Preparation and structure of an enantiomeric water-bridged dinuclear indium complex containing two homochiral N atoms and its performance as an initiator in polymerization of rac-lactide

ppm-Level Thermally Switchable Yttrium Phenoxide Catalysts for Moisture-Insensitive and Controllably Immortal Polymerization of rac-Lactide

“…Hence, some efforts have been devoted to find alternatives to overcome the problems of the commercially used Sn­(Oct) 2 . Although some simple air stable metal salts or complexes, such as MgCO 3 , CaCO 3 , Zn­(OAc) 2 , ZnCl 2 , , zinc complexes with bis-guanidine or guanidine–pyridine ligands, and indium complex with pyridine bisphenol as ligand, are active for the ROP of lactide in air; however, the activities, productivities, or controllabilities of these catalysts are not good. Some air-stable complexes of Al, Ti, Y, Fe, Cu, and alkali metal carboxylates have been reported; it is a pity that the polymerizations in air were not explored.…”

Air- and Moisture-Stable Indium Salan Catalysts for Living Multiblock PLA Formation in Air

“…Despite the recent focus in the literature on developing air/water stable catalysts for a range of catalytic applications, fewer efforts have been made to develop air- and moisture-resistant metal-based catalysts for ROP of cyclic esters that can be used under industrially relevant conditions . Zinc complexes bearing guanidine-pyridine ligands, and magnesium–sodium/lithium heterobimetallic complexes are active for the ring-opening polymerization (ROP) of lactide under these conditions; however, the polymerizations are sluggish (high conversion is achieved after 24–48 h) and suffer from extensive transesterification reactions, which limits control over polymer macrostructure. , Indium catalysts bearing pyridine bisphenol ligands polymerize 100 equiv of lactide in air at 80 °C over the course of 24 h with 86% conversion . Air-stable catalysts with Al, Cu, Ti, Y, and Mg–Na/Li have been reported; however, in these studies, polymerizations were carried out under inert conditions.…”

“…We show that this reactivity is a direct result of the tetradentate aminophenolate supporting ligand on indium; previously reported indium complexes for living and immortal polymerization in our group supported by tridentate aminophenolate ( A ) or bisimino-bisphenolate (salen) ( B ) ligands do not always show similar reactivity (Figure ). Since our first publication of complex A , many other indium catalysts for lactide polymerization have been reported. , Of these, there is only one example that polymerizes low equivalents of lactide in air (discussed above) …”

The first pentanuclear heterobimetallic coordination cation with CeIII, CeIV and MnII

“…Each manganese(II) ion is thus 6-coordinated and each cerium(III, IV) ion is 9-coordinated. During the synthesis of 1, the gaseous dioxygen is evolved, due to water oxidation that is attributed to the presence of Ce and Mn in different oxidation states.The structure and bond properties of manganese compounds are of continuing interest in inorganic chemistry [1][2][3][4]. Manganese carboxylates, especially those with nitrogen donor ligands, have been the subject of numerous investigations [5][6][7].…”