Vibrational spectroscopic characterization of cyclic and acyclic molecular rotors with 1,4-diethynylphenylene-d4 rotators

Tomasz Runka; Karolina Olszewska; Piotr Fertsch; Andrzej Łapiński; Izabella Jastrzebska; Rosa Santillan; Norberto Farfán

doi:10.1016/j.saa.2017.11.052

Vibrational spectroscopic characterization of cyclic and acyclic molecular rotors with 1,4-diethynylphenylene-d₄ rotators

Spectrochim Acta A Mol Biomol Spectrosc. 2018 Mar 5:192:393-400. doi: 10.1016/j.saa.2017.11.052. Epub 2017 Nov 26.

Authors

Tomasz Runka¹, Karolina Olszewska², Piotr Fertsch², Andrzej Łapiński³, Izabella Jastrzebska⁴, Rosa Santillan⁵, Norberto Farfán⁶

Affiliations

¹ Faculty of Technical Physics, Institute of Materials Research and Quantum Engineering, Poznan University of Technology, Piotrowo 3, 60-965 Poznań, Poland. Electronic address: tomasz.runka@put.poznan.pl.
² Faculty of Technical Physics, Institute of Materials Research and Quantum Engineering, Poznan University of Technology, Piotrowo 3, 60-965 Poznań, Poland.
³ Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Poznań, Poland.
⁴ Institute of Chemistry, University of Białystok, Ciołkowskiego 1K, 15-254 Białystok, Poland.
⁵ Departamento de Química, Centro de Investigación y de Estudios Avanzados del IPN, México D.F., Apdo. Postal 14-740, 07000, Mexico.
⁶ Facultad de Química, Departamento de Química Orgánica, Universidad Nacional Autónoma de México, 04510 Ciudad de México D.F., Mexico.

PMID: 29195193
DOI: 10.1016/j.saa.2017.11.052

Abstract

The synthesis and characterization of acyclic and cyclic molecular rotors with 1,4-diethynylphenylene-d₄ rotators are described. The ATR-FTIR and Raman spectra of acyclic rotor 3 and cyclic rotor 5E were measured and interpreted. A feature of ATR-FTIR spectrum of rotor 5E is a strong two-component band around 1730cm^-1 attributed to symmetric and asymmetric stretching vibration of the carbonyl group, while this is not observed in rotor 3. Raman investigation in the wide temperature range of 350 - 10K was carried out. The splitting of Raman bands in the region of stretching vibration of CC double and triple bonds at 170 and 260K for rotor 5E is observed. The splitting of bands is due to changes in molecular structure.

Keywords: Molecular rotors; Temperature measurements; Vibrational spectroscopy.