title: Deuterium isotope effects on ¹³C-NMR chemical shifts of 10-hydroxybenzo[h]quinolines.
abstract: Deuterium isotope effects on ¹³C-NMR chemical shifts are investigated in a series of 10-hydroxybenzo[h]quinolines (HBQ's) The OH proton is deuteriated. The isotope effects on ¹³C chemical shifts in these hydrogen bonded systems are rather unusual. The formal four-bond effects are found to be negative, indicating transmission via the hydrogen bond. In addition unusual long-range effects are seen. Structures, NMR chemical shifts and changes in nuclear shieldings upon deuteriation are calculated using DFT methods. Two-bond deuterium isotope effects on 13C chemical shifts are correlated with calculated OH stretching frequencies. Isotope effects on chemical shifts are calculated for systems with OH exchanged by OD. Hydrogen bond potentials are discussed. New and more soluble nitro derivatives are synthesized.
authors.affiliation: Department of Science, Systems and Models, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark. poulerik@ruc.dk
authors.forename: Poul Erik
authors.initials: PE
authors.lastname: Hansen
authors.forename: Fadhil S
authors.initials: FS
authors.lastname: Kamounah
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Gryko
mesh_terms: D002247:Carbon Isotopes / Q000032:analysis / Q000737:chemistry; D003903:Deuterium / Q000032:analysis / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D011522:Protons; D011804:Quinolines / Q000032:analysis* / Q000737:chemistry*
chemical_list: C521323:10-hydroxybenzo(h)quinoline; D002247:Carbon Isotopes; D011522:Protons; D011804:Quinolines; D003903:Deuterium