H2 activation by zirconaziridinium ions: σ-bond metathesis versus frustrated Lewis pair reactivity

Zirconaziridinium salts cleave H2 by a stepwise mechanism, where initial σ-bond metathesis of the Zr–C bond enables subsequent heterolytic splitting through metal–amine cooperation.

The Influence of Temperature on the Copolymerisation of 1,3-butadiene and Styrene using a Modified Lithium-containing Initiating System

The relationships governing 1,3-butadiene copolymerisation in a hexane solvent in the temperature range 30–70°C were studied. The copolymerisation process was initiated by n-butyllithium. A mixture of alkali metal and alkaline earth metal amine-containing alcoholates (AMD) was used as the modifier. The microstructure and macrostructure of the obtained p-SBR specimens were investigated. In p-SBR specimens obtained in the presence of AMD in the investigated temperature range, the distribution of styrene units in block was not found. The introduction of AMD leads to the disappearance of the induction period and to an increase in the copolymerisation rate, i.e. the reactivity of the system increases, and a reduction in temperature accelerates this process. It was shown that, with increase in the process temperature, there is a reduction in the average molecular weights of the copolymer. In the presence of AMD, lowering of the copolymerisation temperature leads to ‘enrichment’ of the butadiene part in 1,2-units (up to 66.3%).

Varied forms of lamellar [Sn3Se7]n2n− anion: the competitive and synergistic structure-directing effects of metal–amine complex and imidazolium cations

Presented are the varied forms of a lamellar [Sn3Se7]n2n− anion produced by the competitive and synergistic structure-directing effects of a metal–amine complex and imidazolium cations.