Dear all,


I was wondering whether the tool available through CSD-Materials on Mercury to screen potential co-crystal components by molecular complementarity is available on the CSD Python API and, if so, how this tools could be accessed.


Thanks for the help!



Dear Luca,

this functionality has been exposed in the CSD Python API, but is currently available only to Research Partners of the CCDC. I believe you are working for Merck at the moment, and they are a Research Partner.  In which case you will be able to download the ccdc_rp package from the Research Partner Portal at CCDC, and gain access to it via

from ccdc_rp.descriptors import MolecularDescriptors
complementarity_screen = MolecularDescriptors.ComplementarityScreen()

I hope this is helpful.  Please get back to me if anything is unclear.

Best wishes


Thanks Richard! I was able to install ccdc_rp. 


However when I try to run a calculation, I am not sure how to get the results from it. 


What I did was:


complementarity_screen = MolecularDescriptors.ComplementarityScreen(), [mol2]) (where mol1 and mol2 are two molecule objects)


When I try to get the results however:


I get

<property at 0x2e396fa64a8>
And I don't know how to actually extract a value from this object.
Am I missing something?

Hi Luca,

the return value of the screen() method is a ComplementarityScreen.ResultSet.  This has a couple of methods for extracting results grouped by active or by coformer, and list-like access to individual results, i.e.

results =, [mol2])

result = results[0]

Then you can get the individual success property:




There is documentation for the ccdc_rp package available on the downloads page of the CCDC,

under the CSD Python API Research Partner Add on documentation.

I hope this is clear.  Get back to me if you would like more information.

Best wishes


Hi Richard,


Thanks a lot, that worked! 



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