Combined Effect of Synthons and Shape

Development of an optimal design strategy that involves both supramolecular synthons and molecular properties requires an understanding of the relative 

2-hydroxyadamantane adamantanone adamantanone oxime 2-adamanlanecarboi lic acid 

The four adamantane derivatives, 2-hydroxyadamantane, 2-adamantanone, 2-adamantanone oxime and 2-adamantanecarboxylic acid (Formula 5.4) all have a nearly spherical shape. Screening experiments were performed with each possible pair of the four compounds, but only two co-crystals were found hydroxyadamantane- adamantanone and adamantanone oxime-adamantane-carboxylic acid. The alcohol-ketone and acid-oxime hydrogen bonds provide strong supramolecular synthons for the formation of these co-crystals, while for the other combinations possible heteromolecular synthons are not preferred to homomolecular ones. The results thus show that shape similarity cannot overcome the effect of good homomolecular synthons. 

The results described above showed that the use of shape- and polarity-matching generally improves the success rate of co-crystallisation experiments. 

As shown in Table 5.5, progesterone forms co-crystals with 19 of the 24 compounds tested, including phenols (e.g., 4-bromophenol), carboxylic adds 

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