Figure 6
Schematic representation of types 1 and 2 hydrogen bonding in (II). Molecules are represented by donor (D) and acceptor (A) centres joined by solid lines and hydrogen bonds by dashed lines. The arrangements shown are (a) a pair of type 1 chains; (b) as (a), but with the introduction of a single type 2 hydrogen bond, D1⋯A2; (c) as (b), but with the introduction of a second, complementary, type 2 hydrogen bond, D2⋯A1. |