FIGURE 1.
H-bonding possibilities for an exocyclic amine. Seven scenarios are depicted, demonstrating amines that are (A) single- or (B) dual-donating. Single-donating scenarios 1, 2, and 3 can become dual-donating by gaining the red H-bonds depicted in scenarios 5, 6, and 7, respectively. In an effort to be comprehensive, diverse scenarios are considered even though not all of them (e.g., 2 and 6) can occur given our H-bond criteria. Bifurcated H-bond examples are present in scenarios 2, 3, 6, and 7, and a trifurcated H-bond example is present in scenario 4.
