The design and synthesis of a non-centric diamond-like network based NH4+ ion

Two novel acentric hydrogen bonded two-dimensional sheet and three-dimensional 2-fold interpenetrating diamond-like networks have been designed and prepared based on a tetrahedral ammonium node and the O,O'-bifunctional linker molecules dipyridine dioxide (dpdo) and trans-bis(4-pyridyl)ethylene dioxide (bpedo).     

Zeolite ionic crystals assembled through direct incorporation of polyoxometalate clusters within 3D metal-organic frameworks

Polyoxometalate-based metal-organic frameworks {[Gd(dpdo)(4)(H(2)O)(3)](PMo(12)O(40))(H(2)O)(2)CH(3)CN}(n) (2), {[Dy(dpdo)(4)(H(2)O)(3)](PMo(12)O(40))(H(2)O)(20CH(3)CN}(n) (3), {[Gd(dpdo)(4)(H(2)O)(3)](H(3)O)(SiMo(12)O(40))(dpdo)(0.5)(CH(3)CN)(0.5) (H(2)O)(3)}(n) (4), {[Ho(dpdo)(4)(H(2)O)(3)](H(3)O)(SiMo(12)O(40))(dpdo)(0.5)(CH(3)CN)(0.5)(H(2)O)(3)}(n) (5), {[Ni(dpdo)(2)(CH(3)CN) (H(2)O)(2)](2)(SiMo(12)O(40))(H(2)O)(2)}(n) (6), and {[Ni(dpdo)(3)](4)(PW(12)O(40))(3)[H(H(2)O)(27)(CH(3)CN)(12)]}(n) (7) (where dpdo is 4,4'-bipyridine-N,N'-dioxide) were constructed via self-assembly by embedding Keggin-type polyanions within the intercrystalline voids as guests or pillars. Compounds 2 and 3 are isomorphic and exhibit three-dimensional (3D) noninterwoven 64 frameworks with distorted-honeycomb cavities occupied by the polyanions. Compounds 4 and 5 are comprised of 3D noninterwoven frameworks formed by linking the adjacent folded sheets through hydrogen bonds and pi-pi stacking interactions relative to the free isolated dpdo ligand. Compound 6 is a pillar-layered framework with the [SiMo(12)O(40)](4-) anions located on the square voids of the two-dimensional bilayer sheets formed by the dpdo ligands and nickel(II) ions. Compound 7 is a 3D metal-organic framework formed by nickel(II) and 4,4'-bipyridine-N,N'-dioxide with the globular Keggin-structure [PW(12)O(4)](3-) anion as the template. A large protonated water cluster H(+)(H(2)O)(27) is trapped and stabilized within the well-modulated cavity.     

Synthesis and Structure of a Cerium Coordination Polymer Templated by Double-Keggin-anion

A porous coordination polymer, {[Ce（dpdo）4（H2O）3]（PMo_12O_40）（dpdo）0.5（H2O）4}n 1 （dpdo = 4,4＇-bipyridine-N,N＇-dioxide）, templated by double-Keggin-type polyanions was synthesized and structurally characterized. The crystal structure was determined by single-crystal X- ray diffraction. The crystal is of triclinic, space group P1 with a = 13.368（4）, b = 16.503（4）, c = 18.506（5）А, α = 88.831（5）, β= 82.095（5）, γ = 83.578（5）°,V= 4018.6（18）А^3, Z=2, C45H50N9O56CeMo12P, Mr = 2935.31, Dc = 2.426 g/m^3, μ= 2.491 mm^-1, F（000） = 2816, the final R=0.0603 and wR = 0.1611 for 11977 observed reflections with I 〉 2σ（I）. Compound 1 exhibits a 3D non-interwoven framework with large cavities housing centrosymmetrically related shoulder-by-shoulder double-Keggin anions as guests.     

Metal-organic frameworks with phosphotungstate incorporated for hydrolytic cleavage of a DNA-model phosphodiester

Five phosphotungstate-incorporated metal-organic frameworks {[Eu(4)(dpdo)(9)(H(2)O)(16)PW(12)O(40)]}(PW(12)O(40))(2)·(dpdo)(3)·Cl(3) (1); {ZnNa(2)(μ-OH)(dpdo)(4)(H(2)O)(4)[PW(12)O(40)]}·3H(2)O (2); {Zn(3)(dpdo)(7)}[PW(12)O(40)](2)·3H(2)O (3); and [Ln(2)H(μ-O)(2)(dpdo)(4)(H(2)O)(2)][PW(12)O(40)]·3H(2)O (Ln = Ho for 4 and Yb for 5) (dpdo = 4,4'-bipyridine-N,N'-dioxide) have been synthesized through a one-step hydrothermal reaction and characterized by elemental analyses, infrared (IR) spectroscopy, photoluminescence, and single-crystal X-ray diffraction (XRD). The structural analyses indicate that 1-5 display diversity structure from one-dimensional (1D) to three-dimensional (3D) series of hybrids. Kinetic experiments for the hydrolytic cleavage of DNA-model phosphodiester BNPP (bis(p-nitrophenyl)phosphate) were followed spectrophotometrically for the absorbance increase at 400 nm in EPPS (4-(2-hydroxyethyl)piperazine-1-propane sulfonic acid) buffer solution, because of the formation of p-nitrophenoxide with 1-5 under conditions of pH 4.0 and 50 °C. Ultraviolet (UV) spectroscopy indicate that the cleavage of the phosphodiester bond proceeds with the pseudo-first-order rate constant in the range of 10(-7)-10(-6) s(-1), giving an inorganic phosphate and p-nitrophenol as the final products of hydrolysis. The results demonstrate that 1-5 have good catalytic activity and reusability for hydrolytic cleavage of BNPP.     

Three porous coordination polymers of Co2+ and dpdo ligands with channels hosting polyanion chains

Three porous coordination polymers, {[Co(dpdo)₄(H₂O)₂][H(H₂O)₆](PMo₁₂O₄₀)} _n (1), {[Co(dpdo)₄(H₂O)₂][H₃O(CH₃OH)₄](PMo₁₂O₄₀)} _n (2) and {[Co(dpdo)₄(H₂O)₂][K(CH₃OH)₄](PMo₁₂O₄₀)} _n (3) (where dpdo is 4,4′-bipyridine-N,N′-dioxide), with special channels for the chain-like assembly of polymeric Keggin-type anions have been synthesized through self-assembly of Co²⁺ and dpdo ligands in acetonitrile/water or methanol/water solutions and characterized by single crystal X-ray diffraction. Based on layers constructed by [Co(dpdo)₄(H₂O)₂]^{2 +} and different bridging units for charge compensation between layers, the three compounds exhibit similar noninterwoven networks with large channels occupied by the poly-Keggin-anion chains. Thermogravimetric analyses suggest that the three supramolecular networks have different thermal stabilities based on different cationic bridging units.     

Synthesis and Characterization of Cobalt(Ⅱ) and Copper(Ⅱ) Tricyanomethanide (tcm) Complexes with 2,2'-Dipyridyl N, N'-Dioxide (dpdo) as Co-ligands: [Co(dpdo)(tcm)2], [Cu(dpdo)(tcm)2] and Cu(dpdo)2(tcm)2

Three new transition metal tricyanomethanide complexes [Co(dpdo)(tcm)₂] ( 1 ), [Cu(dpdo)(tcm)₂] ( 2 ) and Cu(dpdo)₂(tcm)₂ ( 3 ) were synthesized and structurally characterized. In compound 1 each Co(II) ion is coordinated to four disorder tcm anions and one dpdo molecule to give a distorted octahedral geometry. In compound 2 each Cu(II) ion is surrounded by four tcm anions and one dpdo ligand to form a square bipyramidal geometry. Both compounds 1 and 2 display a µ_1,5‐tcm bridged infinite chain structure. Interestingly, in compound 3 coordination geometry around the central ion is square‐planar, each Cu(II) ion is coordinated by two dpdo molecules to form a cationic part, the cationic parts is linked with the free tcm anionic parts via electrostatic attraction, leading to the formation of a mononuclear structure. Magnetic susceptibility measurement in the range 2 – 300 K indicates that there are antiferromagnetic couplings between adjacent metal ions in 1 (θ=?2.33 K, C=2.13 cm³·mol^?1·K) and 2 (J=?0.30, g=2.20) respectively.     

Synthesis and Structure of a POMs-based 3D Zeolike Ionic Crystal, {[Co（dpdo）2（H2O）2（CH3CN）]2（SiMo12O40）（H2O）2}n

A POMs-based 3D zeolike ionic crystal 1, {[Co（dpdo）2（CH3CN）（H2O）2]2（SiMo12O40）- （HEO）2}n （dpdo = 4,4＇-bipyridine-N,N＇-dioxide）, was constructed via self-assembly by embedding Keggintype [SiMo12O40]^4- polyanions within the intercrystalline voids as pillars and structurally characterized. The crystal structure was determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group P1 with a = 11.430（3）, b = 12.242（3）, c = 14.279（3）A, α = 106.196（4）,β = 94.316（4）, γ = 98.294（3）°, V = 1884.5（7）A^3 Z = 1, C44H50N10O54CoEMo12Si, Mr = 2880.17, Dc = 2.538 g/cm^3, p = 2.484 mm^-1,F（000） = 1388, the final R = 0.0383 and wR = 0.1096 for 7753 observed reflections with I 〉 2σ（I）. Flack factor is 0.22（3）. Compound 1 is a pillar-layered framework with the [SiMo12O40]^4- anions linearly located on the square voids between the 2D bilayers which are formed by the dpdo ligands and cobalt（II） ions.     

Observation of an octameric water cluster containing a book-shaped hexamer in a 4f-3d complex

An octameric water cluster consisting of a book-shaped water hexamer and two dangling water molecules has been observed in a 4f-3d ionic pair complex [Y(dpdo)2(H2O)4][Co(CN)6].4H2O.     

Constructing porous lanthanide coordination polymers of 4,4′-bipyridine- N,N ′-dioxide templated by single- and double-Keggin anions

Three porous coordination polymers, {[Nd(dpdo)₂(H₂O)₅(CH₃OH)₂](PMo₁₂O₄₀)(CH₃OH)-(H₂O)₅} _n (1), {[Tb(dpdo)₄(H₂O)₃](PMo₁₂O₄₀)(H₂O)₂CH₃CN} _n (2) and {[Tb(dpdo)₄(H₂O)₃]H(SiMo₁₂O₄₀)(dpdo)_0.5(CH₃CN)_0.5(H₂O)₄} _n (3) (where dpdo is 4,4′-bipyridine-N,N′-dioxide), templated by single- or double-Keggin polyanions were synthesized and characterized by single crystal X-ray diffraction. The compounds exhibit three different 3D non-interwoven frameworks with large cavities occupied by the single- or double-Keggin-type anions. Thermogravimetric analyses suggest different stability for the three metal-organic frameworks. The SHG (second harmonic generation) efficiency of 1 confirms its noncentric framework.     

A Potassium Organic-inorganic Hybrid Complex with Channels Hosting Decorated Poly-anion Chains

A potassium organic-inorganic hybrid complex {H2[K（PMo12O40）（CH3CN）3]- （dpdo）2（H2O）}n 1 （dpdo = 4,4＇-bipyridine-N,N＇-dioxide） with special channels for the chain-like assembly of decorated Keggin-type anions was synthesized and structurally characterized. The crystal structure was determined by single-crystal X-ray diffraction. The crystal is of orthorhombic, space group Cmcm with a = 20.5328（17）, b = 16.8877（14）, c = 16,1454（14） A, V = 5598.4（8） A^3, Z = 4, C26H29N7O45KMo12P, Mr= 2380.91, Dc = 2.825 g/cm^3,μ = 2.813 mm^-1, F（000） = 4528, the final R = 0.0324 and wR = 0.0880 for 2577 observed reflections with I 〉 2σ（I）. Compound 1 exhibits a 3D network structure with large channels hosting decorated poly-anion chains as guests.     

A new extended structural compound based on saturated Wells-Dawson polyoxoanions

A new 3D extended structural compound,(dpdo)_2H_2{[Cu(2,2'-bipy)_2]_2(P_2W_(18)O_(62))}·5H_2O 1(dpdo = 4,4'-bipyridine-N,N'-dioxide; 2,2'-bipy = 2,2'-bipyridine),has been hydrothermally synthesized and characterized by elemental analyses,IR,TG analyses,cyclic voltammetry,and single-crystal X-ray diffraction.Compound 1 is built up of[P_2W_(18)O_(62)]~(6-) cluster as the structural motif covalently linked by[Cu(2,2'-bipy)_2]~(2+) coordination complexes to yield the 1D chains,which are further in close cont...     

A porous Cu(II)-MOF containing [PW12O40]3− and a large protonated water cluster: synthesis,structure, and proton conductivity

A proton-conducting metal–organic framework (MOF), {[Cu₄(dpdo)₁₂][H(H₂O)₂₇(CH₃CN)₁₂][PW₁₂O₄₀]₃}_n (where dpdo is 4,4′-bipyridine-N,N′-dioxide) (1), was synthesized by the reaction of CuHPW₁₂O₄₀·nH₂O and dpdo at room temperature. Single-crystal X-ray diffraction analysis at 293?K revealed that 1 crystallized in the cubic space group Im-3 and presented a non-interwoven 3-D framework with cubic cavities and guest molecules. A large ionic water cluster H⁺(H₂O)₂₇, consisting of a water shell (H₂O)₂₆ and an encaged H⁺(H₂O) as a center core, was trapped in the cubic cavity of the MOF {[Cu₄(dpdo)₁₂(PW₁₂O₄₀)₃]^?}_∞. Thermogravimetric analysis suggests that 1 has high thermal stability, indicating that such a non-interwoven 3-D framework with cubic cavities is a suitable host for researching protonated water clusters. Its water vapor adsorption isotherm at room temperature and pressure shows that the water vapor adsorbed in it was 65.1 cm^3?g^?1 at the maximum allowable humidity. It exhibits good proton conductivities of 10^?5–10^?4?S^?cm^?1 at 100 °C in the relative humidity range 35–98%.     

Density functional theory study of the adsorption of formaldehyde on Pd4 and on Pd4/gamma-Al2O3 clusters

B3LYP/LANL2DZ and B3LYP/6-31G(d)-restricted and -unrestricted calculations are employed to calculate energies and adsorption forms of formaldehyde adsorbed on planar and on tetrahedral Pd4 clusters and on a Pd4 cluster supported on Al10O15. Formaldehyde adsorbs on planar Pd4 in the eta(2)(C,O)-di-sigma adsorption mode, while on tetrahedral Pd4, it adsorbs in the eta(2)(C,O)-pi adsorption mode. The adsorption energy on planar Pd4 is -21.4 kcal x mol(-1), whereas for the tetrahedral Pd4 cluster, the adsorption energy is -13.2 kcal x mol(-1). The latter value is close to experimental findings (-12 to -14 kcal x mol(-1)). Adsorption of formaldehyde on Pd4 supported on an Al10O15 cluster leads essentially to the same result as that found for adsorption on the tetrahedral Pd4 cluster. Charge density analysis for the interaction between formaldehyde and the Pd4 clusters indicates strong backdonation in the eta(2) adsorption mode, leading to positive charge on the Pd4 cluster. NBO analysis shows that the highly coordinated octahedral aluminum atoms of Al10O15 donate electron density to the supported Pd4 cluster, while tetrahedral aluminum atoms with lower coordination number have acidic nature and therefore act as electron acceptors.     

On the composition and crystal structure of the new quaternary hydride phase Li4BN3H10

X-ray data on single crystals of the quaternary metal hydride near the composition LiB(0.33)N(0.67)H(2.67), previously identified as "Li3BN2H8", reveal that its true composition is Li4BN3H10. The structure has body-centered-cubic symmetry [space group I2(1)3, cell parameter a = 10.679(1)-10.672(1) Angstroms] and contains an ordered arrangement of BH4- and NH2- anions in the molar ratio 1:3. The borohydride anion has an almost ideal tetrahedral geometry (angleH-B-H approximately 108-114 degrees), while the amide anion has a nearly tetrahedral bond angle (angleH-N-H approximately 106 degrees). Three symmetry-independent Li atom sites are surrounded by BH4- and NH2- anions in various distorted tetrahedral configurations, one by two B and two N atoms, another by four N atoms, and the third by one B and three N atoms. The Li configuration around B is nearly tetrahedral, while that around N resembles a distorted saddlelike configuration, similar to those in LiBH4 and LiNH2, respectively.     

Cation distribution in co-doped ZnAl2O4 nanoparticles studied by X-ray photoelectron spectroscopy and 27Al solid-state NMR spectroscopy

Co(x)Zn(1-x)Al(2)O(4) (x = 0.01-0.6) nanoparticles were synthesized by the citrate sol-gel method and were characterized by X-ray powder diffraction and transmission electron microscopy to identify the crystalline phase and determine the particle size. X-ray photoelectron spectroscopy and (27)Al solid-state NMR spectroscopy were used to study the distribution of the cations in the tetrahedral and octahedral sites in Co(x)Zn(1-x)Al(2)O(4) nanoparticles as a function of particle size and composition. The results show that all of the as-synthesized samples exhibit spinel-type single phase; the crystallite size of the samples is about 20-50 nm and increases with increasing annealing temperature and decreases with Co-enrichment. Zn(2+) ions are located in large proportions in the tetrahedral sites and in small proportions in the octahedral sites in Co(x)Zn(1-x)Al(2)O(4) nanoparticles. The fraction of octahedral Zn(2+) increases with increasing Co concentration and decreases with increasing particle size. Besides the tetrahedral and octahedral coordinations, the presence of the second octahedrally coordinated Al(3+) ions is observed in the nanoparticles. The change of the inversion parameter (2 times the fraction of Al(3+) ions in tetrahedral sites) with Co concentration and particle size is consistent with that of the Zn fraction in octahedral sites. Analysis of the absorption properties indicates that Co(2+) ions are located in the tetrahedral sites as well as in the octahedral sites in the nanoparticles. The inversion degree of Co(2+) decreases with increasing particle size.     

Catalytic effect of a second H3PO2 in the mechanism of stabilisation of the unstable pyramidal tautomer of H3PO2 coordinated at [Mo3S4M'] clusters (M' = Ni, Pd)

Kinetic and DFT studies indicate that the stabilization of a single pyramidal H(3)PO(2) molecule at the M' site of [Mo(3)S(4)M'] clusters requires the participation of two tetrahedral H(3)PO(2) molecules, the role of the second one being assisting tautomerization of a previously coordinated tetrahedral H(3)PO(2).     

Encapsulation of small base molecules and tetrahedral/cubane-like clusters of group V atoms in the boron buckyball: a density functional theory study

A density functional theory study of small base molecules and tetrahedral and cubane-like group V clusters encapsulated in B(80) shows that the boron buckyball is a hard acid and prefers hard bases like NH(3) or N(2)H(4) to form stable off-centered complexes. In contrast, tetrahedral and cubane-like clusters of this family are metastable in the cage. The most favorable clusters are the mixed tetrahedral and cubane clusters formed by nitrogen and phosphorus atoms such as P(2)N(2)@B(80), P(3)N@B(80), and P(4)N(4)@B(80). The boron cap atoms are electrophilic centers, and prefer mainly to react with electron rich nucleophilic sites. The stability of the complexes will be governed by the size and electron donating character of the encapsulated clusters. B(80) forms stable complexes with hard materials where a bidentate interaction of the encapsulated molecule with two boron cap atoms is preferred over a single direct complex toward a single endohedral boron.     

A rubidium organic-inorganic hybrid complex with channels hosting decorated polyanion chains

A rubidium organic-inorganic hybrid complex, {H₂[Rb(PMo₁₂O₄₀)(CH₃CN)₃](dpdo)₂(H₂O)₂} _n (1), (where dpdo is 4,4′-bipyridine-N,N′-dioxide) with special channels for the chainlike assembly of decorated Keggin-type anions was synthesized and structurally characterized. The crystal structure was determined by single-crystal X-ray diffraction. The crystal is Orthorhombic space group Cmcm with a = 20.4713(18) ?, b = 17.0529(15) ?, c = 16.1968(14) ?, V = 5654.2(9) ?³, Z = 4, C₂₆H₃₁N₇O₄₆RbMo₁₂P, M = 2445.30, D _c = 2.873 Mg m⁻³, μ = 3.570 mm⁻¹, F(000) = 4640, the final R = 0.0438 and wR = 0.1350 for 2065 observed reflections with I > 2σ(I). Compound 1 exhibits a 3D network with large channels hosting decorated polyanion chains as guests.     

Superweak complexes of tetrahedral P4 molecules with the silver cation of weakly coordinating anions

The silver aluminates AgAl[OC(CF3)2(R)]4 (R = H, CH3, CF3) react with solutions of white phosphorus P4 to give complexes that bind one or two almost undistorted tetrahedral P4 molecules in an fashion: [Ag(P4)2]+[Al(OC(CF3)3)4]+ (1) containing the first homoleptic metal-phosphorus cation, the molecular species (P4)AgAl[OC(CH3)(CF3)2]4 (2), and the dimeric Ag(mu,eta2-P4)Ag bridged [(P4)AgAl[OC(H)(CF3)2]4]2 (3). Compounds 1-3 were characterized by variable-temperature (VT) 31P NMR spectroscopy (1 also by VT 32P MAS-NMR spectroscopy), Raman spectroscopy, and single-crystal X-ray crystallography. Other Ag:P4 ratios did not lead to new species, and this observation was rationalized on thermodynamic grounds. The Ag(P4)2+ ion has an almost planar coordination environment around the Ag+ ion due to d(x2 - y2)(Ag) --> sigma*(P-P) backbonding. Calculations (HF-DFT) on six Ag(P4)2+ isomers 4a-f showed that the planar eta2 form 4a is only slightly favored by 5.2 kJ mol(-1) over the tetrahedral eta2 species 4b; eta1-P4 and eta3-P4 complexes are less favorable (27-76 kJ mol(-1)). The bonding of the P4 moiety in [RhCl(eta2-P4)(PPh3)2], the only compound in which an eta2 bonding mode of a tetrahedral P4 molecule has been claimed, must be regarded as a tetraphosphabicyclobutane, and not as a tetrahedro-P4 complex, on the basis of the published NMR and vibrational spectra, the calculated geometry of [RhCl(P4)(PH3)2] (10), the highly endothermic (385 kJ mol(-1)) calculated dissociation enthalpy of 10 into P4 and RhCl(PH3)2 (11), as well as atoms in molecules (AIM) and natural bond orbital (NBO) population analyses of 10 and the Ag(P4)2+ ion. Therefore, 1-3 are the first examples of species containing eta2-coordinated tetrahedral P4 molecules.