Keggin anion to a much higher pH than usually observed.     

有机-无机复合杂多化合物的合成、结构及表征

利用常规水溶液法制备了三种基于饱和Keggin结构阴离子的有机-无机复合杂多化合物[Pr(pydc)(H2O)6]2H[PMo12O40]·4H2O(1)、[Nd(pydc)(H2O)6]2H[PMo12O40]·4H2O(2)和[Tb(pydc)(H2O)6]2H[PMo12O40]·4H2O(3)(pydc=2,6...     

Crystal structure of a novel two-dimensional supramolecular network based on polyoxoanion and yttriumIII coordination cation

A novel compound (NH4)2Y(H2O)8[PMo10V2O40]·10H2O has been prepared in an aqueous solution and characterized by elemental analysis, IR, and TG-DTG analysis. X-ray diffraction analysis was carried out on (NH4)2Y(H2O)8 [PMo10V2O40]·10H2O single crystal, which crystallizes in the monoclinic system of a space group P21/c with a=0.9871(3) nm,b=1.5424(5) nm, c=2.7924(9) nm, β= 94.183(5)° and Z=2. In the compound, a two-dimensional network is constructed by the PMo10V2O54-0 anion and the Y(H2O)83+ cation building blocks via hydrogen bonding exhibiting the porous structure.     

Formation of p-phenylenediamine-crown ether-[PMo12O40]4- salts

Electron transfer from the electron donor of p-phenylenediamine (PPD) to the electron acceptor of (H+)3[PMo12O40]3- forms a one-electron-reduced Keggin cluster of [PMo12O40]4-, bearing a S = 1/2 spin, while proton transfer from the proton donor of (H+)3[PMo12O40]3- to the proton acceptor of PPD yielded mono- and diprotonated cations of 4-aminoanilinium (HPPD+) and p-phenylenediammonium (H2PPD2+). By introduction of crown ether receptors during the crystallization process, supramolecular cations of (HPPD+)(crown ethers) and/or (H2PPD2+)(crown ethers) were successfully introduced into three new alpha-[PMo12O40]4- salts of (H2PPD2+)2([12]crown-4)4[PMo12O40]4- (1), (HPPD+)4([15]crown-5)4[PMo12O40]4- (2), and (HPPD+)2(H2PPD2+)([18]crown-6)4[PMo12O40]4- (3) as the countercation. The protonated states of PPD and molecular-assembly structures of the supramolecular cations depended on the size of the crown ethers. In salt 3, a novel mixed-protonated state of HPPD+ and H2PPD2+ was confirmed to be complexed in the cation structure. According to the changes in the cation structures, the anion arrangements were modulated from those of the two-dimensional layer for salt 1 to the isolated cluster for salts 2 and 3. The temperature-dependent magnetic susceptibilities of salts 1-3 were consistent with the isolated spin arrangements of [PMo12O40]4-. The electronic spectra of salts 1-3 indicated the intervalence optical transition from pentavalent Mo(V) to hexavalent Mo(VI) ions within the [PMo12O40]4- cluster. Temperature-dependent electron spin resonance spectra of salt 2 revealed the delocalization-localization transition of the S = 1/2 spin at 60 K. The spin on the [PMo12O40]4- cluster was localized on a specific Mo(V) site below 60 K, which was thermally activated with an activation energy of 0.015 eV.     

Polyoxometalate-templated lanthanide-organic hybrid layers based on 6(3)-honeycomb-like 2D nets

The reaction of a double-betaine-containing ligand with LnPMo(12)O(40)·nH(2)O (Ln = Dy, Tb and Er) led to the isolation of new polyoxometalate-templated lanthanide-organic hybrid layers with the molecular formula [Ln(L)(1.5)(H(2)O)(5)][PMo(12)O(40)]·1.5CH(3)CN·2H(2)O (Ln = Dy (1), Tb (2) and Er (3); L = 1,4-bis(pyridinil-4-carboxylato)-l,4-dimethylbenzene). All compounds were characterized by elemental analyses, TG analyses, IR and the single-crystal X-ray diffraction. Compounds 1-3 are isostructural and possess a 2D undulating cationic network [Ln(L)(1.5)(H(2)O)(5)](n)(3n+) with the honeycomb-like cavities. Interestingly, the interval 2D networks are further connected by the H-bonds to form a 3D supramolecular framework. Moreover, two of such identical supramolecular frameworks are 2-fold interpenetrated with each other and encapsulate the α-Keggin-type [PMo(12)O(40)](3-) anionic templates and the solvent molecules. These composite compounds display both luminescent properties (induced by organic ligands and/or lanthanide ions) and electrocatalytic activities towards the reduction of nitrite.     

Polyoxomolybdodiphosphonates: examples incorporating ethylidenepyridines

We have synthesized and structurally characterized three pyridylethylidene-functionalized diphosphonate-containing polyoxomolybdates, [{Mo(VI)O(3)}(2){Mo(V)(2)O(4)}{HO(3)PC(O)(CH(2)-3-C(5)NH(4))PO(3)}(2)](6-) (1), [{Mo(VI)(2)O(6)}(2){Mo(V)(2)O(4)}{O(3)PC(O)(CH(2)-3-C(5)NH(4))PO(3)}(2)](8-) (2), and [{Mo(V)(2)O(4)(H(2)O)}(4){O(3)PC(O)(CH(2)-3-C(5)NH(4))PO(3)}(4)](12-) (3). Polyanions 1-3 were prepared in a one-pot reaction of the dinuclear, dicationic {Mo(V)(2)O(4)(H(2)O)(6)}(2+) with 1-hydroxo-2-(3-pyridyl)ethylidenediphosphonate (Risedronic acid) in aqueous solution. Polyanions 1 and 2 are mixed-valent Mo(VI/V) species with open tetranuclear and hexanuclear structures, respectively, containing two diphosphonate groups. Polyanion 3 is a cyclic octanuclear structure based on four {Mo(V)(2)O(4)(H(2)O)} units and four diphosphonates. Polyanions 1 and 2 crystallized as guanidinium salts [C(NH(2))(3)](5)H[{Mo(VI)O(3)}(2){Mo(V)(2)O(4)}{HO(3)PC(O)(CH(2)-3-C(5)NH(4))PO(3)}(2)]·13H(2)O (1a) and [C(NH(2))(3)](6)H(2)[{Mo(VI)(2)O(6)}(2){Mo(V)(2)O(4)}{O(3)PC(O)(CH(2)-3-C(5)NH(4))PO(3)}(2)]·10H(2)O (2a), whereas polyanion 3 crystallized as a mixed sodium-guanidinium salt, Na(8)[C(NH(2))(3)](4)[{Mo(V)(2)O(4)(H(2)O)}(4){O(3)PC(O)(CH(2)-3-C(5)NH(4))PO(3)}(4)]·8H(2)O (3a). The compounds were characterized in the solid state by single-crystal X-ray diffraction, IR spectroscopy, and thermogravimetric and elemental analyses. The formation of polyanions 1 and 3 is very sensitive to the pH value of the reaction solution, with exclusive formation of 1 above pH 7.4 and 3 below pH 6.6. Detailed solution studies by multinuclear NMR spectrometry were performed to study the equilibrium between these two compounds. Polyanion 2 was insoluble in all common solvents. Detailed computational studies on the solution phases of 1 and 3 indicated the stability of these polyanions in solution, in complete agreement with the experimental findings.     

Synthesis, crystal structure of α-Keggin heteropolymolybdates with pyridine-2,6-dicarboxylate based frameworks, and associated RhB photocatalytic degradation and 2D-IR COS tests

Three α-Keggin heteropolymolybdates with the formula [(C(5)H(4)NH)COOH](3)[PMo(12)O(40)] 1, {[Sm(H(2)O)(4)(pdc)](3)}{[Sm(H(2)O)(3)(pdc)]}[SiMo(12)O(40)]·3H(2)O 2 and {[La(H(2)O)(4)(pdc)](4)}[PMo(12)O(40)]F 3 (H(2)pdc = pyridine-2,6-dicarboxylate), have been synthesized under hydrothermal condition and characterized by single crystal X-ray diffraction analyses, elemental analyses, inductively coupled plasma atomic emission spectroscopy (ICP-AES), IR, thermal gravimetric analyses, thermal infrared spectrum analyses and powder X-ray diffraction (PXRD) analyses. Single crystal X-ray diffraction indicates all three compounds comprise ball-shaped Keggin type [XMo(12)O(40)](n-) polyoxometalates (POMs) (n = 3, X = P; n = 4, X = Si, respectively) with different types of carboxylic ligands derived from H(2)pdc, and these cluster anions are isostructural. In order to explore structural characteristics, Rhodamine B photocatalytic (RhB) degradation and two-dimensional infrared correlation spectroscopy (2D-IR COS) tests, are investigated for 1, 2 and 3. In RhB degradation, all compounds show good photocatalytic activity. For 1, the activity mainly comes from POMs. While in 2 and 3, POMs' photocatalytic activity is enhanced by the Ln(iii)-pdc metal-organic frameworks. Structural properties like POM's stability and magnetic sensitivity are discussed by 2D-IR COS under thermal/magnetic perturbations.     

New high-dimensional networks based on polyoxometalate and crown ether building blocks

Three novel supramolecular assemblies constructed from polyoxometalate and crown ether building blocks, [(DB18C6)Na(H(2)O)(1.5)](2)Mo(6)O(19).CH(3)CN, 1, and [(Na(DB18C6)(H(2)O)(2))(3)(H(2)O)(2)]XMo(12)O(40).6DMF.CH(3)CN (X = P, 2, and As, 3; DB18C6 = dibenzo-18-crown-6; DMF = N,N-dimethylfomamide), have been synthesized and characterized by elemental analyses, IR, UV-vis, EPR, TG, and single crystal X-ray diffraction. Compound 1 crystallizes in the tetragonal space group P4/mbm with a = 16.9701(6) A, c = 14.2676(4) A, and Z = 2. Compound 2 crystallizes in the hexagonal space group P6(3)/m with a = 15.7435(17) A, c = 30.042(7) A, gamma = 120 degrees, and Z = 2. Compound 3 crystallizes in the hexagonal space group P6(3)/m with a = 15.6882(5) A, c = 29.9778(18) A, gamma = 120 degrees, and Z = 2. Compound 1 exhibits an unusual three-dimensional network with one-dimensional sandglasslike channels based on the extensive weak forces between the oxygen atoms on the [Mo(6)O(19)](2)(-) polyoxoanions and the CH(2) groups of crown ether molecules. Compounds 2 and 3 are isostructural, and both contain a novel semiopen cagelike trimeric cation [(Na(DB18C6)(H(2)O)(2))(3)(H(2)O)(2)](3+). In their packing arrangement, an interesting 2-D "honeycomblike" "host" network is formed, in which the [XMo(12)O(40)](3)(-) (X = As and P) polyoxoanion "guests" resided.     

Tetra- to dodecanuclear oxomolybdate complexes with functionalized bisphosphonate ligands: activity in killing tumor cells

We report the synthesis and characterization of five novel Mo-containing polyoxometalate (POM) bisphosphonate complexes with nuclearities ranging from 4 to 12 and with fully reduced, fully oxidized, or mixed-valent (Mo(V), Mo(VI)) molybdenum, in which the bisphosphonates bind to the POM cluster through their two phosphonate groups and a deprotonated 1-OH group. The compounds were synthesized in water by treating [Mo(V)(2)O(4)(H(2)O)(6)](2+) or [Mo(VI)O(4)](2-) with H(2)O(3)PC(C(3)H(6)NH(2))OPO(3)H(2) (alendronic acid) or its aminophenol derivative, and were characterized by single-crystal X-ray diffraction and (31)P NMR spectroscopy. (NH(4))(6)[(Mo(V)(2)O(4))(Mo(VI)(2)O(6))(2)(O(3)PC(C(3)H(6)NH(3))OPO(3))(2)]·12H(2)O (1) is an insoluble mixed-valent species. [(C(2)H(5))(2)NH(2)](4)[Mo(V)(4)O(8)(O(3)PC(C(3)H(6)NH(3))OPO(3))(2)]·6H(2)O (2) and [(C(2)H(5))(2)NH(2)](6)[Mo(V)(4)O(8)(O(3)PC(C(10)H(14)NO)OPO(3))(2)]·18H(2)O (4) contain similar tetranuclear reduced frameworks. Li(8)[(Mo(V)(2)O(4)(H(2)O))(4)(O(3)PC(C(3)H(6)NH(3))OPO(3))(4)]·45H(2)O (3) and Na(2)Rb(6)[(Mo(VI)(3)O(8))(4)(O(3)PC(C(3)H(6)NH(3))OPO(3))(4)]·26H(2)O (5) are alkali metal salts of fully reduced octanuclear and fully oxidized dodecanuclear POMs, respectively. The activities of 2-5 (which are water-soluble) against three human tumor cell lines were investigated in vitro. Although 2-4 have weak but measurable activity, 5 has IC(50) values of about 10 μM, which is about four times the activity of the parent alendronate molecule on a per-alendronate basis, which opens up the possibility of developing novel drug leads based on Mo bisphosphonate clusters.     

Photoreductive self-assembly from [Mo7O24]6- to carboxylates-coordinated {Mo142} Mo-blue nanoring in the presence of carboxylic acids

The primary steps of the photoredox reaction between [Mo7O24]6- and carboxylic acid electron (and proton) donors in aqueous solutions are investigated by the chemically induced dynamic electron spin polarization (CIDEP) spectroscopy. The excitation of the O-->Mo ligand-to-metal charge-transfer (LMCT) bands of [Mo7O24]6- in the presence of CH3CO2H induces the emissive electron spin polarization (ESP) of *CH2CO2 and *CH3 radicals with an accompanying formation of the one-electron reduced species [Mo7O23(OH)]6-, which is demonstrated by the triplet mechanism involving the O --> Mo LMCT triplet states. The prolonged photolysis of the solution containing [Mo7O24]6- and CH3CO2H at pH = 3.4 leads to the formation of the acetate/propionate-coordinated {Mo142} Mo-blue nanoring, [MoV28MoV(I)114O429H10(H2O)(49)(CH3)CO2 triple bond Ac5(C2H5CO2 triple bond Pr)]30- (1a) through the formation of the cis-configured dimeric dehydrative condensation to two-electron reduced Mo-blue [(Mo7O23)2]10- ({Mo14}). 1a is isolated as a [NH4]+/[Me3NH]+-mixed salt which is formulated as [NH4]27[Me3NH]3[Mo(V)28Mo(VI)114O429H10(H2O)49(CH3CO2)5(C2H5CO2)].150 +/- 10H2O (1) by results of elementary analysis, single-crystal X-ray analysis, 1H NMR, IR, and UV/Vis measurements, and manganometric redox titration. Based on the building-block sequence of for 1a, the bottom-up processes from [Mo7O24]6- to the {Mo142} ring in the coexistence of beta-[Mo8O26]4- are discussed by (i) the stabilization of the molecular curvature of {Mo14} through both the intramolecular transfer of monomolybdates and the intermolecular transfer of monomolybdates as degradation fragments of beta-[Mo8O26]4-, to yield {Mo21} and {Mo20} building blocks, (ii) the outer-ring formation resulting from seven successive two-electron-photoreductive condensations among {Mo21} and {Mo20}, and (iii) inner-ring formation resulting from eight successive dehydrative condensations between monomolybdate linkers attached to the neighboring head Mo sites.     

Hydrothermal Synthesis and Characterization of a Two-dimensional Layer Based on Keggin POM Cluster Units: [Cu2(DMPz)2PMo12O40]·HDMPz

The title compound, [Cu2(DMPz)2PMo12O40]·HDMPz (1, DMPz = 2,5-dimethyl pyrazine), has been synthesized and characterized by single-crystal X-ray diffraction analysis. It crystallizes in triclinic, space group P1 with a = 11.075(2), b = 11.551(2), c = 11.886(2) A, α = 106.352(2), β = 109.862(3), γ = 109.504(1)°, V = 1206.8(3) A3, C18H26Cu2Mo12N6O40P, Mr = 2275.78, Z = 1, Dc = 3.131 g/cm3,μ = 4.011 mm-1, F(000) = 1073, S = 1.066, the final R = 0.0389 and wR = 0.1056 for 3739 observed reflections with I > 2σ(I). The structural analysis indicates that the title compound is composed of Keggin clusters [PMo12O40]3- connected by one-dimensional [Cu(DMPz)]2n2n+ chains to form a two-dimensional grid layer with holes occupied by mono-protonated DMPz molecules. In the solid of the title compound, the 2D grid layers are stacked together in an ABAB packing mode.     

In operando X-ray absorption fine structure studies of polyoxometalate molecular cluster batteries: polyoxometalates as electron sponges

We carried out in operando Mo K-edge X-ray absorption fine structure measurements on the rechargeable molecular cluster batteries (MCBs) of polyoxometalates (POMs), in which a Keggin-type POM, [PMo(12)O(40)](3-), is utilized as a cathode active material with a lithium metal anode. The POM-MCBs exhibit a large capacity of ca. 270 (A h)/kg in a voltage range between V = 4.0 V and V = 1.5 V. X-ray absorption near-edge structure analyses demonstrate that all 12 Mo(6+) ions in [PMo(12)O(40)](3-) are reduced to Mo(4+) in the discharging process. This means the formation of a super-reduced state of the POM, namely, [PMo(12)O(40)](27-), which stores 24 electrons, and this electron number can explain the large capacity of the POM-MCBs. Furthermore, extended X-ray absorption fine structure analyses reveal the molecular structure of [PMo(12)O(40)](27-), which is slightly reduced in size compared to the original [PMo(12)O(40)](3-) and involves Mo(4+) metal-metal-bonded triangles. Density functional theory calculations suggest that these triangles are formed because of the large number of additional electrons in the super-reduced state.     

Hydrothermal Synthesis,Crystal Structure and Property of a Novel Inorganic-organic Hybrid Compound Based On Phosphomolybdate Anion[H-IDP]4[PMo12O40]·8H2O(IDP=4-(Imidazole-1-y1)phenol)

A novel compound[H-IDP]4[PMo12O40]·8H2O 1 based on Keggin-type phosphormolybdate has been synthesized by hydrothermal method and characterized by IR spectroscopy, elemental analyses and single-crystal X-ray diffraction.The composite crystallizes in the moflo- clinic system,space group C2/m with a=13.937(5),b=27.033(5),C=10.857(5)(A),β= 122.489(5)°.V=3450(2)(A)3,Mr=2611.11,Z=2,Dc=2.498g/cm3,F(000)=2486,μ=2.243 mm-1.the final R=0.0568 and wR=0.1216 for 2707 observed reflections with I>2σ(I).X-ray structural study shows that 1 consists of a[PMo12O40]4- polyanion.four protonated IDP cations and eight H2O molecules.In the structure of 1,a 3D network forms by hydrogen bond of [PMo12O40]4- polyanion,HIDP+cation and H2O molecules.Upon excitation wavelength of 280 nm in hydroxylic solvents at room temperature,1 shows fluorescence property.     

Structural and functional characteristics of rhenium clusters derived from redox chemistry of the triangular [ReIII3(mu-Cl)3] core unit

The present study investigates structural and functional aspects of the redox chemistry of rhenium(III) chloride [Re3Cl9] (1) in aqueous and organic solvents, with emphasis on the dioxygen-activating capabilities of reduced rhenium clusters bearing the Re3(8+) core. Dissolution of 1 in HCl (6 M) generates [Re3(mu-Cl)3Cl9]3- (2a), which can be isolated as the tetraphenylphosphonium salt (2b). Anaerobic one-electron reduction of 1 by Hg in HCl (6-12 M) produces [(C6H5)4P]2[Re3(mu-Cl)3Cl7(H2O)2].H2O (3), the structure of which features a planar [Re3(mu-Cl)3Cl3] framework (Re3(8+) core), involving two water ligands that occupy out-of-plane positions in a trans arrangement. Compound 3 dissociates in the presence of CO, yielding [(C6H5)4P]2[ReIII2Cl8] (4) and an unidentified red carbonyl species. In situ oxidation (O2) of the reduced Re3(8+)-containing cluster in HCl (6 M) produces quantitatively 2a, whereas oxidation of 3 in organic media results in the formation of [(C6H5)4P]4[(Re3(mu-Cl)3Cl7(mu-OH))2].2CH2Cl2 (5). The structure of 5 reveals that two oxygen ligands (hydroxo units) bridge asymmetrically two Re3(9+) triangular clusters. The origin of these hydroxo units derives from the aquo ligands, rather than O2, as shown by 18O2 labeling studies. The hydroxo bridges of 5 can be replaced by chlorides upon treatment with Me3SiCl to afford the analogous [(C6H5)4P]4[(Re3(mu-Cl)3Cl7(mu-Cl))2].10CH2Cl2 (6). The reaction of 5 with Hg in HCl (6 M)/tetrahydrofuran regenerates compound 3. Complexes 1-3 exhibit nitrile hydratase type activity, inducing hydrolysis of CH3CN to acetamide. The reaction of 3 with CH3CN yields [(C6H5)4P]2[Re3(mu-Cl)3Cl6.5(CH3CN)1.5(CH3C(O)NH)0.5] (7), the structure of which is composed of [Re3(mu-Cl)3Cl7(CH3CN)2]2- (7a) and [Re3(mu-Cl)3Cl6(CH3CN)(CH3C(O)NH)]2- (7b) (Re3(8+) cores) as a disordered mixture (1:1). Oxidation of 7 with O2 in CH3CN affords [(C6H5)4P]2[Re3(mu-Cl)3Cl7(CH3C(O)NH)].CH3CN (8) and small amounts of [(C6H5)4P][ReO4] (9). Compound 8 is also independently isolated from the reaction of 2b with wet CH3CN, or by dissolving 5 in CH3CN. In MeOH, 5 dissociates to afford [(C6H5)4P]2[Re3(mu-Cl)3Cl8(MeOH)].MeOH (10).     

Redistribution and fluxionality in heteropolyoxoperoxo complexes: [PO4[M2O2(mu-O2)2(O2)2]2]3- with M = Mo and/or W

When peroxotetramolybdophosphate, [(n-C4H9)4N]3[PO4[Mo2O2(mu-O2)2(O2)2]2], denoted (NBu4)3PMo4, and its tungsten(VI) analogue, (NBu4)3PW4, are mixed in acetonitrile at room temperature, redistribution occurs with the formation of three mixed-addenda species [PO4[Mo4-xWxO20]]3- (x = 1-3). The temperature dependence of the phosphorus-31 NMR spectra of a 1 1 mixture and of the pure salts, (NBu4)3PMo4 or (NBu4)3PW4, shows that [MO(O2)2] species are in chemical exchange, as are the [MOp] units of certain heteropolyacids (e.g. H3[PMo12O40] x aq and H3[PW12O40] x aq). However, there is no chemical exchange between free phosphate and [MO(O2)2] species in these systems; but there is fluxional behaviour involving PMo2W2, PMo4 and PW4. This is attributed to the rapid equilibrium between isomers (PMo2W2) and to equilibrium between anionic structures with tridentate (mu-eta2:eta1-O22-) and bidentate (eta2-O22-) modes of coordination for the two peroxo groups of the [M2O2(mu-O2)2(O2)2] moieties.     

含氧桥的笼状化合物[Mo_5P_2O_(23)]~(6-)[(CH_3)_2NH_2]_5~(5+)-[H_3O]~+·1/2(CH_3)_2NCHo·1/2H_2O的合成和结构

[Mo_5P_2O_(23)]~(6-)[(CH_3)_2NH_2]_5~(5+)[H_3O]~+·1/2DMF·1/2H_2O(DMF=(CH_3)_2NC-HO)(M_r=1204.67)的晶体属三斜晶系,空间群P,晶胞参数a=16.438(6);b=22.22(1);c=11.325(5),α=104.25(4);β=108.97(3);γ=97.68(4)°,V=3688(3),Z=4,D_c=2.17gcm~(-1),R=0.056,R_w=0.074,晶胞中每个不对称单元含有两个[Mo_5P_2O_(23)]~(6-)[(CH_3)_2NH_2]_5~(5+)[H_3O]~+·1/2DMF·1/2H_2O,阴离子[Mo_5P_2O_(23)]~(6-)中的Mo、P原子成一个畸变五角双锥构型。有一个阴离子的所有原子(Mo、P、O)位置完全确定,而另一个阴离子有一个磷酸根的三个氧原子位置出现二重位置统计分布。化合物的阳离子为二甲胺阳离子和水合氢离子。     

Hydrogen-bonded assemblies of two-electron reduced mixed-valence [XMo12O40] (X = P and Si) with p-phenylenediamines

Hydrogen-bonded assemblies of the two-electron reduced mixed-valence Keggin clusters [PMo(12)O(40)](5-) and [SiMo(12)O(40)](6-) were obtained by the one-pot electron-transfer reactions between p-phenylenediamine (PPD) or 2,3,5,6-tetramethyl-PPD (TMPPD) (donors) and H(+)(3)[PMo(12)O(40)](3-) or H(+)(4)[SiMo(12)O(40)](4-) (acceptors) in CH(3)CN. The redox states of the [PMo(12)O(40)](5-) and [SiMo(12)O(40)](6-) clusters were confirmed by the redox titrations and electronic absorption measurements. In (HPPD(+))(3)(H(+))(2)[PMo(12)O(40)](5-)(CH(3)CN)(3-6) (1), the N-H ~ O hydrogen-bonded interactions between the monoprotonated HPPD(+) (or diprotonated H2PPD(2+)) and the [PMo(12)O(40)](5-) resulted in a windmill-like assembly and hydrophilic one-dimensional channels are formed with a cross-sectional area of 0.065 nm(2), and these are filled by the CH(3)CN molecules. Also, the CH(3)CN molecules in salt 1 were removed by immersing the single crystals of 1 into H(2)O, CH(3)OH, and C(2)H(5)OH solvents. In the compound, (HTMPPD(+))(6)[SiMo(12)O(40)](6-)(CH(3)CN)(6) (2), the N-H ~ O hydrogen-bonded interactions between the monoprotonated HTMPPD(+) molecules and the [SiMo(12)O(40)](6-) formed a "Saturn-ring"-like assembly. Each Saturn-ring was arranged into an hexagonally packed array via hydrogen-bonded and π-stacking interactions of HTMPPD(+), while the CH(3)CN solvent present in salt 2 are only found in the zero-dimensional isolated cavities.     

A novel zirconium polyoxometalate complex that contains both a coordinated saturated anion, [PMo12O40]3-, and a coordinated unsaturated anion, [PMo11O39]7-

The novel 8-coordinate zirconium compound (NH(4))(6)[Zr(PMo(12)O(40))(PMo(11)O(39))].26H(2)O (1) has been synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, and vibrational and (31)P NMR spectroscopy. It is the first example of a metal complex containing both parent, [PMo(12)O(40)](3)(-), and monovacant lacunary, [PMo(11)O(39)](7)(-), anions. Furthermore, this is the first crystallographic determination of the [PMo(11)O(39)](7)(-) anion.