6 Molecular and Crystal Structures of Polymorphic …
239
(a) A
(b) B
a
b
O
c
a
b
O
c
(c) C
(d) D
a
b
O
c
a
b
O
c
Fig. 6.9 Packing motifs of the four polymorphs of N,N’-butylated QA: a A-form (WAMFAS01),
b B-form (WAMFAS02), c C-form (WAMFAS03) and d D-form (WAMFAS04). For the A-form,
the stacking dimers and their arrangement are illustrated. The arrangements of the B- and C-forms
are viewed perpendicular (upper) and parallel (lower) to the QA ring. For the D-form, the two
columns formed by the two independent molecules are viewed from two directions
239
(a) A
(b) B
a
b
O
c
a
b
O
c
(c) C
(d) D
a
b
O
c
a
b
O
c
Fig. 6.9 Packing motifs of the four polymorphs of N,N’-butylated QA: a A-form (WAMFAS01),
b B-form (WAMFAS02), c C-form (WAMFAS03) and d D-form (WAMFAS04). For the A-form,
the stacking dimers and their arrangement are illustrated. The arrangements of the B- and C-forms
are viewed perpendicular (upper) and parallel (lower) to the QA ring. For the D-form, the two
columns formed by the two independent molecules are viewed from two directions