Destruction of Chitosan and Its Complexes with Cobalt(II) and Copper(II) Tetrasulphophthalocyanines

Chitosan is a naturally occurring polysaccharide derived from chitin with a wide range of uses. Phthalocyanines are macroheterocyclic compounds that have a number of useful properties such as coloring and catalytic and antioxidant activity. Phthalocyanines are able to immobilize on chitosan, forming complexes with new useful properties. In this work, we evaluated the ability of phthalocyanines to increase the thermal stability of chitosan. Chitosan (CS) forms complexes with copper(II)-(CuPc) and cobalt(II)-(CoPc) tetrasulphophthalocyanines. The processes of destruction of chitosan (CS) and its complexes with sulphophthalocyanines CuPc and CoPc in oxidizing and inert atmospheres have been studied. It was established that, regardless of the atmosphere composition, the first chemical reactions taking place in the studied systems are elimination reactions. The latter ones in the case of chitosan and complex CS-CuPc lead to the formation of spatially crosslinked polymer structures, and it causes the release of CuPc from the polymer complex. It was found that in the case of CS-CoPc elimination reactions did not lead to the formation of crosslinked polymer structures but caused the destruction of the pyranose rings with a partial release of CoPc. Metallophthalocyanines showed antioxidant properties in the composition of complexes with chitosan, increasing the temperature of the beginning of glycosidic bond cleavage reaction by 30–35 °C in comparison with the similar characteristics for chitosan.

Force-modulated reductive elimination from platinum(ii) diaryl complexes

The influence of mechanical force on the rates of model reductive elimination reactions depends on the structure of the force-transducing ligand and provides a measure of geometry changes upon reaching the transition state.

Polymeric dimethylytterbium and the terminal methyl complex (TptBu,Me)Yb(CH3)(thf)

Pyrophoric redox-sensitive [YbMe2]n is obtained from [Yb{N(SiMe3)2}2]2 and methyllithium and its existence proven by 171Yb CP/MAS NMR spectroscopy and distinct methane elimination reactions.

Experimental study on light volatile products from thermal decomposition of lignin monomer model compounds: effect of temperature, residence time and methoxyl group

Effects of temperature, residence time and methoxyl on the decomposition of phenol, guaiacol and syringol, were investigated. Thermal decomposition pathways of the three model compounds were discussed based on ring reduction/CO elimination reactions.

Synthesis of novel fluorinated building blocks via halofluorination and related reactions

A study exploring halofluorination and fluoroselenation of some cyclic olefins, such as diesters, imides, and lactams with varied functionalization patterns and different structural architectures is described. The synthetic methodologies were based on electrophilic activation through halonium ions of the ring olefin bonds, followed by nucleophilic fluorination with Deoxo-Fluor®. The fluorine-containing products thus obtained were subjected to elimination reactions, yielding various fluorine-containing small-molecular entities.