Investigation of equilibria in solution. Determination of equilibrium constants with the HYPERQUAD suite of programs.

Current status and future perspectives in atom transfer radical polymerization (ATRP) are presented. Special emphasis is placed on mechanistic understanding of ATRP, recent synthetic and process development, and new controlled polymer architectures enabled by ATRP. New hybrid materials based on organic/inorganic systems and natural/synthetic polymers are presented. Some current and forthcoming applications are described.

Atom Transfer Radical Polymerization (ATRP): Current Status and Future Perspectives

http://www.hyperquad.co.uk/documents/hyss.pdf

Hyperquad simulation and speciation (HySS): a utility program for the investigation of equilibria involving soluble and partially soluble species

This Perspective presents recent advances in macromolecular engineering enabled by ATRP. They include the fundamental mechanistic and synthetic features of ATRP with emphasis on various catalytic/initiation systems that use parts-per-million concentrations of Cu catalysts and can be run in environmentally friendly media, e.g., water. The roles of the major components of ATRP—monomers, initiators, catalysts, and various additives—are explained, and their reactivity and structure are correlated. The effects of media and external stimuli on polymerization rates and control are presented. Some examples of precisely controlled elements of macromolecular architecture, such as chain uniformity, composition, topology, and functionality, are discussed. Syntheses of polymers with complex architecture, various hybrids, and bioconjugates are illustrated. Examples of current and forthcoming applications of ATRP are covered. Future challenges and perspectives for macromolecular engineering by ATRP are discussed.

Macromolecular Engineering by Atom Transfer Radical Polymerization

1,3-bis(4-nitrophenyl)urea (1) interacts through hydrogen bonding with a variety of oxoanions in an MeCN solution to give bright yellow 1:1 complexes, whose stability decreases with the decreasing basicity of the anion (CH3COO- > C6H5COO- > H2PO4- > NO2- > HSO4- > NO3-). The [Bu4N][1·CH3COO] complex salt has been isolated as a crystalline solid and its molecular structure determined, showing the formation of a discrete adduct held together by two N−H···O hydrogen bonds of moderate strength. On the other hand, the F- ion first establishes a hydrogen-bonding interaction with 1 to give the most stable 1:1 complex, and then on addition of a second equivalent, induces urea deprotonation, due to the formation of HF2-. The orange-red deprotonated urea solution uptakes carbon dioxide from air to give the tetrabutylammonium salt of the hydrogencarbonate H-bond complex, [Bu4N][1·HCO3], whose crystal and molecular structures have been determined.

Nature of Urea−Fluoride Interaction: Incipient and Definitive Proton Transfer

A new computer program has been developed in which formation constants are determined by minimisation of an error-square sum based on measured electrode potentials. The program also permits refinement of any reactant concentration or standard electrode potential. The refinement is incorporated into a new procedure which can be used for model selection.

Peter Gans

Papers

Investigation of equilibria in solution. Determination of equilibrium constants with the HYPERQUAD suite of programs.

Hyperquad simulation and speciation (HySS): a utility program for the investigation of equilibria involving soluble and partially soluble species

SUPERQUAD: an improved general program for computation of formation constants from potentiometric data

Miniquad-A general computer programme for the computation of formation constants from potentiometric data.

Nuclear Magnetic Resonance as a Tool for Determining Protonation Constants of Natural Polyprotic Bases in Solution