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In this work we describe synthesis of new chloride and alkoxo-titanium (IV) complexes 3–7 with diol O,O-type ligands from readily available and scalable precursors. Structure of complex 6 was established by X-ray diffraction. Titanium atom adopts a tetrahedral geometry formed by three oxygen atoms of ligands and one oxygen atom of isopropoxo group. The resulting complexes 3–6 are moderately or highly active in ethylene polymerization in the presence of {3Et2AlCl?+?Bu2Mg} binary co-catalyst. Obtained polymers are linear polyethylene of ultrahigh molecular weight (3.7–8.8·106?g/mole) with a broad molecular weight distribution. Polymers are suitable for the modern methods of polymer processing - the solventless solid state formation of super high-strength (breaking strength over 2.3?GPa) and high-modulus (elastic modulus over 150?GPa) oriented films and film tapes.

A series of 3,3,6,6-tetraaryl1,2-dioxanes (TADs) have been investigated at an inert electrode by using cyclic voltammetry, constant potential electrolysis and digital simulations. The series consists of the phenyl-substituted TAD (la), p-methoxy-aryl TADs (lb, Ic) and the p-methoxy/nitro-bearing TAD (Id). The heterogeneous electron-transfer (ET) reduction is dissociative, causing rupture of the oxygenoxygen bond, which generates a distonic radical-anion that reacts competitively either by β-scission fragmentation or ET Fragmentation of the distonic radical anion yields an alkene, a substituted benzophenone, and a benzophenone radical anion. The benzophenone radical-anion propagates an efficient homogeneous ET-fragmentation chain reaction that accounts for the potential dependence of the product ratios and the low charge consumption observed in the controlled potential electrolysis experiments. Digital simulation of the experimental cyclic voltammograms allowed for estimates of the rate constants of the heterogeneous ET to the 0-0 bond, and for the rate constants for the β-scission fragmentation of the distonic radical-anions. Density functional theory calculations corroborate the differences in the heterogeneous kinetics of the initial dissociative ET The endoperoxides 1a-1c react predominantly by a concerted dissociative ET mechanism, although the data suggests a stepwise dissociative pathway is also competitive. Bearing a nitro-aryl substituent, Id provides a rare example of an endoperoxide that proceeds by a stepwise dissociative ET mechanism. Irrespective of the initial mechanistic details, we find a propagating radicalanion cycle is a general mechanistic feature.

Electron-rich 1,1-diarylethylenes (1a-e) afford 3,3,6,6-tetraaryl-1,2-dioxanes (3a-e) in high yields (>90percent) when subjected to electrontransfer photooxygenation in the presence of DCA.Whereas 1,1-diphenylethylene (1f) and 1,1-di(p-chlorophenyl)ethylene (1h) yield the 1,2-dioxanes 3f and 3h at 30percent and less than 10percent, respectively, there is negligible (if any) 1,2-dioxane formation with 1,1-di(m-anisyl)ethylene (1i). 1,2-Dioxane formation proceeds in a chain reaction (Scheme 1).N-Vinylcarbazol (1g), however, yields the 1,2-dioxane 3g via the cyclobutane derivative 7 (Scheme 2).