Year: 2021
Type: article
Abstract: After the existence of molecules was established at the turn of the 20th century, chemists focussed on studying how molecules react. That molecules can also be programmed to interact was brought into focus by the 1987 Cram-Lehn-Pedersen Nobel Prize 'for their development and use of molecules with structure-specific interactions of high selectivity'.1 Their initial insights can be seen to have birthed the field of supramolecular chemistry, or 'the chemistry of the intermolecular bond',2 which has evolved into a mature field.3 One implication of intermolecular bonding is the phenomenon of molecular recognition,4 which must be at least as old as life on earth; this is evident from the various bio-machineries that have been unravelled in the past half-decade or so.5 A contemporary example is the SARS-CoV-2 virus, which infects cells by recognising a membrane enzyme (ACE2) with its spike proteins.6 Besides the relevance of molecular recognition to understand biology on a molecular level, typical areas of application include: chemical biology, sensing, purification/separation, crystal engineering, nanotechnology, (small molecule) drug development and site-selective (supramolecular) catalysis. Given these diverse fields of applications, it is no surprise that the number of articles mentioning 'molecular recognition' in the title or topic section has been climbing over the past fifty years to nearly 13 000 in the last decade (see Figure 1). We see no reason why this trend would break, especially as advanced techniques to study molecular recognition phenomena are increasingly routine. One might think about two-dimensional NMR techniques using strong-field spectrometers, various optical techniques and computational tools such as large cluster super computers or even increasingly powerful multi-core desktop PCs. Web of Science search for the number of articles published per decade containing 'molecular recognition' in the title or topic section. The maturity of the field and its techniques notwithstanding, there are ample opportunities to expand the research area, of which we highlight four. One avenue is the computational evaluation of lesser-known intermolecular (σ- and π-hole) interactions and attempt to translate this into molecular recognition properties. There is a clear precedence for such developments in the literature of Halogen7 and Chalcogen8 bonding interactions.9 Another opportunity is presented by the development of stimulus (e. g. hν) driven recognition and/or release of specific molecules. This concept could, for example, be exploited to selectively release a drug or to switch between activated/deactivated transport molecules. A third prospect is the development of molecules that can selectively recognise carbohydrates, which are the largest and most diverse class of biomolecules. The subtle differences between regioisomers, stereoisomers and enantiomers make this a daunting task, but recent developments suggest that it is a tenable goal. Finally, a common challenge is the bio-orthogonality of synthetic molecules designed for their molecular recognition properties. Achieving water solubility is not as straightforward as one might hope, and molecular recognition is often highly solvent dependent. Moreover, not all tricks to solubilise organic molecules results in toxicologically benign compounds. We are eager to see how our collective efforts will capitalise on the diverse molecular recognition challenges such as those highlighted above. Hopefully, some of the breakthroughs will be realised by authors of this special issue on molecular recognition. The eleven computational inquiries and five experimental studies present a step in the right direction and we are grateful to all authors for accepting our invitation and trusting us with their work.
Source: ChemPhysChem
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W4241649248