(CH3)2NH(CH2)2NH(CH3)2][(UO2)2F2(HPO4)2]: a new organically templated layered uranium phosphate fluoride--synthesis, structure, characterization, and ion-exchange reactions

A new organically templated layered uranium phosphate fluoride, [(CH(3))(2)NH(CH(2))(2)NH(CH(3))(2)][(UO(2))(2)F(2)(HPO(4))(2)] has been synthesized by hydrothermal reaction of UO(3), H(3)PO(4), HF, and (CH(3))(2)NCH(2)CH(2)N(CH(3))(2) at 140 degrees C. [(CH(3))(2)NH(CH(2))(2)NH(CH(3))(2)][(UO(2))(2)F(2)(HPO(4))(2)] has a layered crystal structure consisting of seven-coordinated UO(5)F(2) pentagonal bipyramids and four-coordinated HPO(4) tetrahedra. Each anionic layer containing three-, four-, and six-membered rings is separated by [(CH(3))(2)NH(CH(2))(2)NH(CH(3))(2)](2+) cations. The [(CH(3))(2)NH(CH(2))(2)NH(CH(3))(2)](2+) cations may be readily exchanged with the M(2+) ions (M = Ba, Sr and Ca) in water to give high crystalline AE(UO(2))(2)(PO(4))(2).6H(2)O (AE = Ca, Sr, Ba).     

Kinetic and mechanistic investigations of hydrothermal transformations in zinc phosphates

The room-temperature crystallization of [C(6)N(2)H(18)][Zn(HPO(4))(H(2)PO(4))(2)], an organically templated zinc phosphate containing [Zn(2)(HPO(4))(2)(H(2)PO(4))(4)](4)(-) molecular anions, and its transformation to compounds containing either one- or two-dimensional inorganic components, [C(6)N(2)H(18)][Zn(3)(H(2)O)(4)(HPO(4))(4)], [C(4)N(2)H(12)][Zn(HPO(4))(2)(H(2)O)], or [C(3)N(2)H(6)][Zn(4)(OH)(PO(4))(3)], under hydrothermal conditions were studied in-situ using energy-dispersive X-ray diffraction. The ability to collect data during reactions in a large volume ( approximately 23 mL) Teflon-lined autoclave under real laboratory conditions has allowed for the elucidation of kinetic and mechanistic information. Kinetic data have been determined by monitoring changes in the integrated peak intensities of Bragg reflections and have been modeled using the Avrami-Erofe'ev expression. The crystallization of [C(6)N(2)H(18)][Zn(HPO(4))(H(2)PO(4))(2)] is a diffusion-controlled process, while nucleation is increasingly more important in determining the overall rate of the formation of [C(6)N(2)H(18)][Zn(3)(H(2)O)(4)(HPO(4))(4)], [C(4)N(2)H(12)][Zn(HPO(4))(2)(H(2)O)], and [C(3)N(2)H(6)][Zn(4)(OH)(PO(4))(3)]. The transformation of [C(6)N(2)H(18)][Zn(HPO(4))(H(2)PO(4))(2)] to [C(4)N(2)H(12)][Zn(HPO(4))(2)(H(2)O)] and [C(3)N(2)H(6)][Zn(4)(OH)(PO(4))(3)] occurs via a dissolution-reprecipitation mechanism, while the transformation to [C(6)N(2)H(18)][Zn(3)(H(2)O)(4)(HPO(4))(4)] may be the first observation of a direct topochemical conversion of one organically templated solid to another under hydrothermal conditions.     

One- and two-dimensional silver and zinc uranyl phosphates containing bipyridyl ligands

The reaction of AgCN with UO2, 4,4'-bipy, and phosphoric acid in water at 160 degrees C under autogeneously generated pressure results in the formation of [Ag(4,4'-bipy)]2[(UO2)2H3(PO4)3] (AgUP-1). Ag(2,2'-bipy)(UO2)2(HPO4)(PO4) (AgUP-2) has been prepared from the hydrothermal reaction (at 180 degrees C) of KAg(CN)2 with UO2(C2H3O2)2.2H2O and 2,2'-bipy. [Zn(2,2'-bipy)]2[UO2(HPO4)3] (ZnUP-1) was isolated from the hydrothermal reaction of UO2, 2,2'-bipyridyl, Zn(CN)2, and H3PO4. Single crystal X-ray diffraction experiments reveal that the structure of AgUP-1 consists of 2infinity[(UO2)2H3(PO4)3]2- expanded autunite-like layers in the [ac] plane, separated by 1infinity[Ag(4,4'-bipy)]+ chains of two-coordinate Ag+ bridged by 4,4'-bipy. The structure of AgUP-2 is composed of chains of edge-sharing UO7 pentagonal bipyramids that are linked by phosphate anions into 2infinity[(UO2)2(HPO4)(PO4)]1- sheets with the beta-uranophane topology that extend in the [ab] plane. Both sides of the sheets are decorated by [Ag(2,2'-bipy)]+ units, where the Ag+ cations are found in distorted trigonal planar environments. The structure of ZnUP-1 is 1D and consists of UO7 pentagonal bipyramids that are connected by phosphate anions that also bind four-coordinate zinc(II) to the periphery of the chains and five-coordinate zinc within the chains. Intense fluorescence from these compounds was observed.     

The role of hydrogen bonding in the crystal structures of zinc phosphate hydrates

The compounds alpha- and beta-hopeite have been synthesised by hydrothermal crystallisation from aqueous solution at 90 degrees C and 20 degrees C, respectively. The crystal structures of these polymorphic forms of zinc phosphate tetrahydrate (ZPT), Zn(3)(PO(4))(2).4 H(2)O, have been resolved. Single-crystal analysis proves that the main difference between the alpha and beta forms of ZPT is caused by the difference in orientation of one of the water molecules in the ZnO(6) octahedral network, indicating two different hydrogen-bonding patterns. A previously unknown hopeite, Zn(3)(HPO(4))(3).3 H(2)O (ZHPT), has been isolated and analysed. This helps to achieve a better understanding of the mechanism of formation of zinc phosphate compounds. Unambiguous identification of each phase is established by analysis of their unique thermal behaviour and thermodynamic interrelationship.     

Chirality transfer from guest chiral metal complexes to inorganic framework: the role of hydrogen bonding

The structure elucidation of a new zinc phosphate [Co(II)(en)(3)][Zn(4)(H(2)PO(4))(3)(HPO(4))(2)(PO(4))(2 H(2)O)(2)] (1) reveals that the racemic cobalt complex templates the zinc phosphate framework in such a way that the local C(2) point symmetry of the structural motif of the inorganic framework conforms with that of the cobalt complex pairing with it, in essence transferring its chirality to the inorganic host. An analysis of hydrogen bonding between the guest molecules and the inorganic host framework reveals that hydrogen bonding is responsible for the stereospecific structural arrangement. Upon examining previously reported chiral metal-complex-templated structures of metal phosphates, it is revealed that such hydrogen bonding is the common origin for inducing chirality transfer in metal-phosphate frameworks templated with chiral metal complexes. Crystal data of 1: orthorhombic, Pbcn (no. 60), a=10.4787(8) A, b=20.0091(14) A, c=14.9594(10) A, and Z=2.     

Hydro/solvothermal synthesis and structures of new zinc phosphates of varying dimensionality

Hydro/solvothermal reactions of ZnO, HCl, H(3)PO(4), 1,4-diazacycleheptane (homopiperazine), and H(2)O under a variety of conditions yielded three new organic-inorganic hybrid materials, [C(5)N(2)H(14)][Zn(HPO(4))(2)].xH(2)O (x = approximately 0.46), I, [C(5)N(2)H(14)][Zn(3)(H(2)O)(PO(4))(2)(HPO(4))], II, and [C(5)N(2)H(14)][Zn(2)(HPO(4))(3)].H(2)O, III. While I has a one-dimensional structure, II possesses a two-dimensional layered structure, and III has a three-dimensional structure closely related to the ABW zeolitic architecture. All the compounds consist of vertex linking of ZnO(4), PO(4), and HPO(4) tetrahedral units. The fundamental building unit, single four-membered ring (S4R), is present in all the cases, and the observed differences in their structures result from variations in the connectivity between the S4R units. Thus I has a corner-shared S4R forming an infinite one-dimensional chain, II has two corner-shared chains fused through a 3-coordinated oxygen atom forming a strip and a layer with eight-membered apertures, and III has S4R units connected via oxygen atoms to give rise to channels bound by eight T atoms (T = Zn, P) in all crystallographic directions. Crystal data: I, monoclinic, space group = P2(1)/n (No. 14), a = 8.6053(3) A, b = 13.7129(5) A, c = 10.8184(4) A, beta = 97.946(1) degrees, V = 1264.35(8) A(3), Z = 4; II, monoclinic, space group = P2(1)/c (No. 14), a = 11.1029(1) A, b = 17.5531(4) A, c = 8.2651(2) A, beta = 97.922(2) degrees, V = 1595.42(5) A(3), Z = 4; III, monoclinic, space group = P2(1) (No. 4), a = 8.0310(2) A, b = 10.2475(3) A, c = 10.570(3) A, beta = 109.651(1) degrees, V = 819.24(3) A(3), Z = 2.     

Synthesis, crystal structure, and solid-state NMR spectroscopy of a new open-framework aluminophosphate (NH(4))(2)Al(4)(PO(4))(4)(HPO(4))xH(2)O

A new three-dimensional open-framework aluminophosphate (NH(4))(2)Al(4)(PO(4))(4)(HPO(4)).H(2)O (denoted AlPO-CJ19) with an Al/P ratio of 4/5 has been synthesized, using pyridine as the solvent and 2-aminopyridine as the structure-directing agent, under solvothermal conditions. The structure was determined by single-crystal X-ray diffraction and further characterized by solid-state NMR techniques. The alternation of the Al-centered polyhedra (including AlO(4), AlO(5), and AlO(6)) and the P-centered tetrahedra (including PO(4) and PO(3)OH) results in an interrupted open-framework structure with an eight-membered ring channel along the [100] direction. This is the first aluminophosphate containing three kinds of Al coordinations (AlO(4), AlO(5), and AlO(6)) with all oxygen vertexes connected to framework P atoms. (27)Al MAS NMR, (31)P MAS NMR, and (1)H --> (31)P CPMAS NMR characterizations show that the solid-state NMR techniques are an effective complement to XRD analysis for structure elucidation. Furthermore, all of the possible coordinations of Al and P in the aluminophosphates with an Al/P ratio of 4/5 are summarized. Crystal data: (NH(4))(2)Al(4)(PO(4))(4)(HPO(4))xH(2)O, monoclinic P2(1) (No. 4), a = 5.0568(3) A, b = 21.6211(18) A, c = 8.1724(4) A, beta = 91.361(4) degrees , V = 893.27(10) A(3), Z = 2, R(1) = 0.0456 (I > 2 sigma(I)), and wR(2) = 0.1051 (all data).     

Uranyl heteropolyoxometalate: synthesis, structure, and spectroscopic properties

A novel uranium heteropolyoxometalate, [H(3)O](4)[Ni(H(2)O)(3)](4){Ni[(UO(2))(PO(3)C(6)H(4)CO(2))](3)(PO(4)H)}(4)·2.72H(2)O, has been prepared under mild hydrothermal conditions using the diethyl(2-ethoxycarbonylphenyl)phosphonate ligand and in situ ligand synthesis of the HPO(4)(2-) anion. The cluster is derived from a common UO(7), pentagonal bipyramid and is constructed by employing nickel(II) metal ions as linkers. The 3d-5f heteropolyoxometalate core incorporates 12 classical pentagonal uranyl groups and four Ni(2+) octahedral units.     

Pentasubstituted ferrocene and dirhodium(II) tetracarboxylate as building blocks for discrete fullerene-like and extended supramolecular structures

The synthesis of a penta(1-methylpyrazole)ferrocenyl phosphine oxide ligand (1) [Fe(C(5)(C(3)H(2)N(2)CH(3))(5))(C(5)H(4)PO(t-C(4)H(9))(2))] is reported together with its X-ray crystal structure. Its self-assembly behavior with a dirhodium(II) tetraoctanoate linker (2) [Rh(2)(O(2)CC(7)H(15))(4)] was investigated for construction of fullerene-like assemblies of composition [(ligand)(12)(linker)(30)]. Reaction between 1 and 2 in acetonitrile resulted in the formation of a light purple precipitate (3). Evidence for the ligand-to-linker ratio of 1:2.5 expected for a fullerene-like structure [Fe(C(5)(C(3)H(2)N(2)CH(3))(5))(C(5)H(4)PO(t-C(4)H(9))(2))](12)[Rh(2)(O(2)CC(7)H(15))(4)](30) was obtained from (1)H NMR and elemental analysis. IR and Raman studies confirmed the diaxially bound coordination environment of the dirhodium linker by comparing the stretching frequencies of the carboxylate group and the rhodium-rhodium bond with those in model compound (5), [Rh(2)(O(2)CC(7)H(15))(4)](C(3)H(3)N(2)CH(3))(2), the bis-adduct of linker 2 with 1-methylpyrazole. X-ray powder diffraction and molecular modeling studies provide additional support for the formation of a spherical molecule topologically identical to fullerene with a diameter of approximately 38 ? and a molecular formula of [(1)(12)(2)(30)]. Dissolution of 3 in tetrahydrofuran (THF) followed by layering with acetonitrile afforded purple crystals of [(1)(2)(2)](∞) (6) [Fe(C(5)(C(3)H(2)N(2)CH(3))(5))(C(5)H(4)PO(t-C(4)H(9))(2))][Rh(2)(O(2)CC(7)H(15))(4)](2) with a two-dimensional polymeric structure determined by X-ray crystallography. The dirhodium linkers link ferrocenyl units by coordination to the pyrazoles but only four of the five pyrazole moieties of the pentapyrazole ligand are coordinated. The ligand-to-linker ratio of 1:2 in 6 was confirmed by (1)H NMR spectroscopy and elemental analysis, while results from IR and Raman are in agreement with the diaxially coordinated environment of the linker observed in the solid state.     

Novel zinc phosphate topologies defined by organic ligands

Six new zinc phosphates [C18H20N4][Zn4(HPO4)4(H2PO4)2(C18H18N4)3].2H2O (1), [Zn4(HPO4)4(C18H18N4)3].4H2O (2), [Zn3(HPO4)3(H2PO4)(C22H22N8)0.5(C22H24N8)0.5] (3), [Zn2(HPO4)2(C18H16N4)] (4), [Zn(HPO4)(C18H14N2)] (5), and [Zn2(HPO4)2(C12H10N4)] (6) have been synthesized under mild hydrothermal conditions in the presence of 1,4-bis(N-benzimidazolyl)butane (L1), 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene (L2), 1,4-bis(imidazol-1-ylmethyl)naphthalene (L3), 9-(imidazol-1-ylmethyl)anthracene (L4), and 1,4-bis(1-imidazolyl)benzene (L5), respectively, and their structures were determined by X-ray crystallography. Compound 1 exhibits a unique inorganic motif of isolated 8-rings interconnected by L1. Compound 2, also formed from L1, contains a previously unobserved chain structure composed of edge-sharing 4-rings and 8-rings. Compound 3, prepared from L2, possesses an unusual one-dimensional framework, which is composed of vertex-sharing 4-rings and triple fused 4-rings. The inorganic portions of 4, 5, and 6 each adopt a layer structure. The sheets in 4 and 5 have a 4.8(2) topology, and in 6, a 6(3) topology is observed. The zinc atoms in compounds 1-6 are all tetrahedrally coordinated by a combination of phosphate groups and organic ligands. Potential relationships between the inorganic motifs reported in the present study are identified. These are indicative of a possible pattern of self-assembly of zinc and phosphorus tetrahedra and indicative of the role of the organic ligands in the formation of hybrid structures.     

Solid-state (14)N MAS NMR of ammonium ions as a spy to structural insights for ammonium salts

The high resolution offered by magic-angle spinning (MAS), when compared to the static condition in solid-state NMR of powders, has been used to full advantage in a (14)N MAS NMR study of some ammonium salts: CH(3)NH(3)Cl, (NH(4))(2)(COO)(2) x H(2)O, (CH(3))(3)(C(6)H(5)CH(2))NCl, (CH(3))(3)(C(6)H(5))NI, [(n-C(4)H(9))(4)N](2)Mo(2)O(7), (NH(4))(2)HPO(4), and NH(4)H(2)PO(4). It is shown that the high-quality (14)N MAS NMR spectra, which can be obtained for these salts, allow determination of the (14)N quadrupole coupling parameters, i.e. C(Q) (the quadrupole coupling constant) and eta(Q) (the asymmetry parameter), with very high precision. In particular, it is shown that precise C(Q), eta(Q) parameters can be determined for at least two different (14)N sites in case the individual spinning-sideband (ssb) intensities arise from a single manifold of ssbs, i.e. the ssbs for the two sites cannot be resolved. This feature of (14)N MAS NMR, which is the first demonstration for manifolds of ssb in MAS NMR without the potential information from a central transition, becomes especially useful at the slow spinning frequencies (nu(r) = 1000-1500 Hz) applied to some of the ammonium salts studied here. The detection of the number of sites has been confirmed by the corresponding crystal structures determined from single-crystal X-ray diffraction (XRD), either in this work for the unknown structure of benzyl trimethylammonium chloride or from reports in the literature. The magnitudes of the (14)N quadrupole coupling constants for the ammonium salts studied here are in the range from C(Q) approximately 20 kHz to 1 MHz while the asymmetry parameters span the full range 0 < or = eta(Q) < or = 1. Clearly, the (14)N quadrupole coupling parameters (C(Q), eta(Q)) for ammonium ions appear highly sensitive toward crystal structure and therefore appreciably more informative for the characterization of ammonium salts in comparison to the isotropic (14)N (or (15)N) chemical shifts.     

{Zn3(Et2O)2[(EtO)PO2(C6H5NH)]6.2THF}: a trinuclear zinc amidophosphate with an hourglass structure

The reaction of ZnMe2 and the N-substituted phosphoramidic monoester [Et2NH2][(EtO)PO2(C6H5NH)] produces the trinuclear zinc cluster Zn(3)(Et2O)2[(EtO)PO2(C6H5NH)]6.2THF, demonstrating that the P-N bond can survive under mild solvothermal reaction conditions.     

New amine-templated zinc phosphates with a temperature-induced increase of structural dimensionality

Three new amine-templated zinc phosphates, [C4N2H14][Zn(HPO4)2].H2O, AU-I, [C4N2H14][Zn2(H(0.5)PO4)2(H2PO4)], AU-II, and [C4N2H14][Zn5(H2O)(PO4)4], AU-III, are prepared by hydrothermal synthesis using an organic amine, N,N'-dimethylethylendiamine CH3NHCH2CH2NHCH3, as structure-directing agent. The three materials are prepared from the same reaction mixture, 1Zn(CH3CO2)2:3.05H3PO4:2.25CH3NHCH2CH2NHCH3:138H2O (pH = 5.1), AU-I at RT, AU-II at 60 degrees C, and AU-III at 170 degrees C. The materials are built from corner-sharing ZnO4 and PO4 tetrahedra forming chains, layers, or framework structures for AU-I to III, respectively, and are linked together by hydrogen bonds via the diprotonated amine ions. The complete hydrogen-bond scheme is resolved for these new compounds and reveals some interesting phenomena, for example, a hydrogen shared between two phosphate groups in AU-II, thereby forming H(0.5)PO4 groups. Furthermore, the water molecules are different; that is, in AU-I they act as hydrogen-bond donor and acceptor, whereas they act as ligand in AU-III with coordination to Zn. The structures of the compounds are determined by single-crystal X-ray diffraction analysis. AU-I, [C4N2H14][Zn(HPO4)2].H2O, crystallizes in the triclinic space group P-1, a = 8.215(2), b = 8.810(3), c = 8.861(3) A, alpha = 88.001(4) degrees , beta = 89.818(5) degrees , and gamma = 89.773(5) degrees , Z = 2. AU-II, [C4N2H14][Zn2(H(0.5)PO4)2(H2PO4)], is monoclinic, P2/n, a = 11.7877(4), b = 5.2093(2), c = 12.2031(4) A, beta = 98.198(1) degrees , Z = 2. AU-III, [C4N2H14][Zn5(H2O)(PO4)4], crystallizes in the orthorhombic space group Pna2(1) with lattice parameters, a = 20.723(2), b = 5.2095(6), c = 17.874(2) A, Z = 4. The phase stability investigated by systematic hydrothermal synthesis is presented, and the materials are further characterized by 31P solid-state MAS NMR, for example, by determination of 31P chemical shift anisotropies for AU-III, while the thermal behavior is investigated by thermogravimetry (TG).     

Five new zinc phosphite structures: tertiary building blocks in the construction of hybrid materials

The syntheses and structures of five new zinc phosphites [Zn(HPO(3))(C(4)H(6)N(2))] (1), [Zn(2)(HPO(3))(2)(C(10)H(10)N(2))(2)](2) (2), [Zn(HPO(3))(C(14)H(14)N(4))(0.5)] (3), [Zn(2)(HPO(3))(2)(C(14)H(14)N(4))].0.4H(2)O (4), and [Zn(2)(HPO(3))(2)(C(14)H(14)N(4))] (5) are reported. In compounds 1-3, the zinc atoms are ligated by 1-methylimidazole, 1-benzylimidazole, and 1,4-bis(imidazol-1-ylmethyl)benzene, respectively, while compounds 4 and 5 are synthesized in the presence of the same bifunctional ligand, 1,3-bis(imidazol-1-ylmethyl)benzene. The inorganic framework of compound 1 is composed of vertex-shared ZnO(3)N and HPO(3) tetrahedra that form 4-rings, which, in turn, are linked to generate a one-dimensional ladder structure. In 2, the inorganic framework is composed of 4-rings and 8-rings to form the well-known 4.8(2) 2D network. This is connected via C-H...pi interactions between 1-benzylimidazole ligand to generate a pseudo-pillared-layer structure. In 3, the inorganic framework again has the 4.8(2) topology pillared by the bis(imidazole) ligand, 1,3-bis(imidazol-1-ylmethyl)benzene. In 4, a new layer pattern is observed. Specifically, three edge-sharing 4-rings form triple-fused 4-rings. These tertiary building units are further connected to form 12-rings. The alternating triple 4-rings and 12-rings form a previously unknown 2D inorganic sheet. The sheets are joined together by the bis(imidazole) ligand, 1,3-bis(imidazol-1-ylmethyl)benzene, to generate a 3D pillared-layer structure. In 4, benzene rings and imidazole rings stack in a zigzag pattern in the interlayer space. A significant role for the triple 4-ring tertiary building unit in the formation of hybrid inorganic/organic metal phosphite structures is proposed for 4 and 5. In 5, the triple 4-rings fuse to give a 1D stair-step structure. Calculations show that the triple 4-ring pattern observed in the linear ladder structure of 1 is more stable than that in the stair step pattern of 5.     

A novel organic-inorganic hybrid based on an 8-electron-reduced Keggin polymolybdate capped by tetrahedral, trigonal bipyramidal, and octahedral zinc: synthesis and crystal structure of (CH3NH3)(H2bipy)[Zn4(bipy)3(H2O)2MoV8MoVI4O36)(PO4)].4H2O

Hydrothermal reaction of H(3)PO(3), CH(3)NH(2), zinc(II) acetate, 4,4'-bipyridine (bipy), and (NH(4))(6)Mo(7)O(24).4H(2)O at 180 degrees C led to a novel organic-inorganic layered hybrid, [CH(3)NH(3)][H(2)bipy][Zn(4)(bipy)(3)(H(2)O)(2)Mo(V)(8)Mo(VI)O(36)(PO(4))].4H(2)O (1). Its structure was established by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P2(1)/c with cell parameters of a = 17.3032(2), b = 17.8113(3), and c = 23.4597 (4) A, beta = 106.410(1) degrees, V = 6935.6(2) A(3), and Z = 4. The structure of compound 1 features a novel 2D layer built from the 8e-reduced tetracapped Keggin [Zn(4)Mo(12)O(36)(PO(4))](3)(-) anions, which are further interconnected by bridging bipy ligands. The four zinc(II) ions are in tetrahedral, trigonal bipyramidal, and octahedral coordination geometries, respectively.     

Formation of one-, two-, and three-dimensional open-framework zinc phosphates in the presence of a tetramine

Five new open-framework zinc phosphates, encompassing the entire hierarchy of open-framework structures, have been synthesized hydrothermally in the presence of triethylenetetramine. The structures include one-dimensional ladders, two-dimensional layers, and three-dimensional structures as well as a zinc phosphate where the amine acts as a ligand. [C6N4H22]0.5[Zn(HPO4)2] (I): monoclinic, space group P2(1)/c (no. 14), a = 5.2677(1) A, b = 13.3025(1) A, c = 14.7833(1) A, beta = 96.049 degrees, Z = 4. [C6N4H22]0.5[Zn2(HPO4)3] (II): triclinic, space group P1 (no. 2), a = 7.515(1) A, b = 8.2553(1) A, c = 12.911(1) A, alpha = 98.654(1) degrees, beta = 101.274(1) degrees, gamma = 115.791(1) degrees, Z = 2. [C6N4H22]0.5[Zn2P2O8] (III): triclinic, space group P1 (no. 2), a = 8.064(1) A, b = 8.457(1) A, c = 9.023(1) A, alpha = 111.9(1) degrees, beta = 108.0(1) degrees, gamma = 103.6(1) degrees, Z = 2. [C6N4H22]0.5[Zn3(PO4)2(HPO4)] (IV): triclinic, space group P1 (no. 2), a = 5.218(1) A, b = 8.780(1) A, c = 16.081(1) A, alpha = 89.3(1) degrees, beta = 83.5(1) degrees, gamma = 74.3(1) degrees, Z = 2. [C6N4H20]0.5[Zn4P4O16] (V): monoclinic, space group P2(1)/c (no. 14), a = 9.219(1) A, b = 15.239(1) A, c = 10.227(1) A, beta = 105.2(1), Z = 4. The structure of I is composed of ZnO4 and HPO4 tetrahedra, which are edge-shared to form four-membered rings, which, in turn, form a one-dimensional chain (ladder). In II, these ladders are fused into a layer. The structures of III and IV comprise networks of ZnO4 and PO4 tetrahedra forming three-dimensional architectures. In V, the amine molecule coordinates to the Zn and acts as a pillar supporting the zinc phosphate layers, which possess infinite Zn-O-Zn linkages. The 16-membered one-dimensional channel in IV and the ZnO3N pillar, along with infinite Zn-O-Zn linkages in V, are novel features. The structure of the open-framework zinc phosphates is found to depend sensitively on the relative concentrations of the amine and phosphoric acid, with high concentrations of the latter favoring structures with lower dimensions.     

Syntheses, characterizations and properties of [Mo2O2S2]-based oxothiomolybdenum wheels incorporating bisphosphonate ligands

We report the syntheses and characterizations of the first polyoxothiometalate complexes isolated from the reaction of the oxothiocationic [Mo(V)(2)O(2)S(2)](2+) precursor and bisphosphonate ligands H(2)O(3)PCR(OH)PO(3)H(2) (R = C(4)H(5)N(2), zoledronic acid; R = C(3)H(6)NH(2), alendronic acid). [(Mo(2)O(2)S(2)(H(2)O))(4)(O(3)PC(O)(C(4)H(6)N(2))PO(3))(4)](8-) (Mo(8)S(8)(Zol)(4)) and [(Mo(2)O(2)S(2)(H(2)O))(4)(O(3)PC(O)(C(3)H(6)NH(3))PO(3))(4)](8-) (Mo(8)S(8)(Ale)(4)) contain four Mo(V) dimers connected via bisphosphonate ligands. These compounds offer a unique opportunity to compare the structures and properties of cyclic compounds obtained with [Mo(2)O(2)S(2)](2+) and with [Mo(2)O(4)](2+). The oxothio compounds appear less stable in solution than the oxo analogue, confirming the higher lability and versatility of [Mo(2)O(2)S(2)]-based compounds compared to [Mo(2)O(4)]-based POMs. Multinuclear and multidimensional solid-state NMR studies were carried out to complement X-ray diffraction analysis. Information on short-range interactions, dynamic behaviors, and local disorder within the crystalline materials are therefore reported. Furthermore, the electrocatalytic properties of Mo(8)S(8)(Ale)(4) and of the analogous [(Mo(2)O(4)(H(2)O))(4)(O(3)PC(O)(C(3)H(6)NH(3))PO(3))(4)](8-) (Mo(8)O(8)(Ale)(4)) immobilized onto the surface of a glassy carbon electrode were studied, thus evidencing the ability of [Mo(2)O(2)S(2)]-based cycles to promote the reduction of protons into hydrogen, whereas the oxo analogue appeared inactive.     

Octahedral Ru(II) amido complexes TpRu(L)(L')(NHR) (Tp = hydridotris(pyrazolyl)borate; L = L' = P(OMe)3 or PMe3 or L = CO and L' = PPh3; R = H,Ph, or tBu): synthesis,characterization, and reactions with weakly acidic C-H bonds

The octahedral Ru(II) amine complexes [TpRu(L)(L')(NH(2)R)][OTf] (L = L' = PMe(3), P(OMe)(3) or L = CO and L' = PPh(3); R = H or (t)Bu) have been synthesized and characterized. Deprotonation of the amine complexes [TpRu(L)(L')(NH(3))][OTf] or [TpRu(PMe(3))(2)(NH(2)(t)Bu)][OTf] yields the Ru(II) amido complexes TpRu(L)(L')(NH(2)) and TpRu(PMe(3))(2)(NH(t)Bu). Reactions of the parent amido complexes or TpRu(PMe(3))(2)(NH(t)Bu) with phenylacetylene at room temperature result in immediate deprotonation to form ruthenium-amine/phenylacetylide ion pairs, and heating a benzene solution of the [TpRu(PMe(3))(2)(NH(2)(t)Bu)][PhC(2)] ion pair results in the formation of the Ru(II) phenylacetylide complex TpRu(PMe(3))(2)(C[triple bond]CPh) in >90% yield. The observation that [TpRu(PMe(3))(2)(NH(2)(t)Bu)][PhC(2)] converts to the Ru(II) acetylide with good yield while heating the ion pairs [TpRu(L)(L')(NH(3))][PhC(2)] yields multiple products is attributed to reluctant dissociation of ammonia compared with the (t)butylamine ligand (i.e., different rates for acetylide/amine exchange). These results are consistent with ligand exchange reactions of Ru(II) amine complexes [TpRu(PMe(3))(2)(NH(2)R)][OTf] (R = H or (t)Bu) with acetonitrile. The previously reported phenyl amido complexes TpRuL(2)(NHPh) [L = PMe(3) or P(OMe)(3)] react with 10 equiv of phenylacetylene at elevated temperature to produce Ru(II) acetylide complexes TpRuL(2)(C[triple bond]CPh) in quantitative yields. Kinetic studies indicate that the reaction of TpRu(PMe(3))(2)(NHPh) with phenylacetylene occurs via a pathway that involves TpRu(PMe(3))(2)(OTf) or [TpRu(PMe(3))(2)(NH(2)Ph)][OTf] as catalyst. Reactions of 1,4-cyclohexadiene with the Ru(II) amido complexes TpRu(L)(L')(NH(2)) (L = L' = PMe(3) or L = CO and L' = PPh(3)) or TpRu(PMe(3))(2)(NH(t)Bu) at elevated temperatures result in the formation of benzene and Ru hydride complexes. TpRu(PMe(3))(2)(H), [Tp(PMe(3))(2)Ru[double bond]C[double bond]C(H)Ph][OTf], [Tp(PMe(3))(2)Ru=C(CH(2)Ph)[N(H)Ph]][OTf], and [TpRu(PMe(3))(3)][OTf] have been independently prepared and characterized. Results from solid-state X-ray diffraction studies of the complexes [TpRu(CO)(PPh(3))(NH(3))][OTf], [TpRu(PMe(3))(2)(NH(3))][OTf], and TpRu(CO)(PPh(3))(C[triple bond]CPh) are reported.     

Molecular properties of adsorbates that affect the growth kinetics of archerite (KDP)

We explore the molecular properties of adsorbates that dramatically affect growth kinetics and morphology of the [100] face of archerite, also known as potassium dihydrogen phosphate (KH(2)PO(4) or KDP). Aqueous complexes of Al(III), Fe(III), and Cr(III) are known to affect KDP growth, albeit the actual step-pinning complex(es) is unknown. Using in situ atomic force microscopy (AFM), we measured changes in the growth rates of the [100] face of KDP with supersaturation in the presence of trace amounts of [Co(NH(3))(6)](3+), [Fe(CN)(6)](3-), eta(1)-[Co(NH(3))(5)HPO(4)](+), eta(2)-[Co(NH(3))(4)HPO(4)](+), eta(2)-[Co(NH(3))(4)P(2)O(7)H(2)](+), and [Rh(H(2)PO(4))(2)(H(2)O)(4)](+). Unlike in experiments using trivalent-metals, these complexes do not change stoichiometry or structure on the timescale of step motion, so that the actual molecular interactions that affect growth can be studied. Step velocity and morphology on the [100] face are unaffected by outer-sphere coordination complexes of either charge. Surprisingly, inner-sphere phosphatoammine complexes do not affect growth rates regardless of how the phosphate group is coordinated to the metal. However, doping the growth solution with [Rh(H(2)PO(4))(2)(H(2)O)(4)](+) results in profound step pinning, matching the behavior of KDP surfaces grown in the presence of Rh(III) after an equilibration period. Not only is an inner-sphere phosphate group needed to dock a trivalent metal to the step edge, but compatible hydrogen bonding of the remainder of the inner-sphere ligands with the bulk lattice is also essential.     

N-methylmonothiocarbamatopentamminecobalt(III): restricted C-N bond rotation and the acid-catalyzed O- to S-bonded rearrangement

High-resolution (1)H and (13)C NMR studies on the linkage isomers [(NH(3))(5)CoOC(S)NHCH(3)](2+) and [(NH(3))(5)CoSC(O)NHCH(3)](2+) reveal that the O-bonded form exists as a 5:1 mixture of Z and E isomers arising from restricted rotation about the C-N bond. Similarly, restricted rotation is observed (at 20 degrees C) for the S-bonded isomer (Z/E ca. 18:1), but not for the isoelectronic carbamate ion [(NH(3))(5)CoOC(O)NHCH(3)](2+), nor for the unsubstituted carbamato complex [(NH(3))(5)CoOC(O)NH(2)](2+). An analysis of the variable-temperature NMR data for the O-bonded carbamato and urea complexes has provided quantitative data on the rotational barriers, and these ions involve much faster C-N bond rotations than the thiocarbamato complexes. The acid-catalyzed reaction of [(NH(3))(5)CoOC(S)NHCH(3)](2+) is confirmed, but there is much less parallel hydrolysis (ca. 2%) than previously reported (40 +/- 10%) for 0.1 M HClO(4). In 1 M HClO(4), [(NH(3))(5)CoSC(O)NHCH(3)](2+) and [(NH(3))(5)CoOH(2)](3+) are formed in parallel as an 83:17 mixture. The kinetic data suggest that the protonated form is at least 20-fold more reactive than the free ion and that the linkage isomerization and hydrolysis pathways are both acid-catalyzed, the latter clearly more so than the rearrangement.