Article was published on the website of the journal Angewandte Chemie describing the process of synthesis of an oligomer, that is, consisting of several identical fragments of a substance, a specific structure in the form of a spiral staircase. We asked Zhanna Boeva, Candidate of Chemical Sciences, to comment on this study.
The article is devoted to the synthesis of oligomers of a special structure. This is a subclass of helical polymers that have been studied for a long time. For the first time, a substance from the class of spiral polymers was obtained back in the 19th century, and specifically from the subclass discussed in the article – in the 90s of the 20th century. The authors report the synthesis of another interesting oligomer, which has not just a helical conformation twisted in the form of a spiral staircase, but a double structure: in the resulting substance, the second helix is twisted around the main helix of the carbon skeleton in the form of a ribbon.
They succeeded in obtaining an optically active oligomer, but they could not avoid racemization. They synthesized a mixture of structural fragments of the chain, but nevertheless they were ordered in such a way that the substance did not lose its optical activity.
The potential application of such oligomers is actually quite wide, because the synthesis of helical structures is of interest, for example, for catalysis or catalysis elements, for substances used in separation columns capable of separating optical isomers.
In terms of catalysis, the motivation for doing this work is the fact that our body contains a large number of biologically active chiral polymers. Synthetically obtained polymers can simulate some biological processes. For example, DNA itself is a helix. Therefore, interest in helical polymers does not stop.
Unfortunately, a specific group of oligomers, to which the one synthesized by the authors of this article belongs, have not yet found practical application, because they are very difficult to synthesize. In this case, the authors had to come up with seven stages to obtain this substance, while part of the reaction was uncontrolled. So the synthesis of such compounds is still very laborious, it is necessary to apply very complex approaches. If it were possible to synthesize them on a single catalyst, as is done in the case of simpler helical polymers, then they could be used. At the moment, the synthesis of this substance is interesting in terms of narrow-profile synthetic polymer chemistry, that is, it is more interesting for a specialist, but it is quite possible that in the future it will find its application.