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In an attempt to grow 8-hydroxyquinoline–acetaminophen co-crystals from equimolar amounts of conformers in a chloroform–ethanol solvent mixture at room temperature, the title compound, C 9 H 7 NO, was obtained. The molecule is planar, with the hydroxy H atom forming an intramolecular O—H...N hydrogen bond. In the crystal, molecules form centrosymmetric dimers via two O—H...N hydrogen bonds. Thus, the hydroxy H atoms are involved in bifurcated O—H...N hydrogen bonds, leading to the formation of a central planar four-membered N 2 H 2 ring. The dimers are bound by intermolecular π–π stacking [the shortest C...C distance is 3.2997 (17) Å] and C—H...π interactions into a three-dimensional framework. The crystal grown represents a new monoclinic polymorph in the space group P 2 1 / n . The molecular structure of the present monoclinic polymorph is very similar to that of the orthorhombic polymorph (space group Fdd 2) studied previously [Roychowdhury et al. (1978). Acta Cryst. B 34 , 1047–1048; Banerjee & Saha (1986). Acta Cryst. C 42 , 1408–1411]. The structures of the two polymorphs are distinguished by the different geometries of the hydrogen-bonded dimers, which in the crystal of the orthorhombic polymorph possess twofold axis symmetry, with the central N 2 H 2 ring adopting a butterfly conformation.
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Co-crystal formation vs. boron coordination: fluorination in azopyridines regulates supramolecular competition
Fluorination of azopyridine N-donors regulates the formation of either B ← N coordination adducts or a co-crystal with phenylboronic acid catechol ester. Specifically, the formation of B ← N adducts is promoted by azopyridines with up to four fluorines, while perfluorination affords a co-crystal via phenyl–perfluoropyridyl [π⋯πF] contacts. Electrostatic potential maps showed supramolecular bonding competition outcomes to be primarily determined by modulation of electron-donating capacity and π surfaces of azopyridine N-donors using fluorination.
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- Award ID(s):
- 2319929
- PAR ID:
- 10535604
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- CrystEngComm
- Volume:
- 26
- Issue:
- 30
- ISSN:
- 1466-8033
- Page Range / eLocation ID:
- 4017 to 4021
- Subject(s) / Keyword(s):
- boron coordination co-crystallization self-assembly crystallization supramolecular chemistry
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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