Efficient in-situ end-functionalization of polydienes by isothiocyanate via neodymium mediated coordinative chain transfer polymerization system

End-functionalization of polydiene rubbers can not only improve its compatibility with inorganic fillers,but also enhance the overall mechanical properties.Nevertheless,for traditional neodymium(Nd)diene polymerization systems,it is highly challenging to achieve such end-functionalizations,because most of polydienyl chains are capped withη3-allyl-Nd moiety during the end of polymerization,which shows very poor reactivity with nucleophile compounds.We launched a new diene polymerization strategy calling coordinative chain transfer polymerization(CCTP)[1].In such a system,all the polydienyl chains are capped withη1-allyl-Al moieties,which reveal greater reactivity with cyclic esters and epoxide compounds,providing an effective manner to prepare polydiene-polyester amphiphilic block copolymers.Inspired by such findings,we now show herein how such types of chain-ends react with isot-hiocyanate to demonstrate an efficient in-situ manner to access end-functionalized polydienes by using CCTP.

对Ag（NH3）2^＋中的Ag^＋是sp杂化成键的商榷

对Ａｇ（ＮＨ_３）_２~＋中的Ａｇ~＋是ｓｐ杂化成键的商榷夏泽吉（四川达县师专化学系６３５０００）目前在国内一些高等院校使用的《无机化学》［１，２］教材中，对Ａｇ（ＮＨ３）配离子中的Ａｇ（Ⅰ）均认为是ｓｐ杂化成键，而且有的《无机化学》［３］为了强调形成配...

Closed-loop Supply Chain Systems Constructed by 4PL and Performance Evaluation by Using Exergoeconomics

This paper introduces a new concept of 4PL, which is a contractor of the closed-loop supply chain coordination based on the division of community and the outsourcing development. The concept enriches the connotation of 4PL and broadens the thought for 4PL development. Secondly, according to the characteristics of the closed-loop supply chain in the different duration of the collaborative relationship and the dynamic characteristics of the closed-loop supply chaini we apply the fractal theory to establish a fractal system of 4PL coordinating closed-loop supply chain and propose different strategies for 4PL coordinating with different types of closed-loop supply chains in the various links of the system. Moreover, some strategic and proactive thinking are provided for 4PL＇s practices. Then based on the exergoeconomics theory, the closed-loop supply chain is regarded as a huge energy system with the new view, and the sustainability of the closed-loop supply chain system is discussed under the circumstance of exergoeconomics, and then the metric about “system negative environment effect” is introduced to measure the closed-loop supply chain system performance in the point of energy, a case study illustrates our conclusions.

Cation-induced assembly of Zn(Ⅱ),Cd(Ⅱ) and Hg(Ⅱ) coordination complexes and DFT calculations to evaluate weak interactions between the helical chains

Two new coordination polymers [ZnLI2]∞ （1） and [CdLI2]∞ （2） （L： 3,6-di-（1,2,4-triazole-l-yl）-N-hexylcarbazole） were syn- thesized and their crystal structures were determined by single-crystal X-ray diffraction techniques. Complexes are both constructed with the helical chains along the 2l screw axis. The coordination bond, C-H...I weak interactions and π-π interactions play significant roles in constructing their 3D or 2D frameworks. Two different DFT calculations are performed for the weak interactions between the helical chains of the three different coordination polymers （[ZnLI2]∞[CdLI2]∞, and the reported [HgLI2]∞）. The results reveal that weak interactions play important roles in these supramolecular systems of helical configuration, namely, the trend is the shorter H…I distance and π-π stacking distance, the stronger the intermolecular interactions. The photoluminescence of the complexes measured in the solid state at room temperature indicates that the emission intensity varies extensively, which can be rationalized by the heavy atom effect. helical configuration, weak interactions, DFT calculations, photoluminescence