Experimental (FT-IR and Raman) and theoretical (DFT) studies on the vibrational dynamics in cytisine

• Published in: Vibrational spectroscopy Vol. 36; no. 1; pp. 105 - 115
• Main Authors: Górnicka, Elżbieta, Rode, Joanna E., Raczyńska, Ewa D., Dasiewicz, Beata, Dobrowolski, Jan Cz
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 18.10.2004
• Subjects: Association; Conformation; Cytisine; DFT; Infrared; Raman; Cytisine; Raman; DFT; Association; Infrared; Conformation
• ISSN: 0924-2031; 1873-3697
• DOI: 10.1016/j.vibspec.2004.04.002

Infrared and Raman spectra were recorded for solid cytisine—an agonist of nicotinic acetylcholine receptors (nAChRs), and analysed with help of the semiempirical (AM1) and ab initio {DFT(B3PW91)/6-311++G ∗∗} calculations performed for monomeric and associated structures (dimer, trimer and tetramer). Among two stable conformers of cytisine ( 1a and 1b) identified in solution, only one ( 1a) is present in the solid state, where it is stabilized by intermolecular H-bonds (  C O⋯ HN ). Two different environments for the associated molecules give two different spectral properties. Two component bands can be distinguished for the piperidine ν(NH) and γ(NH) as well as for the pyridine ν(CH), ν(CO) and ν(CC) contours.