稀土硝酸盐冠醚配合物(Ⅺ)——Y(NO_3)_3·3H_2O-B15C5-C_2H_5OH三元体系18℃时溶解度的研究

我们曾用自己设计的半微量相平衡方法,研究了Y(NO_3)_5·3H_2O与冠醚B15C5分别在乙腈和丙酮中的溶解度。本文进一步研究了Y(NO_3)_3·3H_2O与冠醚B15C5在乙醇中的配合行为,以观察溶剂对所形成配合物组成的影响。图1是Y(NO_3)_3·3H_2O-B15C5-C_2H_5OH三元体系在18℃时的溶解度结果。     

Yb(NO_3)_3·3H_2O与B15C5在乙醇中配合行为的研究

关于稀土冠醚配合物的研究近年来一直为人们所重视。但多采用直接合成的方法进行研究,采用溶剂多为乙腈或丙酮。为了考查溶剂对稀土盐与冠醚间配合行为的影响,我们用半微量相平衡方法研究了Yb(NO_3)_3·3H_2O-B15C5-C_2H_5OH三元体系在18℃时的溶解度。此外,还用其它方法对该体系中形成的配合物进行了考查。     

稀土硝酸盐冠醚络合物的研究(XV)La(NO_3)_3·4H_2O-B15C5-CH_3CH_2OH和Pr(NO_3)_3·4H_2O-B15C5-CH_3COCH_3体系溶解度的研究

用半微量相平衡法测定了La(NO_3)_34H_2O-B15C5-CH_3CH_2OH和Pr(NO_3)_3·4H_2O-B15C5-CH_3COCH_3三元体系在25℃的溶解度。两个体系的溶解度曲线皆由三支组成,各有一支覆盖范围很宽的溶解度曲线与组成为Ln(NO_3)_3·B15C5·4H_2O(Ln=La或Pr)的络合物固相相对应。考查了络合物中水的稳定性。     

希土硝酸盐冠醚Yb(NO3)3·3H2O/B15C5配合物的研究

用改进的半微量相平衡方法研究了Yb(NO_3)_3·3H_2O-Bl5C5-CH_3COCH_3三元体系在18℃时的溶解度,测定了各液相的折光率。结果指出只有一种化学计量的配合物(Yb(NO_3)_3·B15C5·3H_2O·2CH_3COCH_3)生成。分离、洗涤、浓硫酸干燥器中恒重后,经化学分析,确定配合物的组成为:Yb(NO_3)_3·B15C5·3H_2O·065CH_3COCH_3。用红外光谱、DTG、TG及DSC等对配合物进行了研究。测得配合物的脱溶剂与热分解的热焓值(△H)。按照Kissinger法,求得配合物热分解过程的表现活化能。     

希土硝酸盐冠醚配合物--Ⅸ.La(NO3)3·4H2O-NO2B15C5-CH3CN三元体系在25℃和15℃时溶解度的研究

改进了半微量相平衡研究方法,研究了La(NO_3)_3·4H_2O-NO_2B15C5-CH_3CN三元体系在25℃和15℃时的溶解度,测定了25℃各饱和溶液的折光率。结果表明,在该体系中只有一种计量配合物La(NO_3)_3·NO_2B15C5·4H_2O生成,该配合物的溶解度随温度的降低而减小,溶解度曲线覆盖的范围很大。利用不同方法获得了固态配合物La(NO_3)_3·NO_2B15C5·4H_2O。通过化学分析、紫外光度分析、红外光谱和差热与热重分析等研究了它的组成和性质,考查了它的水合度与后处理条件的关系。制得了二水合物La(NO_3)_3·NO_2B15C5·2H_2O及无水物。     

1,2-环己二胺缩邻香兰素单核与四核镱稀土配合物的近红外性质（英文）

通过配体1,2-环己二胺缩邻香兰素(H2L)和不同的镱盐反应,合成了4个镱稀土配合物[Yb(H_2L)_2](ClO_4)_3·2CH_3OH·H_2O(1),[Yb_4(L)_4(NO_3)2(H_2O)_2](PF_6)_2·4CH_3CN(2),[Yb_4(L)_4(H_2O)_2Cl_2](PF6)_2·2CH_2Cl_2·2H_2O(3)和[Yb_4(L)_4(NO_3)_2(H2O)_2][Yb(NO_3)_3(H_2O)_2(CH_3OH)](NO_3)_2·4CH_2Cl_2·6CH_3OH(4)。X射线单晶衍射分析表明配合物1为零维的单核结构,配合物2~4均为四核结构。研究了4个配合物的近红外发光性能。     

稀土硝酸盐冠醚配合物Y(NO_3)_3·3H_2O—B15C5—CH_3CN三元体系18℃时溶解度的研究

提出了一种适用于金属盐-冠醚-有机溶剂三元体系溶解度测定的半微量相平衡研究方法.用该法研究了Y(NO_3)_3·3H_2O-B15C5-CH_3CN三元体系在18℃时的溶解度.实验证明该体系中生成的配合物只有一种组成,而且该配合物存在的相区相当大,排除了其它组成的配合物存在的可能性,为在乙腈中合成该配合物合理选择盐、醚比提供了依据.考查了由水合钇盐引入体系的水的去向.制得了固态配合物Y(NO_3)_3·B15C5·3H_2O,研究了它的某些性质和热分解过程.还考查了该配合物的水合度与它所处条件的关系.     

三元体系La(NO_3)·4H_2O-B15C5-(CH_3)_CO在18℃时溶解度的研究

我们曾用自己设计的半微量相平衡方法研究了La(NO_3)_3·4H_2O-B15C5-CH_3CN三元体系在25℃时的溶解度,发现同生成它的母液处于平衡状态时的固态络合物的组成为La(NO_3)_3·B15C5·4H_2O,在一般条件下的相对稳定形式为La(NO_3)_3B15C5·2H_2O。说明了Cassol和King等人所得无水络合物La(NO_3)_3·B15C5是由于后处理条件不当所引起的。为了弄清楚在雨酮中水合镧盐与冠醚B15C5生成的络合物的组     

Dy(NO_3)_33·H_2O与18C6在乙醇中配合行为的研究

采用改进的半微量相平衡法研究了Dy(NO_3)_3·3H_2O—18C_6—C_2H_5OH三元体系在25℃时的溶解度。溶解度曲线与配合物Dy(NO_3)_3·18C6·3H_2O·C_2H_5OH的固相相对应;饱和溶液的折光率曲线与溶解度曲线相对应。在液相和固相中,H_2O与Dy(NO_3)_3的摩尔比均为3:1,制得配合物的组成为Dy(NO_3)_3·18C6·3H_2O。用UC、IR、DTG及TG等手段研究了该配合物的性质。     

萘咪唑类稀土配合物的晶体结构和荧光性质（英文）

通过2-(2′-羟基-3′-甲氧基)萘咪唑(HL)和Ln(NO)_3·6H_2O反应,合成了4种单核稀土配合物[Ln(HL)_2(NO_3)_3]·CH_2Cl_2(Ln=Sm(1),Eu(2),Tb(3))和[Ln(HL)_2(NO_3)_2(CH_3OH)]NO_3·CH_3OH(Ln=Yb(4))。X射线单晶衍射分析表明配合物1~4均通过配体萘环间的π-π作用呈现蝴蝶状结构。荧光性质表明仅有配合物4显示Yb3+稀土离子的特征发光,固态和在乙腈溶液中的荧光寿命分别为8.27μs和4.40μs。     

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.     

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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

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.