Crystal Engineering through Halogen Bonding. 2. Complexes of Diacetylene-Linked Heterocycles with Organic Iodides

Abstract

The bis(aryl)diacetylenes 1,4-bis(3-quinolyl)-1,3-butadiyne (1), 1,4-bis(4-isoquinolyl)-1,3-butadiyne (2), and 1,4-bis(3-pyridyl)-1,3-butadiyne (3) form strongly halogen bonded complexes with organic iodides, including tetraiodoethylene (TIE), 1,4-diiodotetrafluorobenzene (F4DIB), and 1,4-diiodooctafluorobutane (F8DIBut). The crystal structures for the new donor, 2, as well as for six complexes, 1·TIE, 1·F4DIB, 2·TIE, 2·F4DIB, 3·(F4DIB)2, and 3 2· (F8DIBut)2, are reported. Extended chain structures consisting of donor and acceptor molecules are observed in all cases, except that of 3 2·(F8DIBut)2, which forms a molecular adduct. In most cases, the complexes segregate into columns of donors and acceptors, as is typical for this class of complexes. However, 1·F4DIB displays an unusual “crosshatched” pattern with each acceptor directly above the diacetylene moiety of another donor along the b-axis. In addition to 1·F4DIB, 3 2·(F8DIBut)2 also exhibits packing that does not consist of segregated stacks (i.e., the acceptor in the chain sits on top of one end of the donor and the uncomplexed F4DIB sits on top of the other end). Neither diacetylene 2, nor any of the complexes, pack in a manner that would allow for topotactic polymerization of the diacetylene moiety.

Pillars of assembled pyridyl bis-urea macrocycles: a robust synthon to organize diiodotetrafluorobenzenes

“…3 Typical examples include the alignment of stilbene and diacetylene derivatives through crystal engineering to favor topochemical [2 + 2] photodimerization 4 in the solid-state and topotactic polymerization. 5 However, there are fewer reports of donor-acceptor complexes utilizing the O⋯I halogen bond, especially the CO⋯I supramolecular synthon in crystal engineering. 6 Here, we test a robust 1D pillar whose exterior is lined with basic oxygen lone pair as a synthon to cocrystallize guests through CO⋯I interactions into predictable structures.…”

Molecular Assemblies from Imidazolyl‐Containing Haloalkenes and Haloalkynes: Competition between Halogen and Hydrogen Bonding

“…[16,31] Also, this alkene has been cocrystallized with various diacetylenic molecules in the hope of obtaining host-guest complexes in which the diacetylenic fragments are suitably oriented for topochemical polymerization. [32,33] Halogen bonding involving haloalkynes has been studied in both the solid state and solution. Various complexes between 1-halo-2-phenylacetylenes and halide ions have been prepared, and the structures and stoichiometries of these complexes were found to depend on the nature of the halide ion and type of organic cation.…”

“…[11] The I···N distance reported herein is slightly shorter than those observed previously in complexes of TIE with nitrogen bases. [16,32,33] The only exceptions are 1,2-bis(4-pyridyl)ethylene·TIE (2.840 ) [16] and 1,4-bis(3-quinolyl)-1,3-butadiyne·TIE (2.884 ). [33] The centroid···cent-roid distance between two adjacent imidazole rings in one stack is 4.795 , and the angle between the centroid···cent-roid vector and the ring normal is 50.18.…”

Halogen-Bond Preferences in Co-crystal Synthesis

“…Halogen bonds possess all the necessary requirements of a suitable supramolecular tool as they have tunable strength [3][4][5] and considerable directionality [6][7][8][9]. It has been shown that n-donors generally work better than p-donors and an increase in hybridization (for a given heteroatom) typically leads to an increase in interaction energy [10], and perfluorocarbon halides are significantly better Lewis acids than the corresponding hydrocarbon halides.…”