氮杂冠醚与碱金属离子配位反应的研究

滴定量效法是研究反应热化学和热力学的重要手段之一．用这种方法对冠醚与金属离子的配位反应热力学性质进行研究一直受到很大关注【且S习．但是对氨杂冠林，尤其是一系列结构相似的氨杂冠醚体系进行系统的热力学性质研究的报导不多．前文K则曾报导了用自组装的消定量热计对银（I）－a吹体系和铜（11）·N，N’一问位取代革基乙二胺体系的配位反应热化学研究结果·本文报导从（对位取代革基）k杂15冠5卜RPW15CS，R＝CIZH；CHa；CHso）与碘化钠和碘化钾在25T、无水乙过溶液中进行配位反应的消定量效研究结果．讨论了配体上取代基的电…     

铜（Ⅱ）－4－（吡啶－2′－甲基）－1，4，7，10－四氮杂环十三烷－11，13－二酮－α－氨基酸（5－取代邻菲罗啉）三元配合物的稳定性研究

用ｐＨ法在２５．０±０．１℃，Ｉ＝０．１ｍｏｌ·ｄｍ－３ＫＮＯ３条件下，测定铜（Ⅱ）－４－（吡啶－２′－甲基）－１，４，７，１０－四氮杂环十三烷－１１，１３－二酮－α－氨基酸（５－取代邻菲罗啉）三元配合物的稳定常数；比较了带吡啶甲基二氧四胺大环配体和二氧四胺大环配体与Ｃｕ（Ⅱ）的配位能力、配位方式；研究了该三元体系配合物稳定性与配体α－氨基酸酸碱强度之间的直线自由能关系；探讨了Ｃｕ（Ⅱ）和５－取代邻菲罗啉之间的ｄ－ｐ反馈π键以及邻菲罗啉取代基Ｈａｍｍｅｔｔ诱导效应与该三元配合物稳定性之间的关系。讨论了４－（吡啶－２′－甲基）－１，４，７，１０－四氮杂环十三烷－１１，１３－二酮和４－（喹啉－２′－甲基）－１，４，７，１０－四氮杂环十三烷－１１，１３－二酮与Ｃｕｘｐｈｅｎ所形成配合物的不同空间结构及其对配合物稳定性产生的影响。     

钴(Ⅱ)-5-取代邻菲罗啉-α-氨基酸三元配合物的稳定性研究

本文在25.0±0.1℃,I=0.1mol·dm^-3KNO₃存在下,采用pH法测得了5-取代邻菲罗啉的质子化常数以及钴(Ⅱ)与5-取代邻菲罗啉、α-氨基酸的二元、三元配合物的稳定常数。结果表明三元配合物的稳定性与5-取代邻菲罗啉的质子化常数、取代基常数均存在直线自由能关系。并用三元配合物稳定性的表征值logK_M、△logK,讨论了三元配合物的稳定性,发现钴(Ⅱ)与配体5-取代邻菲罗啉之间也存在着d-p反馈π键。该π健的强度对三元配合物稳定性有着显著影响。     

Synthesis and characterization of biodegradable amphiphilic ABC Y‐shaped miktoarm terpolymer by click chemistry for drug delivery

Biodegradable amphiphilic ABC Y‐shaped triblock copolymer (MPBC) containing PEG, PBLA, and PCL segments was synthesized via the combination of enzymatic ring‐opening polymerization (ROP) of epsilon‐caprolactone, ROP of BLA‐N‐carboxyanhydride and click chemistry, where PEG, PBLA, and PCL are poly(ethylene glycol), poly(benzyl‐l ‐aspartate), and polycaprolactone, respectively. Propynylamine was employed as ROP initiator for the preparation of alkynyl‐terminated PBLA and methyloxy‐PEG with hydroxyl and azide groups at the chain‐end was used as enzymatic ROP initiator for synthesis of monoazido‐midfunctionalized block copolymer mPEG‐b‐PCL. The subsequent click reaction led to the formation of Y‐shaped asymmetric heteroarm terpolymer MPBC. The polymer structures were characterized by different analyses. The MPBC terpolymer self‐assembled into micelles and physically encapsulated drug doxorubicin (DOX) to form DOX‐loaded micelles, which showed good stability and slow drug release. In vitro cytotoxicity study indicated that the MPBC micelles were nontoxic and the DOX‐loaded micelles displayed obvious anticancer activity similar to free DOX against HeLa cells. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3346–3355     

Studies of artificial hydrolytic metalloenzymes: The catalyzed carboxyester hydrolysis by copper(II), zinc(II) and cobalt(II) complexes of the tripod ligand tris(2-benzimidazylmethyl)amine

The hydrolysis kinetics of p-nitrophenyl acetate (NA) catalyzed by Cu^II, Zn^II and Co^II complexes of tris(2-benzimidazylmethyl)amine (NBT) have been studied. The hydrolysis rate is first-order in both metal(II) complex and NA. The second-order rate constants, k_cat are 0.083, 0.241 and 0.285mol^–1Ls^–1 (298K, I = 0.10molL^–1 KNO₃, 0.02molL^–1 tris buffer, 40% MeCN aqueous solution) for Zn–NBT, Co–NBT and Cu–NBT complexes, respectively. The result indicates that the hydrolytic metalloenzyme activity of different metal complexes increases with the electrophilicity of the metal ions and that the complexes, in this paper, constitute that most efficient hydrolytic metalloenzyme models reported to date. An increase in MeCN content in the solution greatly reduces the hydrolytic activity of the nucleophiles.     

Study of kinetics and mechanism of the acid dissociation of copper(II) complex of novel C-functionalized macrocyclic dioxotetraamines

The kinetics of the acid dissociation of copper(II) complexes of novel C-functionalized macrocyclic dioxotetraamines has been studied by means of a stopped-flow spectrophotometer. The acid dissociation rate follows the law V_d = C_comkK₁K₂H ²/(1+K₁H+K₁K₂H ²). From the experimental facts we have obtained, the dissociation kinetics are interpreted by a mechanism involving the negatively charged carbonyl oxygen of the complex being rapidly protonated in a pre-equilibrium step, the rate-determining step being intramolecular hydrogen (enolic tautomer) migration (to imine nitrogen). The dissociation rate reached a plateau in the strongly acidic solution. By means of temperature coefficient method, ΔH ^φ, ΔS ^φ of the pre-equilibrium step and ΔH ^≠, ΔS^≠ of the rate-determining step were obtained. The results of 13-membered macrocyclic dioxotetraamines have been discussed. The influence of the substituents to the acid dissociation rates has also been discussed. The Bronsted type linear free energy relationships do also exist in these C-functionalized dioxotetraamine copper(II) complexes.     

Facile synthesis of thermosensitive functional polyaspartamide derivatives by click chemistry

Biodegradable and thermosensitive polyaspartamide derivatives containing pendant azide groups P(Asp‐Az)_X‐HPAs were synthesized from poly(l ‐succinimide) via the ring‐opening reaction with 2‐azidoethylamine (Az) and 5‐hydroxypentylamine (HPA). Then hydrophobic phenethyl (PEA) and imidazole (IMZ) moieties were introduced successfully with very high reaction efficiency above 90% to the side chains of P(Asp‐Az)_X‐HPA by click reaction to obtain thermoresponsive polyaspartamide derivatives containing pendant aromatic rings P(Asp‐Az)_X‐HPA‐PEAs and the thermo/pH‐responsive polyaspartamide derivatives containing pendant imidazole rings P(Asp‐Az)_X‐HPA‐IMZs, respectively. The thermoresponsive behaviors of P(Asp‐Az)_X‐HPA‐PEAs and P(Asp‐Az)_X‐HPA‐IMZs were confirmed by dynamic light scattering (DLS) and transmittance measurements, and the cloud point can be tuned by designed amounts of azide groups and can be further adjusted by the grafting molar percentage of hydrophobic phenethyl or imidazole moieties to the side chains of P(Asp‐Az)_X‐HPA via click chemistry. The pH‐responsive behavior of P(Asp‐Az)_X‐HPA‐IMZs can also be tuned. These results indicate that the obtained polyaspartamide‐based functional polymers can be further functionalized with hydrophilic long PEG chain and/or targeted moieties via click chemistry for drug delivery. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1296–1303     

Synthesis of N,N′-bis(isopropylaminoethyl)-1,10-phenanthroli ne- 2,9-dimethanamine and N,N′-bis(diethylaminoethyl)-1,10-phenanthroline -2,9-dimethanamine and potentiometric determination of the formation constants of their complexes with manganese(II), cobalt(II), copper(II) and zinc(II)

Two hexadentate compounds incorporating 1,10-phenanthroline and four alkylamino donors have been prepared. The protonation constants and the formation constants of dipositive ion (Mn2+, Co2+, Cu2+ and Zn2+) complexes have been determined in aqueous solution by pH titration at 25 ± 0.1 °C and I = 0.1 mol·dm–3 NaNO3.     

锌、镉及汞卟啉生成反应动力学研究

对四－间甲基－苯基卟啉Ｈ２Ｔ，ＰＰ与Ｚｎ，Ｃｄ，Ｈｇ在丙酮中，四苯基卟啉Ｈ２ＴＰＰ与Ｚｎ在丙酮和ＤＭＦ中的生成反应动力学进行研究。根据我们的实验结果和对前人工作的总结，提出了较为合理的反应机理，用非线性拟合的方法求得各基元步骤的动力学参数。     

Modular Assembly of Host–Guest Metal–Phenolic Networks Using Macrocyclic Building Blocks

The manipulation of interfacial properties has broad implications for the development of high‐performance coatings. Metal–phenolic networks (MPNs) are an emerging class of responsive, adherent materials. Herein, host–guest chemistry is integrated with MPNs to modulate their surface chemistry and interfacial properties. Macrocyclic cyclodextrins (host) are conjugated to catechol or galloyl groups and subsequently used as components for the assembly of functional MPNs. The assembled cyclodextrin‐based MPNs are highly permeable (even to high molecular weight polymers: 250–500 kDa), yet they specifically and noncovalently interact with various functional guests (including small molecules, polymers, and carbon nanomaterials), allowing for modular and reversible control over interfacial properties. Specifically, by using either hydrophobic or hydrophilic guest molecules, the wettability of the MPNs can be readily tuned between superrepellency (>150°) and superwetting (ca. 0°).