Reversible Switching of Tb(III) Emission by Sensitization from 2,3-Dihydroxynaphthalene in an Isothermally Reversible Ionic Liquid.
A reversible room-temperature ionic liquid (ILO) was prepared by the addition of CO2 to an equimolar mixture of hexylamidine (AD) and butylamine (AN). The ILO and AD/AN mixture were cycled repeatedly by alternating the passage of CO2 and N2 gases through the liquid. The ILO was utilized to sensitize very efficiently energy transfer to and emission by Tb(III) ions when 2,3-dihydroxynaphthalene (DHN) was irradiated. The emission was nearly completely quenched in the AD/AN mixture. The process described here is unique in its use of CO2 and N2 to "switch on and off" the emission by a lanthanide ion, Tb(III) in this case. In the corresponding amidinium dithiocarbamate ionic liquid (ILS), no appreciable Tb(III) emission was found due to quenching of the excited singlet state of DHN by thio groups. The ILS was not reconverted to the AD/AN mixture upon adding N2; N2 bubbling did not result in the displacement of CS2.
†Department of Chemistry and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, District of Columbia 20057-1227, United States.|‡Department of Chemistry, PSMO College, Tirurangadi, Malappuram, Kerala, India 676 306.
Kizhmuri P
KP
Divya
†Department of Chemistry and Institute for Soft Matter Synthesis and Metrology, Georgetown University, Washington, District of Columbia 20057-1227, United States.
Richard G
RG
Weiss
2,3-dihydroxynaphthalene; energy transfer; lanthanide sensitization; reversible emission; room-temperature ionic liquid