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The synthesis is described of macrocyclic poly( -methylstyrene) (PAMS) by the lithium naphthalide initiated polymerization of AMS followed by high dilution end to end coupling with 1,4-bis(bromomethyl)benzene (DBX). The cyclization is carried out by simultaneous addition of tetrahydrofuran solutions of the PAMS dianion and DBX at about -100ºC. A sample of the matching linear PAMS is obtained by protonation of the PAMS dianion. The purified cycles are obtained by fractional precipitation that is monitored by size exclusion chromatograhy. A careful study of the coupling reactions carried out at high concentrations indicates that coupling is efficient and this is borne out by the ratios () of apparent molecular weights (MW's) of cycles and matching linear polymers. The values of the cycles tend to vary with MW in the same manner as was demonstrated for polystyrene and other vinyl polymers and increase from around 0.74 at MW of about 30000 to values of around 0.82 at MW of about 2500. A higher apparent value was observed for a very low MW PAMS but this sample could not be purified and analyzed adequately. As was also observed for other macrocyclic vinylpolymers, the glass transition temperatures of the cycles are MW independent above MW of about 5000 but decrease sharply at lower MW's.

The synthesis, isolation, and characterization are reported of a polystyrene−poly(2-vinylpyridine) block copolymer “catenane” with a molecular weight of about 10 000 and containing about equal masses of each of the rings. This catenane is prepared by end-to-end coupling of a P2VP dianion lithium salt with 1,4-bis(bromomethylbenzene) in THF in the presence of a PS macrocycle (M p = 4500). The catenane was isolated by precipitation−extraction procedures that were optimized using a 50/50 PS-b-P2VP macrocycle as a model for the catenane. The catenane copolymer was characterized by SEC, 1H NMR, and emission (fluorescence) spectroscopy.

The end-to-end cyclization reaction of living monodisperse a,o-dianion precursors with difunctional electrophiles (EX,) in the presence of partial anion termination is described. A computer simulation was developed to establish the relationship among the initial concentration, the molecular weight of the dianion precursor, the extent of anion termination, and the yield distribution for all of the cyclic and linear polymer species. A master curve is calculated allowing the determination of the macrocycle yield as a function of MW and concentration of the dianion precursor, and degree of anion termination.

A zero-order reaction converts cis-dilithiostilbene (1), formed upon reduction of diphenylacetylene by lithium, into the trans isomer 2. The cis-monolithiated adduct acts as a catalyst.

In einer Reaktion nullter Ordnung wird cis‐Dilithiostilben 1, das aus Diphenylacetylen und Lithiummetall in Diethylether zugänglich ist, in das trans‐Isomer 2 umgelagert. Monolithiiertes Stilben fungiert dabei als Katalysator.

Dalian Free Trade Zone has realized the development direction of taking service trade as the core, international division of labor as the goal, and new opening strategy as the guidance. However, due to the bottleneck of financial system reform and the limitation of system mechanism and policy, especially the slow pace of reform in the aspects of foreign exchange control, free floating of exchange rate and marketization of interest rate related to the free flow of capital, Dalian’s “four centers”: economic center, financial center, trade center and shipping center, the pace of construction is limited to a certain extent It is also difficult to further expand the space for the development of the liberal economy. The competition and cooperation conditions in Liaoning free trade zone are quite different from those in other free trade zones, so this paper makes an in-depth study around Liaoning free trade zone.