首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The Insertion of Oxygen Atoms into Ga–Ga and In–In Bonds – Formation of the Monomeric Compounds R2E–O–ER2 [R = CH(SiMe3)2] with Strongly Enlarged Angles E–O–E The tetraalkyldielement compounds R2Ga–GaR2 ( 1 ) und R2In–InR2 ( 2 ) [R = CH(SiMe3)2] reacted with trimethylamine N-oxide by the insertion of oxygen atoms in their element-element single bonds. The products R2E–O–ER2 are monomeric in the solid state due to the high steric shielding by the voluminous bis(trimethylsilyl)methyl groups. As shown by crystal structure determinations, the E–O–E bridges have large angles of 142.7 (E = Ga, 3 ) and 138.6° (E = In, 4 ) and short separations between the oxygen and the coordinatively unsaturated Ga and In atoms. Both products are extremely hygroscopic.  相似文献   

2.
Investigations on the Insertion of Carbenes into Al–Al, Ga–Ga, and In–In Bonds Tetrakis[bis(trimethylsilyl)methyl]dialane(4) 1 reacts with methylthiomethyl lithium LiCH2SMe by the formation of lithium thiomethanolate LiSMe and the insertion of the remaining carbene CH2 into its Al–Al single bond. A chelating Lewis acid is formed exhibiting a central R2Al–CH2–AlR2 group with two coordinatively unsaturated Al atoms, which coordinate the thiomethanolate anion by Al–S bonds. The product (μ-methylene)(μ-thiomethanolato)bis{bis[bis(trimethylsilyl)methyl]aluminate} ( 4 ) was characterized by a crystal structure determination and has a strongly folded Al2CS heterocycle in the molecular core. In contrast, the corresponding compounds with Ga–Ga or In–In bonds show on treatment with methylthiomethyl lithium a fragmentation, and the carbene intermediate could not be detected in both isolated products, which were identified as [R2E(CH2SMe)2][Li(TMEDA)] (E = Ga: 5 ; E = In: 6 ) and LiCH(SiMe3)2 probably formed by a metal exchange reaction.  相似文献   

3.
Polysulfonylamines. CXVI. Destructive Complexation of the Dimeric Diorganyltin(IV) Hydroxide [Me2Sn(A)(μ‐OH)]2 (HA = Benzene‐1,2‐disulfonimide): Formation and Structures of the Mononuclear Complexes [Me2Sn(A)2(OPPh3)2] and [Me2Sn(phen)2]2⊕ · 2 A · MeCN Destructive complexation of the dimeric hydroxide [Me2Sn(A)(μ‐OH)]2, where A is deprotonated benzene‐1,2‐disulfonimide, with two equivalents of triphenylphosphine oxide or 1,10‐phenanthroline in hot MeCN produced, along with Me2SnO and water, the novel coordination compounds [Me2Sn(A)2(OPPh3)2] ( 3 , triclinic, space group P 1) and [Me2Sn(phen)2]2⊕ · 2 A · MeCN ( 4 , monoclinic, P21/c). In the uncharged all‐trans octahedral complex 3 , the heteroligands are unidentally O‐bonded to the tin atom, which resides on a crystallographic centre of inversion [Sn–O(S) 227.4(2), Sn–O(P) 219.6(2) pm, cis‐angles in the range 87–93°; anionic ligand partially disordered over two equally populated sites for N, two S and non‐coordinating O atoms]. The cation occurring in the crystal of 4 has a severely distorted cis‐octahedral C2N4 coordination geometry around tin and represents the first authenticated example of a dicationic tin(IV) dichelate [R2Sn(L–L′)2]2⊕ to adopt a cis‐structure [C–Sn–C 108.44(11)°]. The five‐membered chelate rings are nearly planar, with similar bite angles of the bidentate ligands, but unsymmetric Sn–N bond lengths, each of the longer bonds being trans to a methyl group [ring 1: N–Sn–N 71.24(7)°, Sn–N 226.81(19) and 237.5(2) pm; ring 2: 71.63(7)°, 228.0(2) and 232.20(19) pm]. In both structures, the bicyclic and effectively CS symmetric A ions have their five‐membered rings distorted into an envelope conformation, with N atoms displaced by 28–43 pm from the corresponding C6S2 mean plane.  相似文献   

4.
Treatment of the digallium compound R2Ga–GaR2 [ 1 , R = CH(SiMe3)2] with a broad variety of functionalized carboxylic acids in the presence of water yielded μ‐hydroxo‐μ‐carboxylatodigallium compounds ( 2 – 10 ) containing intact Ga–Ga bonds in high to moderate yields. The compounds form dimeric formula units in which the unsupported Ga–Ga bonds are bridged by two hydroxo and two carboxylato ligands. Each gallium atom is terminally coordinated by a bulky alkyl group. NMR spectroscopy revealed mixtures of two isomeric compounds in solution in all cases. The second component may show a different bridging mode with each Ga–Ga bond bridged by a bidentate carboxylato ligand to form Ga2O2C five‐membered heterocycles.  相似文献   

5.
Synthesis, Structure, and Properties of [nacnac]MX3 Compounds (M = Ge, Sn; X = Cl, Br, I) Reactions of [nacnac]Li [(2,6‐iPr2C6H3)NC(Me)C(H)C(Me)N(2,6‐iPr2C6H3)]Li ( 1 ) with SnX4 (X = Cl, Br, I) and GeCl4 in Et2O resulted in metallacyclic compounds with different structural moieties. In the [nacnac]SnX3 compounds (X = Cl 2 , Br 3 , I 4 ) the tin atom is five coordinated and part of a six‐membered ring. The Sn–N‐bond length of 3 is 2.163(4) Å and 2.176(5) Å of 4 . The five coordinated germanium of the [nacnac]GeCl3 compound 5 shows in addition to the three chlorine atoms further bonds to a carbon and to a nitrogen atom. In contrast to the known compounds with the [nacnac] ligand the afore mentioned reaction creates a carbon–metal‐bond (1.971(3) Å) forming a four‐membered ring. The Ge–N bond length (2.419(2) Å) indicates the formation of a weakly coordinating bond.  相似文献   

6.
The crystal structures of uncharged tetrahedral dithiocyanato zinc complexes with N-methylated ethylenediamines have been determined with a view to a study of intermolecular hydrogen-bonding interactions in these compounds. It is found that the H(N) hydrogen atoms are exhaustively engaged in N–H(N) … S bonds. The majority of these bonds are branched (bifurcated or trifurcated), and the hydrogen-bond systems they form all contain one of the two characteristic primitive core motifs: either a discrete centrosymmetric […S…H…]2 dimer or an infinite […S…H…] helix about a 21 or pseudo-21 axis. The hydrogen bonding is analyzed in detail, with particular attention to the existence of correlations between the N–H(N)–S angles and the H(N) … S distances as well as between the corresponding N–H(N)–S/H(N)…S pairs in the bifurcated N–H(N)…2 S bonds.  相似文献   

7.
Synthesis, Structure, and Properties of the Tantalum‐rich Silicide Chalcogenides Ta15Si2QxTe10–x (Q = S, Se) The quaternary tantalum silicide chalcogenides Ta15Si2QxTe10–x (Q = S, Se) are accessible from proper, compacted mixtures of the respective dichalcogenides, silicon and elemental tantalum at 1770 K in sealed molybdenum tubes. The structures were determined from the strongest X‐ray intensities of fibrous crystals with cross sections of about 3 μm and confirmed by fitting the profile of single phase X‐ray diffractograms. The phases Ta15Si2S3.5Te6.5 and Ta15Si2Se3.5Te6.5 crystallize in the monoclinic space group C2/m with two formula units per unit cell, a = 2393.7(1) pm, b = 350.08(2) pm, c = 1601.2(1) pm, β = 124.700(4)°, and a = 2461.3(2) pm, b = 351.70(2) pm, c = 1601.7(1) pm, β = 124.363(5)°, respectively. Tri‐capped trigonal prismatic Ta9Si clusters stabilized by encapsulated Si atoms can be seen as the characteristic unit of the structure. The clusters are fused into twin columns which are connected by additional Ta atoms, thus forming corrugated layers. The remaining valences at the surfaces of the layered Ta–Si substructure are saturated by those of chalcogen atoms which are coordinated only from one side by three, four or five Ta atoms. Few bridging covalent Ta–S–Ta and Ta–Se–Ta bonds and, otherwise, dispersive interactions between the Q atoms hold these nearly one nanometer wide slabs together. The phases are moderate metallic conductors. There is no evidence for any electronic instability within 10–310 K in spite of the high anisotropy of the structures.  相似文献   

8.
The title compounds were prepared by reacting the elements in an arc‐melting furnace and subsequent annealing. The LaRuSn3 type structure of the new compounds LnPtIn3 (Ln = La, Ce, Pr, Nd, Sm) was refined from single crystal X‐ray data for LaPtIn3: Pm3n, a = 980.4(2) pm, wR2 = 0.0271, 399 F2 values, 15 variables. Striking structural motifs of LaPtIn3 are condensed distorted trigonal [PtIn6] prisms with Pt–In distances of 269 pm. The lanthanum atoms occupy large cavities within the polyhedral network. Besides Pt–In bonding In–In bonding also plays an important role in LaPtIn3 with In–In distances of 299 and 327 pm. The La1 position is occupied only to 91%, resulting in a composition La0.98(1)PtIn3. The La1 atoms show an extremely large displacement parameter indicating a rattling of these atoms in the In12 cages. The so far most indium rich compound in the ternary system lanthanum‐platinum‐indium is LaPtIn4 which was characterized on the basis of Guinier powder data: YNiAl4‐type, Cmcm, a = 455.1(2) pm, b = 1687.5(5) pm, and c = 738.3(2) pm. The platinum atoms in LaPtIn4 center trigonal prisms with the composition [La2In4]. Together with the indium atoms the platinum atoms form a complex three‐dimensional [PtIn4] polyanion in which the lanthanum atoms occupy large hexagonal tubes. The structure of Ce2Pt2In is confirmed: Mo2FeB2‐type, P4/mbm, a = 779.8(1) pm, c = 388.5(1) pm, wR2 = 0.0466, 433 F2 values, 12 parameters. It is built up from CsCl and AlB2 related slabs with the compositions CeIn and CePt2, respectively. Chemical bonding in the [PtIn3] and [PtIn4] polyanions of LaPtIn3 and LaPtIn4 is discussed.  相似文献   

9.
Phosphoraneiminato Complexes of Hafnium. Crystal Structures of [Hf(NPPh3)4] · 3 THF and [Hf(NPPh3)2Cl2(HNPPh3)2] The phosphoraneiminato complexes [Hf(NPPh3)4] · 3 THF ( 1 · 3 THF) and [Hf(NPPh3)2Cl2(HNPPh3)2] ( 2 ) have been prepared as colourless, moisture sensitive single crystals by reactions of hafnium tetrachloride with [CsNPPh3]4 · 2 toluene in tetrahydrofurane solutions by application of different ratios of the educts. Both complexes are characterized by IR spectroscopy and X‐ray crystal structure determinations. 1 · 3 THF: space group P 1, Z = 4, lattice dimensions at 193 K: a = 2007.6(1); b = 2064.2(1); c = 2115.9(1) pm; α = 109.193(4)°; β = 111.285(4)°; γ = 96.879(4)°; R1 = 0.0506. 1 forms monomeric molecules with tetrahedral coordination of the nitrogen‐atoms of the (NPPh3)‐groups towards the Hafnium atom. The HfN distances of 200.9 pm in average correspond with double bonds. 2 : space group P 1, Z = 4, lattice dimensions at 193 K: a = 1444.0(1); b = 1928.1(1); c = 2455.8(2) pm; α = 67.273(8)°; β = 87.445(8)°; γ = 87.082(8)°; R1 = 0.0312. 2 has a monomeric molecular structure with octahedral coordination of the hafnium atom. The chlorine atoms are in trans position to one another, whereas the nitrogen atoms of the phosphoraneiminato groups (NPPh3) are in trans position towards the nitrogen atoms ot the phosphorane imine molecules (HNPPh3). The HfN bond lengths of the (NPPh3) groups of 199.7 pm in average correspond with double bonds, whereas the HfN distances of the HNPPh3 molecules with bond lengths of 230.2 pm in average are of donor‐acceptor type.  相似文献   

10.
Pnictogenidostannates(IV) with Discrete Tetrahedral Anions: New Representatives (E1)4(E2)2[Sn(E15)4] (with E1 = Na, K; E2 = Ca, Sr, Ba; E15 = P, As, Sb, Bi) of the Na6[ZnO4] Type and the Superstructure Variant of K4Sr2[SnAs4] The silvery to dark metallic lustrous compounds (E1)4(E2)2[Sn(E15)4] (E1 = Na, K; E2 = Ca, Sr, Ba; E15 = P, As, Sb, Bi) were prepared from melts of stoichiometric mixtures of the elements. They crystallize in the Na6[ZnO4]‐type structure (hexagonal, space group: P63mc, Z = 2; Na4Ca2[SnP4]: a = 938.94(7), c = 710.09(8) pm; K4Sr2[SnAs4]: a = 1045.0(2), c = 767.0(1) pm; K4Ba2[SnP4]: a = 1029.1(6), c = 780.2(4) pm; K4Ba2[SnAs4]: a = 1051.3(1), c = 795.79(7) pm; K4Ba2[SnSb4]: a = 1116.9(2), c = 829.2(1) pm; K4Ba2[SnBi4]: a = 1139.5(2), c = 832.0(2) pm). The anionic partial structure consists of tetrahedra [Sn(E15)4]8– orientated all in the same direction along [001]. In the cationic partial structure one of the two cation positions is occupied statistically by alkali and alkaline earth metal atoms. Up to now only for K4Sr2[SnAs4] a second modification could be isolated, forming a superstructure type with three times the unit cell volume (hexagonal, space group: P63cm, Z = 6; a = 1801.3(2), c = 767.00(9) pm) and an ordered cationic partial structure.  相似文献   

11.
On Chalcogenide Halogenides of Rhenium: Synthesis and Crystal Structures of the Triangular Clusters Re3E7X7 (E = S, Se; X = Cl, Br) The compounds Re3E7X7 are obtained from rhenium tetrahalides ReX4, elemental chalcogens and the respective chalcogen halides E2X2 or SeX4 (E = S, Se; X = Cl, Br). Re3S7Cl7, Re3S7Br7 and Re3Se7Br7 are formed in solutions of sulfur or selenium halides or SiBr4 in form of black crystals and crystallize isotypically in the trigonal space group P31c. Re3Se7Cl7 is formed by solid state reaction of ReCl4, Se and SeCl4 or by thermal decomposition of Se4[ReCl6], crystallizing as red, in thin layers transparent crystals in the orthorhombic space group Pbcm. The crystal structures consist of discrete positively charged cluster units and halide ions according to the formula [Re33-E)(μ2-E2)3X6]+X. In the rhenium triangular clusters the Re–Re distances range from 269,0 to 270,4 pm for the sulfur and from 273,3 to 275,3 pm for the selenium containing compounds. The Re3 units are capped by chalcogen atoms, three E2 groups form bridges over the edges of the Re3 triangles. The trigonal and the orthorhombic structure type show differences in the site symmetry of the clusters (C3 vs. Cs) and in the stacking sequence of the molecules, which are packed in the motif of a closest packing of spheres.  相似文献   

12.
Rubidium und Caesium Compounds with the Isopolyanion [Ta6O19]8– – Synthesis, Crystal Structures, Thermogravimetric and Vibrational Spectrocopic Analysis of the Oxotantalates A8[Ta6O19] · n H2O (A = Rb, Cs; n = 0, 4, 14) The compounds A8[Ta6O19] · n H2O (A = Rb, Cs; n = 0, 4, 14) contain the isopoly anion [Ta6O19]8–, which consists of six [TaO6] octahedra connected via corners to form a large octahedron. They transform into each other by reversible hydratation/dehydratation processes, as shown from thermoanalytic measurements (TG/DSC), and show also structural similarities. Cs8[Ta6O19] (tetragonal, I4/m, a = 985.9(1) pm, c = 1403.3(1) pm, Z = 2), the isotypic phases A8[Ta6O19] · 14 H2O (A = Rb/Cs; monoclinic, P21/n, a = 1031.30(6)/1055.4(1) pm, b = 1590.72(9)/1614.9(6) pm, c = 1150.43(6)/1171.4(1) pm, β = 100.060(1)/99.97(2)°, Z = 2) and Rb8[Ta6O19] · 4 H2O (monoclinic, C2/c, a = 1216.9(4) pm, b = 1459.2(5) pm, c = 1414.7(4) pm, β = 90.734(6)°, Z = 4) have been characterised on the basis of single crystal x‐ray data. Furthermore the RAMAN spectra allow a detailled comparison of the hexatantalate ions in the four compounds.  相似文献   

13.
Syntheses and Crystal Structures of the Nitrido‐chloro‐molybdates [Mg(THF)4{NMoCl4(THF)}2] · 4 CH2Cl2 and [Li(12‐Crown‐4)(NMoCl4)]2 · 2 CH2Cl2 Both the title compounds as well as [Li(12‐crown‐4)2]+MoNCl4 were made from MoNCl3 and the chlorides MgCl2 and LiCl, respectively, in dichloromethane suspensions in the presence of tetrahydrofuran and 12‐crown‐4, respectively. They form orange‐red moisture‐sensitive crystals, which were characterized by their IR spectra and partly by crystal structure analyses. [Mg(THF)4{NMoCl4(THF)}2] · 4 CH2Cl2 ( 1 ): space group C2/m, Z = 2, lattice dimensions at –50 °C: a = 1736.6(1), b = 1194.8(1), c = 1293.5(2) pm; β = 90.87(1)°; R1 = 0.037. In 1 the magnesium ion is coordinated octahedrally by the oxygen atoms of the four THF molecules and in trans‐position by the nitrogen atoms of the two [N≡MoCl4(THF)] ions. [Li(12‐crown‐4)(NMoCl4)]2 · 2 CH2Cl2 ( 2 ): space group P 1, Z = 1, lattice dimensions at –70 °C: a = 930.4(1), b = 957.9(1), c = 1264.6(1) pm; α = 68.91(1)°, β = 81.38(1)°, γ = 63.84(1)°; R1 = 0.0643. 2 forms a centrosymmetric ion ensemble in the dimeric cation of which, i. e. [Li(12‐crown‐4)]22+, the lithium ions on the one hand are connected to the four oxygen atoms each of the crown ether molecules in a way not yet known; and in addition, each of the lithium ions enters into a intermolecular Li–O bond with neighboring crown ether molecules under formation of a Li2O2 four‐membered ring. The two N≡MoCl4 counterions are loosely coordinated to one oxygen atom each of the crown ether molecules with Mo–O distances of 320.2 pm.  相似文献   

14.
Preparation, Crystal Structure and IR Spectra of BeSeO3 · H2O – Hydrogen Bonds and Correlation of IR and Structure Data in the Monohydrates MSeO3 · H2O (M = Be, Ca, Mn, Co, Ni, Zn, Cd) BeSeO3 · H2O (oP32) has been obtained by treating amorphous BeSeO3 · 4 H2O precipitated from Be(HSeO3)2 solutions hydrothermally at 150 °C. The crystal structure (P212121, a = 560.59(4), b = 755.25(5), c = 781.14(5) pm, Z = 4, DX = 3.092 gcm–3, R = 0.018 for the 2034 reflections with I > 2σI of the enantiomer investigated) contains BeO3(H2O) tetrahedra built up from three selenite and one water oxygen atoms. The BeO3(H2O) tetrahedra are 3 D‐connected via Se atoms of trigonal pyramidal SeO32– ions. The Be–O distances are 161.8 to 164.4 pm. The Se–O bond lenghts (169.2–170.3 pm) and the O–Se–O bond angles (98.1–101.4°) are normal. The water molecules of crystallization form together with the SeO32– ions screw‐like hydrogen bond systems along [100]. Despite the strong synergetic effect of the Be2+ ions, the hydrogen bonds (d(OH…O) = 267.4 and 276.4 pm, respectively; νOD of matrix isolated HDO molecules: 2244 and 2405 cm–1, respectively) are normal compared to other neutral selenite hydrates. Together with the hitherto known monohydrates MIISeO3 · H2O and other beryllium salt hydrates, the hydrogen bonds of BeSeO3 · H2O are discussed with regard to their geometry and IR spectroscopy.  相似文献   

15.
Synthesis and Structures of the Dinuclear Nitrido Complexes [(Me2PhP)3(MeCN)ClRe≡N–MCl5] with M = Sn and Zr The water sensitive complexes [(Me2PhP)3(MeCN)ClRe≡N–MCl5] (M = Sn ( 1 ) und Zr ( 2 )) are obtained in dichloromethane from [ReNCl2(PMe2Ph)3] and the acetonitrile adducts of SnCl4 or ZrCl4. The compounds crystallize as dichloromethane solvate isotypically with [(Me2PhP)3(MeCN)ClRe≡N–TiCl5] · CH2Cl2 in the space group P21/n. From toluene crystallize monoclinic crystals of 1 · MeCN · C7H8. In the diamagnetic complexes 1 and 2 an anion [MCl5] coordinates to the nitrido ligand of the cationic complex [ReNCl(MeCN)(PMe2Ph)3]+. The resulting nitrido bridges Re≡N–M are almost linear and asymmetric with Re–N = 169.5 pm, Sn–N = 230.1 pm and Re–N–Sn = 164.5° for 1 and Re–N = 168.4 pm, Zr–N = 237.2 pm and Re–N–Zr = 165.6° for 2 . The phosphine ligands at the Re atom are in a meridional arrangement.  相似文献   

16.
The new ternary rhodium borides Mg3Rh5B2 and Sc3Rh5B2 (P4/mbm, Z = 2; a = 943.4(1) pm, c = 292.2(1) pm and a = 943.2(1) pm, c = 308.7(1) pm, respectively) crystallize with the Ti3Co5B2 type structure. Mg and Sc may in part be substituted by a variety of elements M. For M = Si and Fe, homogeneity ranges were found according to A3–xMxRh5B2 with 0 ≤ x ≤ 1.0 for A = Sc and with x up to 1.5 for A = Mg. Quaternary compounds with x = 1 (A2MRh5B2: A/M in short) were prepared with M = Be, Al, Si, P, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Sn (Co, Ni only with A = Mg; Sn only with A = Sc; P, As with deficiencies). Single crystal X‐ray investigations show an ordered substitutional variant of the Ti3Co5B2 type in which the M atoms are arranged in chains along [001] with intrachain and interchain M–M distances of about 300 pm and 660 pm, respectively. Measuring the magnetisation (1.7 K–800 K) of the phases Mg/Mn, Sc/Mn, Mg/Fe, and Sc/Fe reveals antiferromagnetic interactions in the first and dominating ferromagnetic intrachain interactions in the remaining ones. Interchain interactions of antiferromagnetic nature are evident in Sc/Mn and Mg/Fe leading to metamagnetism below TN = 130 K, while Sc/Fe behaves ferromagnetically below TC = 450 K. The overall trend towards stronger ferromagnetic interactions with increasing valence electron concentration is obvious.  相似文献   

17.
The Crystal Structure of the Hydrated Cyano Complexes NMe4MnII[(Mn, Cr)III(CN)6] · 3 H2O and NMe4Cd[MIII(CN)6] · 3 H2O (MIII = Fe, Co): Compounds Related to Prussian Blue The crystal structures of the isotypic tetragonal compounds (space group I4, Z = 10) NMe4MnII · [(Mn, Cr)III(CN)6] · 3 H2O (a = 1653.2(4), c = 1728.8(6) pm), NMe4Cd[Fe(CN)6] · 3 H2O (a = 1642.7(1), c = 1733.1(1) pm) and NMe4Cd[Co(CN)6] · 3 H2O (a = 1632.1(2), c = 1722.4(3) pm) were determined by X‐rays. They exhibit ⊥ c cyanobridged layers of octahedra [MIII(CN)6] and [MIIN4(OH2)2], which punctually are interconnected also || c to yield altogether a spaceous framework. The MII atoms at the positions linking into the third dimension are only five‐coordinated and form square pyramids [MIIN5] with angles N–MII–N near 104° and distances of Mn–N: 1 × 214, 4 × 219 pm; Cd–N: 1 × 220 resp. 222, 4 × 226 resp. 228 pm. Further details and structural relations within the family of Prussian Blue are reported and discussed.  相似文献   

18.
UO2(H2AsO4)2 · H2O was synthesized by dissolving elemental uranium in arsenic acid (80.5%) for twelve weeks at room temperature. The resulting small crystals were transparent and of yellow‐green color. The crystal structure was refined from single‐crystal X‐ray data: C2/c, a = 1316.4(3) pm, b = 886.2(2) pm, c = 905.0(3) pm, β = 124.41(3)°, R1 = 0.023, wR2 = 0.060, 981 structure factors, and 65 variable parameters. The uranium atoms of this new structure type are coordinated by two very close oxygen atoms in linear arrangement. Four further oxygen atoms which belong to four different AsO4 tetrahedra and the oxygen atom of the water molecule complete the 7‐fold coordination of the uranium atoms. [UO2(H2O)]2+ and two H2AsO4 units form infinite electroneutral chains which are the main building units of the structure and which are interconnected by hydrogen bridging bonds. IR heating experiments show that dehydration around 500 K leads to a complete decomposition of the structure. Magnetic measurement gave a diamagnetic behavior with a susceptibility of χ = –8.68 10–9 m3/mol in good agreement with the diamagnetic increment of the compound (χ = –8.20 10–9 m3/mol) calculations with U6+.  相似文献   

19.
The Reaction of Ytterbium with N‐iodo‐triphenylphosphaneimine. Crystal Structures of [Yb2I(THF)2(NPPh3)4] · 2 THF, [YbI2(HNPPh3)(DME)2], and [{YbI2(DME)2}2(μ‐DME)] When treated with ultrasound, the reaction of ytterbium powder with INPPh3 in tetrahydrofuran leads to [YbI2(THF)4] and to the mixed‐valence phosphoraneiminato complex [Yb2I(THF)2(NPPh3)4] · 2 THF ( 1 ), which forms red single‐crystals. In the analogous reaction in 1,2‐dimethoxyethane (DME) only the ytterbium(II) iodide solvates [YbI2(HNPPh3)(DME)2] ( 2 ) and [{YbI2(DME)2}2 · (μ‐DME)] ( 3 ) can be isolated, which form yellow single crystals. All compounds were characterized by crystal structure analyses. 1 : Space group P1, Z = 2, lattice dimensions at –80 °C: a = 1337.6(5), b = 1389.6(5), c = 2244.2(17) pm; α = 86.11(7)°, β = 88.06(7)°, γ = 88.63(4)°; R = 0.0759. In 1 the two ytterbium atoms are connected via the N atoms of two phosphoraneiminato groups (NPPh3) to form a planar Yb2N2 four‐membered ring. The structure can also be described as an ion pair consisting of [YbI(THF)2]+ and [Yb(NPPh3)4]. 2 : Space group P21, Z = 2, lattice dimensions at –80 °C: a = 811.9(1), b = 1114.0(1), c = 1741.3(1) pm; β = 95.458(5)°; R = 0.0246. 2 forms molecules in which the ytterbium atom is coordinated in a pentagonal‐bipyramidal fashion with the iodine atoms in the axial positions. The O atoms of the two DME‐chelates and the N atom of the phosphaneimine ligand HNPPh3 are in the equatorial positions. 3 : Space group P1, Z = 2, lattice dimensions at –70 °C: a = 817.5(1), b = 1047.7(1), c = 1115.5(2) pm; α = 90.179(10)°, β = 97.543(15)°, γ = 91.087(12)°; R = 0.0317. 3 has a dimeric molecular structure, in which the two fragments {YbI2(DME)2} are connected centrosymmetrically via a μ‐DME bridge. As in 2 , the ytterbium atoms are coordinated in a pentagonal‐bipyramidal fashion with the iodine atoms in the axial positions, as well as with the two DME chelates and with one O atom each of the μ‐DME ligand in the equatorial positions.  相似文献   

20.
Synthesis and Crystal Structures of the homoleptic Phosphoraneiminato Cations [E(NPPh3)3]+ (E = S, Se, Te) with Iodide and Triiodide Counter Ions N‐Iod‐triphenylphosphaneimine, INPPh3, reacts with the chalcogenes sulfur, selenium and tellurium in boiling tetrahydrofuran to give the phosphoraneiminato complexes [E(NPPh3)3]+[1/2 I3, 1/2 I] · THF (E = S ( 1 ), E = Se ( 2 )) and [Te(NPPh3)3]+I3 ( 3 ), respectively. The componds form red crystals which are characterized by IR spectroscopy and by crystal structure determinations. The homoleptic cations [E(NPPh3)3]+ have pyramidal structures with short EN and PN bond lengths, corresponding to double bonds. 1 : Space group Pa 3, Z = 8, lattice dimensions at –80 °C: a = b = c = 2192.9(1) pm, R1 = 0.0299. 2 : Space group Pa 3, Z = 8, lattice dimensions at –80 °C: a = b = c = 2202.5(1) pm, R1 = 0.0357. 3 : Space group Pca21, Z = 4, lattice dimensions at –90 °C; a = 1075.8(2); b = 1988.8(4); c = 2437.2(3) pm, R1 = 0.0443.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号