Copper(II) complexes containing N,N′-bidentate N-substituted N-(pyridin-2-ylmethyl)amine: Synthesis, structure and application towards polymerization of rac-lactide

Mechanism and Stereocontrol in Isotactic rac-Lactide Polymerization with Copper(II) Complexes

“…These catalysts are in general more robust against temperature or moisture than catalysts optimized for coordination–insertion polymerization, but activities are typically low, polymer molecular weight control is often difficult (with some exceptions , ), and there is no stereocontrol. L m Cu­(OR) n complexes, suitable for coordination–insertion polymerization, are more difficult to prepare and more sensitive to temperature and protic impurities but display higher activities (by orders of magnitude) and excellent polymer molecular weight control. , They also represent the first examples of stereocontrol with Cu­(II)-based catalysts, either to the heterotactic polymer , or, in the case of 1 but not 2 , to isotactic PLA . The following presents a discussion of the mechanism of rac -lactide polymerization by 1 and 2 , a determination of the origin of stereocontrol, and an explanation of how the initiating group can determine isoselectivity.…”

Synthesis and structures of copper complexes bearing unsymmetric derivatives of (R,R)‐1,2‐diaminocyclohexane: An efficient catalyst for asymmetric Henry reaction

“…The Cu 2+ ion in [L 4 CuCl 2 ] 2 adopted a distorted square planar geometry by coordinating with two nitrogen atoms of the ( R , R )‐1,2‐diaminocyclohexane backbone in a chelating manner, and with one terminal and one bridging chloro ligand. The Cu–N [2.037(5)–2.043(6) Å] and Cu–Cl [2.253(2)–2.2972(2) Å] bond lengths were well within the expected range . The 2.7239(2)–2.7239(2) Å distance between Cu1···Cl3 and Cu2···Cl1 in [L 4 CuCl 2 ] 2 suggests a weak interaction ( Table ).…”

Crystal structure of {2-methyl-2-[(pyridin-2-ylmethyl)amino]propan-1-ol-κ3 N,N′,O}bis(nitrato-κO)copper(II) from synchrotron data

“…Transition-metal complexes containing amine or its derivative ligands have attracted considerable attention owing to their diverse coordination geometries and their various applications in catalysis (Ahn et al, 2017), as magnetic materials (Liu, Zhou et al, 2017) and fluorescent substances (Chia & Tay, 2014) as well as sensing materials (Liu, Wang et al, 2017). In addition, polyamine ligands containing hydroxyl groups can easily form multinuclear complexes (such as dinuclear or trinuclear) with various transition-metal ions and hydrogenbonded supramolecular compounds due to the deprotonation of hydroxyl groups by the transition-metal ions and anions (Shin et al, 2014).…”