Imino(phenoxide) compounds of magnesium: Synthesis, structural characterization, and polymerization studies

Abstract

A plethora of magnesium compounds containing imino(phenoxide) (1–4) and bis(imino)phenoxide (5–10) ligand backbone have been synthesized via the reaction of diethyl magnesium with two equivalent of the corresponding ligand. These compounds were completely characterized by different spectroscopic techniques and elemental analyses. The monomeric nature of the magnesium complexes 3, 5, 6, 9, and 10 were further confirmed by single crystal X‐ray diffraction studies. The magnesium centers posses distorted trigonal bipyramidal geometry. The controlled hydrolysis compound Mg7O8 (C22H28NO2)6 (11) was adequately characterized using 1H, 13C NMR, ESI‐MS, and the biscubane structure was further confirmed by single crystal X‐ray diffraction studies. The Mg7O8 core is deeply embedded with the ligand periphery. These compounds (1–10) were found to be active towards the bulk ring opening polymerization (ROP) of lactides, yielding polymers with high number average molecular weight (Mn) and controlled molecular weight distributions (MWDs). In addition, these compounds have been shown to be highly active toward the copolymerization of carbon dioxide with cyclohexene oxide and styrene oxide. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1474–1491

Cubane‐Type Polynuclear Zinc Complexes Containing Tridentate Schiff Base Ligands: Synthesis, Characterization, and Ring‐Opening Polymerization Studies of rac‐Lactide and ε‐Caprolactone

“…ROP processes offer excel control in terms of molecular weight ( M n ), polydispersity (MWDs) and microstructure . Several complexes have been successfully employed in the ROP of lactide, including lithium, sodium, potassium, magnesium, calcium, strontium, aluminum, tin, zinc, some transition metals, and rare‐earth metals . Since complete elimination of catalyst rests from the polymer is virtually impossible, it is highly preferable to use non‐ or low toxic metals (for instance for biomedical applications).…”

Synthesis and Application of Bimetallic Zinc(II) Phenoxy-Imine Complexes as Initiators for Production of Lactide Polymers

“…L1 and L2 were synthesized in high yields according to a modified literature procedure. [14][15][16][17]22 Complexes C1 and C2 ( Figure 1) were also obtained in high yields. The structures of these ligands allow the coordination of two zinc(II) centers while the vast majority of the phenoxy-imine ligands coordinate to only one metal.…”

“…Yield: 62%; mp > 300 °C; elemental analysis for C 24 C1 was prepared using a modified literature procedure. [14][15][16][17] In a 25 mL Schlenk flask, 15% hexane solution of ZnEt 2 (0.20 mL, 0.22 mmol) was added dropwise to a solution of L1 (0.100 g, 0.11 mmol) in dry toluene (10 mL) at 0-4 °C (L1/ZnEt 2 molar ratio = 1:2). The reaction mixture was stirred overnight at room temperature.…”

Syntheses of Sterically Bulky Schiff‐Base Magnesium Complexes and Their Application in the Hydrosilylation of Ketones

“…For example, Rood et al have prepared three (salicylaldiminato)magnesium complexes and studied the coordination environment around the magnesium center dependend on the local steric environment of the ligand . Subsequently, Chakraborty et al reported that similar imino(phenoxido)magnesium complexes were found to be active towards the controlled ring opening polymerization (ROP) of lactides and the copolymerization of carbon dioxide with cyclohexene oxide and styrene oxide …”