Project Details Nomenclature of Sequence-Controlled Polymers

Project No.:
2019-041-3-400
Start Date:
20 December 2019
End Date:
Division Name:
Polymer Division
Division No.:
400

Objective

This project intends to provide a first and comprehensive set of guidelines for the nomenclature and terminology of sequence-controlled polymer structures. It will deliver recommendations for both structure- and source-based nomenclature allowing to uniquely identify linear polymers and copolymers that feature a defined sequence of skeletal structures. The recommendations will provide and complement IUPAC recommendations on polymer nomenclature.

Description

The field of sequence-controlled polymers has grown considerably during the last years (even though first approaches have been around for more than 50 years) and it has become a major topic in fundamental polymer science [Science 341, 1238149 (2013); Sequence-Controlled Polymers, Jean-François Lutz (Editor), Wiley-VCH 2018, ISBN: 978-3-527-34237-2]. A growing number of synthetic approaches allow for the synthesis of more and more precise polymers that feature a defined sequence of incorporated monomer units without a currently existing nomenclature and terminology. Hence, until today, no IUPAC nomenclature and terminology recommendations have been worked out for this class of precision polymers. Yet, first attempts of a glossary have been collected recently [Macromol. Rapid Commun. 38, 1700582 (2017)].

A nomenclature for the class of sequence-controlled polymers is challenging because the degree of precision along a polymer chain can dramatically vary. Sequence-controlled polymers cover non-natural macromolecules and bio-hybrid polymers that aim to mimic structurally defined natural occurring polymers (e.g. DNA, proteins). On one hand, a completely precise sequence of incorporated monomers can be installed leading to sequence-defined oligomers/polymers with lower molecular weights and dispersities approaching or being Đ = 1.0, while on the other hand the synthesis of multiblock copolymers with overall higher molecular weights (and Đ > 1.0) but leads to distributions of incorporated monomer units for each sequential step (i.e. sequence-controlled polymers). Accordingly, the synthetic approaches to polymers with a perfect sequence control and low molecular weights have to be compared to the approach with a less perfectly defined sequence control but with higher molecular weight. Yet, it is important to note that with synthetic advances this gap between sequence-defined and sequence-controlled polymers is about to vanish. Therefore, clear classifications have to be given, which shall be defined within the present project. To cope with the diversity of polymers and their synthesis (ranging from chain polymerization, addition polymerizations and polycondensations to solid-phase synthesis) the following proposed subprojects will be worked on:

• Precise positioning of single units along a polymer chain
• Sequence-controlled polymers
• Sequence-defined oligomers/polymers
• Degree of irregularity allowed in a sequence-defined polymer
• Stereoisomers
• Generalized structures as reduced structure motifs

 

The task group will collect and review all reported cases in the scientific literature of sequence control in polymer synthesis in order to work out a first set of rules for the development of a nomenclature. Emphasis will be laid on monomer sources suitable for precision sequence-control. The main task will be to develop and unify the recommendations for nomenclature of polymer structures with different degree of precision of sequence control. Additionally, considerations for recommendations for nomenclature of multiblock (segmented) copolymers will be given.

In all cases, the analogy and in ideal cases, the compatibility with nomenclature recommendations for polypeptides should be maintained. At the moment, the discipline of sequence-controlled polymers is rapidly taking momentum and definitions and terminologies are still malleable and should be manifested as soon as possible. Consequently, the present project will provide a recommended terminology.

Progress

Page last updated 20 Dec 2019