Synthesis, Characterization, DNA-Binding, and DNA-Photocleavage Properties of RuII Complexes

Abstract

A new polypyridyl ligand 2-benzo[b]thiophen-3-yl- 1H-1,3,7,8-tetraazacyclopenta[l]phenanthrene (BTCP) and its Ru II complexes [Ru(bpy) 2 (BTCP)] 2+ (1) (bpy = 2,2 -bipyridine), [Ru(phen) 2 (BTCP)] 2+ (2) (phen = 1,10-phenanthroline), and [Ru(dmb) 2 (BTCP)] 2+ (3) (dmb = 4,4 -dimethyl-2,2 -bipyridine), have been synthesized and characterized. The DNAbinding properties of the three complexes were investigated by spectroscopic methods and viscosity measurements. The results indicate that complexes 1, 2, and 3 bind to DNA by an intercalative mode and the ancillary ligands have a significant effect on the binding strengths of Ru II complexes to DNA. When irradiated at 365 nm, complex 2 was found to be a more effective DNA-cleaving agent than complexes 1 and 3. Results and Discussion Synthesis and CharacterizationAn outline of the synthesis of the Ru II complexes 1, 2, and 3 with the new BTCP ligand is presented in Scheme 1. The ligand was prepared through condensation of 1,10-phenanthroline-5,6dione (4) with benzo[b]thiophene-3-carboxaidehyde (5) according to literature methods. [36] The complexes 1, 2, and 3 were then prepared in yields of 39, 53, and 44%, respectively, by

Synthesis and Characterization of Ru(II) Complexes with π‐Expansive Imidazophen Ligands for the Photokilling of Human Melanoma Cells

“…The protons b and e in phenanthroline moiety of complexes 1-7 that appeared within 7.93-7.63 ppm were assigned based on their correlation with c and f. For all complexes, a and d appeared as a doublet within 8.26-7.97 ppm. Downfield chemical shifts were observed for the aromatic protons attached to the 4,4 0 -dmb unit in the Ru(II) complexes in the following order: 3 0 ,3 > 6 0 ,6 > 5 0 ,5 as reported previously in the literature(29). For 2, methylene proton h appeared as a singlet at 4.14-4.13 ppm.…”

Electronic/substituents influence on imidazole ring donor–acceptor capacities using 1H-imidazo[4,5-f][1,10]phenanthroline frameworks

“…B-2H, 3.02 AE 0.04 and C-3H, 3.02 AE 0.14; Table 2), results suggest that conjugation significantly increases the N-base electron density donation ability, but the absence of difference between data for the phenanthreneyl B-2H and the phenanthrolineyl C-3H probably suggests that, beyond certain extent of conjugation, N-base donor strengths may not be sensitive to slight changes in conjugation. It may then be reasonable to suggest that coordination of 1H-imidazo [4,5-f] [1,10]phenanthroline ligands to transition metal centers such as in Ru(II) complexes, which enjoy wide applications in DNA binding/photocleavage studies, [25][26][27][28][29][30][31][32][33][34][35][36] may not offer significant modification of donor/acceptor characteristics of the imidazole function relative to the free 1H-imidazo [4,5-f] [1,10]phenanthrolines.…”

Investigation of antibacterial activity and related mechanism of a ruthenium(II) polypyridyl complex

“…The consequences of this resulted in the study of many ruthenium complexes for biological activities, such as NAMI-A and KP109, which are entered into clinical trials [14,15]. Ruthenium polypyridyl complexes have received special attention due to their strong metal to ligand charge transfer (MLCT) absorption and unique emission characteristics, the perturbance of which could be exploited to study their DNA binding properties [16][17][18][19][20]. In previous studies, ruthenium complexes of diimine ligands such as 2,2′-bipyridine (bpy) and 1,10-phenanthroline (phen) are widely used in bioinorganic chemistry particularly as probes for DNA.…”