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.
Trans-[Cr(NH3)4(H2O)Cl]Cl2 (A) crystallizes in the monoclinic space group P21/m (No. 11) with a = 6.556(1), b = 10.630(5), c = 6.729(2) Å and β = 96.15(3)°. Trans-[Cr(NH3)4Cl2]I (B) has monoclinic C2/m (No. 12) space group and a = 9.877(2), b = 8.497(2), c = 6.047(2) Å and β = 108.98(2)°. Both unit cells contain two formula units. Cr? Cl, Cr? O(H2O) and three independent Cr? N(NH3) distances for A are 2.98(1), 2.023(2), 2.067(2), 2.086(3) and 2.064(3) °. Cr? Cl and Cr? N(NH3) bonds in B are 2.325(1) and 2.071(2) °. All octahedral angles are close to 90 and 180°. Both structures were refined to very low R values. Water molecule from trans-[Cr(NH3)4(H2O)Cl]2+ is hydrogen bonded to both ionic chlorides. Cation and two anions form the motive which repeats itself in the crystal. Cations and anions of the second structure are distributed in layers. Each cation and anion have coordination number eight.  相似文献   

2.
An ionic crystal K2[Cr3O(OOCC2H5)6(H2O)3]2[alpha-SiW12O40] x 3H2O (1a) is synthesized by the complexation of a Keggin-type polyoxometalate of [alpha-SiW12O40]4- with K+ and a macrocation of [Cr3O(OOCC2H5)6(H2O)3]+. Compound 1a possesses both hydrophilic and hydrophobic channels in the crystal lattice. The 3 mol mol(-1) of the water of crystallization in 1a resides in the hydrophilic channel. The water of crystallization is removed by the evacuation at 303 K to form the guest-free phase 1b with small changes in the lattice lengths (+/-0.2 A). The water sorption profile is reproduced by the single rate constant. Therefore, the water sorbed probably resides in the hydrophilic channel. Compound 1b sorbs various kinds of polar organic molecules, and the amounts of < or = C3 alcohols are comparable to or larger than that of water, while chlorocarbons with no hydrogen-bonding ability and nonpolar molecules are excluded. Thus, 1b showed the amphiphilic sorption property. The states of the polar organic molecules sorbed in 1b have been quantitatively investigated using ethanol as a probe molecule. The IR, NMR, and single-crystal X-ray diffraction studies combined with the sorption kinetics reveal that ethanol molecules are mainly sorbed into the hydrophilic channel at P/P0 < or = 0.5, while the sorption into the hydrophobic channel is dominant at P/P0 > or = 0.6. Thus, it is demonstrated that ethanol molecules enter both hydrophilic and hydrophobic channels of 1b.  相似文献   

3.
Thermolysis of the double-metal complex [Co(NH3)6][Cr(C2O4)3] was studied in air at 200, 350, and 500°C and in a hydrogen atmosphere at 200, 350, 500, 700, and 900°C, as well as the composition and properties of thermolysis products. Oxidative thermolysis produces mixed oxides CoCr2O4 and Co2CrO4; reductive thermolysis produces Co + Cr2O3 mixture. Specific surface areas were measured for reductive thermolysis products; the maximal specific surface area and, therefore, maximal dispersion are reached at 500°C. The morphology of the reductive thermolysis products and the thermolysis chemism were studied in relation to the nature of the complex anion.  相似文献   

4.
《Thermochimica Acta》1987,114(2):347-358
The kinetics of isothermal decomposition of K2[V2O3(O2)2] and K3[Ta(O2)2F4] have been investigated in the temperature range 413–493 K using a constant volume apparatus. The α vs. time plots for both these solids are sigmoidal in nature. The kinetics obey the Avrami-Erofeev equation (n = 2) for the initial stage of the decomposition. The contracting volume equation fits well for the deceleratory region. The activation energies are 164.8 and 105.4 kJ mol−1 for K2[V2O3(O2)2F2], and 85.2 and 76.6 kJ mol−1 for K3[Ta.(O2)2F4].The absence of lattice water in these two solids may be responsible for the appearance of a short induction, followed by an acceleratory region in pristine solids, in contrast to hydrated fluoroperoxo zirconates, wherein the dehydration step preceding peroxide decomposition leads to facile nucleation and a deceleratory nature of decomposition.The kinetic characteristics of the decomposition of fluoroperoxo species so far studied are summarized and discussed.  相似文献   

5.
6.
Preparation, Structures, and Properties of Tris-hexamethyl-trisila-tetraphospha-nortricyclene-bis-chromiumtricarbonyl [P4(Sime2)3]3[Cr(CO)3]2 Hexamethyl-trisila-tetraphospha-nortricyclene P4(Sime2)3 1 reacts with C6H6Cr(CO)3 or (CHT)Cr(CO)3 (CHT ? Cycloheptatriene) under formation of [P4(Sime2)3]3[Cr(CO)3]2 3 (red crystals), in which each of the Cr atoms is attached to one P atom of a P3 ring of the three molecules 1 . 3 can also be prepared by heating a solution of P4(Sime2)3Cr(CO)5 in benzene or THF up to 120–1307deg;C. The compound 3 crystallizes in an orthorhombic and a hexagonal form, the latter being stabilized by one mole toluene. As revealed by single crystal investigations, the symmetry ¯6, distances and angles are nearly unchanged. The o-form corresponds to a face centered cubic packing of the molecules, whereas the h-form is hexagonal close packed.  相似文献   

7.
The structure of two trinuclear iron acetates [Fe3O(CH3COO)6(H2O)3]Cl· 6H2O (I) and [Fe3O(CH3COO)6(H2O)3][FeCl4] · 2CH3COOH (II) was determined by X-ray diffraction analysis. Crystals I and II are ionic and belong to the orthorhombic system with parameters a = 13.704(3), b = 23.332(5), c = 9.167(2) Å, R = 0.0355, space goup P21212 for I and a = 10.145(4), b = 15.323(6), c = 22.999(8) Å, R = 0.0752, space group Pbc21 for II. The complex cation [Fe3O(CH3COO)6(H2O)3]+ has a μ3-O-bridged structure typical for trinuclear iron (III) compounds. As shown by Mössbauer spectroscopy, the iron(III) ions are in the high-spin state. In trinuclear cations, antiferromagnetic exchange interaction takes place between the Fe(III) ions with the exchange parameter J = -26.69 cm?1 for II (Heisenberg-Dirac-Van Vleck model for D3h, symmetry).  相似文献   

8.
The double complex salts [Ni(NH3)6]3[Fe(CN)6]2 and [Ni(NH3)6]3[Cr(CNS)6]2 were synthesized and their thermal decomposition in air was studied. The values of interplanar distances in crystal lattices were determined. The compounds are proposed as precursors for producing homogeneous bimetallic nanodimensional powders.  相似文献   

9.
研究了多金属氧酸盐分子基化合物K3[Cr3O(OOCH)6(H2O)3][α-GeW12O40]·17H2O的合成、晶体结构及其结晶水可逆脱附和吸附性能.该化合物属于单斜晶系,C2/m空间群,α=2.738 3(6)nm,b=1.58 3 0(3)nm,c=1.730 4(4)nm,β=102.43(3)°,V=7.325(3)nm3,Z=4,R1(wR2)=0.067 8(0.171 9).该晶体具有孔道结构,孔道内的结晶水能够可逆的脱附和吸附,而晶体结构随之恢复,因此具有分子筛的特性.  相似文献   

10.
Oxo-phosphoraneiminato Complexes of Molybdenum and Tungsten. Crystal Structures of [Mo(O)2(NPPh3)2] and [WO(NPPh3)3]2[W6O19] The dioxo-phosphoraneiminato complexes [Mo(O)2(NPPh3)2] ( 1 ) and [W(O)2(NPPh3)2] ( 2 ) originate from hydrolysis of the nitrido complexes [MN(NPPh3)3] (M = Mo, W). They form colourless crystals, which are characterized by IR and NMR spectroscopy as well as by mass spectrometry. According to the crystal structure analysis of 1 (space group Fdd2, Z = 8; lattice dimensions at –83 °C: a = 1953.3(1), b = 3275.8(3), c = 953.4(1) pm) there are monomeric molecules with tetrahedrally coordinated molybdenum atoms. The distances MoO of 171.2 pm and MoN of 185.9 pm correspond to double bonds. In dichloromethane solution 2 undergoes further hydrolysis with colourless crystals of [WO(NPPh3)3]2[W6O19] ( 3 ) originating, which are characterized crystallographically (space group Pbcn, Z = 4; lattice dimensions at –50 °C: a = 3225.1(6), b = 1803.6(3), c = 1811.9(3) pm). 3 consists of cations [WO(NPPh3)3]+ with tetrahedrally coordinated tungsten atoms and of the known [W6O19]2– anions. The tungsten atoms of the cations show distances WO of 171.8 pm and WN of 182 pm which correspond to double bonds as in 1 .  相似文献   

11.
Polyoxometallates are capable of including transition metals in their crystal structures as either discrete cations or heteroatoms. The title compound crystallizes with triclinic symmetry and consists of a centrosymmetric [V10O28]6? anion, a trimeric {[Na(H2O)3][Ni(H2O)6][Na(H2O)3]}4+ cation, an [Ni(H2O)6]2+ cation and four water molecules of crystallization. The compound possesses two Ni atoms (each on independent inversion centres), one as a discrete cation and one in a disodium–nickel trimeric cation involved in the one‐dimensional polycation–polyanion hybrid polymer. The polymers are bound together via hydrogen bonds to the water mol­ecules and the nickel(II) hexahydrate cation. Several structures of decavanadate compounds having transition metal atoms, monovalent cations and [V10O28]6? anions in the ratio 2:2:1 have been reported previously. However, the present compound differs from these in its arrangement of monovalent cations and transition metal atoms.  相似文献   

12.
Reactions of K4[SnSe4], Na4[GeS4] or Ba2[GeSe4] with different 1,2‐diaminoethane (= en) coordinated complexes of CrCl3 ([Cr(en)2Cl2]Cl or [Cr(en)3]Cl3) in MeOH or aqueous solution yielded three novel compounds that contain complexes of Cr3+ with ortho‐chalcogenotetrelate anions [E′E4]4? (E′ = Ge, Sn; E = S; Se): the crystal structures of [K6(MeOH)9][Sn2Se6][Cr(en)2(SnSe4)]2 ( 1 ), [Na(H2O)4][Cr(en)3]2[GeS3OH]2[Cr(en)2(GeS4)] ( 2 ), and [Ba(H2O)10][{Cr(en)}2(GeSe4)2] ( 4 ) have been determined by means of single crystal X‐ray diffraction ( 1 : triclinic space group ; lattice dimensions at 203 K: a = 1175.7(2), b = 1315.3(3), c = 1326.7(3) pm, α = 61.99(3)°, β = 64.05(3)°, γ = 83.57(3)°, V = 1617.4(6)·106 pm3; R1 [I > 2σ(I)] = 0.0788; wR2 = 0.1306; 2 : monoclinic space group C2/c; lattice dimensions at 203 K: a = 2445.3(5), b = 1442.5(3), c = 1579.3(3) pm, β = 94.61(3)°, V = 5552.9(19)·106 pm3; R1 [I > 2σ(I)] = 0.0801; wR2 = 0.2046; 4 : triclinic space group ; lattice dimension at 203 K: a = 1198.4(2), b = 1236.8(3), c = 1297.5(3) pm, α = 65.69(3)°, β = 63.35(3)°, γ = 81.21(3)°, V = 1565.2(5)·106 pm3; R1 [I > 2σ(I)] = 0.0732; wR2 = 0.1855). 1 and 2 show the yet unprecedented complexation of transition metal ions by non‐bridging, single chalcogenotetrelate ligands to produce dinuclear, heterobimetallic complexes. Compound 2 contains the first structurally characterized complex with an ortho‐thiogermanate ligand. The formation of these compounds, and of a by‐product of 2 , [Cr(en)3][GeS3OH]·6H2O ( 3 : monoclinic space group C2/c; lattice dimensions at 203 K: a = 2396.8(5), b = 1463.4(3), c = 1740.1(4) pm, β = 132.99(3)°, V = 4463.8(15)·106 pm3; R1 [I > 2σ(I)] = 0.0462; wR2 = 0.1058), provides some insight in fundamental differences between the reaction behavior of [SnE4]4? anions one the one hand and [GeE4]4? anions on the other hand. The crucial role of the counterion charge becomes evident when comparing the structure motifs of the ternary anions in 1 and 2 with that observed in the Ba2+ compound 4 .  相似文献   

13.
The structure of the title compound, ammineaquadi‐μ5‐phosphato‐trizinc(II), [Zn3(PO4)2(H2O)0.8(NH3)1.2], consists of two parts: (i) PO4 and ZnO4 vertex‐sharing tetrahedra arranged in layers parallel to (100) and (ii) ZnO2(N/O)2 tetrahedra located between the layers. Elemental analysis establishes the ammine‐to‐water ratio as 3:2. ZnO2(N/O)2 tetrahedra are located at special position 4e (site symmetry 2) in C2/c. The two O atoms of ZnO2(N/O)2 are bonded to neighbouring P atoms, forming two Zn—O—P linkages and connecting ZnO2(N/O)2 tetrahedra with two adjacent bc plane layers. A noteworthy feature of the structure is the presence of NH3 and H2O at the same crystallographic position and, consequently, qualitative changes in the pattern of hydrogen bonding and weaker N/O—H...O electrostatic interactions, as compared to two closely related structures.  相似文献   

14.
Single crystals of [Cr(H2O)6]2[B12H12]3 · 15H2O and [In(H2O)6]2[B12H12]3 · 15H2O were obtained by reactions of aqueous solutions of the acid (H3O)2[B12H12] with chromium(III) hydroxide and indium metal shot, respectively. The title compounds crystallize isotypically in the trigonal system with space group R$\bar{3}$ c (a = 1157.62(3), c = 6730.48(9) pm for the chromium, a = 1171.71(3), c = 6740.04(9) pm for the indium compound, Z = 6). The arrangement of the quasi‐icosahedral [B12H12]2– dianions can be considered as stacking of two times nine layers with the sequence …ABCCABBCA… and the metal trications arrange in a cubic closest packed …abc… stacking sequence. The metal trications are octahedrally coordinated by six water molecules of hydration, while another fifteen H2O molecules fill up the structures as zeolitic crystal water or second‐sphere hydrating species. Between these free and the metal‐bonded water molecules, bridging hydrogen bonds are found. Furthermore, there is also evidence of hydrogen bonding between the anionic [B12H12]2– clusters and the free zeolitic water molecules according to B–Hδ ··· δ+H–O interactions. Vibrational spectroscopy studies prove the presence of these hydrogen bonds and also show slight distortions of the dodecahydro‐closo‐dodecaborate anions from their ideal icosahedral symmetry (Ih). Thermal decomposition studies for the example of [Cr(H2O)6]2[B12H12]3 · 15H2O gave no hints for just a simple multi‐stepwise dehydration process.  相似文献   

15.
Reaction of C(NMe2)4 with Ni(CO)4 – Syntheses and Structures of [C(NMe2)3][(CO)3NiC(O)NMe2], [C(NMe2)3]2[Ni5(CO)12], and [C(NMe2)3]3[Ni6(CO)12][O2CNMe2] The reaction of C(NMe2)4 with Ni(CO)4 in THF produces the carbamoyl complex [C(NMe2)3][(CO)3NiC(O)NMe2] ( 1 ); side products are the purple cluster compound [C(NMe2)3]2[Ni5(CO)12] · THF ( 2 · THF) and the red cocristallization product [C(NMe2)3]3[Ni6(CO)12][O2CNMe2] ( 3 ). All compounds were studied by X‐ray diffraction analyses. The cations of 3 are all disordered but not those of 1 and 2 . The unit cell of 1 contains two crystallographically independent anions (I and II) which differ in the dihedral angle between the plane of the carbamoyl ligand and the plane defined by the atoms CCarbamoyl–Ni–CO amounting 0° in the anion I and 18° in the anion II.  相似文献   

16.
Summary.  The new clusters Zr6O2(OBu)10(OMc)10 and Zr6O2(OMe)4(OBu)2(OMc)14 were prepared from Zr(OBu)4 and methacrylic acid. For the preparation of Zr6O2(OMe)4(OBu)2(OMc)14, partial exchange of the butoxy groups is necessary. The clusters consist of two Zr3 subunits that dimerize via alkoxide bridges. The structures are of the same type, except that four terminal butoxy ligands in Zr6O2(OBu)10(OMc)10 are exchanged for chelating methacrylate ligands in Zr6O2(OMe)4(OBu)2(OMc)14. Received March 26, 2001. Accepted April 17, 2001  相似文献   

17.
Synthesis and Crystal Structure of [Cr(NH3)6][Cr(NH3)2F4][BF4]2 The action of ammonium fluoride on a mixture of boron and chromium in a sealed Monel ampoule at 300 °C yields single crystals of [Cr(NH3)6][Cr(NH3)2F4][BF4]2. The crystal structure (tetragonal, P4/mbm, Z = 2, a = 1056.0(1), c = 781.7(1) pm; R1 = 0.0414; wR2 = 0.1087 for 411 reflections with I0 > 2σ(I)) contains [Cr(NH3)6]3+ and [Cr(NH3)2F4] octahedra and twice as many [BF4] tetrahedra that are arranged in a quadrupled super‐structure of the CsCl‐type of structure.  相似文献   

18.
[(n‐Bu)2Sn(O2PPh2)2] ( 1 ), and [Ph2Sn(O2PPh2)2] ( 2 ) have been synthesized by the reactions of R2SnCl2 (R=n‐Bu, Ph) with HO2PPh2 in Methanol. From the reaction of Ph2SnCl2 with diphenylphosphinic acid a third product [PhClSn(O2PPh2)OMe]2 ( 3 ) could be isolated. X‐ray diffraction studies show 1 to crystallize in the monoclinic space group P21/c with a = 1303.7(1) pm, b = 2286.9(2) pm, c = 1063.1(1) pm, β = 94.383(6)°, and Z = 4. 2 crystallizes triclinic in the space group , the cell parameters being a = 1293.2(2) pm, b = 1478.5(4) pm, c = 1507.2(3) pm, α = 98.86(3)°, β = 109.63(2)°, γ = 114.88(2)°, and Z = 2. Both compounds form arrays of eight‐membered rings (SnOPO)2 linked at the tin atoms to form chains of infinite length. The dimer 3 consists of a like ring, in which the tin atoms are bridged by methoxo groups. It crystallizes triclinic in space group with a = 946.4(1) pm, b = 963.7(1) pm, c = 1174.2(1) pm, α = 82.495(6)°, β = 66.451(6)°, γ = 74.922(6)°, and Z = 1 for the dimer. The Raman spectra of 2 and 3 are given and discussed.  相似文献   

19.
Bis(2-furoinate)triphenyl- and tri-p-tolylantimony and bis(3-niacinate)triphenylanitmony were synthesized by reacting triarylantimony (Ar3Sb; Ar = Ph, p-Tol) with 2-furancarboxylic and 3-pyridinecarboxylic acids in the presence of hydrogen peroxide. According to X-ray diffraction data, Sb atoms have trigonal bipyramidal coordination polyhedra. The Sb–O distances are 2.117(4), 2.137(4) Å; 2.136(2), 2.158(2) Å, and 2.112(1), 2.101(2) Å, the Sb···O distances are 2.866(4), 2.798(4) Å; 2.816(2), 2.774(2) Å, and 3.054(2), 3.168(2) Å, respectively.  相似文献   

20.
The crystal and molecular structure of dipotassium di‐μ‐oxo‐bis[aqua(oxalato‐O1,O2)oxomolybdenum(III)] trihydrate, K2­[Mo2O4(C2O4)2(H2O)2]·3H2O, has been determined from X‐ray diffraction data. In the dimeric anion, which has approximate twofold symmetry, each Mo atom is in a distorted octahedral coordination, being bonded to one terminal oxo‐O atom, two bridging O atoms, two O atoms from the oxalato ligand and one from the water mol­ecule. Bond lengths trans to the multiple‐bonded terminal oxo ligand are larger than those in the cis position, confirming the trans influence as a generally valid rule.  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