排序方式: 共有14条查询结果,搜索用时 15 毫秒
1.
2.
Hydrothermal reactions of cadmium(II) chloride with three amino-diphosphonic acids, C6H5CH2N(CH2PO3H2)2 (H4L1), C6H5CH2CH2N(CH2PO3H2)2 (H4L2) and 4-CH3-C6H4CH2N (CH2PO3H2)2) (H4L3) resulted in three new metal amino-diphosphonates, namely, Cd(H3L1)2, 1 Cd(H3L2)2·2H2O 2 and Cd(H3L3)23. In all three complexes, the Cd(II) ion is octahedrally coordinated by six phosphonate oxygen atoms from six ligands. Complexes 1 and 3 have a similar structure in which the CdO6 octahedra are cross-linked by bridging ligands into a double chain along the c-axis, such double chains are further interlinked via hydrogen bonds between non-coordinated phosphonate oxygen atoms to form 〈100〉 and 〈200〉 layers with the phenyl groups of the ligands orientated toward the interlayer space. The structure of complex 2 features a 〈100〉 cadmium(II) diphosphonate layer. The effects of the substitute groups attached to the amine groups on the structures of the metal phosphonates are also discussed. 相似文献
3.
本文报道了一个新的有机双膦酸铜化合物Cu3{(C5NH11)C(OH)(PO3)2}2(H2O)4·4H2O(1)的合成及结构。该化合物呈梯子型双链结构,由Cu(1)O5四方锥体和Cu(2)O6八面体通过{PO3C}四面体以共顶点方式连接而成。相邻的双链以几乎相互垂直的方式堆积,通过氢键作用形成了具有孔道的三维超分子网络结构,晶格水分子填充其中。磁性研究表明在铜离子间存在反铁磁相互作用。 相似文献
4.
MR imaging findings in recurrent primary osseous Ewing sarcoma 总被引:1,自引:0,他引:1
William M. Kauffman Barry D. Fletcher Soheil L. Hanna William H. Meyer 《Magnetic resonance imaging》1994,12(8):1147-1153
The objective of this study was to determine the value of magnetic resonance (MR) imaging in diagnosing local recurrence of Ewing sarcoma. We retrospectively reviewed radiographs, Tc99m-methylene diphosphonate (MDP) skeletal scintigraphy, computed tomography scans, and MR studies of 11 patients who had local recurrences of osseous Ewing sarcoma following initial responses to chemotherapy and local radiation. The MR images were compared to those of a control group of nine patients who had no evidence of relapse. T1- and T2-weighted MR images identified 9 of the 11 recurrences. Computed tomography was diagnostic in 4 of 6 cases evaluated, Tc99m-MDP bone scintigraphy in 4 of 11 cases, and plain radiographs in 2 of 10. MR findings at relapse included changes in signal intensity, increased extent of abnormal marrow signal on T1- and T2-weighted images, and identification of a new soft tissue mass. These findings suggest that MR imaging is valuable in the routine follow-up of parimary osseous Ewing sarcoma. 相似文献
5.
FU Rui-Biao HU Sheng-Min ZHANG Hui-Shuang WANG Long-Sheng LI Ya-Min HUANG Xi-He WU Xin-Tao ② 《结构化学》2005,24(11):1231-1241
1 INTRODUCTION From 1970s many research interests have focused on metal organophosphonates due to their structural diversities, including layers[1, 2], zeolite-like[3], inor- ganic channel with organic shell[4], cage-like[5], homo- chiral framework[6] and ring-[7] or sphere-like[8] clus- ters, as well as their potential or practical applica- tions as Langmuir-Blodgett Film (LB)[9], meso/mi- cro-porous materials[10, 11], ion-exchangers [12], small molecular sensors[13], adsorptions/desorp… 相似文献
6.
Gas Sorption Studies on a Microporous Coordination Polymer Assembled from 2D Grid Layers by Strong π–π Interactions 下载免费PDF全文
Dr. Xiaoxia Lv Dr. Liangjun Li Xiaoming Sun Prof. Hongyu Zhang Jinjun Cai Chao Wang Prof. Sifu Tang Prof. Xuebo Zhao 《化学:亚洲杂志》2014,9(3):901-907
The microporous coordination polymer [Co(H2L)(bipy)0.5] ? 2 H2O ( 1 , bipy=4,4′‐bipyridine) was synthesized on the basis of the V‐shaped flexible diphosphonate ligand (2,4,6‐trimethyl‐1,3‐phenylene)bis(methylene)diphosphonic acid (H4L) and the auxiliary bipy ligand under hydrothermal conditions. The structure of this compound was characterized by single‐crystal X‐ray diffraction. By joining the diphosphonate ligands and bipy through tetrahedral [CoO3N] clusters, a 2D square grid layered network was formed. Further stacking of these layers on the basis of π–π interactions resulted in a pseudo‐3D microporous network with 1D channels running through the a axis. Gas sorption studies for CO2, H2, CH4, N2, and O2 on this coordination polymer were performed, and the results revealed interesting dynamic and hysteresis sorption behavior toward H2 at low temperature. 相似文献
7.
以pH-敏感介孔膦酸锆作为药物载体, 选用治疗时辰节律性疾病(风湿性关节炎)的药物双氯芬酸钠作为药物模型, 利用蘸涂的方法对载药的pH-敏感介孔膦酸锆进行时滞膜的包覆, 建立起一个时滞型和pH-敏感型相结合的口服结肠靶向给药系统. 在系统研究pH-敏感介孔膦酸锆对双氯芬酸钠吸附和释放的基础之上, 通过调控时滞膜的厚度控制释放双氯芬酸钠的时滞时间约为6 h. 该给药系统在人工模拟胃液中3 h内完全不释放双氯芬酸钠, 而在人工模拟肠液中最初的3 h(可以看成发生在小肠)所释放的双氯芬酸钠仅为全部释放量的9%, 在之后的46 h内(可以看成发生在结肠)缓慢释放的双氯芬酸钠则占全部释放量的90%以上. 这样, pH-敏感介孔膦酸锆作为新型药物载体与时滞效应相结合, 通过时滞和pH-敏感双重控制实现了治疗时辰节律性疾病药物在结肠的定位释放. 相似文献
8.
水热条件下合成了一个新的有机二膦酸钴配合物[Co(en)3][Co2(Hedbbp)2].7H2O,[H4edbbp=N,N’-二(苄基膦酸)乙二胺].X射线单晶衍射结构分析表明:配合物属三斜晶系,空间群P,ī晶胞参数:a=1.505.6(3)nm,b=1.524 8(3)nm,c=1.649 7(3)nm,α=63.10(3)°,β=78.12(3)°,γ=75.62(3)°,晶胞体积为V=3.252 4(11)nm3,Z=2.配合物结构单元中包含一个二膦酸钴的二聚单元阴离子[Co2(Hedbbp)2]2-和一个三乙二胺合钴螯合阳离子单元[Co(en)3]2 和七个水分子. 相似文献
9.
M. Mosquet Y. Chevalier P. Le Perchec A. Foissy J.-P. Guicquero 《Colloid and polymer science》1999,277(12):1162-1171
Nonionic poly(oxyethylene) polymers having a diphosphonate group at one chain end strongly adsorb onto CaCO3 particles. The main consequence is a considerable lowering of the viscosity of concentrated slurries. This effect occurs
because of the break up and redispersion of aggregates of flocculated CaCO3 particles by the polymer adsorption. The mechanism of colloidal stabilization is steric, the particles becoming uncharged
as the polymer adsorbs at their surface. As a consequence, the colloidal suspensions remain stable and fluid at high volume
fractions and at high ionic strengths. On the other hand, because of the strong affinity of these polymers for CaCO3 surfaces, the larger part of the polymer is adsorbed until the coverage of the particles reaches completion. The easy to
handle polymer-to-solid weight ratio can then be used as a formulation parameter. The depletion flocculation by the nonadsorbed
polymer is avoided.
Received: 12 March 1999 Accepted in revised form: 2 July 1999 相似文献
10.
M. P. Minimol K. Prabhakara Rao Y. Ram Sai K. Vidyasagar 《Journal of Chemical Sciences》2003,115(5-6):419-429
Three new, isostructural methylenediphosphonates of molybdenum, A[MoO2(O3PCH2PO3H)] (A = Rb (1), NH4 (2) and Tl (3)) have been synthesized by hydrothermal method and structurally characterised by X-ray diffraction and spectroscopic
techniques. These compounds crystallize in monoclinic space group,P2
1
/c with Z = 4 and consist of [MoO2(O3PCH2PO3H)]-anionic layers interleaved with A+ ions.
Dedicated to Professor C N R Rao on his 70th birthday 相似文献