Figure 2. Distribution of distances between nitrogen and oxygen atoms involved in N-H…O hydrogen bonds in small molecule structures containing intermolecular carboxylate-guanidine-carboxylate (charge-triad mimic) motifs surveyed in the Cambridge Structural Database (CSD).

A total of 109 structures that possess the charge-triad mimics were extracted from the CSD and hydrogen bonding patterns analyzed to generate the histogram. Only intermolecular hydrogen bonds formed between COO⁻…H-N⁺-H…⁻OOC were counted in the histogram.