Crystal Engineering of Stacked Aromatic Columns. Three-Dimensional Control of the Alignment of Orthogonal Aromatic Triads and Guest Quinones via Self-Assembly of Hydrogen-Bonded Networks

We here determined the crystal structures of several adducts of
the bis(resorcinol) and bis(pyrimidine)
derivatives of anthracene or anthraquinone
(1−3) as orthogonal aromatic triads.
Anthracene-bis(resorcinol) compound
1 forms molecular sheets consisting of hydrogen-bonded
homopolymeric chains of resorcinol together with
anthracene
stack columns having a face-to-face distance of
I fa-a =
12.0−13.4 Å; large supramolecular cavities left are
occupied
by two solvent molecules as guests via hydrogen bonding.
Cocrystallization of compound 1 with
anthracene-bis(pyrimidine) derivative 2 affords adduct
1·2, whose molecular sheets are composed of
hydrogen-bonded resorcinol-pyrimidine alternate copolymeric chains and closer anthracene columns
with I fa-a
= 8.40 or 8.49 Å. Columns in
neighboring sheets are in a close proximity or even partially
overlapped as a result of interpenetration of the sheets.
Compound 1 also forms a 1:1 adduct with
anthraquinone-bis(pyrimidine) derivative 3. The
resulting adduct 1·3
exclusively forms a resorcinol-pyrimidine O−H···N
hydrogen-bonded network as above but in a different way.
The resulting sheets are layered so as to give segregated columns
of anthracene
(I fa-a =
11.78 Å) and anthraquinone
(I fq-q =
10.56 Å) which are partially overlapped with each other. Compound
1 and quinone form 1:2 (1 to
quinone)
adducts. An extensive 1-quinone hydrogen-bonded network
in the benzoquinone adduct leads to 3-fold
interpenetrating
or polycatenating molecular sheets having highly slided anthracene
columns
(I fa-a =
3.99 Å) and quinone columns
(I fq-q =
2.87 Å). The anthraquinone adduct, on the other hand, forms
hydrogen-bonded one-dimensional alternate
chains composed of 1 and face-to-face stacked quinone dimer.
These chains are so arranged as to give segregated
and partially overlapped columns for anthracene
(I fa-a =
5.24 Å) and anthraquinone
(I fq-q =
3.03 or 3.55 Å). It
is remarkable that many of the columns are constructed via
self-assembly of hydrogen-bonded one-dimensional
(1D) or two-dimensional (2D) networks. The
network-self-assembly strategy thus opens the door to a
three-dimensional
(3D) control of aromatic columns in molecular crystals, i.e.,
co-alignment in proximity of donor columns and acceptor
columns.