LUMINESCENCE QUENCHING OF MIXED-LIGAND RUTHENIUM (II) COMPLEXES BY DIFFERENT QUENCHERS

Nathir A. F. Al-Rawashdeh,* Khaled Shawakfeh
Department of Applied Chemical Sciences, Jordan University of Science & Technology, Irbid-22110, Jordan, Phone. 00-962-2-7095111 Ext. 22466, Fax No. 00-962-2-7095143, nathir@just.edu.jo

Sumaia Khadir
Department of Applied Chemical Sciences, Jordan University of Science & Technology, Irbid-22110, Jordan
 

ABSTRACT

The effect of ionic strength and acidity (pH) on the luminescence quenching of the excited states of a number of mixed-ligand Ru(II) complexes have been studied. The mixed-ligand Ru(II) complexes of diphenyl-thioethylene (dpte); 2,2-bipyridine (bpy), 2-(2-pyridyl)-quinoline (pyq); 4,6-dichloro-2-(2-pyridyl)pyrimidine (dcppm); 4,6-dichloro-5-methyl-2-(2-pyridyl)pyrimidine (dcmppm); 4,6-dichloro-5-phenyl-2-(2 pyridyl)pyrimidine (dcpppm) with three quenchers: N,N,N,N-tetramethyl-p-phenlyene-diamine (TMPD2+), methyl viologen (Mv2+), and ethylenediaminetetraacetic acid (EDTA) have been used to study the effect of acidity. Whereas, for the effect of ionic strength, [Ru(dpte)2(dcpppm)]2+ /EDTA system has been used. The quenching rate constant (kq) was found to increase with decreasing the ionic strength, while pH has the opposite effect. The quenching of mixed-ligand Ru(II) complexes by TMPD2+ in aqueous solutions was shown to be dynamic and static in nature.