Tb2Fe17和Tb2（Fe,Si）17磁性单晶的生长和相图

利用磁悬浮冷坩埚提拉法技术生长了Tb2Fe17和Tb2(Fe,Si)17的单晶,并用差热分析等方法研究了材料的相图。研究结果表明：Tb2Fe17的相关系并非以往报道的包晶反应。而是同成分熔化。本文还给出了Tb2Fe17化合物附近的新相图。采用优化后的生长条件,获得了缺陷较少的Tb2Fe17和Tb2(Fe,Si)17高质量单晶,分析了Si替代对于化合物结构的影响,测量了Tb2Fe17单晶样品的基本磁性。从材料的一级磁化过程的测量可以看出,在理想配比条件下最容易获得缺陷密度低的单晶样品,这种磁性测量方法为了解单晶的完整性提供了一个有效的间接观察方法。     

Crystal structure of 17β-hydroxy-17α-methyl-5α-androstano [2,3-C] Furazan (Furazabol)

The crystal and molecular structure of 17-hydroxy-17-5-androstano [2,3-C] Furazan, Furazabol (C₂₀H₂₄N₂O₂), has been determined by direct methods and refined by full matrix least squares to a final R of 0.0528 for 1927 observed reflections and 216 parameters, CuK, = 1.54178 Å. The compound crystallizes with two molecules in the asymmetric unit, Z = 4, Dc = 1.131 Mg m^–3 space group P2₁, with unit cell parameters a = 18.747(3), b = 6.346(5), c = 15.647(4) Å, = 99.96(2)°, V = 1833.9 ų, (CuK) = 0.584 mm^–1. Whilst the two independent molecules have similar overall geometry there are small differences in bond lengths, bond angles and torsion angles in rings A and D and significant conformational differences in ring A. The A ring adopts a half-chair conformation in molecule A and an intermediate between a half-chair and a sofa in molecule B. The D ring in molecule A has a 13/14 half-chair conformation and in molecule B a conformation between an envelope and half-chair.     

Crystal structure of γ-2-trans-2,6-diphenylthian-1,1-dioxide-4-one oxime, C17H17NO3S

The X-ray crystal structure of -2-trans-2,6-diphenylthian-1,1-dioxide-4-one oxime is determined [C₁₇H₁₇NO₃S, space group P2₁ n, a = 8.177(1) b = 9.574(1)c = 19.730(5) Å, = 97.35(5)°]. The oxime group does not form an oxime dimer, but is involved in an O-H···O=S hydrogen bond.     

Crystal structure of a synthetic anabolic agent: stanazolol ethanol solvate, 17β-hydroxy-17α methylandrostano[3,2-c]pyrazole ethanoate

The crystal and molecular structure of 17-hydroxy-17 methylandrostano[3,2-c]pyrazole ethanoate (stanazolol ethanol solvate), C₂H₃₀N₂OC₂H₅OH, has been determined by direct methods and refined by full-matrix least squares to a final R of 0.0577 for 4021 observed reflections and 245 parameters using Cu K radiation, = 1.54178 Å. The compound crystallizes in space group P2₁2₁2₁ with Z = 4 molecules per unit cell. In the steroid skeleton the ring A adopts a half-chair conformation, being considerably strained, as a consequence of the fused planar pyrazole ring E. Rings B and C however are chairs and ring D has a 13,14 half-chair conformation. All rings of the steroid skeleton are trans-connected. The OH group of the solvated ethanol molecule is hydrogen bonded to the -oriented carbonyl substituent O(20) of ring D. The molecules are further held together in the crystal structure by head–tail hydrogen bonding between N(1)H in the pyrazole ring and O(20), which consequently is an acceptor for the two H-bonds. Overall the molecule lacks any significant curvature with no interplanar dihedral angle greater than 7°. Possible binding modes of stanazolol with the human androgen receptor are discussed.     

Crystal and molecular structure of 3,5-cycloandrostan-6β-ol-17-one

The crystal and molecular structure of 3,5-cycloandrostan-6-ol-17-one has been determined by X-ray analysis,¹³C-NMR,¹H-NMR, IR and elemental analyses. The compound was obtained from dehydroepiandrosterone (DHEA) via the 3-tosyl derivative by refluxing in a butan-2-one/water mixture. The X-ray analysis shows that the planar cyclopropane ring is predominantly orientated and the formation of the C(3)-C(5) bond enables the A ring to adopt a distorted boat conformation. Spectroscopic evidence for the presence of the cyclopropane ring and the 6-hydroxy group are presented.     

Steroids and related studies,part 75: The crystal and molecular structure of 17a-(2-hydroxyethyl)-17a-aza-D-homo-5-androsten-3βol (HS407)

The crystal structure of 17a-(2 hydroxyethyl)-17a-aza-D-homo-5-androsten-3ol, C₂₂ NO₂ H₃₃ (HS407), an intermediate in the formation of azasteroidal neuromuscular blocking agents, has been determined by Vector Verification and refined by full-matrix least-squares toR=0.058 for 1805 reflections, Cu K radiation,65.49°. The space group is P2₁2₁2,a=25.537(5),b=9.847(4),c=7.545(5) Å,Z=4. The rings in the modified steroid nucleus are alltrans connected, with A and C in distorted chair conformations, D a symmetrical chair, and B a half-chair. The hydroxyethyl side-chain in position N (17a) adopts two distinct conformations with approximately equal statistical occupancies: the first, having a coiled conformation, forms a close intramolecular contact with N(17a) in the enlarged ring D of the steroid nucleus, while the alternative side chain position, which is extended, participates in tail-to-tail intermolecular hydrogen bonding. A switch mechanism is thus formed which could influence the mode of binding of this type of drug moleculein vivo.     

Crystal and molecular structure of 17-β-methyllupanineN(16)-oxide perchlorate hemihydrate

[C₁₆H₂₇N₂O₂]⁺·C1O ₄ ^– ·1/2H₂O,M _r =387.86, is monoclinic:P2₁,a=8.934(1),b=14.625(1),c=14.449(1) Å, =103.03(1)°,V _c =1839.3(2) ų,Z=4,D _x =1.40(1) g cm^–3, (CuK)=1.54178 Å,(CuK)=20.29 cm^–1,F(000)=808 e,T=292K,R=0.057 for 3428 observed reflections. Two independent cations are connected into chains along [101] by short hydrogen bonds between their oxygen atoms O(C2) and O(N16); distances, 2.607(5) and 2.625(5) Å. The water molecule has short contacts with the two independent perchlorate anions, which indicates that the anions are linked by weak hydrogen bonds utilizing the water molecule. The conformations of the two independent cations are similar and can be described as distorted half-chair, chair, distorted boat, and chair for ringsA, B, C, andD, respectively. Except for the flexible ringA, few changes in conformation of the cations are observed in comparison to the cations of lupanineN(16)-oxide perchlorate or 17--meth-yllupanine perchlorate.     

BaMgAl10O17∶Eu3+红色荧光粉的合成及其发光性能

采用助熔剂固相合成法,合成了BaMgAl10O17∶Eu3+荧光粉,并分析了材料的光学性能,研究了助熔剂对合成温度、晶体结构和发光性能的影响.结果表明,制备的BaMgAl10O17∶Eu3+属于六方晶系.助熔剂固相法合成温度比传统高温固相法合成温度降低了300℃.BaMgAl10O17∶Eu3+荧光粉能被394 nm的紫外光有效激发,其发射主峰位于612 nm,属于占据非对称中心格位Eu3+的5D0→7F2的电偶极(ED)跃迁.在394 nm激发下,BaMgA110O17∶Eu3+荧光粉的色度坐标为(0.655,0.345),这说明助熔剂固相法合成的样品的色纯度较高,光色为橙红色.     

Structure of 6α-methyl-17α-hydroxyprogesterone butanoate,C26H38O4

The title compound crystallizes in space groupP2₁2₁2₁ with lattice constantsa=16.253(3),b=17.107(3), andc=8.486(2) Å. The A ring has 1,2-half-chair conformation. The calculated steric energy of a 6-methyl-17-ester progesterone molecule is lower by about 4 kJ/mol for the normal A-ring conformation. The progesterone side chain has typical conformation for 17-ester steroids; the C(16)-C(17)-C(20)-O(20) torsion angle is –24.9(4)°.     

Crystal and molecular structure of 17-β-methyl-α-isolupanineN-(16)-oxide perchlorate monohydrate

[C₁₆H₂₇N₂O₂]⁺·ClO ₄ ^– ·H₂O,M _r=396.87, orthorhombicP2₁2₁2₁ a=13.708(4),b=16.930(7),c=8.311(3) Å,V=1928.3(13) ų,Z=4,D _x=1.367(2) g cm^–3,(MoK)=0.71068 Å,(MoK)=1.95 cm^–1,F(000)=848,T=292 K,R=0.061 for 1324 unique reflections. RingsA,B,C,D have half-chair, chair, chair and chair conformations, respectively; the quinolizidone moietyA/E has a quasi-trans and the quinolizidine moietyC/D has a trans configuration. The cations are connected into chains along the crystallographic direction [001] by strong hydrogen bonds utilizing the water molecule: C(2)=O(5)O(W)O(6)-N(16) of 2.623(7) and 2.574(7) Å, respectively. The water molecule is also hydrogen-bonded to one oxygen atom of the perchlorate anion: O(W)O(2) is 3.106(10) Å. A very short intramolecular distance between N(1) and O(6) of 2.696(7) Å, due to the quasitrans-trans configuration of the-isolupanine skeleton, is observed.     

Structure of 17β-hydroxy-4-pregnen-20-yn-3-one,C21H28O2

The crystal structure of 17-hydroxy-4-pregnen-20-yn-3-one, C₂₁H₂₈O₂, was determined by means of X-ray diffraction methods.M _r=312.5, space groupP2₁,a=6.493(1),b=21.065(3),c=6.478(1) Å,=105.97(1)°,V _c=851.9(3) ų,Z=2,D _x=1.22 Mg m^–3, CuK radiation (=1.54184 Å),(CuK)=5.5 cm^–1,F(000)=340. The structure was solved withMultan; final conventionalR=0.032 (R _w=0.032) for 1803 reflections. The molecule studied (I) has an overall conformation almost identical to 19-norethindrone (II), although ringA of molecule (I) is slightly more bent toward the direction of the steroid skeleton in comparison with molecule (II).     

Structure of 6-methyl-3,20-dioxo-4,6-pregnadien-17α-yl acetate,C24H32O4

The X-ray structure of 6-methyl-3,20-dioxo-4,6-pregnadien-17-yl acetate is reported. The crystals are monoclinic, space groupP2₁,Z=4,a=28.955(7),b=6.597(2),c=11.064(3) Å,/gb=90.80(2) °. The two crystallographically independent molecules have very similar overall geometries. The A rings have intermediate sofa-half-chair conformations and are bent relative to the steroid skeleton. The conformation of the 17-progesterone side chain is stabilized by the 17-ester substituent; the C(16)-C(17)-C(20)-O(20) torsion angle is –19.4(6) and –20.6(7)°.     

Structure of 17α-methyl-testosterone semihydrate,C20H30O2·1/2 H2O

The crystal structure of 17-methyltestosterone hemihydrate, C₂₀H₃₀O₂·1/2H₂O, has been determined:M _r =312.5, space groupP2₁2₁2₁2₁,a=6.374(2),b=12.807(2),c=43.398(5)Å,V _c =3543(2)ų,Z=8,D _x =1.172 mg^–3, CuK radiation ( = 1.54184 Å),(CuK)=5.5 cm^–1,F(000)=1376. The structure was solved usingMultan. The final conventionalR=0.053 (R _w =0.052) for 3634 reflections. The structure contains two crystallographically independent molecules in the asymmetric part of the unit cell that have almost identical geometry.     

Structure of 17β-hydroxy-1,4-androstadien-3-one monohydrate C19H26O2·H2O

The structure of the title compound, C₁₉H₂₆O₂·H₂O, was determined by X-rays.M _r=304.4, space groupP2₁,a=10.3113(6),b=10.3978(21),c=7.8710(9) Å, =89.527(9)°,V _c=844(1) ų,Z=2,D _x=1.194 Mg m^–3. CuK radiation ,(CuK)=5.9 cm^–,F(000)=332. FinalR factor=0.046 (R _w=0.047) for 1002 unique reflections. The structure was solved usingMultan. The water molecule is the hydrogen donor to O(3) and a hydrogen acceptor from the O(17) hydroxyl group. RingA is rather flat relative to the rest of the steroid backbone and the O(3)-plane distance is 1.99 Å.     

Human 17β-hydroxysteroid dehydrogenase-ligand complexes: crystals of different space groups with various cations and combined seeding and co-crystallization

Human estrogenic 17β-hydroxysteroid dehydrogenase (17β-HSD1) is responsible for the synthesis of active estrogens that stimulate the proliferation of breast cancer cells. The enzyme has been crystallized using a Mg²⁺/PEG (3500)/β-octyl glucoside system [Zhu et al., J. Mol. Biol. 234 (1993) 242]. The space group of these crystals is C2. Here we report that cations can affect 17β-HSD1 crystallization significantly. In the presence of Mn²⁺ instead of Mg²⁺, crystals have been obtained in the same space group with similar unit cell dimensions. In the presence of Li⁺ and Na⁺ instead of Mg²⁺, the space group has been changed to P2₁2₁2₁. A whole data set for a crystal of 17ß-HSD1 complex with progesterone grown in the presence of Li⁺ has been collected to 1.95 Å resolution with a synchrotron source. The cell dimensions are a=41.91 Å, b=108.21 Å, c=117.00 Å. The structure has been preliminarily determined by molecular replacement, yielding important information on crystal packing in the presence of different cations. In order to further understand the structure–function relationship of 17β-HSD1, enzyme complexes with several ligands have been crystallized. As the steroids have very low aqueous solubility, we used a combined method of seeding and co-crystallization to obtain crystals of 17β-HSD1 complexed with various ligands. This method provides ideal conditions for growing complex crystals, with ligands such as 20α-hydroxysteroid progesterone, testosterone and 17β-methyl-estradiol-NADP⁺. Several complex structures have been determined with reliable electronic density of the bound ligands.     

PEG对纳米BaMgAl10O17:Eu2+蓝色荧光粉颗粒形貌及其发光性能的影响

以聚乙二醇(PEG)为改性剂,采用溶液燃烧法成功制备了准球形的PDP用BaMgAl10O17:Eu2+(BAM)蓝色荧光粉.通过X射线粉末衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)以及荧光光谱对获得的试样进行了表征.结晶表明,获得的BAM荧光粉颗粒为准球形、颗粒尺寸为20～40nm.当PEG的分子量(MW)为10000且质量百分比浓度为5.0;时,能获得最佳形貌和最高发光强度的BAM蓝色荧光粉.     

Crystal and molecular structure ofN-benzyl-1-phenylsulfinyl-1-propenyl-2-amine monohydrate,C16H17NOS·H2O

The crystal and molecular structure ofN-benzyl-1-phenylsulfinyl-1-propenyl-2-amine monohydrate, named enamineI, has been determined on the basis of X-ray data. The structure found in the solid state was compared with the structure found from NMR spectra in solution. CompoundI exists as enamine in theE configuration in the crystal, whereas the enamine is in theZ configuration and as a mixture of both theZ and theE imines in solution. Three intermolecular H bonds involving each molecule ofI and water of crystallization have been found in the crystal. The NMR spectra in a range of the solvents of different H-bond donor-acceptor properties and polarizability suggest the formation of hydrogen-bonded molecule-solvent aggregates stabilizing the enamine structure ofI in solution. Crystal data:a=9.42(1),b=16.924(4),c=10.557(6) Å,=111.01(2)°, space groupP2₁/n,Z=4, MoK radiation,R=0.050 for 1059 independent reflections.     

Molecular structures of 17αβ-acetoxy-3-methoxy-6-oxa-D-homo-8-isoestra-1,3,5(10)-triene and its 4-methyl derivative

The molecular structures of 17αβ-acetoxy-3-methoxy-6-oxa-D-homo-8-isoestra-1,3,5(10)-triene (I) and 17αβ-acetoxy-3-methoxy-4-methyl-6-oxa-D-homo-8-isoestra-1,3,5(10)-triene (II) have been established by X-ray diffraction analysis. The presence of the methyl group at the C(4) atom in compound II leads to slight changes in the conformation of the carbon skeleton of this molecule and the orientation of the methoxy group with respect to the C(2)-C(3) bond.     

Ca–Mg mixing in aluminosilicate glasses: An investigation using 17O MAS and 3QMAS and 27Al MAS NMR

To better understand non-framework cation mixing in Ca–Mg aluminosilicate glasses, ¹⁷O MAS and 3QMAS NMR studies were done on glasses on the Mg₃Al₂Si₃O₁₂–Ca₃Al₂Si₃O₁₂ join as well as several compositions with lower Al/Si ratios. While not all of the oxygen sites are fully resolved, the non-bridging oxygen associated with two Ca and one Mg cations is under-represented relative to that predicted by a model assuming random Ca/Mg mixing. Therefore, local non-bridging oxygen environments are rich in Mg, and extra Ca must be associated with charged bridging oxygens such as Al–O–Si. The deviation from random mixing increases as the Al/Si ratio decreases and as X_Mg approaches 0.50, suggesting a reduction in configurational entropy that may be compensated for by other sources, including mixing of network forming cations. Al–O–Al is detected, and appears to increase with increasing X_Mg and increasing Al/Si. High field ²⁷Al MAS NMR also shows that these glasses all have substantial concentrations of ^[5]Al, but no detectable ^[6]Al (0.5% detection limit). The amount of ^[5]Al increases non-linearly as X_Mg increases and very slightly as Al/Si increases.