Is N,N,N',N'-tetramethylethylenediamine a good ligand for lithium?

Anionic vinyl polymerization—50 years after Michael Szwarc

Stereoregular polymerization of α-substituted acrylates

This article deals with developments in the field of anionic polymerization of nonpolar monomers by the use of the lithium counter-ion. The topics discussed include structure and bonding of organolithium compounds, the initiation and propagation reactions in hydrocarbon solvents, the influence of polar co-solvents on chain propagation, the stereochemistry of polydienes and chain end functionalization. Furthermore, the bonding energies of organolithium aggregates are discussed with regard to the identity of the active species in the initiation and propagation events.

Anionic polymerizations of non-polar monomers involving lithium

Aggregation of stereoregular poly(methyl methacrylates)

Lithium-potassium exchange in alkyllithium/potassium t-pentoxide systems: XIV. Interactions of alkoxides

The growth center in the anionic polymerization of methacrylic esters is stabilized with alkaline alkoxides, sodium tert-butoxide in particular. The lifetime of the growth center was investigated in the polymerization of methyl methacrylate by evaluating yield and molecular weight distribution of the polymer formed when the monomer was added in two doses. The average lifetime of the original growth center stabilized by sodium tert-butoxide at 20°C under the given conditions was longer than several minutes. The stabilization of the growth center was also used in the stepwise copolymerization of n-butyl methacrylate and methyl methacrylate. The copolymer thus obtained in high yield was characterized as a block copolymer on the basis of its solubility, nuclear magnetic resonance (NMR) spectra, and measurements of the complex shear modulus.

Metallo esters. VII. Stabilizing effect of sodium tert‐butoxide on the growth center in the anionic polymerization of methacrylic esters

Interactions of alkoxides

Preparation d'un complexe, a transfert de charge par reaction du polyacetylene avec le dehydronaphtyline de sodium; ce complexe amorce la polymerisation anionique du methacrylate de methyle

A soluble graft copolymer of polyacetylene

The rate constants of polymerization and cyclization and the equilibrium constants of polymerization are calculated from kinetic data of the anionic oligomerization of methyl methacrylate initiated by methyl α-lithioisobutyrate in THF at 25°C, and of the “disproportionation” of living oligomers. The numeric method reported earlier was improved. The rate constants of cyclization decrease with chain-length, due to increasing steric hindrance. The rate constants of polymerization depend on the concentration of active centres, due to the formation of associates. Rate and equilibrium constants of polymerization decrease with chain-length. This is discussed in terms of intramolecular coordination of the counterion with ester groups of the chain.

Jiří Trekoval

Papers

Lithium-potassium exchange in alkyllithium/potassium t-pentoxide systems: XIV. Interactions of alkoxides

Metallo esters. VII. Stabilizing effect of sodium tert‐butoxide on the growth center in the anionic polymerization of methacrylic esters

Interactions of alkoxides

A soluble graft copolymer of polyacetylene

Equilibria in the anionic polymerization of methyl methacrylate, 1. Chain‐length dependence of the rate and equilibrium constants