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Beyond Rotatable Bond Counts: Capturing 3D Conformational Flexibility in a Single Descriptor
Jerome G P Wicker1, Richard I Cooper1
1Chemical Crystallography, University of Oxford , Oxford OX1 3TA, U.K.
Abstract:
A new molecular descriptor, nConf20, based on chemical connectivity, is presented which captures the accessible conformational space of a molecule. Currently the best available two-dimensional descriptors for quantifying the flexibility of a particular molecule are the rotatable bond count (RBC) and the Kier flexibility index. We present a descriptor which captures this information by sampling the conformational space of a molecule using the RDKit conformer generator. Flexibility has previously been identified as a key feature in determining whether a molecule is likely to crystallize or not. For this application, nConf20 significantly outperforms previously reported single-variable classifiers and also assists rule-based analysis of black-box machine learning classification algorithms.
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