title: Diastereo-specific conformational properties of neutral, protonated and radical cation forms of (1R,2S)-cis- and (1R,2R)-trans-amino-indanol by gas phase spectroscopy.
abstract: Chirality effects on the intramolecular interactions strongly depend on the charge and protonation states. Here, the influence of chirality on the structure of the neutral, protonated, and radical cation forms of (1R,2S)-cis- and (1R,2R)-trans-1-amino-2-indanol diastereomers, prototypical molecules with two chiral centers, is investigated in a molecular beam by laser spectroscopy coupled with quantum chemical calculations. The neutral systems are structurally characterised by double resonance IR-UV spectroscopy, while IR-induced dissociation spectroscopy is employed for the charged molecules. The sterical constraints due to the cyclic nature of the molecule emphasise the chirality effects, which manifest themselves by the formation of an intramolecular hydrogen bond in neutral or protonated (1R,2S)-cis-amino-indanol. In contrast, this interaction is not possible in (1R,2R)-trans-amino-indanol. In the protonated species, chirality also influences the spectroscopic probes in the NH/OH stretch range by fine-tuning subtle effects such as the hyperconjugation between the σ(OH) orbital and σ* orbitals localised on the alicyclic ring. The radical cation undergoes opening of the alicyclic ring, which results in an ionisation-induced loss of the chirality effects.
authors.affiliation: Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin, Germany. dopfer@physik.tu-berlin.de.
authors.forename: Aude
authors.initials: A
authors.lastname: Bouchet
authors.forename: Johanna
authors.initials: J
authors.lastname: Klyne
authors.forename: Giovanni
authors.initials: G
authors.lastname: Piani
authors.forename: Otto
authors.initials: O
authors.lastname: Dopfer
authors.forename: Anne
authors.initials: A
authors.lastname: Zehnacker
mesh_terms: D005740:Gases / Q000737:chemistry; D007189:Indans / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011522:Protons; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism; D014466:Ultraviolet Rays
chemical_list: D005740:Gases; D007189:Indans; D011522:Protons; C116915:aminoindanol