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树形聚酰胺胺与 Cu2+的络合作用 总被引:1,自引:0,他引:1
合成了4.0代聚酰胺胺 (PAMAM)树形分子 ,并合成出端基为羟基的PAMAM树形分子衍生物。用分光光度法研究了4.0代PAMAM树形分子及其衍生物与Cu2 的络合作用。结果表明当存在树形聚酰胺胺分子时 ,Cu2 水溶液的最大吸收波长显著紫移 ,随n(Cu2 )/n(PAMAM)增加 ,最大吸收波长红移 ;PAMAM树形分子与Cu2 的络合作用有多种形式 ,对端胺基树形分子主要存在Cu -N4 和Cu -N2 两种配位方式 ;对端羟基树形分子主要存在Cu -N2 的配位方式 ;随Cu2 的加入 ,络合形式和各种络合形式的相对比例发生变化 ;pH对络合形式有较大影响;随代数的增加 ,树形分子所能络合Cu2 的最大数目不断增加 ,但理论值与实验值有一定的误差 相似文献
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高纯度树状大分子聚酰胺-胺的合成与表征 总被引:2,自引:0,他引:2
以乙二胺为核,通过Michael加成,与丙烯酸甲酯交替反应,合成了0.5代到5.0代聚酰胺 胺树状大分子。 利用傅里叶变换红外光谱、核磁共振氢谱、液相色谱和元素分析等对各代产品进行了表征,探索了反应温度、时间及反应物配比对产物的影响,确定生成聚酰胺-胺(PAMAM)的半代产物时反应温度为25 ℃,整代产物时反应温度为35 ℃;0.5G的反应时间为18 h,1.0G、1.5G的反应时间为24 h,2.0G、2.5G反应36 h,3.0G、3.5G反应48 h,4.0G、4.5G反应3 d,5.0G反应4 d。 分离提纯是树状大分子制备中遇到的最大困难,通过选择性溶剂萃取的方法对产品分离纯化,筛选出乙醚作萃取剂、甲醇作溶剂交换剂,大大提高了产品的纯度。 相似文献
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树形聚酰胺胺与Cu^2+的络合作用 总被引:7,自引:0,他引:7
合成了4.0代聚酰胺胺(PAMAM)树形分子,并合成出端基为羟基的PAMAM树形分子衍生物,用分光光度法研究了4.0代PAMAM树形分子及其衍生物与Cu^2 的络合作用,结果表明当存在树形聚胺胺分子时,Cu2 水溶液的最大吸收波长显著紫移,随n(Cu2 )/n(PAMAM)增加,最大吸收波长红移,PAMAM树形分子与Cu2 的络合作用有多种形式,对端胺基树形分子主要存在Cu-N4和Cu-N2两种配位方式;对端羟基树形分子主要存在Cu-N2的配位方式,随Cu2 的加入,络合形式和各种络合形式的相对比例发生变化,PH对络合形式有较大影响;随代数的增加,杩形分子所能络合Cu2 的最大数目不断增加,但理论与实验值有一定的误差。 相似文献
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以PAMAM树形分子为模板制备Pd纳米簇合物 总被引:1,自引:0,他引:1
以酯端基聚酰胺-胺树形分子(PAMAM)为模板在甲醇溶剂中制备了Pd纳米簇合物. 采用紫外-可见分光光度法和红外光谱法研究了Pd2+与树形分子的作用机理, 结果表明, Pd2+与树形分子内部胺基基团(主要为叔胺基)产生了络合作用. 采用硼氢化钠还原法制备了树形分子包裹的、粒径为2 nm的球形面心立方Pd纳米簇合物. 紫外-可见吸收光谱研究结果表明, Pd2+与树形分子的摩尔比越小, 生成的纳米簇合物尺寸越小; 由于高代数树形分子具有封闭结构, 且其内部配体数目较多, 采用较高代数的树形分子(5.5代)比低代数(3.5代)更有利于得到尺寸小、分散性较好的Pd纳米簇合物. 相似文献
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外端为偶氮苯基团的聚酰胺-胺树枝状分子对光和H~+的响应行为 总被引:1,自引:0,他引:1
合成了1到5代外端修饰有偶氮苯基团的聚酰胺-胺(PAMAM)树枝状分子.H-NMR、FTIR和元素分析等表明得到了目标产物,外端接枝率在70%~90%.结构分析表明经修饰的PAMAM分子在3代和4代之间存在一个结构转变.UV-Vis和H-NMR分析结构显示,在中性条件下,Gn-azo表现出类似于小分子偶氮苯基团的光响应行为.而在酸性条件下,偶氮苯基团的顺反异构转化率较质子化前低.包裹及释放实验表明,虽然G4-azo包裹水杨酸分子的能力弱于G4PAMAM,但它对于客体小分子具有缓释作用,光照使偶氮苯基团发生由反式到顺式的异构转化之后,缓释效应更明显. 相似文献
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《有机化学》2016,(3)
将具有聚集诱导荧光的4-(2-吡啶乙烯基)-1,8-萘酰亚胺单元通过酰胺化反应连接到聚酰胺-胺(PAMAM)树形分子上,制备了一种水溶性吡啶萘酰亚胺-聚酰胺-胺荧光树形分子PN-PAMAM.结构经核磁共振氢谱、核磁共振碳谱、红外及高分辨质谱表征.吡啶萘酰亚胺-聚酰胺-胺树形分子PN-PAMAM具有明显的聚集诱导荧光增强(AIEE)特性.在固体态时的最大荧光发射波长为532 nm,紫外灯下发出黄绿色荧光.在纯水中的最大荧光发射波长为494 nm,荧光量子产率为4.42%.在水含量为60%的水/四氢呋喃混合溶液中,其荧光强度达到最大,荧光发射波长为485 nm,荧光量子产率增大到17.54%.制备了一种负载聚集诱导荧光染料PN-PAMAM的二氧化硅纳米粒子PN-PAMAM/Si O_2,测得该纳米粒子的荧光发射波长为473 nm,粒径约为40 nm.测定了水溶液中树形分子PN-PAMAM与乳腺癌细胞MCF-7共同孵化后的共聚焦荧光成像,得到清晰的蓝场荧光照片.研究表明,吡啶萘酰亚胺-聚酰胺-胺树形分子PN-PAMAM是一种水溶性荧光分子,具有明显的聚集诱导荧光增强特性,可广泛应用于肿瘤定位、生物追踪及纳米材料等重要领域. 相似文献
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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%. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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. 相似文献
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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. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
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. 相似文献
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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. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
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. 相似文献
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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. 相似文献
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《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative. 相似文献
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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. 相似文献