水杨醛缩氨基硫脲稀土有机配合物的合成及表征

由水杨醛缩氨基硫脲与三茂稀土Cp3Ln(Ln=La，Tb，Dy，Ho，Er，Yb)在THF中反应合成了6种新型配合物,经元素分析、IR，MR，XPS等表征表明它们为同时含Ln-0，Ln-N和Ln-S键的二聚体[CpLn(μ-O)C3H7N3S]2。     

稻壳基二氧化硅/碳复合材料的表面改性及对天然橡胶的影响

以稻壳基二氧化硅/碳复合材料(SiCB)作为天然橡胶(NR)的补强填料, 采用表面化学改性的方法将天然乳胶(NRL)接枝到SiCB表面, 改善其与NR基体的相容性. 研究了不同处理方法对接枝NRL效率的影响, 以及填料填入NR后对硫化橡胶力学性能的影响. 结果表明, 经过硝酸和γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(γ-MPTMS)预处理, NRL能高效接枝在SiCB表面, 得到的样品SiCB_MR10比未处理的SiCB_P有更强的补强能力. 硫化胶NR/SiCB_MR10的拉伸强度、 300%定伸和撕裂强度较NR/SiCB_P分别提高了61.06%, 27.15%和15.90%, 与传统炭黑产品N774填充的硫化胶NR/N774的力学性能相近. 经过NRL接枝改性的SiCB_MR10具有替代商业炭黑的应用前景.     

稀土化合物处理高耐磨炭黑填充粉末丁腈橡胶

以经稀土化合物处理的高耐磨炭黑和丁腈胶乳为原料,以凝聚共沉法制备粉末丁腈橡胶.研究了分散剂和稀土化合物对粉末胶颗粒粒径及其硫化胶性能的影响.结果表明,粉末胶颗粒粒径随分散剂用量的增加而减小,随La3+用量的增加而增大.La3+改善了硫化胶的性能,特别是扯断伸长率和拉伸强度.进一步分析得出,硫化胶性能得以改善的根本原因是La3+改善了炭黑粒子在橡胶基体中的分散均匀性及其与橡胶基体的黏结牢固性.     

磺胺嘧啶稀土络合物的研究

以磺胺嘧啶钠的甲醇溶液与水合氯化稀土的甲醇溶液反应制得了十五种稀土磺胺类络合物。研究了它们的溶解性、稳定性、红外光谱、x衍射数据、热分析结果、核磁共振谱、电导行为等。确定了络合物的组成为:La(SD)_3·3CH_3OH(SD=磺胺嘧啶根);Ln(SD)_3·2CH_3OH·H_2O(Ln=Eu、Yb、Lu);Ln(SD)_3·CH_3OH·2H_2O(Ln=Ce、Pr、Nd、Sm、Dy、Ho)和Ln(SD)_3·3H_2O(Ln=Gd,Tb、Er、Tm、Y)指出了在磺胺嘧啶稀土络合物的结构中,La～Ho和Y的离子通过异构化的磺胺嘧啶离子上的杂环氮和磺酰胺上的氧成键生成螯环,而Er～Lu仅与磺胺嘧啶离子上的磺酰胺的氮成键。     

γ-[SiW10O36]8-夹心型稀土元素单取代多酸化合物的合成与表征

利用缺位填充法合成了12个γ-[SiW10O36]8-夹心型稀土元素单取代多酸化合物K13[Ln(SiW10O36)2]·nH2O(Ln=La3+,Ce3+,Pr3+,Nd3+,Sm3+,Eu3+,Gd3+,Tb3+,Dy3+,Ho3+,Er3+,Yb3+).通过元素分析确定其组成,由红外光谱、紫外-可见吸收光谱、循环伏安及室温磁化率测定结果确认稀土离子与γ-[SiW10O36]8-相配位;183WNMR及荧光光谱结果则表明,稀土离子处于2个γ-[SiW10O36]8-构成的八配位环境中,标题化合物具有夹心型D2d对称性结构.     

稀土季铵盐络合物的研究(Ⅲ)——硝酸合稀土酸四丁基季铵盐粉末衍射数据

借助于X射线衍射仪的慢扫描和最小二乘法修正,得到了[(C_4H_9)_4N]_xLn[NO_3)_y系列14个络合物的晶胞参数和粉末衍射数据当Ln=La、Pr、Nd时,x=3,y=6;Ln=Sm、Eu、Gd、Tb、Dy、Ho、Er,Tm、Yb、Lu、Y时,x=2,y=5)。发现,随稀土离子原子序数的增大,络合物的晶胞体积减小和密度增大。     

1,5-二苯基-1,3,5-戊三酮(H_2DBA)及邻菲咯啉(phen)、羟基离子([OH]~-)希土混配配合物的合成及性质研究

本文在乙醇-水溶液中合成了H_2DBA及phen、[OH]~-与希土离子的混配配合物Ln(HDBA)_2(OH)(phen)·H_2O(Ln=La、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Y)十三个.通过化学分析,元素分析及电导分析确定了配合物的组成;研究了配合物的紫外、红外光谱及热行为,并对可能的配合物结构进行了推测.     

稀土十二氢十二硼酸盐的甲撑双二苯基氧化膦配合物的研究

报告了稀土十二氢十二硼酸盐的甲撑双二苯基氧化膦配合物的合成、波谱(IR、Raman和~(31)PNMR)和热稳定性。配合物的分子式为:(Ln(mppo)_n]_2(B_(12)H_(12))_3式中mppo为甲撑双二苯基氧化膦,Ln=La,n=4;Ln=Pr、Nd、Sm、n=3.5;Ln=Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu,n=3。     

[Et_4NB_(12)H_(11)NHCOCH_2CONH_2]~-及bipyO_2的稀土混配配合物研究

将[Et_4]_2B_(12)H_(12)与丙二腈反应,生成化合物Et_4NB_(12)H_(11)NCCH_2CN,水解后得[Et_4NB_(12)H_(11)NHCOCH_2CONH_2]~-·[Et_4NBN]~-,该衍生物与稀土氯化物(LnCl_3)及2,2＇-联吡啶-N,N＇-二氧化物(bipyO_2)反应,合成了几种新型的混配稀土配合物Ln(bipyO_2)_4(Et_4NBN)_3(Ln=La,Nd,Sm,Gd,Dy,Ho,Er).元素分析确定了它们的组成,通过IR、UV、~1H NMR、ESR、摩尔电导测定及TG-DTA等对其性质进行了研究。     

二烷基单硫代膦酸萃淋树脂吸附重稀土(Ⅲ)的研究

本文研究了Cyanex302萃淋树脂从硝酸介质中吸附重稀土（Ⅲ），吸附能力为Lu＞Yb＞Tm＞Er＞Ho＞Dy＞Tb＞Gd。考察了平衡水相酸度、稀土浓度、温度等对吸附平衡的影响。计算了重稀土（Ⅲ）间的平均分离系数β~z+1_z＝3．55，表明分离稀土（Ⅲ）的选择性优于HDEHP、HEH／EHP萃淋树脂，有可能用于制备高纯单一重稀土。Cyanex302萃淋树脂饱和吸附稀土（Ⅲ）的红外光谱表明，P＝S键参与了配位。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.