Solvent-Free Synthesis Using Nb2O5 and a Theoretical-Experimental Study of Solvent Effect in New Rhodamine Dyes

Author(s)

Sacoman Torquato da Silva, Bruno Henrique ^[1] ; Riehl, Luiza Olbera ^[2] ; dos Santos, Giovanny Carvalho ^[2] ; Roldao, Juan Carlos ^[2] ; da Silva-Filho, Luiz Carlos ^[2]

Affiliation

^[1] Fed Univ Uberlandia UFU, Chem Inst, BR-38408144 Uberlandia, MG - Brazil

^[2] Sao Paulo State Univ UNESP, Sch Sci, Dept Chem, BR-17033360 Bauru, SP - Brazil

• Document type: Journal article
• Source: CHEMISTRYSELECT; v. 5, n. 4, p. 1455-1463, JAN 31 2020.
• Web of Science Citations: 0

Abstract

Rhodamine dyes have several applications based on properties, such as high molar absorptivity, high fluorescence quantum yield, photostability, absorption and emission wavelengths in the visible region. In this paper, we describe the solvent-free synthesis of rhodamines between m-aminophenol derivatives (3-dimethylamino and 3-diethylaminophenol) and phthalic anhydride derivatives (with and without halogens in the benzene ring) using Nb2O5 as catalyst. The compounds were produced in high yields (79 to 90%) within one hour of reaction time and with catalyst recovery. Additionally, a solvatochromic study of rhodamine derivatives was described. These compounds have absorption and emission bands at wavelengths in the visible region and a high quantum yield that potentially makes them good dyes for use in electronic devices (e. g. lasers, OLEDs). The DFT calculations provided a basis for understanding the effect of the solvent on the structural forms of rhodamine and corroborated with the experimental data, where the zwitterionic form is predominant in polar solvents, while in apolar solvents the lactonic form is the most stable. (AU)

• FAPESP's process: 14/01337-1 - Studies about the use of Niobium pentachloride, as Lewis acid, in Friedel Crafts acylation reactions, aiming the synthesis of compounds with potential application as sensitized dyes in organic eletronic devices.
• Grantee: Bruno Henrique Sacoman Torquato da Silva
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 16/01599-1 - Studies about the use of NbCl5 in multicomponent reactions for the synthesis of organic dyes
• Grantee: Luiz Carlos da Silva Filho
• Support type: Regular Research Grants
• FAPESP's process: 15/00615-0 - Studies on the synthesis and photochemical and photophysical characterization of quinoline derivatives with donor-p-acceptor structure for use as sensitizing dyes in organic electronic devices
• Grantee: Giovanny Carvalho dos Santos
• Support type: Scholarships in Brazil - Doctorate