title: Thermally stable intermolecular proton bonds in polyaromatic aldehyde crystals.
abstract: We have synthesized self-assembled red-colored proton complexes of the aldehyde derivatives of polyaromatic hydrocarbon with strong intermolecular hydrogen bonding. These intermolecularly proton-bonded polyaromatic aldehydes formed as 1-pyrenecarbaldehyde (Py-CHO) reacted with HAuCl(4) to produce [(Py-CHO)(2)H][AuCl(4)] under dry conditions. The formation of [(Py-CHO)(2)H][AuCl(4)] was confirmed by single-crystal structure determination and IR spectral analysis at various temperatures. The compounds are distinctively hydrophobic in nature and are soluble only in a few organic polar solvents. The proton bonds are clearly observed from both the electron density in X-ray analysis and the characteristic IR frequency signature. The proton complex units have an O-H(+)-O distance of the typical Zundel-like cationic hydrogen bond (in which two O atoms share a proton-like H in the midpoint of the short O-O distance of ≈2.4 Å). The proton bonds are thermally stable, even over 100 °C, because the complexes are stabilized in layered structures with π-π intermolecular interactions of the polyaromatic hydrocarbon ligands. The IR signatures at around 900, 1200, and 1700 cm(-1) for the Zundel-like proton bond are clearly characterized.
authors.affiliation: Department of Chemistry, Pohang University of Science and Technology, Pohang 790-784, Korea.
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Heo
authors.forename: In-Chul
authors.initials: IC
authors.lastname: Hwang
authors.forename: Young
authors.initials: Y
authors.lastname: Chun
authors.forename: Jung Woo
authors.initials: JW
authors.lastname: Lee
authors.forename: N Jiten
authors.initials: NJ
authors.lastname: Singh
authors.forename: Seung Bin
authors.initials: SB
authors.lastname: Kim
authors.forename: Kwang S
authors.initials: KS
authors.lastname: Kim