Related Experiment Video
Updated: Feb 1, 2026
Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst
Published on: June 8, 2016
Mononuclear Salen-Sodium Ion Pairs as Catalysts for Isoselective Polymerization of rac-Lactide
Yaqin Cui1, Jinxing Jiang1, Xiaoyang Mao1
1State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Key Laboratory of Nonferrous Metal Chemistry and Resources Utilization of Gansu Province , Lanzhou University , Lanzhou 730000 , People's Republic of China.
Abstract:
A series of mononuclear salen-sodium anions, as the first examples, were synthesized with tetra-alkyl ammonium as a counterpart cation. These complexes are efficient catalysts for the isoselective ring-opening polymerization of rac-lactide; the molecular weights of polymers are under control and molecular weight distributions are narrow when five equivalents of BnOH is used as an initiator. The best isoselectivity value of Pm = 0.82 was achieved at -70 °C. The experimental results together with a density functional theory calculation show that a ligand-assisted activated monomer mechanism is more reasonable than an activated monomer mechanism for this system.
Related Concept Videos
01:17Pore Transport and Ion-Pair Transport
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct...
03:45Formation of Complex Ions
03:24Common Ion Effect
03:11Precipitation of Ions
The equation that describes the equilibrium between solid calcium carbonate and its solvated ions is:
02:54Ions as Acids and Bases
Salts are ionic compounds composed of cations and anions, either of which may be capable of undergoing an acid or base ionization reaction with water. Aqueous salt solutions, therefore, may be acidic, basic, or neutral, depending on the relative acid-base strengths of the salt’s constituent ions. For example, dissolving the ammonium chloride in water results in its dissociation, as described by the equation:
02:27DNA Base Pairing