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-a-a(f) = 12.0-13.4 Angstrom; 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-a-a(f) = 8.40 or 8.49 Angstrom. Columns in neighboring sheets are in a close proximity or even partially overlapped as a result of interpenetration ofthe 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-a-a(f) = 11.78 Angstrom) and anthraquinone (I-q-q(f) = 10.56 Angstrom) 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-a-a(f), = 3.99 Angstrom) and quinone columns (I-q-q(f) = 2.87 Angstrom). 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-a-a(f) = 5.24 Angstrom) and anthraquinone (I-q-q(f) = 3.03 or 3.55 Angstrom). 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.