“…The spectrum immediately after dissolution contains two peaks at 340 (ε = 1 × 10 4 M -1 cm -1 ) and 440 nm (ε = 4 × 10 3 M -1 cm -1 ). In accordance with the analysis given for related Ru II complexes of bispyridylpyrazine and arenes, the peak at 340 nm is assigned to a LC transition on 2,3-dpp, while the peak at 440 nm is assigned to an MLCT transition from Ru to 2,3-dpp. , The most apparent change is the decrease in the absorbance of the 440 nm peak and the appearance of a new peak at 520 nm. 3 Thermal reactivity of 1 in aqueous solution.…”
Section: Resultssupporting
confidence: 80%
“…In accordance with the analysis given for related Ru II complexes of bispyridylpyrazine and arenes, the peak at 340 nm is assigned to a LC transition on 2,3-dpp, while the peak at 440 nm is assigned to an MLCT transition from Ru to 2,3-dpp. 36,37 The most apparent change is the decrease in the absorbance of the 440 nm peak and the appearance of a new peak at 520 nm.…”
The dinuclear RuII arene complexes [{(eta6-arene)RuCl}2(mu-2,3-dpp)](PF6)2, arene=indan (1), benzene (2), p-cymene (3), or hexamethylbenzene (4) and 2,3-dpp=2,3-bis(2-pyridyl)pyrazine, have been synthesized and characterized. Upon irradiation with UVA light, complexes 1 and 2 readily underwent arene loss, while complexes 3 and 4 did not. The photochemistry of 1 was studied in detail. In the X-ray structure of [{(eta6-indan)RuCl}2(mu-2,3-dpp)](PF6)2 (1), 2,3-dpp bridges two RuII centers 6.8529(6) A apart. In water, aquation of 1 in the dark occurs with replacement of chloride with biexponential kinetics and decay constants of 100+/-1 min-1 and 580+/-11 min-1. This aquation was suppressed by 0.1 M NaCl. UV or visible irradiation of 1 in aqueous or methanolic solution led to arene loss. The fluorescence of the unbound arene is approximately 40 times greater than when it is complexed. Irradiation of 1 also had a significant effect on its interactions with DNA. The DNA binding of 1 is increased after irradiation. The non-irradiated form of 1 preferentially formed DNA adducts that only weakly blocked RNA polymerase, while irradiation of 1 transformed the adducts into stronger blocks for RNA polymerase. The efficiency of irradiated 1 to form DNA interstrand cross-links was slightly greater than that of cisplatin in both 10 mM NaClO4 and 0.1 M NaCl. In contrast, the interstrand cross-linking efficiency of non-irradiated 1 in 10 mM NaClO4 was relatively low. An intermediate amount of cross-linking was observed when the sample of DNA already modified by non-irradiated 1 was irradiated. DNA unwinding measurements supported the conclusion that both mono- and bifunctional adducts with DNA can form. These results show that photoactivation of dinuclear RuII arene complexes can simultaneously produce a highly reactive ruthenium species that can bind to DNA and a fluorescent marker (the free arene). Importantly, the mechanism of photoreactivity is also independent of oxygen. These complexes, therefore, have the potential to combine both photoinduced cell death and fluorescence imaging of the location and efficiency of the photoactivation process.
“…The spectrum immediately after dissolution contains two peaks at 340 (ε = 1 × 10 4 M -1 cm -1 ) and 440 nm (ε = 4 × 10 3 M -1 cm -1 ). In accordance with the analysis given for related Ru II complexes of bispyridylpyrazine and arenes, the peak at 340 nm is assigned to a LC transition on 2,3-dpp, while the peak at 440 nm is assigned to an MLCT transition from Ru to 2,3-dpp. , The most apparent change is the decrease in the absorbance of the 440 nm peak and the appearance of a new peak at 520 nm. 3 Thermal reactivity of 1 in aqueous solution.…”
Section: Resultssupporting
confidence: 80%
“…In accordance with the analysis given for related Ru II complexes of bispyridylpyrazine and arenes, the peak at 340 nm is assigned to a LC transition on 2,3-dpp, while the peak at 440 nm is assigned to an MLCT transition from Ru to 2,3-dpp. 36,37 The most apparent change is the decrease in the absorbance of the 440 nm peak and the appearance of a new peak at 520 nm.…”
The dinuclear RuII arene complexes [{(eta6-arene)RuCl}2(mu-2,3-dpp)](PF6)2, arene=indan (1), benzene (2), p-cymene (3), or hexamethylbenzene (4) and 2,3-dpp=2,3-bis(2-pyridyl)pyrazine, have been synthesized and characterized. Upon irradiation with UVA light, complexes 1 and 2 readily underwent arene loss, while complexes 3 and 4 did not. The photochemistry of 1 was studied in detail. In the X-ray structure of [{(eta6-indan)RuCl}2(mu-2,3-dpp)](PF6)2 (1), 2,3-dpp bridges two RuII centers 6.8529(6) A apart. In water, aquation of 1 in the dark occurs with replacement of chloride with biexponential kinetics and decay constants of 100+/-1 min-1 and 580+/-11 min-1. This aquation was suppressed by 0.1 M NaCl. UV or visible irradiation of 1 in aqueous or methanolic solution led to arene loss. The fluorescence of the unbound arene is approximately 40 times greater than when it is complexed. Irradiation of 1 also had a significant effect on its interactions with DNA. The DNA binding of 1 is increased after irradiation. The non-irradiated form of 1 preferentially formed DNA adducts that only weakly blocked RNA polymerase, while irradiation of 1 transformed the adducts into stronger blocks for RNA polymerase. The efficiency of irradiated 1 to form DNA interstrand cross-links was slightly greater than that of cisplatin in both 10 mM NaClO4 and 0.1 M NaCl. In contrast, the interstrand cross-linking efficiency of non-irradiated 1 in 10 mM NaClO4 was relatively low. An intermediate amount of cross-linking was observed when the sample of DNA already modified by non-irradiated 1 was irradiated. DNA unwinding measurements supported the conclusion that both mono- and bifunctional adducts with DNA can form. These results show that photoactivation of dinuclear RuII arene complexes can simultaneously produce a highly reactive ruthenium species that can bind to DNA and a fluorescent marker (the free arene). Importantly, the mechanism of photoreactivity is also independent of oxygen. These complexes, therefore, have the potential to combine both photoinduced cell death and fluorescence imaging of the location and efficiency of the photoactivation process.
“…Mononuclear compounds of platinum group metals containing nitrogen-based ligands have received considerable attention owing to their photochemical properties [1][2][3][4][5], catalytic activities [6][7][8][9][10][11][12], electrochemical behavior [13][14][15][16], as well as in the development of new biological active agents [17][18][19][20][21]. In particular, g 6 -arene metal complexes have emerged as versatile intermediates in organic synthesis as a consequence of the availability of three labile coordinate sites and rigid arene ring occupying another three coordinate sites [22,23].…”
“…This is expected because these transitions tend to have low intensities because they are Laporte forbidden 59 and are buried under the high‐intensity MLCT or LMCT bands 60 . The assignment of the transitions in Table 5 was based on similar ruthenium polypyridyl complexes 57,61,62 …”
Section: Resultsmentioning
confidence: 99%
“…60 The assignment of the transitions in Table 5 was based on similar ruthenium polypyridyl complexes. 57,61,62…”
A new polypyridyl ligand 4‐(4‐nitrophenoxy)‐N,N‐bis (pyridin‐2‐ylmethyl)aniline (L1) and its three ruthenium (II/III) complexes, [Ru (Cl)3L1] (C1), [Ru(L1)2]Cl (C2), and [RuCl (dpa)L1] (C3) where dpa = 2,2‐dipyridylamine, have been successfully synthesized and characterized using Fourier‐transform infrared spectroscopy (FTIR), elemental analysis, proton nuclear magnetic resonance (1H NMR), high‐resolution electrospray ionization mass spectrometry (HR‐ESI‐MS), thermal analysis (thermogravimetric analysis [TGA] and differential scanning calorimetry [DSC]), UV/Vis absorption, and magnetic susceptibility. The structures of the ligand and the complexes were optimized, and the structural characteristics were determined by density functional theory (DFT) using the B3LYP‐GD3/6‐311G++(d,p) method. Optimized FTIR vibrational frequencies and 1H NMR chemical shifts agreed well with the corresponding experimental FTIR and 1H NMR data. In vitro cytotoxicity of the ligand and the complexes were evaluated against the MCF‐7 breast cancer cell line. Ligand L1 was the most potent with an IC50 of 38.45 μM, followed by C2 with an IC50 of 45.23 μM. However, the ligand and the complexes showed low antiproliferative activity compared to cisplatin, which had an IC50 of 9.67 μM. To predict the reactivity trend of L1 and the complexes, frontier molecular orbital (FMO) analysis was performed. The FMO energy gap (Eg = ELUMO − EHOMO) for C2 was found to be 1.675 eV, which was the lowest among all the complexes or L1. In addition, molecular docking studies were carried out so as to predict the binding capacity of L1 and the complexes to estrogen receptor alpha (ER‐α). The results showed that C2 has the most negative binding energy score (−9.63 kcal/mol), which indicates more stable adducts with the key amino acid residues at the active sites of ER‐α. Furthermore, C2 displayed the lowest inhibition constant (Ki) of 0.09 μM compared to all the complexes or L1. These results are very promising and show that the novel complex C2 may help in the development of anticancer drugs.
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