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1.
The molecular and crystal structures of two p-alkoxybenzylidene)-p′-toluidines C2H5O-C6H4-CH=N-C6H4-CH3 (1) and C4H9O-C6H4-CH=N-C6H4-CH3 (2) are determined by X-ray diffraction. Crystals 1 and 2 contain four and two crystallographically independent molecules, respectively. In 1, the geometry of the independent molecules is almost identical. In 2, the independent molecules differ in the conformation of the alkyl chain, which is disordered in one of them. An analysis
of the crystal packing of 2 reveals the alternation of spacious layers formed by loosely packed aliphatic fragments of molecules and layers of closely
packed aromatic fragments, which ensures the formation of the mesogenic phase in the course of melting of crystals 2. In crystal 1, loose aliphatic layers are absent.
Original Russian Text ? L.G. Kuz’mina, N.S. Kucherepa, M.N. Rodnikova, 2008, published in Kristallografiya, 2008, Vol. 53,
No. 6, pp. 1072–1078. 相似文献
2.
Benjamin G. Harvey Atta M. Arif Richard D. Ernst 《Journal of chemical crystallography》2010,40(9):783-787
Abstract
The reactions of imines of the formula (C6H5)CH=NR (R = C6H5, i-C3H7) with Ti(C5H5)(2,4-C7H11)(PMe3) (C7H11 = dimethylpentadienyl) lead to expulsion of the PMe3 and coupling between the imine’s carbon atom and a single terminus of the 2,4-C7H11 ligand, resulting in C5H5, “diene,” and π-amide coordination in the 16 electron products. Examination of the Ti–C and C–C bonding parameters for the “diene” ligands reveals that they may be more appropriately regarded as enediyl ligands, leading to a formal +4 oxidation state for titanium. Both complexes crystallize in the triclinic space group P[`1] P\overline{1} . For the R = C6H5 coupling product, a = 10.4590(2) ?, b = 11.6407(2) ?, c = 17.3729(3) ?, α = 74.7610(7)°, β = 79.8600(6)°, γ = 82.2895(11)°, V = 2000.28(6) ?3, D calc = 1.293 g/cm3 at 150(1) K. For the R = i-C3H7 coupling product, a = 8.1039(2) ?, b = 9.4115(2) ?, c = 13.0116(4) ?, α = 88.9906(18)°, β = 73.2780(15)°, γ = 83.3088(16)°, V = 943.82(4) ?3, D calc = 1.250 g/cm3 at 150(1) K. 相似文献3.
The crystal and molecular structure of p-(decaoxybenzylidene)-p′-toluidine C10H21O-C6H4-CH=N-C6H4-CH3 is studied. The molecule is nearly planar. In the crystal packing, loose regions formed by aliphatic fragments of molecules alternate with pseudostacks of aromatic fragments of molecules that are related by the centers of symmetry. The stacks are built of dimers, in which molecules are linked by π-stacking interactions between benzene rings. There are no weak directional interactions between dimers in a stack. The presence of a single structure-forming element in the crystal, namely, the π-stacking interactions in the dimers, along with the similarity of the crystal packing to that of the C8H17O-homologue, which forms a nematic mesophase on melting, indicate that the crystals under study should exhibit nematic properties. 相似文献
4.
L. B. Serezhkina M. S. Grigor’ev I. S. Kuz’menko V. N. Serezhkin 《Crystallography Reports》2012,57(2):258-263
Compounds K2[UO2(C3H2O4)2] · H2O (I) and Rb2[UO2(C3H2O4)2] · H2O (II) are synthesized and their crystal structures are determined by X-ray diffraction. The compounds crystallize in the monoclinic
crystal system; for I, a = 7.1700(2) ?, b =12.3061(3) ?, c = 14.3080(4) ?, β = 95.831(2)°, space group P21/n, Z = 4, and R = 0.0275; for II, a = 7.1197(2) ?, b = 12.6433(4) ?, c = 14.6729(6) ?, β = 96.353(2)°, space group P21/n, Z = 4, and R = 0.0328. It is found that I and II are isostructural. The main structural units of the crystals are the [UO2(C3H2O4)2]2− chains, which belong to the AT
11
B
01 (A = UO22+, T
11, and B
01 = C3H2O42−) crystal chemical group of uranyl complexes. The chains and alkali metal ions R (R = K or Rb) are connected by electrostatic interactions and hydrogen bonds. Some specific structural features of [UO2(C3H2O4)2]2− complex groups are discussed. 相似文献
5.
L. S. Smirnov K. Wozniak P. Dominiak A. Loose I. Natkaniec M. V. Frontasyeva E. V. Pomyakushina A. I. Baranov V. V. Dolbinina 《Crystallography Reports》2008,53(3):418-427
The crystal structure of a mixed [Rb0.11(NH4)0.89]3H(SO4)2 crystal was refined using single-crystal X-ray and neutron diffraction at 300 K. The refinement confirmed that the phase
II of the crystal belongs to the monoclinic crystal system (space group C2/c). It was shown that, according to the single-crystal neutron diffraction data, ammonium ions can be represented as regular
tetrahedra. The analysis of the constructed difference Fourier maps of the electron and nuclear densities of ammonium ions
revealed the presence of additional peaks, which can indicate the dynamic disorder of ammonium ions in the phase II. The results
obtained con-firmed that the phase transition to the orientational-glass state can occur in the mixed [Rb0.11(NH4)0.89]3H(SO4)2 crystal with a decrease in the temperature.
Original Russian Text ? L.S. Smirnov, K. Wozniak, P. Dominiak, A. Loose, I. Natkaniec, M.V. Frontasyeva, E.V. Pomyakushina,
A.I. Baranov, V.V. Dolbinina, 2008, published in Kristallografiya, 2008, Vol. 53, No. 3, pp. 450–459. 相似文献
6.
L. B. Serezhkina E. V. Peresypkina A. V. Virovets A. G. Verevkin D. V. Pushkin 《Crystallography Reports》2009,54(2):259-266
Single crystals of the compounds (C3N6 H7)4(CN3H6)2[UO2(CrO4)4] · 4H2O (I) and (H3O)6[UO2(CrO4)4] (II) are synthesized, and their structures are investigated using X-ray diffraction. Compound I crystallizes in the triclinic system with the unit cell parameters a = 6.3951(8) ?, b = 10.8187(16) ?, c = 16.9709(18) ?, α = 93.674(4)°, β = 97.127(4)°, γ = 92.020(4)°, space group, P
Z = 1, V = 1161.6(3) ?3, and R = 0.0470. Crystals of compound II belong to the monoclinic system with the unit cell parameters a = 14.3158(4) ?, b = 11.7477(3) ?, c = 13.1351(4) ?, β= 105.836(1)°, space group C2/c, Z = 4, V = 2125.2(1) ?3, and R = 0.0213. The uranium-containing structural units of crystals I and II are mononuclear anionic complexes of the composition [UO2(CrO4)4]6− with an island structure, which belong to the crystal-chemical group Am
14 (A = UO2+2, M
1 = CrO2−4) of the uranyl complexes. The [UO2(CrO4)4]6− anionic complexes are joined into a three-dimensional framework through the electrostatic interactions with outer-sphere
cations and a system of hydrogen bonds.
Original Russian Text ? L.B. Serezhkina, E.V. Peresypkina, A.V. Virovets, A.G. Verevkin, D.V. Pushkin, 2009, published in
Kristallografiya, 2009, Vol. 54, No. 2, pp. 284–290. 相似文献
7.
Abstract The mononuclear complex [Na(C7H6O4)(H2O)3](C7H5O4) · 2H2O has been synthesized and characterized by IR, single crystal X-ray and thermal analysis. The compound crystallizes in the
monoclinic space group P21 with a = 3.623(2) ?, b = 15.872(6) ?, c = 15.650(5) ?, β = 93.13(4)°, V = 896.6(7) ?3 and Z = 2. The central sodium ion is six coordinated with distorted octahedral geometry by two oxygen atoms from two bridging 3,5-dihydroxybenzoate
ligands and four ones from different water molecules. The notable feature of the title complex is the formation of a three-dimensional
network, through the combination of coordination bonds, hydrogen bonds and π···π interactions. There are one-dimensional channels
in the structure, filled in by water molecules. The compound dehydrates in the temperature range of 70–125 °C and then is
stable up to 230 °C.
Index Abstract The mononuclear complex [Na(C7H6O4)(H2O)3](C7H5O4) · 2H2O has been synthesized and characterized by IR, single crystal X-ray and thermal analysis.
相似文献
8.
Shishir Ghosh Faruque Ahmed Rafique Al-Mamun Daniel T. Haworth Sergey V. Lindeman Tasneem A. Siddiquee Dennis W. Bennett Shariff E. Kabir 《Journal of chemical crystallography》2009,39(8):595-602
Abstract Treatment of Mn2(CO)10 with 2-thiazoline-2-thiol in the presence of Me3NO at room temperature afforded the dimanganese complexes [Mn2(CO)7(μ-NS2C3H4)2] (1) and [Mn2(CO)6(μ-NS2C3H4)2] (2) in 51 and 34% yields, respectively. Compound 1 was quantitatively converted into 2 when reacted with one equiv of Me3NO. Reaction of 1 with triphenylphosphine at room temperature furnished the mononuclear complex [Mn(CO)3(PPh3)(κ
2-NS2C3H4)] (3) in 66% yield. All three new complexes have been characterized by elemental analyzes and spectroscopic data together with
single crystal X-ray diffraction studies for 1 and 3. Compound 1 crystallizes in the orthorhombic space group Pbca with a = 12.4147(2), b = 16.2416(3), c = 19.0841(4) ?, β = 90°, Z = 8 and V = 3848.01(12) ?3 and 3 crystallizes in the monoclinic space group P 21/n with a = 10.41730(10), b = 14.7710(2), c = 14.9209(2) ?, β = 91.1760(10)°, Z = 4 and V = 2295.45(5) ?3.
Graphical Abstract Two new dimanganese complexes [Mn2(CO)7(μ-NS2C3H4)2] (1) and [Mn2(CO)6(μ-NS2C3H4)2] (2) were formed when [Mn2(CO)10] was treated with 2-thiazoline-2-thiol in the presence of Me3NO. Compound 2 reacts with PPh3 to give the monomeric complex [Mn(CO)3(PPh3
)(κ
2-NS2C3H4)]. The structures of 1 and 3 were established by crystallography. Shishir Ghosh, Faruque Ahmed, Rafique Al-Mamun, Daniel T. Haworth, Sergey V. Lindeman,
Tasneem A. Siddiquee, Dennis W. Bennett, Shariff E. Kabir Investigations of 2-thiazoline-2-thiol as a ligand: Synthesis and
X-ray structures of [Mn2(CO)7(μ-NS2C3H4)2] and [Mn(CO)3
(PPh3)(κ
2-NS2C3H4)].
相似文献
9.
Maxime A. Siegler Sylvestre Bonnet Antoine M. M. Schreurs Robertus J. M. Klein Gebbink Gerard van Koten Anthony L. Spek 《Journal of chemical crystallography》2010,40(9):753-760
Abstract
Crystals of the complex [Ru(C5Me5)(η6-1,3-(Me2NCH2)2C6H4)](BF4) have been examined over the temperature range 150–300 K via X-ray diffraction measurements. This study shows that the Ru complex is a two-phase system in this T-range and the solid–solid transition is reversible. At 150 K, phase II (P21/c, Z′ = 4) is ordered and non-merohedrally twinned, a = 16.4396 (9) ?, b = 17.3226 (4) ?, c = 32.1874 (11) ?, β = 91.375 (2)°. At 295 K, phase I (Pbca, Z′ = 1) is disordered, a = 8.5071 (3) ?, b = 17.1567 (3) ?, c = 32.8250 (8) ?. The relationship between the two phases is obvious because the packing remains similar in the two phases. The greatest structural changes between the two phases are found in the rows of adjacent cations [Ru(C5Me5)(η6-1,3-(Me2NCH2)2C6H4)]+ packed along the a direction. These rows are ordered in phase II but are disordered in phase I. The phase transition is first order. Significant changes in thermal motion for the cations are considered as being the driving force for the occurrence of this phase transition. 相似文献10.
John J. Allen Christopher E. Hamilton Andrew R. Barron 《Journal of chemical crystallography》2009,39(8):573-580
Abstract The molecular structures of RN(H)Py [R = 2,4,6-Me3C6H2 (1), 2,6-Et2C6H3 (2), -CPh3 (3)] have been determined along with the copper(I) complex [Cu{(2,4,6-Me3C6H2)N(H)Py}2]BF4 (4). Each of the amines exists as a hydrogen-bonded head-to-tail dimer. Compound 3 has four independent molecules in the asymmetric unit as a consequence of changes in the relative orientation of the pyridyl
and phenyl rings. The copper in 4 is two-coordinate with the conformation of the aryl rings being dominated by inter-cation packing. Crystal data: 1 space group P21/c, a = 14.047(3), b = 7.154(1), c = 13.890(3) ?, β = 116.45(3)°; V = 1,249.7(4) ?3, Z = 4, R = 0.0547, wR
2 = 0.1397; 2 space group P21/n, a = 13.035(3), b = 8.120(1), c = 13.562(3) ?, β = 111.87(3)°; V = 1,345.2(5) ?3, Z = 4, R = 0.0669, wR
2 = 0.1512; 3 space group P21/c, a = 26.729(5), b = 17.008(3), c = 18.903(4) ?, β = 92.42(3)°; V = 8,586(3) ?3, Z = 8, R = 0.0911, wR
2 = 0.163; 4 space group P21/c, a = 9.149(1), b = 15.901(3), c = 19.703(4) ?, β = 102.89(3)°; V = 2,794(1) ?3, Z = 4, R = 0.0504, wR
2 = 0.1291.
Graphical Abstract The hydrogen-bonded head-to-tail dimer structures of RN(H)Py [R = 2,4,6-Me3C6H2, 2,6-Et2C6H3, -CPh3] have been determined along with the two-coordinate copper complex [Cu{(2,4,6-Me3C6H2)N(H)Py}2]BF4
相似文献
11.
Abstract Both the title multi-sulfur molecules C5H2S5 (1) and C5H2OS4 (2) have a chair conformation, while molecule 1 has a higher degree of π-conjugation. Both the crystals are characterized by short S···S intermolecular contacts and by face-to-face
column-like packing style, but crystal 1 has been more stabilized which may be the result of its stronger π–π intermolecular interactions. Compound 1 crystallizes in non-centrosymmetric polar space group Pmn21 with a = 10.6826(17), b = 9.3633(11), c = 4.0764(6) ?, V = 407.74(10) ?3, and Z = 2. The molecular dipole moment of 1 is ±62.5(1)° away from the macro-polarization direction along the c-axis. Consequently, the crystalline powder of crystal 1 exhibit a second harmonic generating (SHG) intensity 0.5 time strong as that of urea standard powder crystals when irradiated
by a 1,080 nm of Nd:YAP laser beam. Compound 2 shows no SHG effect because it crystallizes in centrosymmtric space group Pbca with a = 11.4208(8), b = 7.8843(9), c = 33.587(3) ?, V = 3024.3(5) ?3, and Z = 16.
Index Abstract Structures and Non-linear Optical Properties of Multi-Sulfur π-Conjugated Compounds 4,5-Vinylenedithio-1,3-dithiole-2-thione
(C5H2S5) and 4,5-Vinylenedithio-1,3-dithiole-2-one (C5H2OS4)
Gang Xue, Qi Fang,* Wen-Tao Yu, Xia Chen, and Hong Lei
Compound C5H2S5 crystallizes in the polar space group Pmn21 and its crystalline powder exhibits a second harmonic generating (SHG) intensity 0.5 times that of urea standard (1080 nm → 540 nm),
while the similar compound C5H2OS4 has no SHG effect because of its centrosymmetric space group Pbca.
相似文献
12.
Hossni Ziyat Moulay Youssef Ait Itto Mustapha Ait Ali Abdellah Karim Abdelkhalek Riahi Jean-Claude Daran 《Journal of chemical crystallography》2011,41(3):338-342
Abstract
The title compounds C11H16Cl2O3 (III) and C11H16Br2O3 (IV) have been prepared from (S)-Limonen. Their crystal structure and absolute configuration have been determined by X-ray analysis which confirmed the 1′S absolute configuration at the cyclopropyl moiety, in agreement with the known absolute configuration of the starting material. Both (III) and (IV) are orthorhombic, space group P212121 with a = 7.2558(4) ? (for III) 7.4058(6) ? (for IV), b = 9.7885(5) ? (for III) 9.7459(7) ? (for IV), c = 17.7551(10) ? (for III) 18.0354(14) ? (for IV), α = 90°, β = 90°, γ = 90° and Z = 4. 相似文献13.
William H. Watson Tao Chen Michael G. Richmond 《Journal of chemical crystallography》2004,34(11):797-805
Replacement of the acetonitrile ligands in Ru3(CO)10(MeCN)2 by the diphosphine ligand 1,2-bis(diphenylphosphino)cyclobutenedione (bpcbd) initially gives the unstable bpcbd-bridged cluster Ru3(CO)10(bpcbd) (1), followed by its subsequent transformation to the triruthenium cluster Ru3(CO)10(bma) (2). The decomposition of cluster 2 serves to produce the ruthenium compounds Ru3(CO)10[2,3-bis(diphenylphosphino)succinic anhydride] (3) and Ru2(CO)6(bma) (4). Compounds 2–4 provide the experimental evidence for the ring expansion of the cyclobutenedione ring via the formal insertion of an oxygen atom into the four-membered ring and hydrogen addition to the bond upon exposure to the atmosphere and/or moisture. Both 3 and 4 have been isolated and characterized in solution by IR and 31P NMR spectroscopies, and the molecular structure of each product has been verified by X-ray crystallography. Ru3(CO)10[2,3-bis(diphenylphosphino)succinic anhydride] crystallizes, as the CH2Cl2 solvate, in the monoclinic space group P21/c, a = 12.178(2)Å, b = 15.988(2)Å, c = 22.472(3)Å, = 95.115(2)°, V = 4358(1)Å3, Z = 4, and dcalc = 1.732 Mg/m3; R = 0.0344, Rw = 0.0931 for 5683 reflections with I > 2(I). The dinuclear compound Ru2(CO)6(bma) crystallizes in the triclinic space group P-1, a = 9.298(3)Å, b = 12.020(3)Å, c = 30.858(8)Å, = 81.774(5)°, = 89.276(5)°, = 83.545(4)°, V = 3391(1)Å3, Z = 4, and dcalc = 1.730 Mg/m3; R = 0.0670, Rw = 0.1444 for 8766 reflections with I > 2a(I). 相似文献
14.
L. B. Serezhkina E. V. Peresypkina A. V. Virovets A. G. Verevkin D. V. Pushkin 《Crystallography Reports》2009,54(1):63-67
Single crystals of the compound K8[(UO2)2(C2O4)2(SeO4)4] · 2H2O (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 14.9290(4) ?, b = 7.2800(2) ?, c = 15.3165(4) ?, β = 109.188(1)°, V = 1572.17(7) ?3, space group P21/n, Z = 2, and R = 0.0297. The uranium-containing structural units of crystals I are dimers of the composition [(UO 2)2(C2O4)2(SeO4)4]8−, which belong to the crystal-chemical group AB
01
B
2
M
1 (A = UO22+, B
01 = C2O42−, B
2 = SeO42−, M
1 = SeO42−) of the uranyl complexes. The [(UO2)2(C2O4)2(SeO4)4]8− dimers are joined into a three-dimensional framework through electrostatic interactions with the outer-sphere potassium cations.
Original Russian Text ? L.B. Serezhkina, E.V. Peresypkina, A.V. Virovets, A.G. Verevkin, D.V. Pushkin, 2009, published in
Kristallografiya, 2009, Vol. 54, No. 1, pp. 68–71. 相似文献
15.
L. B. Serezhkina A. V. Vologzhanina N. A. Neklyudova V. N. Serezhkin 《Crystallography Reports》2009,54(1):59-62
Single crystals of the compound {NH2(C2H5)2}2[(UO2)2C2O4(CH3COO)4] · 2H2O (I) are synthesized, and their structure is investigated using X-ray diffraction. Compound I crystallizes in the monoclinic system with the unit cell parameters a = 9.210(2) ?, b = 14.321(3) ?, c = 12.659(3) ?, β = 105.465(13)°, V = 1609.2(6) ?3, space group P21/c, Z = 2, and R = 0.0198. The structural units of crystals I are binuclear groups of the composition [(UO2)2C2O4(CH3COO)4]2− with an island structure, which belong to the crystal-chemical group A
2
K
02
B
401 (A = UO22+, K
02 = C2O42−, B
01 = CH3COO−) of the uranyl complexes, diethylammonium cations, and water molecules. The uranium-containing groups are joined into a three-dimensional
framework through electrostatic interactions with diethylammonium cations and a system of hydrogen bonds, which are formed
with the participation of the atoms involved in the composition of the water molecules, oxalate ions, acetate ions, and diethylammonium
cations.
Original Russian Text ? L.B. Serezhkina, A.V. Vologzhanina, N.A. Neklyudova, V.N. Serezhkin, 2009, published in Kristallografiya,
2009, Vol. 54, No. 1, pp. 65–67. 相似文献
16.
Abstract
The [Cu(C4H8ONH(C3H5))(H2O)2]SiF6·H2O compound (I) was obtained by alternating current electrochemical synthesis, starting from a solution containing CuSiF6·4H2O and N-allylmorpholinium hexafluorosilicate. Compound I crystallizes in a trigonal P 31 space group, a = 8.6449(4), c = 16.5629(11) Å, V = 1071.98(10) Å3, Z = 3 for Cu(C7H14NO)SiF6·3H2O composition, R = 0.0569 for 2987 reflections and 182 refined parameters. The C=C bond of one N-allylmorpholinium cation, elongated to 1.38(1) Å, the O-atom from another ligand moiety, and two oxygen atoms from two water molecules form the trigonal-pyramidal environment of the metal atom. The bridging function of the ligand moiety results in infinite metal-organic chains. One more water molecule is fixed in the crystal space by hydrogen bonds only. 相似文献17.
Antonio Jesús Martínez-Martínez María Teresa Chicote Delia Bautista 《Journal of chemical crystallography》2011,41(12):1961-1967
Abstract
The crystal structures of trans-[PdI{C=N(Xy)CH(R)NHC6H4-2}(CNXy)2]OTf (R = Me (1·CHCl3) space group P-1, a = 8.7665(4) ?, b = 15.5346(8) ?, c = 16.2415(8) ?, α = 72.698(2)o, β = 78.310(3)o, γ = 88.310(2)o, CH = CH2 (2·0.5Et2O) space group P21/c, a = 15.7868(6) ?, b = 14.5066(6) ?, c = 18.5814(7) ?, β = 106.707(2)o, C6H4Me-4 (Tol) (3) space group P-1, a = 11.96075(5) ?, b = 12.9452(51) ?, c = 13.1263(5) ?, α = 93.306o, β = 95.822(2)o, γ = 94.572(2)o) have been measured. The structural data suggest the existence of some electron delocalization over the heterocyclic ring, the extension of which seems to depend on the R substituent. The complex [PdI{C6H4(N=CHTol)-2}(bpy)] (Tol = C6H4Me-4, bpy = 2,2′-bipyridine, 4) is the fourth imino-substituted aryl palladium complex. Complex 4 crystallizes in triclinic P-1 with a = 8.7873(5) ?, b = 8.8936(5) ?, c = 13.8375(8) ?, α = 90.116(2)o, β = 92.760(2)o, γ = 106.243(2)o. 相似文献18.
K. Yu. Suponitskii D. V. Gusev L. N. Kuleshova M. Yu. Antipin 《Crystallography Reports》2002,47(4):610-615
Two polymorphic modifications of 1-acetyl-3-(4-nitrophenyl)-5-(2′-furyl)pyrazoline (I) are investigated by X-ray diffraction with the purpose of analyzing the factors responsible for the formation of crystal structures of the optical nonlinear organic compounds. Both modifications crystallize simultaneously upon slow evaporation of a solution of compound I in an isopropanol-acetonitrile (3: 1) mixture. It is found that the molecular geometry of the polymorphic modifications is characterized by the rotation of the furan substituent with respect to the plane of the pyrazoline ring. The molecular hyperpolarizabilities (β) of both conformers are calculated. 相似文献
19.
Rehan Basta Atta M. Arif Richard D. Ernst 《Journal of chemical crystallography》2011,41(10):1433-1437
Abstract
The reactions of Ti(C5H5)(6,6-dmch)(PMe3) and Zr(C5H5)(6,6-dmch)(PMe3)2 with two equivalents of C6H5C(H)=N(C6H5) have led to couplings of the imines to the 1,5 (terminal) positions of the 6,6-dmch ligands. In both cases the PMe3 ligands are lost, and the metal complexes each attain 18 electron configurations via η5-(C5H5), η3-allyl, and bis(π-amide) coordination. The complexes each crystallize in the monoclinic space group P21/c. For the titanium complex, a = 10.4336(1) ?, b = 9.0407(1) ?, c = 32.5547(6) ?, β = 94.2939(5)°, V = 3062.17(7) ?3, Dcalc = 1.264 at 200(1) K. For the zirconium complex, a = 13.8900(3) ?, b = 10.0873(2) ?, c = 22.4543(6) ?, β = 90.7638(7)°, V = 3145.85(12) ?3, Dcalc = 1.322 at 150(1) K. 相似文献20.
A. V. Shlyakhtina A. E. Sokolov V. A. Ul’yanov V. A. Trunov M. V. Boguslavski? A. V. Levchenko L. G. Shcherbakova 《Crystallography Reports》2009,54(1):25-30
The crystal structure of pyrochlore-like solid solutions (Yb1 − x
Ca
x
)2Ti2O7 (x = 0, 0.05, 0.10) synthesized by high-temperature annealing of mechanically activated initial oxides at temperatures of 1300–1500°C
is studied using neutron diffraction. It is found that the Ca2+ cations are located in the ytterbium sublattice, which apparently favors the splitting of one of the oxygen sublattices [O(2)
(48f)] of the pyrochlore structure: the decrease in the occupancy of this sublattice is accompanied by the formation of a new
sublattice O(3) (8b), whereas the other oxygen sublattice O(1) (8a) remains unchanged. This rearrangement of the anions in the oxygen subsystem due to the incorporation of an alkaline-earth
cation explains the high ionic conductance (∼0.2 S/cm at 1000°C) for (Yb0.9Ca0.1)2Ti2O7 ∼ 0.2, which is the maximum value observed to date for pyrochlores of the A
2
B
2O7 type, where A = Ln and B is a Subgroup IVA element of the periodic system. The bulk and grain-boundary components of the conductivity of (Yb0.95Ca0.05)2Ti2O7 synthesized at temperatures of 1300, 1400, and 1500°C are studied using impedance spectroscopy. It is found that the (Yb0.95Ca0.05)2Ti2O7 sample synthesized at 1500°C has the highest total conductivity due to the increased grain-boundary component. The bulk component
of the ionic conductivity of (Yb0.95Ca0.05)2Ti2O7 is hardly affected by the synthesis temperature and depends mainly on the degree of heterovalent substitution.
Original Russian Text ? A.V. Shlyakhtina, A.E. Sokolov, V.A. Ul’yanov, V.A. Trunov, M.V. Boguslavskiĭ, A.V. Levchenko, L.G.
Shcherbakova, 2009, published in Kristallografiya, 2009, Vol. 54, No. 1, pp. 31–36. 相似文献