The effects of linear assembly of two carbazole groups on acid–base and DNA-binding properties of a ruthenium(II) complex

Off–on–off pH luminescence switching and DNA binding properties of a free terpyridine-appended ruthenium complex

“…In contrast, the electron in excited [Ru(bpy) 2 (HL 1 )] 2+⁎ was localized on bpy rather than on HL 1 , which typically leads to comparable or increased excited-state acidity with respect to the ground-state acidity. This behavior is similar to the behaviors exhibited by the imidazolecontaining Ru(II) complexes we and others have previously reported [39][40][41][42][43][44][45]50]. and could be rationalized by the absence of a Coulombic effect between the imidazole ring on H 2 L 1 and the metal center as evidenced by experimental and theoretical studies on an analogous Ru(II) complex of [Ru(bpy) 2 (PhenImHPh)] 2+ (PhenImHPh = 2-(3,5-di-tert-butylphenyl)imidazo[4,5-f]-[1,10]phenanthroline) [50].…”

“…1. The pK a1 and pK a3 values fall within the corresponding pK a ranges of 0.31-2.48 and 8.21-9.65 that we previously reported for the acid ionization constant values of protonated imidazolium on analogous Ru(II) complexes [37][38][39][40][41][42][43][44][45]. The value of pK a2 agrees well with pK a = 3.55-4.65 for the uncoordinated peripheral pyridyl of the terpyridine on 4-phosphonato-2,2′:6′,2″-terpyridine [46] and dimethylaminostyrylterpyridine [47].…”

“…In addition, the T m value increased linearly by 1.05, 3.02, and 8. [60], and falls into the rather broad ΔT m range of 5.9 to 19.3°C previously reported for analogous Ru(II) complex-based DNA intercalators under identical experimental conditions with [Ru]/DNA = 0.10 [37][38][39][40][41][42][43][44][45]. In addition, this ΔT m value is similar to a ΔT m value of 9.3°C that we have recently reported for a Ru(II) complex DNA binder with a mixed binding mode involving classic intercalation plus partial intercalation [23], and greater than only small T m increases of ≤ 2 and 3°C previously reported for an organic DNA binder of 1,4,7,10-tetraazacyclododecane appended with two anthracenyl moieties that showed mixed binding modes of partial intercalator and groove binding [61], and partially intercalative Ru(II) complex of [Ru(H 2 PDTA)(phen)]Cl (H 4 PDTA = propylene-1,2-diaminetetra-acetic acid) [32], respectively.…”

pH and copper ion luminescence on/off sensing by a dipyrazinylpyridine-appended ruthenium complex

“…complexes we previously reported [48][49][50][51]. Similarly, pK a * values for 2 were derived to be pK a1 * = 2.33, pK a2 * = 3.49 and pK a3 * = 8.68, in which pK a1 * value is greater than pK a by only 0.47 pH units, while pK a2 * and pK a3 * values are comparable to or less than corresponding ground-state ones (3.43, 9. …”