牛黄酸及水杨酸系药物对镁铝层状复合氢氧化物的插层组装

通过XRD和IR表征对镁铝层状复合氧氧化物(LDH)与水杨酸、乙酰氨基酚、乙酰水杨酸,以及谷氨酸、色氨酸、牛黄酸反应产物的比较分析,研究了不同药物对有关组装方式的适宜性.结果表明水杨酸类药物均可通过离子交换组装到LDH层间,晶胞参数c由2.3893 nm依次增大为2.4024、2.4110和2.4111nm,通道高度h由0.3194 nm增大为0.3238、0.3267和0.3268 nm;通过离子交换能将谷氨酸组装到LDH层间,产物的IR吸收、热分解行为及TEM形貌与前体有明显区别,晶胞参数c由2.3765nm增大为2.3851nm,h由0.3152nm增大为0.3180nm;共沉淀法适宜制备LDH-牛黄酸插层复合物,但简单的离子交换不能使色氨酸与LDH有效复合.     

氯离子柱撑水滑石共沉淀法合成反应动力学

根据氯离子型层状复合氢氧化物(LDH-Cl)制备过程中溶液浓度变化的监测结果和不同反应进程时产物的EDS、IR、XRD、TEM、TG-DTA表征结果,研究了合成LDH-Cl的共沉淀反应动力学特征及机理.实验结果表明, LDH-Cl的生成符合多核层表面反应动力学模型;反应过程中LDH的晶胞参数c从2.421 nm变为2.399 nm,通道高度h由0.3321 nm减小为0.3228 nm,粒子直径Da由6.40 nm增大为15.16 nm, Dc由7.43 nm增大到10.93 nm,纵横比由0.86增大为1.39; IR和TG-DTA特征变化表明了层板对阴离子作用的强度和层板的结构稳定性随反应进程而提高.     

F2＋2HI=2HF＋I2反应机理的研究

根据氯离子型层状复合氢氧化物(LDH-Cl)制备过程中溶液浓度变化的监测结果和不同反应进程时产物的EDS、IR、XRD、TEM、TG-DTA表征结果,研究了合成LDH-Cl的共沉淀反应动力学特征及机理.实验结果表明, LDH-Cl的生成符合多核层表面反应动力学模型;反应过程中LDH的晶胞参数c从2.421 nm变为2.399 nm,通道高度h由0.3321 nm减小为0.3228 nm,粒子直径Da由6.40 nm增大为15.16 nm, Dc由7.43 nm增大到10.93 nm,纵横比由0.86增大为1.39; IR和TG-DTA特征变化表明了层板对阴离子作用的强度和层板的结构稳定性随反应进程而提高.     

偏氯乙烯共聚物/层状双金属氢氧化物纳米复合材料的制备与表征

通过硝酸根插层层状双金属氢氧化物(LDH)与可逆加成-断裂链转移(RAFT)试剂S,S’-对(α,α’-二甲基-α″-乙酸)三硫代碳酸酯(CTA)阴离子的离子交换制备CTA阴离子插层LDH,再通过原位RAFT活性自由基聚合制备偏氯乙烯-丙烯酸甲酯(VDC-MA)共聚物/LDH纳米复合材料.采用傅里叶变换红外光谱、元素分析和X-射线衍射、透射电子显微镜、凝胶渗透色谱仪和热失重仪表征了CTA阴离子插层LDH和纳米复合材料的结构和性能.结果表明,CTA阴离子可以置换硝酸根阴离子插入到LDH层间,LDH层间距由0.89 nm增大到1.50 nm;在原位RAFT聚合过程中,LDH逐渐剥离,LDH以纳米层板形式分散在VDC-MA共聚物基体中;VDC-MA共聚物数均分子量随加入的插层CTA阴离子含量增加而减小,聚合具有活性特征.此外,含量LDH的引入可明显提高VDC-MA共聚物的热稳定性.     

CuC_2O_4多孔球的可控合成

采用温和水溶液法,以CuCl2.2H2O和H2C2O4.2H2O为原料合成了新颖结构的CuC2O4多孔球。产物结构与形貌用X射线衍射、扫描电子显微镜测试技术进行了表征。研究了反应温度、反应物浓度、不同体积阴离子等对产物形貌与尺寸的影响。结果表明,单斜结构的CuC2O4多孔球直径为400～540nm,每个多孔球由50～80nm的纳米粒子自组装而成。反应物浓度及阴离子体积能调节纳米粒子的团聚尺寸,而反应温度可有效地调节多孔球的尺寸。刻蚀过程解释了CuC2O4多孔球的形成机理。     

聚苯乙烯/层状双金属氢氧化物纳米复合材料的制备与表征

由离子交换法制备4,4′-偶氮二(4-氰基戊酸)根(ACP)单独插层和ACP/对苯乙烯磺酸根(VBS)复合插层的层状双金属氢氧化物(LDH),再通过原位悬浮聚合制得聚苯乙烯(PS)/LDH纳米复合材料,对插层改性LDH和复合材料进行了结构和性能表征.X-射线衍射和元素分析表明ACP可以单独或与VBS一起插入到LDH层间.透射电镜和X-射线衍射分析表明采用ACP/VBS复合插层LDH与苯乙烯原位聚合得到的复合材料中LDH剥离程度高,熔融加工后LDH基本以纳米层板形式分散在PS基体中.LDH的引入可明显提高PS的热稳定性,而熔体流动性下降.     

纳米氧化铪的制备与热膨胀性

制备了尺寸为4 nm的HfO2纳米颗粒,并借助X射线原子对分布函数方法,研究了尺寸约4 nm和体相HfO2颗粒的晶格热膨胀。结果表明,在纳米尺度的HfO2中,晶格沿a,c轴的热膨胀性增大,b轴热膨胀性稍微减小,体积热膨胀性增大。同时纳米HfO2晶格热膨胀的各向异性比体相大。该现象是由于尺寸效应导致结构畸变变大,尤其是次近邻Hf-O-Hf键角减小,随后升温过程中该畸变发生热弛豫趋向恢复至平衡位置导致的。     

钴掺杂的磁性氧化铁纳米粒子的可控合成

通过油酸盐前驱体高温热解法制备出大小均匀的钴掺杂四氧化三铁球形纳米粒子, 其钴/铁摩尔比可以通过调节油酸钴与油酸铁的比例进行调变. 当产物中钴/铁摩尔比从0.024增加到0.156, 所制备的氧化铁纳米粒子的饱和磁矩从39 emu·g^-1逐渐减小到30 emu·g^-1, 而矫顽力从0 Oe升至190 Oe. 在305℃下, 随着反应体系的热解时间由0.5 h 增加到3 h, 所制备出的氧化铁纳米粒子尺寸逐渐由7 nm增加到14 nm. 热解时间较短时, 以高价态的四氧化三铁的晶型为主, 辅之以少量的氧化亚铁; 热解时间增加至2 h, 产物的晶型为四氧化三铁和氧化亚铁的复合物; 而继续增加热解时间至3 h, 除四氧化三铁和氧化亚铁之外, 还出现少量的零价态的CoFe合金, 说明铁(钴)元素经历了由三价到二价, 最后被还原为零价的过程. 随着反应温度的升高, 产物的尺寸逐渐增大, 同时产物中氧化亚铁的含量增多.     

水滑石型磁性纳米载药粒子的制备及其体外药物释放性能研究

通过调变镁铁尖晶石的含量, 采用一步共沉淀法制备了一系列具有核壳结构的水滑石型磁性纳米载药粒子, 对其微结构、热稳定性、磁性和药物释放性能进行了系统的研究. 结果表明这种磁性纳米载药粒子是一种具有以镁铁尖晶石为核层、双氯酚酸(Diclofenac, DIC)插层水滑石(DIC-LDH)为壳层的复合纳米粒子, 粒径在90～180 nm之间. 其中壳层DIC-LDH的晶粒尺寸D₁₁₀和层板电荷密度随磁核含量的增大而逐渐减小. 磁性纳米载药粒子的载药量随磁核含量的增大而逐渐减小, 而其比饱和磁化强度则随着磁核含量的增大逐渐增大. 体外释放实验表明, 无外加磁场时, 磁核含量增大, 壳层DIC-LDH粒径减小, 磁性纳米载药粒子药物释放速率逐渐增大|外加1500 G磁场时, 磁核含量增大, 磁致团聚程度增大, 其药物释放速率逐渐减小.     

硼酸根插层水滑石层间组成及取向结构的控制

以Mg0 .67Al0 .3 3 (OH) 2 (CO3 ) 0 .165·0 .62H2 OLDHs为前体 ,以水为分散介质 ,由离子交换法组装了硼酸根插层LDHs ,并用XRD ,FT IR ,TG DTA ,ICP ,11BMASNMR等手段对样品进行了分析和表征 .结果表明 ,通过控制离子交换时的pH ,可使硼酸根取代Mg Al CO3 LDHs前体层间的CO2 -3 ,且可控制离子交换程度及客体的取向 ,从而控制插层结构 .对硼酸根插层LDHs的结构进行研究发现 ,控制pH =4.5 ,层间阴离子主要是一硼酸根和离子平面与LDHs层板平行的三硼酸根 ,出于结构稳定的需要 ,CO2 -3 不能完全被置换 ;控制pH =3 .5 ,层间阴离子是一硼酸根和离子平面与LDHs层板垂直的三硼酸根     

The crystal structure of LaIr4B4, ThOs4B4, ThIr4B4 (NdCo4B4-type) and URu4B4, UOs4B4 (LuRu4B4-type)

The crystal structure of LaIr₄B₄ has been refined from single crystal counter data. LaIr₄B₄ is tetragonal,P4₂/n,Z=2, isotypic with NdCo₄B₄, |F|/|F _o|=0.039 for 312 independent reflections [|F _o|>2 (F _o)]. ThIr₄B₄ and ThOs₄B₄ also belong to the NdCo₄B₄-type structure. URu₄B₄ and UOs₄B₄ were found to crystallize with LuRu₄B₄-type structure. The crystal chemistry of (RE)T ₄B₄-phases is discussed and simple geometric relations are shown to exist between them.Dedicated to Prof.B. T. Matthias in celebration of his 60th birthday.     

4-巯基-4-脱氧-4'-去甲表鬼臼毒素的立体控制合成

4-巯基-4-脱氧-4'-去甲表鬼臼毒素是合成4位硫取代的4'-去甲表鬼臼毒素的关键中间体,由4'-去甲表鬼臼毒素与硫化氢在BF~3·Et~2O存在下立体控制制备,也可通过以NH~3/CH~CN选择性 地水解4-乙酰硫基-4-脱氧-4'-去甲表鬼臼毒素而制备.     

Synthesis of 4-alkoxy-4-methyl- and 4-alkoxy-4-fluoromethyl-1,3-benzoxazinones

Cyclization of 2-hydroxyacetophenone hydrazones with triphosgene resulted in the formation of 4-methylene-1,3-benzoxazinones. These compounds were converted to 4-alkoxy-4-methyl-1,3-benzoxazinones and 4-fluoromethyl-4-methoxy-1,3-benzoxazinones upon treatment with alcohols under refluxing conditions and F-TEDA-BF₄ in acetonitrile and methanol, respectively.     

Electronic structures of the boron cage molecules B4H4, B4Cl4 and B4F4

Ab initio calculations have been performed on B₄H₄, B₄Cl₄ and B₄F₄ in order to aid our understanding of the bonding in these compounds, which is presumably based on a tetrahedral boron cage. This cage has only 8 electrons and so is less than that expected on the basis of the usual framework electron counting rules. Basis sets with polarisation functions were used at the SCF, CI and CPF levels of theory to confirm that the T _d structures are indeed more stable than the D _4h ones. Davidson-Roby population analyses were able to show that many factors, including 3-centre 2-electron bonding and backbonding from the ligand to the boron cage, are of importance in determining the relative stability of the three compounds, of which B₄Cl₄ is the only one that has yet been observed experimentally.     

Smectic polymorphism of the 4-butyl-4-alkoxyazobenzenes and 4-pentyl-4-alkoxyazobenzenes

Two families of liquid crystalline compounds have been synthesised, the 4-butyl-4- alkoxyazobenzenes and the 4-pentyl-4-alkoxyazobenzenes; for the second family results are presented for the first time for alkoxy chains longer than butyl. The results for both families have been obtained up to the octadecyl homologues. In both families, on the basis of DSC, polarizing microscopy and thermo-optical analysis, a rich polymorphism has been detected (maximum tetramorphism). The smectic properties start with the hexyl derivative (for the butyl family) and with the heptyl derivative (for the pentyl family). Strong odd-even effects for the temperatures of clearing in both groups of compounds were detected. Our results are compared with those of de Jeu et al. and of Adomenas et al. for the 4-butyl-4- alkoxyazobenzenes, for which only one smectic modification was described.     

Fluorination of 4-nitroisoxazoline salts. Synthesis of 4-fluoro-4-nitroisoxazolines and 4-fluoroisoxazoles

Methods for the synthesis of hitherto unknown 4-fluoro-4-nitroisoxazolines by fluorination of 4-nitroisoxazoline salts with FClO₃ in MeOH and 4-fluoroisoxazoles by treatment of fluoronitroisoxazolines bearing the hydrogen atom bound to the C(5) atom of the isoxazole ring with MeONa in MeOH were developed.     

Synthesis of 4H-pyrazolo- and 4H-pyrrolophenothiazin-4-one derivatives

5-Methyl- and 6-methyl-2-phenyl-2H-indazole-4,7-diones were condensed with 2-aminobenzenethiol or 6-substituted-3-aminopyridine-2(1H)thiones 4 to produce a new type of 5-methyl-2-phenyl-4H-pyrazolophenothiazin-4-ones or 8-substituted-7-aza-5-methyl-2-phenyl-4H-pyrazolophenothiazin-4-one derivatives. From 6-bromo-2,5-dimethyl-1,3-diphenyl-2H-isoindole-4,7-dione and 4 8-substituted-7-aza-2,5-dimethyl-1,3-diphenyl-4H-pyrrolophenothiazin-4-one derivatives were also prepared.