Robert J. Doedens

[M3V18O42(H2O)12(XO4)]⋅24 H2O (M=Fe, Co; X=V, S): Metal Oxide Based Framework Materials Composed of Polyoxovanadate Clusters

New framework materials composed of well-defined vanadium oxide clusters were prepared by low-temperature reactions and characterized by X-ray crystal structure analysis. The structures of these solids contain {V18 O42 } cages linked into two interpenetrating three-dimensional networks by bridging {M(H2 O)4 } groups (M=FeII , CoII ; see picture).

Novel water clusters in the crystalline state: structures of a symmetrical, cyclic hexamer and an 'opened-cube' octamer.

Six- and eight-membered hydrogen-bonded water clusters of novel structure types have been found in crystalline hydrates.

Synthesis of the (N2)3− Radical from Y2+ and Its Protonolysis Reactivity To Form (N2H2)2− via the Y[N(SiMe3)2]3/KC8 Reduction System

Examination of the Y[N(SiMe(3))(2)](3)/KC(8) reduction system that allowed isolation of the (N(2))(3-) radical has led to the first evidence of Y(2+) in solution. The deep-blue solutions obtained from Y[N(SiMe(3))(2)](3) and KC(8) in THF at -35 °C under argon have EPR spectra containing a doublet at g(iso) = 1.976 with a 110 G hyperfine coupling constant. The solutions react with N(2) to generate (N(2))(2-) and (N(2))(3-) complexes {[(Me(3)Si)(2)N](2)(THF)Y}(2)(μ-η(2):η(2)-N(2)) (1) and {[(Me(3)Si)(2)N](2)(THF)Y}(2)(μ-η(2):η(2)-N(2))[K(THF)(6)] (2), respectively, and demonstrate that the Y[N(SiMe(3))(2)](3)/KC(8) reaction can proceed through an Y(2+) intermediate. The reactivity of (N(2))(3-) radical with proton sources was probed for the first time for comparison with the (N(2))(2-) and (N(2))(4-) chemistry. Complex 2 reacts with [Et(3)NH][BPh(4)] to form {[(Me(3)Si)(2)N](2)(THF)Y}(2)(μ-N(2)H(2)), the first lanthanide (N(2)H(2))(2-) complex derived from dinitrogen, as well as 1 as a byproduct, consistent with radical disproportionation reactivity.

The Trivalent Neodymium Complex [(C5Me5)3Nd] Is a One-Electron Reductant!

A Se22- complex, Ph3 P, and (C5 Me5 )2 are formed in the reduction of Se=PPh3 by the NdIII complex [(C5 Me5 )3 Nd] [Eq. (a)]. The latter is thus reminiscent of [(C5 Me5 )3 Sm], which, however, appears to be a stronger reductant than [(C5 Me5 )3 Nd]. This suggests that the reductive reactivity of [(C5 Me5 )3 Ln] complexes can be tuned by varying the size of the metal atom.

Hydrothermal synthesis and characterization of a new vanadyl sulfate compound: crystal structure of [V(IV)OSO4(H2O)4]·SO4·[H2N(C2H4)2NH2]

Abstract The hydrothermal reaction of a mixture of vanadylacetylacetonate-VO(acac) 2 , Na 2 SO 4 , piperazine, and diluted H 2 SO 4 at 160°C gives a blue colored solution which yields rectangular blue crystals of [V(IV)OSO 4 (H 2 O) 4 ]·SO 4 ·[H 2 N(C 2 H 4 ) 2 NH 2 ] ( 1 ) in a 60% yield. Complex 1 is a new organic–inorganic compound: a vanadyl sulfate cocrystallized with organic species. The structure of 1 consists of layers of [V(IV)OSO 4 (H 2 O) 4 ] separated by SO 4  2− and doubly protonated piperazine cations [H 2 N(C 2 H 4 ) 2 NH 2 ] 2+ which are hydrogen bonded with each other. Crystal data for 1 : monoclinic, space group P 2 1 / c (no. 14), a =17.1502(10), b =7.2860(4), c =12.4448(7) A, β =107.058(10)°, V =1486.7(2) A 3 , Z =4. The structure was solved by direct methods and least-squares refinement converged at R =0.0305.

Hydrothermal synthesis and characterization of mixed-valence hexatungstates: crystal structures of [(C2H5)4N]3[WVW5VIO19]·0.5H2O and [H3N(CH2)2NH3]2 [WVW5VIO19]·[H2N(CH2)2NH2]Cl·8H2O

Abstract The hydrothermal reaction of a mixture of Na 2 WO 4 ·2H 2 O, MoO 3 , Mo, Et 4 NCl, and H 2 O at 160°C gives bluish-purple crystals of [(C 2 H 5 ) 4 N ] 3 [W V W 5 VI O 19 ] · 0.5H 2 O ( 1 ) in 60% yield. Under analogous reaction conditions, a mixture of Na 2 WO 4 · 2H 2 O, V, H 2 N(CH 2 ) 2 NH 2 ·2HCl, and H 2 O yields brown crystals of [H 3 N(CH 2 ) 2 NH 3 ] 2 [W V W 5 VI O 19 ] · [H 2 N(CH 2 ) 2 NH 2 ]Cl·8H 2 O ( 2 ). 1 and 2 are the first one-electron reduced mixed valence hexatungstatesto be crystallized and fully characterized. The crystal structures of 1 and 2 consist of discrete [W 6 O 19 ] 3− anions, cations, and water molecules of crystallization. Crystal data. 1 : Orthorhombic space group Pbcn (No. 60). a = 19.063(4), b = 22.257(5), c = 19.631(4) A , V = 8329(3) A 3 , Z = 8 . A total of 6617 reflections (2 θ max = 45°) were collected, of which 4434 unique reflections with F 0 > 4 σ ( F 0 ) were used for structural elucidation. The structure was solved by direct methods and least-squares refinement converged at R = 0.0834. 2 : Monoclinic, space group, C 2/ m (No. 12), a = 15.7339(10), b = 11.497(9), c = 9.0934(5) A , β = 100.855 (4)°, V = 1615.5(2) A 3 , Z = 2 . A total of 2473 reflections (2 θ max = 30°) were collected. The structure was solved by direct methods and least-squares refinement converged at R = 0.0600.

Synthesis and structure of mono-THF solvates of bis(cyclopentadienyl)samarium(II) complexes: (C5Me5)2 Sm(THF) and [C5H2(SiMe 3)3][C5H3(SiMe3)2]Sm(THF)

Abstract X-ray crystallographic data have been obtained on the mono-THF solvates of the organosamarium(II) complexes (C5Me5)2Sm(THF) and [C5H2(SiMe3)3][C5H3)(SiMe3)2]Sm(THF). (C5Me5)2]Sm(THF). (C5Me5)2Sm(THF) crystallizes from toluene in space group P21/n with a = 9.7606(13), b = 16.6557(17), c = 14.0710(16) A, β = 90.446(10)°, V = 2287.4(5) A3 and Dcalcd = 1.431 g cm−3 for Z = 4. Least-squares refinement of the model based on 2879 reflections converged to a final RF = 3.1%. {[C5H2(SiMe3)3][C5H3(SiMe3)2]-Sm(THF)}(C6H12)0.5 crystallizes from hexane in space group P 1 with a = 9.3600(17), b = 11.0311(21), c = 20.4697(33) A, α = 83.290(14), β = 80.569 (14), γ = 88.785(15)°, V = 2071.2(6) A3 and Dcalcd = 1.225 g cm−3 for Z = 2. Least-squares refinement of the model based on 5988 reflections converged to a final RF = 3.1%. In these bent metallocenes, the THF oxygen atoms do not adopt the sterically least crowded positions and lie off the plane defined by the two ring centroids and the samarium by 1.54 A for (C5Me5)2Sm(THF) and by 0.85 A for [C5H2(SiMe3)3][C5H3(SiMe3)2]Sm(THF).

Metallation of azobenzenes by fluorine-abstraction: structure of a ruthenium complex containing nonafluoro(phenylazo)phenyl-2C,N′ and diphenyl-2-(η-cyclopentadienylphenyl)phosphine groups

The formation of metallated azobenzene derivatives by fluorine-abstraction reactions using nucleophilic transition metal reagents has been achieved; the structure of an ortho-metallated complex, derived from decafluoroazobenzene and also containing a Ph2P(C6H4C5H4) ligand is described.

Framework materials containing polyoxovanadates as building units: synthesis and characterization of (N2H5)2[M3(H2O)12V18O42(EO4)]·24H2O (M = Mg, Ca) and Li6[Mn3(H2O)12V18O42(EO4)]·24H2O (E = V, S)

Abstract The reaction of an aqueous solution of lithium vanadate with hydrazinium sulfate results in a dark-colored solution that reacts with magnesium sulfate heptahydrate, calcium sulfate dihydrate, and manganese(II) chloride tetrahydrate to yield single crystals of (N2H5)2[M3(H2O)12V18O42(EO4)]·24H2O (M = Mg, Ca) and Li6[Mn3(H2O)12V18O42(EO4)]·24H2O (E = V, S), respectively. The crystal structures of the new solids consist of interpenetrating three-dimensional networks of {V18O42(EO4)} clusters interlinked via bridging {M(H2O)4} (M = Mg, Ca, Mn) groups. The voids in these structures are occupied by lattice water and ion exchangeable cations.

[M3V18O42(H2O)12(XO4)]⋅24 H2O (M = Fe, Co; X = V, S): auf Metalloxiden basierende Gerüste aus Polyoxovanadatclustern

Neue Gerustmaterialien, die aus wohldefinierten Vanadiumoxidclustern bestehen, wurden durch Niedertemperatursynthesen hergestellt und rontgenographisch charakterisiert. In den Strukturen dieser Feststoffe sind {V18O42}-Kafige vorhanden, die uber {M(H2O)4}-Brucken (M = FeII, CoII) zu zwei sich gegenseitig durchdringenden dreidimensionalen Netzen verknupft sind (siehe Bild).