Vibrational and nonlinear optical properties of amine-capped push-pull polyynes by infrared and Raman spectroscopy
Pietro Marabotti,
Alberto Milani,
Andrea Lucotti,
Luigi Brambilla,
Matteo Tommasini,
Chiara Castiglioni,
Patrycja Męcik,
Bartłomiej Pigulski,
Sławomir Szafert,
Carlo Spartaco Casari
Affiliations
Pietro Marabotti
Department of Energy, Micro and Nanostructured Materials Laboratory - NanoLab, Energy, Politecnico di Milano, Via Ponzio 34/3, Milano 20133, Italy
Alberto Milani
Department of Energy, Micro and Nanostructured Materials Laboratory - NanoLab, Energy, Politecnico di Milano, Via Ponzio 34/3, Milano 20133, Italy
Andrea Lucotti
Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano Piazza Leonardo da Vinci 32, Milano 20133, Italy
Luigi Brambilla
Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano Piazza Leonardo da Vinci 32, Milano 20133, Italy
Matteo Tommasini
Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano Piazza Leonardo da Vinci 32, Milano 20133, Italy
Chiara Castiglioni
Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano Piazza Leonardo da Vinci 32, Milano 20133, Italy
Patrycja Męcik
Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, Wrocław 50-383, Poland
Bartłomiej Pigulski
Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, Wrocław 50-383, Poland
Sławomir Szafert
Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, Wrocław 50-383, Poland; Corresponding authors.
Carlo Spartaco Casari
Department of Energy, Micro and Nanostructured Materials Laboratory - NanoLab, Energy, Politecnico di Milano, Via Ponzio 34/3, Milano 20133, Italy; Corresponding authors.
The vibrational properties of a series of push-pull polyynes have been studied by infrared and Raman spectroscopy. The simultaneous activation of a strong infrared and Raman mode, i.e. the collective vibration of CC bonds of the sp carbon chain, highlights the effectiveness of a polyyne bridge in promoting charge transfer between the electron donor (D) and acceptor (A) ends, thus suggesting that ad-hoc functionalized polyynes are worth being explored as building blocks of organic materials with attractive first-order optical nonlinearity. The optical, electronic, and vibrational properties of these molecules have been investigated with the support of density functional theory calculations, as well as the electronic and vibrational first hyperpolarizabilities (β). The mid-low region of the IR spectra (800-1600 cm−1) has been analyzed in detail, searching for marker bands of the specific terminations of the different sp carbon chains thus achieving a complete vibrational characterization of sp hybridized push-pull systems.
