FIGURE 3.

Halogen bonding of the P2 substituent. a, the electrostatic surface potential of the P2 substituent of BI 201335 as calculated using a quantum mechanics approach that considers electronic effects exerted by the chemical environment of the bromine (see “Experimental Procedures”). The black arrow indicates the area of positive surface potential located at the tip of the C-8 bromine. b, superposition of BI 201335 and its des-bromine analog 1 illustrating the structural shifts incurred upon halogen bond formation.