Application of big data in science database stimulates our mind to give rise to a novel idea for scientific discovery. Today is the age of data science and numerous public and commercial databases being available and the entries of data are swelling alongside the supporting information related to the main topic. As an approach to utilize precious database, here is interesting research in the field of structural dynamics, which is looking at the Cambridge structural database (CSD)^1),2) to see if the correlation between the distances and angles could serve as an organizing principle of structural data.³⁾ The research represents a practical way for increasing the value of the collection of data and the concept is invaluable for any scientist.

What the author did is rather simple. CSD is a numerical database and statistical analysis to see the correlations of each parameter is just a trivial way for deriving insights from accumulated data. The important thing according to the paper is how you interpret the correlation between parameters. For example, in the field of structural dynamics, elucidation of physical origin of statistical correlation is indispensable and multiple combinations of parameters are essential for the precise analysis of true nature. In the case of hydrogen bond, distances and angles of O.H.O fragments would be the basis but it is also necessary to consider the types of (H₂O.H.OH₂)⁺ and (HO.H.OH)^- interactions to understand the true nature of structures and its dynamics. Dissection of O.H.O correlation is a must to deeply understand the hydrogen bonding and needs to be incorporated the statistical data analysis.

The research takes a look at nucleophilic addition/elimination of nitrogen to carbonyl group, which structural effect is known to have significant impact in the reactivity. Bürgi-Dunitz angle is well-known angle for nucleophilic addition to carbonyl groups⁴⁾ and it is written in major organic chemistry textbooks. However, this correlation is based on a single observation of an unusually short non-bonded distance between an amine nitrogen and a carbonyl carbon atom in free base Methadone.⁵⁾

The author took a look at charge density over the C-N bond formation, stereochemical outcomes and decay of tetrahedral intermediate and nucleophile-carbonyl carbon interactions. Here we don’t go into the detail but Bürgi-Dunitz angle theory is not always applicable to the entire world of chemistry, which is the answer from the analysis of CSD.

The author also analyzed the transition metal and ligand interactions and its structure dynamics in the paper. Structure-reactivity relationships are also the focused topic and the results are that structure dynamics matters in the reactivity, as easily be imagined by chemists’ intuitions. The analyses give you insights for the improvement of catalyst design according to the substrate of interest.

This research presented not only structure-related relationships but also the importance of full use of fruitful database for obtaining any hints. Thorough analysis of big data would give you lots of insights. CSD is widely available and useful as a molecule structure database. The same concept is applicable for any database of the field of interest. Looking back to the what precedents found from the bird’s-eye view through analysis of databases stimulates your brain for innovation.

1. https://www.ccdc.cam.ac.uk/solutions/software/csd/
2. https://doi.org/10.1107/S2052520616003954
3. https://doi.org/10.1063/4.0000244
4. https://doi.org/10.1021/ic50128a021
5. https://doi.org/10.1021/jp953141+