Marcus L. Cole

Selective reductions with stable indium trihydride reagents

The carbene and tertiary phosphine adducts of indane, [InH3{CN(Mes)C2H2N(Mes)}] and [InH3{P(C6H11)3}] (Mes=2,4,6-trimethylphenyl), have been used to reduce unsaturated organic functionalities. The success and selectivity of these reductions relative to those carried out with lighter group 13 hydride complexes is discussed.

Reactions of a carbene stabilised indium trihydride complex, [InH3{CN(Mes)C2H2N(Mes)}] Mes = mesityl, with transition metal complexes

The reactivity of the carbene stabilised indium trihydride complex, [InH3(IMes)] IMes = 1,3-dimesitylimidazol-2-ylidene, toward a variety of transition metal complexes has been investigated. The study has shown that the InH3 complex can act as a carbene and/or hydride transfer reagent to transition metal centres but does not yield heterobimetallic materials. Two new complexes, [Cp2Ti(μ-Cl)2Zn(IMes)Cl] and [CpNi(H)(IMes)], have resulted from this work, both of which have been spectroscopically and structurally characterised.

Lithium and magnesium complexes of ortho-dimethylarsinoaniline and a novel insertion of dimethylsilanone into an Mg–N bond—molecular structures of [{Li(μ2:η1-NHC6H4AsMe2)(thf)2}2] and the insertion product [{Mg2(μ2:η1-NHC6H4AsMe2)2(μ3:η3-OSiMe2NC6H4AsMe2)(thf)}2]

Treatment of ortho-dimethylarsinoaniline (NASH2) with 1.0 equivalents of LiBut or 0.5 equivalents of MgBu2 in tetrahydrofuran affords the complexes [{Li(NASH)(thf)2}2] n(1) and [Mg(NASH)2(thf)1.5] n(2) n(NASHu2006=u2006NHC6H4AsMe2-2). Both complexes have been characterised spectroscopically. The crystal structure determination of 1 reveals a centrosymmetric dimeric structure with an Li2N2 central unit that does not exhibit arsino–lithium donor interactions. Compound 2 reacts with dimethylsilicone grease to yield the unexpected complex [{Mg2(μ2:η1-NHC6H4AsMe2)2(μ3:η3-OSiMe2NC6H4AsMe2)(thf)}2] n(3), via nthe novel and unprecedented insertion of a dimethylsilanone fragment into an Mg–N bond. Compound 3 is tetranuclear with a 12-membered Mg4N6O2 double stacked cube centre that has Mg atoms residing at alternate corners of each cube. The arsino functionalities of the modified η3-bound ligands co-ordinate to Mg atoms on the vertices.

Birchite, a new mineral from Broken Hill, New South Wales, Australia: description and structure refinement

Abstract The new mineral species birchite, idealized formula Cd2Cu2(PO4)2(SO4)·5H2O, occurs on specimens from the Block 14 Opencut, Broken Hill, New South Wales, Australia, as sprays and aggregates of crystals to 0.75 mm across on a host rock composed of quartz, garnet, galena, chalcopyrite, and fluorapatite. It is a late-stage supergene mineral formed as part of a suite of secondary phosphate minerals under low-temperature conditions. Associated secondary minerals are covellite, cerussite, anglesite, plumbogummite-hinsdalite, pyromorphite, libethenite, and sampleite. Individual crystals are bladed to prismatic and acicular in habit, with a maximum length of 0.3 mm and width of 0.05 mm. The crystals are elongated along [001] and sometimes also flattened on (100). The crystal forms are major {100} and {010}, and minor {101} and {001}. Birchite is orthorhombic, space group Pnma, with unit-cell parameters refined from powder X-ray diffraction data, a = 10.489(6), b = 20.901(7), c = 6.155(5) Å, V = 1349.6(3) Å3, and Z = 4. The eight strongest lines in the diffraction pattern are [d(Å)(I)(hkl)]: 10.451(100)(020); 5.146(28)(111); 4.223(38)(131); 3.484(39)(060); 2.902(70)(260); 2.719(33)(132); 2.652(32)(042); 1.919(80)(432). Birchite is translucent (masses) to transparent (crystals); pale blue with a vitreous luster. Optically, birchite is biaxial positive, with nα = 1.624(4), nβ = 1.636(5), nγ = 1.669(4), and 2Vcalc = +63°. The optical orientation is X = b, Y = a, Z = c; the optical axis plane lies within the {100} plane. Birchite shows very faint pleochroism, X = pale bluish, Z = pale greenish, absorption Z ≥ X. Birchite is brittle, has a conchoidal fracture and is nonfluorescent. Hardness (Mohs) is 3.5-4; the measured density is 3.61(4) g/cm3, and the calculated density is 3.647 g/cm3 (from the empirical formula). Average electron microprobe analysis (wt%): CdO 36.79, CuO 21.22, CaO 0.17, MnO 0.17, ZnO 1.07, P2O5 20.21, SO3 9.70, H2O (from crystal-structure analysis) 12.37, total 101.70. The empirical formula, calculated on the basis of 17 O atoms and with H2O calculated to give 5H2O is (Cu1.94,Zn0.10)Σ2.04(Cd2.09,Ca0.02,Mn0.02)Σ2.13P2.07S0.88O12·5H2O. The crystal structure has been refined to an R index of 4.3% for 846 observed reflections measured with MoKα X-radiation. Alternating [CdO4(H2O)2] octahedra and [CuO3(H2O)2] square-pyramids share edges to form chains that extend along the a axis, which are linked by (PO4) tetrahedra to form [CdCu(PO4)(H2O)2O] sheets in the (010) plane. Two such sheets are linked via (PO4) tetrahedra vertices to form a layer in the (010) plane. Two layers, which are related by mirror symmetry, are linked via (SO4) tetrahedra vertices to form a heteropolyhedral framework structure. Interstitial channels within the framework extend along both the a and c axes and are occupied by a H2O group. The mineral is named for William D. Birch, Senior Curator of Geosciences at Museum Victoria, Australia.

Ether and crown ether adduct complexes of sodium and potassium cyclopentadienide and methylcyclopentadienide—molecular structures of [Na(dme)Cp]∞, [K(dme)0.5Cp]∞, [Na(15-crown-5)Cp], [Na(18-crown-6)CpMe] and the “naked Cp−” complex [K(15-crown-5)2][Cp]

The molecular structure, spectroscopy and mass spectrometry of the following compounds are described: [Na(dme)Cp]∞ (polymeric zigzag chain), [K(dme)0.5Cp]∞ (2-dimensional polymeric zigzag), [Na(15-crown-5)Cp] (monomeric), [Na(18-crown-6)CpMe] (monomeric) and [K(15-crown-5)2][Cp] {K(15-crown-5)2 cation/naked cyclopentadienide anion}. The syntheses of the related species [Na(dme)CpMe], [K(dme)0.5CpMe], [Na(15-crown-5)CpMe], [Na(18-crown-6)Cp] and [K(15-crown-5)2][CpMe] are reported. The choice of coordination modes displayed by those species structurally characterised is discussed, particularly in terms of steric and electrostatic considerations.

Synthesis and characterisation of the first carbene–thallium complexes: molecular structure of [TlCl3{CN(Mes)C2H2N(Mes)}], Mes = C6H2Me3-2,4,6

The reaction of the stable carbenes, :CN(Mes)C2R2N(Mes), Rxa0=xa0H (IMes) or Br (IMesBr), with TlX3, Xxa0=xa0Cl or Br, Mesxa0=xa0mesityl, yields the complexes, [TlX3{CN(Mes)C2R2N(Mes)}], one of which, [TlCl3(IMes)], has been crystallographically characterised and its thermal decomposition studied; further reaction of [TlCl3(IMes)] with one equivalent of :CN(Me)C2Me2N(Me) affords the mixed bis-carbene complex [TlCl3(IMes){CN(Me)C2Me2N(Me)}] which has been characterised spectroscopically.

CCDC 882993: Experimental Crystal Structure Determination

Related Article: Marcus L. Cole, Aaron J. Davies, Cameron Jones, Peter C. Junk, Alasdair I. McKay and Andreas Stasch|2015|Z.Anorg.Allg.Chem.|641|2233|doi:10.1002/zaac.201500556

Phosphine and phosphido indium hydride complexes and their use in inorganic synthesis

Reaction of PR3, Rxa0=xa0cyclohexyl (Cy), cyclopentyl (Cyp) or phenyl, with [InH3(NMe3)] affords the 1∶1 indium trihydride complexes, [InH3(PR3)]. The stabilities and spectroscopic properties of these complexes are described in terms of the phosphine ligands’ steric bulk and nucleophilicity. Reaction of two equivalents of PCy3 with [InH3(NMe3)] yields the complex [InH3(PCy3)2] which has been characterised by X-ray crystallography. The first phosphido–indium hydride complex, [{InH2(PCy2)}3], has been prepared by a novel synthetic route which involves treatment of [InH3(NMe3)] with LiPCy2. Its crystal structure shows it to exist as a cyclic trimer in the solid state. The complex, [InH3(PCy3)] has been used to prepare a range of monomeric indium chalcogenolato complexes, [In(EPh)3(PCy3)], Exa0=xa0S, Se or Te, all of which have been structurally characterised.