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1.
A new class of M(II)–Hg(II) (M=Cu(II), Co(II), Ni(II)) mixed-metal coordination polymers, Cu(2-pyrazinecarboxylate)2HgCl2 (4), [Co(2-pyrazinecarboxylate)2(HgCl2)2] · 0.61H2O (5) and [Ni(2-pyrazinecarboxylate)2(HgCl2)2] · 0.77H2O (6), have been prepared by self assembly of metal-containing building blocks, M(2-pyrazinecarboxylate)2 · (H2O)2(M=Cu(II), Co(II), Ni(II)), with HgCl2. Compounds 4–6 were characterized fully by IR, elemental analysis and single crystal X-ray diffraction. Compound 4 crystallized in the monoclinic space group C2/c, with a=17.916(5) Å, b=7.223(2) Å, c=13.335(4) Å, β=128.726(3)°, V=1346.2(6) Å3, Z=4. It contains alternating Hg(II) and Cu(II) metal centers that are cross-linked by 2-pyrazinecarboxylate spacers and chlorine co-ligands to generate a unique three-dimensional Hg(II)–Cu(II) mixed metal framework. Compound 5 crystallized in the triclinic space group P
, with a=6.3879(7) Å, b=6.6626(8) Å, c=13.2286(15) Å, α=96.339(2)°, β=91.590(2)°, γ=113.462(2)°, V=511.71(10) Å3, Z=1. Compound 6 also crystallized in the triclinic space group P
, with a=6.3543(8) Å, b=6.6194(8) Å, c=13.2801(16) Å, α=96.449(2)°, β=92.263(2)°, γ=113.541(2)°, V=506.67(11) Å3, Z=1. Compounds 5 and 6 are isostructural and in the solid state the Hg(II)M(II)Hg(II) units are connected by Hg2Cl2 linkages to produce a novel M(II)–Hg(II) (M=Co(II), Ni(II)) zigzag mixed-metal chain, in which a new type of M–M′–M′–M array was observed. The metal containing building blocks, M(2-pyrazinecarboxylate)2 · (H2O)2 (M=Cu(II), Co(II), Ni(II)), exhibit different connectivities to HgCl2 depending on the metal cation contained within them. 相似文献
2.
Paul M. Forster Andrea R. Burbank Melanie C. O'Sullivan Nathalie Guillou Carine Livage Grard Frey Norbert Stock Anthony K. Cheetham 《Solid State Sciences》2005,7(12):1549
A new form of cobalt succinate has been discovered using high-throughput methods and its structure was solved by single crystal X-ray diffraction. Co7(C4H4O4)4(OH)6(H2O)37H2O crystallizes in the monoclinic space group P21/c with cell parameters: a=7.888(2) Å, b=19.082(6) Å, c=23.630(7) Å, β=91.700(5)°, V=3555(2) Å3, R1=0.0469. This complex structure, containing 55 crystallographically distinct non-hydrogen atoms, is compared to the previously reported nickel phase, characterized using ab initio structure solution from synchrotron powder diffraction data. 相似文献
3.
Investigation into the synthesis of reduced vanadium phosphate has led to the formation of a new form of the barium vanadium (III) pyrophosphate compound β-BaV2(P2O7)2. It is a polymorph of the previously known BaV2(P2O7)2, which is now labeled as the α-phase. The title compound crystallizes in the P-1 (No. 2) space group with a = 6.269(1) Å, b = 7.864(3) Å, c = 6.1592(9) Å, α = 101.34(2)°, β = 105.84(1)°, and γ = 96.51(2)°. The structure consists of corner-shared VO6 octahedra and PO4 tetrahedra that are connected in V-O-P-O-V and V-O-P-O-P-O-V bonding arrangements. This interesting three-dimensional framework is characterized by seven types of intersecting tunnels, three of which are occupied by the barium cation, while the others are empty. It is important to know that one of the empty tunnels has a relatively large window with a minimum diagonal distance of 4.41 Å, which facilitates a possible framework for a lithium ion insertion reaction. The barium atom has a 10-coordination sphere, BaO10, in which the oxygen atoms can be viewed as forming two intersecting pseudohexagonal planes. β-BaV2(P2O7)2 appears to form at a relatively higher temperature than its polymorph, α-BaV2(P2O7)2. A detailed structural analysis and structural comparison with the α-phase, as well as a brief comparison with SrV2(P2O7)2, are presented. 相似文献
4.
Robert J. Morris Scott R. Wilson Gregory S. Girolami 《Journal of organometallic chemistry》1994,480(1-2)
Treatment of the vanadium(II) tetrahydroborate complex trans-V(η1-BH4)2(dmpe)2 with (trimethylsilyl) methyllithium gives the new vanadium(II) alkyl cis-V(CH2SiMe3)2(dmpe)2, where dmpe is the chelating diphosphine 1,2-bis(dimethylphosphino)ethane. Interestingly, this complex could not be prepared from the chloride starting material VCl2(dmpe)2. The CH2SiMe3 complex has a magnetic moment of 3.8 μB, and has been characterized by 1H NMR and EPR spectroscopy. The cis geometry of the CH2SiMe3 complex is somewhat unexpected, but in fact the structure can be rationalized on steric grounds. The X-ray crystal structure of cis-V(CH2SiMe3)2(dmpe)2 is described along with that of the related vanadium(II) alkyl complex trans-VMe2(dmpe)2. Comparisons of the bond distances and angles for VMe2(dmpe) 2, V---C = 2.310(5) Å, V---P = 2.455(5) Å, and P---V---P = 83.5(2)° with those of V(CH2SiMe3)2(dmpe)2, V---C = 2.253(3) Å, V---P = 2.551(1) Å, and P ---V---P = 79.37(3)° show differences due to the differing trans influences of alkyl and phosphine ligands, and due to steric crowding in latter molecule. The V---P bond distances also suggest that metal-phosphorus π-back bonding is important in these early transition metal systems. Crystal data for VMe2(dmpe)2 at 25°C: space group P21/n, with a = 9.041(1) Å, b = 12.815(2) Å, c = 9.905(2) Å, β = 93.20(1)°, V = 1145.8(5) Å3, Z = 2, RF = 0.106, and RwF =0.127 for 74 variables and 728 data for which I 2.58 σ(I); crystal data for V(CH2SiMe3)2(dmpe)2 at −75°C: space group C2/c, with a = 9.652(4) Å, b = 17.958(5) Å, c = 18.524(4) Å, β = 102.07(3)°, V= 3140(3) Å3, Z = 4, RF = 0.033, and RwF = 0.032 for 231 variables and 1946 data for which I 2.58 σ(I). 相似文献
5.
M. Padmanabhan James C. Joseph Xiaoying Huang Jing Li 《Journal of Molecular Structure》2008,885(1-3):36-44
Lewis-base mediated fragmentation of polymeric nickel(II) fumarate and oxalate are attempted using chelating σ-donor diamines like ethylenediamine (en) and 1,3-diaminopropane (dap) in various conditions which yielded [Ni(en)3](fum)·3H2O (1), [Ni(en)3](ox) (2), [Ni(dap)2(fum)] (3) and [Ni(dap)(ox)]·2H2O (4). While 1 and 2 are molecular products each containing octahedral [Ni(en)3]2+ moieties and the anionic dicarboxylate species, 3 and 4 are dap-incorporated polymeric products. The fumarate derivative 1 containing [Ni(en)3]2+ moieties crystallizes in the monoclinic space group C2/c with a = 17.899(4) Å, b = 11.747(2) Å, c = 10.748(2) Å, β = 125.59(3)°, V = 1837.7(6) Å3, Z = 4, while the oxalate analogue 2 is seen to be in the trigonal space group P−31c with a = 8.8770(13) Å, b = 8.8770(13) Å, c = 10.482(2) Å, γ = 120°, V = 715.3(2) Å3, Z = 2. The octahedral [Ni(en)3] units in both 1 and 2 are seen to be strongly H-bonded to the dicarboxylate moieties through the coordinated en units leading to a three-dimensional network. However, in 1 the water molecules also take part in the H-bonding and contribute to the overall 3D structure. In both 1 and 2 the crystal packing is done with the [Ni(en)3]2+ units with absolute configuration Λ(δδδ) and its mirror conformer with Δ configuration in exactly equal numbers. Spectral (IR and UV–Visible) and magnetic measurements were carried out and some of the ligand-field parameters like Dq, B and β were evaluated for all the four compounds. These values suggest the presence of octahedrally coordinated nickel(II) in all the four complexes. Spectral data suggest that 3 has the two chelating dap moieties and the fumarate coordinated in η1 form through both its carboxylate moieties while 4 has one chelating dap and the oxalate moiety coordinated in η4-bis-chelating form. Though both 1 and 2 are made of the same type of [Ni(en)3]2+ units their thermograms give entirely different thermal features; 1 showing three clearly successive and step-wise dissociation of each en unit while 2 having a combined loss of two en units in the first thermal step. The relevant thermodynamic and kinetic parameters like Ea and ΔS also could be evaluated for various thermal steps for the compounds 1–4 using Coats–Redfern equation. 相似文献
6.
The compound [(μ-H)3Re3(CO)8{(EtO)2POP(OEt)2}2] crystallises in the monoclinic space group P21/c with a 18.053(6), b 16.211(5), c 14.800(3) Å, β = 102.41(2)°, and Z = 4. Simultaneous refinement of a single parameter set to fit 3212 X-Ray (sin θ/λ) > 0.352 Å−1 and 1480 neutron data has led to final weighted residuals Rw(F) of 0.096 (X-Ray) and 0.095 (neutron). The molecule exhibits noncrystallographic C2 symmetry, with two edges of the Re3 triangle bridged by (OEt)2POP(OEt)2 ligands. The hydride ligands lie close to the trimetal plane with each hydride bridging an Re---Re vector. Average molecular parameters involving the hydride ligands are Re---H 1.812(17), Re---Re 3.282(17) Å, Re---H---Re 130(3) and H---Re---H 107.6(27)/dg. All eight carbonyl ligands are terminal, the ligand polyhedron being derived from that in H3Re3(CO)12 by substitution of four axial carbonyls by two bidentate phosphite ligands. 相似文献
7.
Mikhail Bykov Anna Emelina Mikhail Kiskin Aleksei Sidorov Grigory Aleksandrov Artem Bogomyakov Zhanna Dobrokhotova Vladimir Novotortsev Igor Eremenko 《Polyhedron》2009,28(16):3628-3634
The solid-state thermolysis (420–450 °С) of the new heterometallic coordination polymer [Li2Co2(Piv)6(μ-L)2]n (1, Piv is the anion of pivalic acid, L is 2-amino-5-methylpyridine) followed by annealing of the decomposition products at 500 °С was shown to afford LiCoO2 in quantitative yield. Compound 1 was characterized by X-ray diffraction and magnetic measurements. 相似文献
8.
Yu Wang Jihong Yu Yi Li Yu Du Ruren Xu Ling Ye 《Journal of solid state chemistry》2003,170(2):303-307
Employing trans-1,4-diaminocyclohexane (trans-1,4-DACH) as a template, a new two-dimensional layered zinc phosphite (C6H16N2)Zn3(HPO3)4H2O (1) has been prepared hydrothermally. Single-crystal X-ray diffraction analysis shows that it crystallizes in the monoclinic space group P21/n with a=10.458(2) Å, b=14.720(3) Å, c=13.079(3) Å, β=97.93(3)°, V=1994.1(7) Å3, Z=4, R1=0.0349 (I>2σ(I)) and wR2=0.0605 (all data). The inorganic layer is built up by alternation of ZnO4 tetrahedra and HPO3 pseudo pyramids forming a 4.6.8-net. The sheet is featured by a series of capped six-membered rings. The diprotonated trans-1,4-DACH molecules reside in the interlayer region and interact with the inorganic network through H-bonds. 相似文献
9.
Zhi-En Lin Jie Zhang Shou-Tian Zheng Qiao-Hua Wei Guo-Yu Yang 《Solid State Sciences》2003,5(11-12):1435-1438
The hydrothermal synthesis, crystal structure and some properties of a zinc phosphite with a neutral cluster, [Zn(2,2′-bipy)]2(H2PO3)4, are reported. This compound crystallizes in the triclinic system of space group P-1 (No. 2), a=8.3067(5) Å, b=8.9545(4) Å, c=10.0893(6) Å, α=95.448(2)°, β=99.7530(10)°, γ=103.461(2)°, V=712.23(7) Å3, Z=1. The cluster consists of 4-membered rings formed by alternating ZnO3N2 square pyramids and H2PO3 pseudo pyramids, with two “hanging” H2PO3 groups attached to each of the Zn centers. The clusters are linked together by extensive multipoint hydrogen bonding involving the phosphite units to form a sheet-like structure. This compound represents the first example of zinc phosphite with P---OH bonds. An intense photoluminescence was observed from this compound upon photoexcitation at 388 nm. 相似文献
10.
The crystal structure of K2Cu3(As2O6)2 was determined from single-crystal X-ray data by a direct method strategy and Fourier summations [a = 10.359(4) Å, B = 5.388(2)Å, C = 11.234(4) Å, β = 110.48(2)°; space group C2/m; Z = 2; Rw = 0.025 for 1199 reflections up to sin /λ = 0.81 Å−1]. In detail, the structure consists of As(V)O4 tetrahedra and As(III)O3 pyramids linked by a common O corner atom to [As(V)As(III)O6]4− groups with symmetry m. The bridging bonds As(V)---O [1.749(3) Å] and As(III)---O [1.838(2) Å] are definitely longer than the other As(V)---O bonds [mean 1.669 Å] and As(III)---O bonds [1.764(2) Å, 2×]. The angle As(V)---O---As(III) is 123.0(1)°. The Cu atoms are [4 + 2]- and [4 + 1]-, and the K atom is [9]-coordinated to oxygen atoms. The As2O6 groups and the Cu coordination polyhedra are linked to sheets parallel to (001). These sheets are connected by the K atoms. Single crystals of K2Cu3(As2O6)2 suitable for X-ray work were synthesized under hydrothermal conditions. 相似文献
11.
The crystal structures of four hydrothermally synthesized alkaline earth-copper-selenites were determined: BaCu(SeO3)2-I [a = 5.247(1), B = 13.353(2), C = 8.981(1) Å, space group Pnm21, Z = 4, Rw = 0.024 for 1270 reflections], BaCu(SeO3)2-II [a = 5.256(1), B = 13.231(2), C = 8.933(1) Å, β = 90.19(1)°, space group P21/c, Z = 4, Rw = 0.046 for 2238 reflections], BaCu(SeO3)2-III [a = 8.031(1), B = 5.185(1), C = 15.823(2) Å, β = 90.83(1)°, space group C2/c, Z = 4, Rw = 0.038 for 1866 reflections], and SrCu(SeO3)2 [a = 7.929(1), B = 5.132(1), C = 14.997(2) Å, β = 90.53(1)°, space group C2/c, Z = 4, Rw = 0.028 for 1414 reflections; isotypic with BaCu(SeO3)2-III].BaCu(SeO3)2-I and -II contain Cu(SeO3)2 sheets lying parallel to (100) formed by CuO4 “squares” and selenite groups. These sheets are topologically different: in BaCu(SeO3)2-I they are formed by the connection of Cu2(SeO3) and Cu6(SeO3)4 rings while in BaCu(SeO3)2-II they are formed by Cu2(SeO3)2 and Cu6(SeO3)6 rings. The Cu(SeO3)2 sheets are rugged in BaCu(SeO3)2-I and they are slightly waved in BaCu(SeO3)2-II. In both compounds they are connected to each other by a fifth Cu---O bond and by the Ba atoms. In BaCu(SeO3)2-III and in its isotypic Sr analog the CuO4 “squares” and the selenite groups form parallel chains [010], which are connected by the alkaline earth atoms. 相似文献
12.
Chloride abstraction from [{M(η3 --- C3H5)Cl}n] (M = Pt, n = 4 or M = Pd, n = 2) by (NBu4)2[cis-Pt(C6F5)2(CCSiMe3)2] (1) gives rise to novel homo- and hetero-dinuclear zwitterionic derivatives (NBu4) [{cis-Pt(C6F5)2(CCSiMe3)2}M(η3-C3H5)] (M = Pt 2; M = Pd 3) which are formed by a M(η3-allyl)+ unit attached to both alkynyl ligands of the {cis-Pt(C6F5)2(CCSiMe3)2}2− fragment. The structure of 3 has been established by X-ray diffraction. 相似文献
13.
The nature of the protonation reaction of (
o(CO)3 (M = Mo, W; R = Me, Ph, p-MeC6H4) (2) (obtained from (CO)3CpMCH2CCR (1) and Co2(CO)8) to give (CO)3
Cp(CO)2 (3) was further investigated by a crossover experiment. Thus, reaction of an equimolar mixture of 2b (M = W, Cp = η5-C5H5, R = Ph) and 2e (M = W, Cp = η5-C5H4Me; R = p-MeC6H4) with CF3COOH affords only 3b (same M, Cp, and R as 2b) and 3e (same M, Cp, and R as 2e) to show an intramolecular nature of this transformation. Reaction of (CO)3CpWCH2CCPh (1b) with Co4(CO)12 was also examined and found to yield 2b exclusively. Treatment of 1 with Cp2Mo2(CO)4 at 0–5°C provides thermally sensitive compounds, possibly (CO)2Cp
oCp(CO)2 (5), which decompose at room temperature to give Cp2Mo2(CO)6 as the only isolated product. 相似文献
Full-size image (1K)
Full-size image (1K)
14.
The hydrothermal reaction of 3,5-pyridinedicarboxylic acid (pydcH2) and Co(NO3)2 or Ni(NO3)2 in the presence of 4,4′-bipyridine results in two novel compounds Co(pydc)(H2O)2 (1) and Ni(pydc)(H2O) (2). Crystal data: 1, monoclinic, C2/c, a=9.900(2), b=11.984(2), c=7.3748(15) Å, β=105.37(3)°, V=843.7(3) Å3, Z=4; 2, monoclinic, P21/c, a=7.7496(6), b=15.0496(11), c=6.4224(5) Å, β=108.437(1)°, V=710.59(9) Å3, Z=4. The structure of 1 is composed of honeycomb layers built up from {CoO4N} trigonal bipyramids and 3,5-pyridinedicarboxylate bridges. The structure of 2 adopts a three-dimensional framework structure in which the Ni atoms are coordinated by the pydc bridges both within the honeycomb layer and between the layers. The magnetic properties of 1 and 2 have been investigated. 相似文献
15.
Hong Zhang Yangguang Li Liying Duan Yang Lan Enbo Wang Changwen Hu Yuangen Yao Jiutong Chen Song Gao 《Journal of solid state chemistry》2003,170(2):232-236
A new mixed Mo/Ni/Ti heteropoly compound [C5H5NH]5 [(NiOH)2Mo10O36(PO4)Ti2] has been hydrothermally synthesized and structurally determined by the single-crystal X-ray diffraction. Black prismatic crystals crystallize in the monoclinic system, space group P2(1)/n, a=11.2075(2), b=37.8328(5) c=13.0888(1) Å, β=101.4580(10)°, M=2276.13, V=5439.19(13) Å3, Z=4. Data were collected on a Siemens SMART CCD diffractometer at 293(2) K in the range of 1.68<θ<25.09° using the ω-scan technique (λ=0.71073 Å R(F)=0.0872 for 9621 reflections). The title compound contains a trimetal heteropolyanion polymer and “trans-titanium”-bridging pseudo-Keggin fragments linked to a chain. 相似文献
16.
Solid solution investigations in the CsHSO4–CsH2PO4system, carried out as part of an ongoing effort to elucidate the relationship between proton conduction, hydrogen bonding, and phase transitions, yielded the new compound Cs5(HSO4)3(H2PO4)2. Single-crystal X-ray diffraction methods revealed that Cs5(HSO4)3(H2PO4)2crystallizes in space groupC2/c(or possiblyCc), has lattice parametersa=34.066(19) Å,b=7.661(4) Å,c=9.158(6) Å, andβ=90.44(6)°, a unit cell volume of 2389.9(24) Å3, a density of 3.198 Mg m−3, and four formula units in the unit cell. Sixteen non-hydrogen atoms and five hydrogen sites were located in the asymmetric unit, the latter on the basis of geometric considerations rather than from Fourier difference maps. Refinement using anisotropic temperature factors for all non-hydrogen atoms and fixed isotropic temperature factors for all hydrogen atoms yielded residuals based onF2(weighted) andFvalues, respectively, of 0.0767 and 0.0340 for observed reflections [F2>2σ(F2)]. The structure contains layers of (CsH2XO4)2that alternate with layers of (CsHXO4)3, whereXis P or S. The arrangement of Cs, H, andXO4groups within the two types of layers is almost identical to that in the end-member compounds, CsH2PO4and CsHSO4-II, respectively. Although P and S each reside on two of the threeXatom sites in Cs5(HSO4)3(H2PO4)2, the number of protons in the structure appears fixed. In addition, the correlation of S–O and S–OH bond distances with O···O distances, where the latter represents the distance between two hydrogen-bonded oxygen atoms, was determined from a review of literature data. 相似文献
17.
A novel thioantimonate(III) [(CH3NH3)1.03K2.97]Sb12S20·1.34H2O was synthesized hydrothermally. It crystallizes in space groupP
, witha=11.9939(7) Å,b=12.8790(8) Å,c=14.9695(9) Å,α=100.033(1)°,β=99.691(1)°,γ=108.582(1)°,V=2095.3(2) Å3, andZ=2. The structure is determined from single crystal X-ray diffraction data collected at room temperature and refined toR(F)=0.037. In the crystal structure, each Sb(III) atoms has short bonds (2.37–2.58 Å) to three S atoms. The pyramidal [SbS3] groups share common S atoms forming two types of centrosymmetric [Sb12S20] rings with the same topology. These rings are interconnected by weaker Sb–S bonds (2.92–3.29 Å) into 2-dimensional layers. Adjacent layers are parallel with K+and CH3NH+3ions and H2O molecules located between them. Variation of bond valence sums calculated for the Sb(III) cations is found to be correlated with the coordination geometry. This is interpreted as due to the stereochemical activity of their lone electron pairs. 相似文献
18.
Two novel heterometallic trinuclear incomplete cubane-like clusters [(CH3CH2)4N][{M2CuS4}(edt)2(PPh3)] (M = Mo, W) have been synthesized by reaction of [(CH3CH2)4N]2[M2S4(edt)2] (M = Mo, W) with Cu(PPh3)2(dtp) [where edt is 1,2-ethane-dithiolato ligand, dtp is S2P(OCH2CH3)2−]. The two crystals are isomorphous in space group P1 (No. 1). The unit cell contains two independent molecules, but the two discrete anions have the same orientation for the PPh3 ligands along one axis so the space group is undoubtedly non-centrosymmetric. The discrete anion contains two edt ligands and one PPh3 ligand attached to one incomplete cubane-like cluster core {M2CuS4}3+ (M = Mo, W). The bond lengths of Mo---Mo[W---W] and the two Mo---Cu[W-Cu] are 2.852(2)[2.844(1)], 2.802(2)[2.765(3)], 2.760(2)[2.762(3)] Å, respectively. The M 2S4(edt)2 (M = Mo, W) moiety remains almost unchanged, except that for the compound 1 the Mo=S double bond length elongates from av. 2.10 to av. 2.165 Å. The title clusters provide a new type of unsymmetric μ2-bridging sulphido ligand. The incomplete cubane-like cluster core {Mo2CuS4}3+ of compound 1 is distorted because the two Cu---μ2---S bond lengths are significantly different (2.313 Å and 2.409 Å), but the core {W2CuS4}3+ of compound 2 has approximately Cs symmetry. The IR spectra of the two title clusters and two starting materials are assigned. 相似文献
19.
[C4H9)4N]2[Mo2O7] reacts with a variety of organic species containing α-diketone groups to give tetranuclear complexes of general composition [RMo4O15X]3−. The complexes [(C4H9)4N]3[(C9H4O)Mo4O15(OCH3)] (I), [(C4H9)4N]3[(C14H10)Mo4O15(C6H5CO2)] (11) and [(C4H9)4N]3[(C14H8)Mo4O15(OH)] (III) were synthesized from the reactions of dimolybdate with ninhydrin, benzil and phenanthraquinone, respectively. Complex II may also be prepared from dimolybdate and benzoin in acetonitrile-methanol solution, from which it co-crystallizes with the binuclear species [(C4H9)4N]2[Mo2O5(C6H5C(O)C(O)C6H5)2] · CH3CN · CH3OH (IV). Complexes I–III exhibit the tetranuclear core, previously described for the α-glyoxal derivatives [(C4H9)4N]3[(HCCH)Mo4O15X], where X = F− or HCO2−. The ligands may be formally described as diketals, formed by insertion of ligand carbonyl subunits into molybdenum-oxygen bonds. The structures I–III differ most dramatically in the identity and coordination mode of the anionic ligand X− which occupies a position opposite the diketal moiety relative to the [Mo4O11]2+ central cage. Thus, I exhibits a doubly bridging methoxy group in this position, while II possesses a benzoate ligand with an unusual μ3-O,O′coordination mode. Complex III presents a hydroxy-group unsymmetrically bonded to three of the molybdenum centres. The stereochemical consequences of the various coordination modes are discussed. Crystal data: Compound I, monoclinic space group Pc, a = 24.888(2), b = 12.897(3), c = 24.900(3) Å, β = 101.94(2)°, Dcalc = 1.28 g cm−1 for Z = 4. Structure solution and refinement based on 8695 reflections with Fo 6σ(Fo) (Mo-Kα, λ = 0.71073 Å) converged at a conventional discrepancy factor of 0.060. Compound II, orthorhombic space group Pbca, a = 20.426(6), b = 26.916(6), c = 32.147(7) Å, V = 17673.2(20) Å3, Dcalc = 1.33 g cm−3 for Z = 8; 5224 reflections, R = 0.076. Compound III, tetragonal space group I41/a, a = b = 48.129(6), c = 13.057(2) Å, V = 30246.2(12) Å3, Dcalc = 1.35 g cm−3 for Z = 16; 5554 reflections, R = 0.053. Compound IV, orthorhombic space group Pnca, a = 16.097(4), b = 16.755(4), c = 25.986(7) Å, V = 7008.1(13) Å3, Z = 4, Dcalc = 1.18 g cm−3 ; 2944 reflections, R = 0.061. 相似文献
20.
Samia Yahyaoui Walid Rekik Houcine Naïli Tahar Mhiri Thierry Bataille 《Journal of solid state chemistry》2007,180(12):3560-3570
The crystal structures of 1,4-diazabicyclo[2.2.2]octane (dabco)-templated iron sulfate, (C6H14N2)[Fe(H2O)6](SO4)2, were determined at room temperature and at −173 °C from single-crystal X-ray diffraction. At 20 °C, it crystallises in the monoclinic symmetry, centrosymmetric space group P21/n, Z=2, a=7.964(5), b=9.100(5), c=12.065(5) Å, β=95.426(5)° and V=870.5(8) Å3. The structure consists of [Fe(H2O)6]2+ and disordered (C6H14N2)2+ cations and (SO4)2− anions connected together by an extensive three-dimensional H-bond network. The title compound undergoes a reversible phase transition of the first-order at −2.3 °C, characterized by DSC, dielectric measurement and optical observations, that suggests a relaxor–ferroelectric behavior. Below the transition temperature, the compound crystallizes in the monoclinic system, non-centrosymmetric space group Cc, with eight times the volume of the ambient phase: a=15.883(3), b=36.409(7), c=13.747(3) Å, β=120.2304(8)°, Z=16 and V=6868.7(2) Å3. The organic moiety is then fully ordered within a supramolecular structure. Thermodiffractometry and thermogravimetric analyses indicate that its decomposition proceeds through three stages giving rise to the iron oxide. 相似文献