Articolo in rivista, 2020, ENG, 10.1016/j.vibspec.2020.103180

A Raman and SERS study on the interactions of aza[5]helicene and aza[6]helicene with a nanostructured gold surface

Zanchi C.; Lucotti A.; Pistaffa M.; Ossi P.M.; Trusso S.; Fontana F.; Carminati G.; Rizzo S.; Tommasini M.

Dipartimento di Chimica, Materiali e Ingegneria Chimica "G. Natta" - Politecnico di Milano, Piazza Leonardo da Vinci, Milano, 32 - 20133, Dipartimento di Chimica, Materiali e Ingegneria Chimica "G. Natta" - Politecnico di Milano, Piazza Leonardo da Vinci, 32 - 20133 Milano, Italy, , Italy; Dipartimento di Energia - Politecnico di Milano, Via Ponzio 34/3, Milano, 20133, Dipartimento di Energia - Politecnico di Milano, Via Ponzio 34/3, 20133 Milano, Italy, , Italy; CNR-IPCF, Istituto per i Processi Chimico-Fisici del CNR, V.le F. S. D'Alcontres 37, Messina, 98158, CNR-IPCF, Istituto per i Processi Chimico-Fisici del CNR, V.le F. S. D'Alcontres 37, 98158 Messina, Italy, , Italy; Dipartimento di Ingegneria e Scienze Applicate, Università di Bergamo, viale Marconi 5, Dalmine, BG, 24044, Dipartimento di Ingegneria e Scienze Applicate - Università di Bergamo - viale Marconi 5, 24044 Dalmine (BG), Italy, , Italy; CSGI Bergamo R.U, Dalmine, CSGI Bergamo R.U, Dalmine, Italy, , Italy; CNR, Inst. of Molecular Science and Technologies, via Golgi 19, Milano, 20133, CNR, Inst. of Molecular Science and Technologies, via Golgi 19, 20133 Milano, Italy, , Italy

We studied the interaction of 5-aza[5]helicene and 5-aza[6]helicene with gold nanostructured substrates by SERS spectroscopy and DFT calculations. By comparing Raman and SERS experiments we observe significant changes for the normal modes involving nitrogen. This behavior, together with further evidence coming from SERS experiments carried out on the quaternary salts of the same azahelicenes, clearly highlight the direct interaction of nitrogen with the gold surface. DFT calculations on azahelicene models interacting with Au gold clusters reveal the charge transfer between azahelicene and gold. The information obtained from this study is useful in the field of sensor applications, where knowledge of the molecular mechanisms of interaction is fundamental for an appropriate design of the device.

Vibrational spectroscopy (Print) 111 , pp. 103180–?

Keywords

Raman, SERS, Nanostructured gold thin film, Azahelicenes

CNR authors

Trusso Sebastiano, Rizzo Simona

CNR institutes