Table 2. Graph-set descriptions.

Graph set	Level	Period	No. of Mol­ecules
(2) a	1		2
(7) <a>a	1		3
(2) b	1		2
(13) >b<b	1	2	3
(2) c	1		2
(13) >c<c	1	2	3
(2) d	1		2
(7) <d>d	1		3
(2) e	1		2
(10) >e<e	1		3
(2) f	1		2
(13) >f<f	1		3
(2) g	1		2
(10) >g<g	1		3
(2) h	1		2
(10) >a>f	2	2	3
(8) >b<c	2	2	2
(20) >a>f>a>f	2	2	4

a = H1A⋯O5, b = H1B⋯O4, c = H2A⋯O3, d = H2B⋯O6, e = H5A⋯O4, f = H5B⋯N2, g = H6A⋯O4 and h = H6B⋯O5.