Fig. 13

Results of SCDS-PIXEL calculations for polymorph VI. a Interaction energies, represented by balls, are separated into internal C-5 interactions (blue) and interactions between neighbouring C-5 tapes (@1, red; @2, orange; @3, green). Internal C-5 interactions are labelled t (two-point H-bonded), o (one-point H-bonded) and n (non-H-bonded). The horizontal bars indicate cumulative PIXEL energies (summation from left to right) relative to the E _T,Cry (scale on the right-hand side). A central molecule A (b) or B (c) (coloured orange) and neighbouring molecules involved in seven (b) or six (c) pairwise interactions (see Additional file 1: Tables S10 and S11). The mean plane of the pyrimidine ring of the central molecule is drawn, H atoms are omitted for clarity and H-bonds are indicated by blue lines