Syntheses, Electronic Absorption, Emission, and Ion-Binding Studies of Platinum(II) C^N^C and Terpyridyl Complexes Containing Crown Ether Pendants

Abstract

Yam et al. have recently established a more accurate equation (Organometallics 2007, 26, 6091–6098) for determining the binding constants K11 and K21 in systems that involve the complexation of metal ions in both 1:1 and 2:1 stoichiometry and would like to update the data found in Chem. Eur. J. 2002, 8, 4066–4076. From the fitting of the revised equation, the binding constants of [Pt(C^N^C)(pyCCB15C5) (5) and [Pt(trpy)(pyCCB15C5)](PF6)2 (9) (HC^N^CH= 2,6-diphenylpyridine, dppy; CB15C5= benzo[15]crown-5; trpy= 2,2′:6′,2′′-terpyridine) to K+ in 1:1 and 2:1 stoichiometries were obtained. In solution (CH3CN/DMF; 8:2 v/v), the log K11 and log K21 values of 5 were found to be 2.73 and 3.01, respectively, whereas those of 9 were 1.73 and 1.78, respectively. The corresponding log K11 and log K21 values of 9 in acetonitrile were 3.40 and 3.13, respectively. In view of the slight or insignificant changes of these values, both the discussions and conclusion remain unchanged and are therefore retained. The authors would like to apologize for any inconvenience caused.