Synthesis,Characterization, and DNA‐Binding Properties of the Chiral Ruthenium(II) Complexes Δ‐ and Λ‐[Ru(bpy)2(dmppd)]2+ (dmppd = 10,12‐Dimethylpteridino[6,7‐f] [1,10]phenanthroline‐11,13(10H,12H)‐dione; bpy = 2,2′‐Bipyridine)

Two novel chiral ruthenium(II) complexes, Δ‐[Ru(bpy)₂(dmppd)]²⁺ and Λ‐[Ru(bpy)₂(dmppd)]²⁺ (dmppd = 10,12‐dimethylpteridino[6,7‐f] [1,10]phenanthroline‐11,13(10H,12H)‐dione, bpy = 2,2′‐bipyridine), were synthesized and characterized by elemental analysis, ¹H‐NMR and ES‐MS. The DNA‐binding behaviors of both complexes were studied by UV/VIS absorption titration, competitive binding experiments, viscosity measurements, thermal DNA denaturation, and circular‐dichroism spectra. The results indicate that both chiral complexes bind to calf‐thymus DNA in an intercalative mode, and the Δ enantiomer shows larger DNA affinity than the Λ enantiomer does. Theoretical‐calculation studies for the DNA‐binding behaviors of these complexes were carried out by the density‐functional‐theory method. The mechanism involved in the regulating and controlling of the DNA‐binding abilities of the complexes was further explored by the comparative studies of [Ru(bpy)₂(dmppd)]²⁺ and of its parent complex [Ru(bpy)₂(ppd)]²⁺ (ppd = pteridino[6,7‐f] [1,10]phenanthroline‐11,13 (10H,12H)‐dione).     

Synthesis,Characterization, and DNA Interaction Studies of the Ruthenium(II) Complexes [Ru(bpy)2(ipbp)]2+ and [Ru(ipbp)(phen)2]2+ (ipbp=3‐(1H‐Imidazo[4,5‐f][1,10]phenanthrolin‐2‐yl)‐4H‐1‐benzopyran‐2‐one; bpy=2,2′‐Bipyridine; phen=1,10‐Phenanthroline)

A novel ligand 3‐(1H‐imidazo[4,5‐f][1,10]phenanthrolin‐2‐yl)‐4H‐1‐benzopyran‐4‐one (ipbp) and its ruthenium(II) complexes [Ru(bpy)₂(ipbp)]²⁺ ( 1 ) and [Ru(ipbp)(phen)₂]²⁺ ( 2 ) (bpy=2,2′‐bipyridine, phen=1,10‐phenanthroline) were synthesized and characterized by elemental analysis and mass, ¹H‐NMR, and electronic‐absorption spectroscopy. The electrochemical behavior of the complexes was studied by cyclic voltammetry. The DNA‐binding behavior of the complexes was investigated by spectroscopic methods and viscosity measurements. The results indicate that complexes 1 and 2 bind with calf‐thymus DNA in an intercalative mode. In addition, 1 and 2 promote cleavage of plasmid pBR 322 DNA from the supercoil form I to the open circular form II upon irradiation.     

Synthesis,DNA‐Binding and Photocleavage Studies of the Ruthenium(II) Complexes [Ru(phen)2(ppd)]2+ and [Ru(phen)(ppd)2]2+ (ppd=Pteridino[6,7‐f] [1,10]phenanthroline‐11,13(10H,12H)‐dione,phen=1,10‐Phenanthroline)

Two new complexes, [Ru(phen)₂(ppd)]²⁺ ( 1 ) and [Ru(phen)(ppd)₂]²⁺ ( 2 ) (ppd=pteridino[6,7‐f] [1,10]phenanthroline‐11,13(10H,12H)‐dione, phen=1,10‐phenanthroline) were synthesized and characterized by ES‐MS, ¹H‐NMR spectroscopy, and elemental analysis. The intercalative DNA‐binding properties of 1 and 2 were investigated by absorption‐spectroscopy titration, luminescence‐spectroscopy studies, thermal denaturation, and viscosity measurements. The theoretical aspects were further discussed by comparative studies of 1 and 2 by means of DFT calculations and molecular‐orbital theory. Photoactivated cleavage of pBR322 DNA by the two complexes were also studied, and 2 was found to be a much better photocleavage reagent than 1 . The mechanism studies revealed that singlet oxygen and the excited‐states redox potentials of the complex may play an important role in the DNA photocleavage.     

Synthesis and Characterization of Polypiridine‐Based Rhenium(I) Complexes with Pyrazino[2,3‐f][1,10]phenanthroline

A series of tricarbonyl rhenium(I) complexes of the type fac‐[Re^I(CO)₃(ppl)(L)]^0/+, where ppl is pyrazino[2,3‐f][1,10]phenanthroline, and where L is Cl^?, TfO^?, 4‐(tert‐butyl)pyridine (^tBu‐py), 4‐methoxypyridine (MeO‐py), 4,4′‐bipyridyl (bpy), or 10‐(picolin‐4‐yl)phenothiazine (pptz), were synthesized and fully characterized. In all complexes, an increment in the electron‐acceptor properties of ppl compared to the free ligand was observed. This effect was more significant for pyridine‐type ligands, especially for pptz, compared to Cl^? or TfO^?. The properties of fac‐[Re(CO)₃(ppl)(pptz)]PF₆ were compared with those of the analogous compound fac‐[Re(CO)₃(dppz)(pptz)]PF₆, where dppz is dipyrido(3,2‐a : 2′,3′‐c)phenazine, the goal being to generate long‐lived excited charge‐transfer (CT) states. In this respect, fac‐[Re(CO)₃(ppl)(pptz)]PF₆ seems to be a promising candidate.     

1H NMR assignment corrections and 1H, 13C, 15N NMR coordination shifts structural correlations in Fe(II), Ru(II) and Os(II) cationic complexes with 2,2′‐bipyridine and 1,10‐phenanthroline

¹H, ¹³C and ¹⁵N NMR studies of iron(II), ruthenium(II) and osmium(II) tris‐chelated cationic complexes with 2,2′‐bipyridine and 1,10‐phenanthroline of the general formula [M(LL)₃]²⁺ (M = Fe, Ru, Os; LL = bpy, phen) were performed. Inconsistent literature ¹H signal assignments were corrected. Significant shielding of nitrogen‐adjacent protons [H(6) in bpy, H(2) in phen] and metal‐bonded nitrogens was observed, being enhanced in the series Ru(II) → Os(II) → Fe(II) for ¹H, Fe(II) → Ru(II) → Os(II) for ¹⁵N and bpy → phen for both nuclei. The carbons are deshielded, the effect increasing in the order Ru(II) → Os(II) → Fe(II). Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis,characterization, and DNA binding of ruthenium(II) complexes with 2-benzo[b] furan-2-yl-1H-imidazo[4,5f][1,10]phenanthroline as an intercalative ligand

DNA-binding properties of a number of ruthenium complexes with different polypyridine ligands are reported. The new polypyridine ligand BFIP (=2-benzo[b] furan-2-yl-1H-imidazo[4,5-f][1,10]phenanthroline) and its ruthenium complexes [Ru(bpy)₂BFIP]²⁺ (bpy = 2,2′-bipyridine), [Ru(dmb)₂BFIP]²⁺ (dmb = 4,4′-dimethyl-2,2′-bipyridine), and [Ru(phen)₂BFIP]²⁺ (phen = 1,10-phenanthroline) have been synthesized and characterized by elemental analysis, mass spectra, IR, UV-Vis, ¹H- and ¹³C-NMR, and cyclic voltammetry. The DNA binding of these complexes to calf-thymus DNA (CT-DNA) was investigated by spectrophotometric, fluorescence, and viscosity measurements. The results suggest that ruthenium(II) complexes bind to CT-DNA through intercalation. Photocleavage of pBR 322 DNA by these complexes was also studied, and [Ru(phen)₂BFIP]²⁺ was found to be a much better photocleavage agent than the other two complexes.     

Synthesis,characterization and DNA binding and photocleavage studies of [Ru(bpy)2BDPPZ]2+, [Ru(dmb)2BDPPZ]2+ and [Ru(phen)2BDPPZ]2+ complexes and their antimicrobial activity

Polypyridyl ligand 9a,13a‐dihydro‐4,5,9,14‐tetraaza‐benzo[b]triphenylene‐11‐yl)‐phenyl‐methanone (BDPPZ) and its complexes [Ru(bpy)₂BDPPZ]²⁺, [Ru(dmb)₂BDPPZ]²⁺ and [Ru(phen)₂BDPPZ]²⁺ (where bpy = 2,2′‐bipyridine, dmb = 4,4′‐dimethyl‐2,2′‐bipyridine, phen = 1,10‐phenanthroline) have been synthesized and characterized by elemental analysis, IR, UV–vis, ¹H‐NMR, ¹³C‐NMR and mass spectra. The DNA‐binding properties of the complexes were investigated by absorption, emission, melting temperature and viscosity measurements. Experimental results indicate that the three complexes can intercalate into DNA base pairs. Photo activated cleavage of pBR‐322 DNA by the three complexes was also studied. Further, all three Ru(II) complexes synthesized were screened for their antimicrobial activity. Copyright © 2009 John Wiley & Sons, Ltd.     

Newly synthesized Cu(II) pyrazino[2,3‐f][1,10]phenanthroline complexes as potential anticancer candidates

New binary and ternary copper(II) complexes, [Cu(py‐phen)₂(NO₃)]NO₃ ( 1 ), [Cu₂(py‐phen)₂(gly)₂(NO₃)₂(H₂O)₂]?3H₂O ( 2 ) and [Cu₂(py‐phen)₂(tyr)₂(H₂O)₂](NO₃)₂?3H₂O ( 3 ) (py‐phen: pyrazino[2,3‐f][1,10]phenanthroline; gly: glycine; tyr: tyrosine), have been synthesized and characterized using CHN analysis, electrospray ionization mass spectrometry, Fourier transform infrared spectroscopy and single‐crystal X‐ray diffraction. Interaction of these complexes with calf thymus DNA has been investigated using absorption spectral titration, ethidium bromide and Hoechst 33258 displacement assay and thermal denaturation measurements. These complexes were found to be efficient cleaving agents and cleavage reactions were mediated by hydrolytic and oxidative pathways. The interaction between these complexes and bovine serum albumin (BSA) was investigated using electronic absorption and fluorescence spectroscopy. The experimental results show that the fluorescence quenching mechanism of these complexes and BSA is a static quenching process. Furthermore, in vitro cytotoxicities of these complexes against tumour cell lines (Caco‐2, MCF‐7 and A549) and healthy cell line (BEAS‐2B) showed that they exhibited anticancer activity with low IC₅₀ values. These complexes were markedly active against the cell lines and can be good drug candidates that are effective and safe for healthy tissue.     

Luminescent Ruthenium(II) Polypyridyl Complexes as Nonviral Carriers for DNA Delivery

Two new luminescent ruthenium(II) polypyridyl complexes, [Ru(bpy)₂(tpt‐phen)]Cl₂ ( 1 ; bpy=2,2′‐bipyridine, tpt‐phen=triptycenyl‐1,10‐phenanthroline) and [Ru(phen)₂(tpt‐phen)]Cl₂ ( 2 ; phen=1,10‐phenanthroline), have been developed as potential nonviral vectors for DNA delivery. Photophysical and electrochemical properties of the complexes have been investigated and corroborated with electronic structure calculations. DNA condensation by these complexes has been investigated by UV/Vis and emission spectroscopy, circular dichroism spectroscopy, atomic force microscopy, dynamic light scattering, confocal microscopy, and electrophoretic mobility studies. These complexes interact with DNA and efficiently condense DNA into globular nanoparticles that are taken up efficiently by HeLa cells. DNA cleavage inability and biocompatibility of complexes have been explored. Both complexes have good gene transfection abilities.     

Dinuclear Complexes of Copper(I) with Crown Ether‐containing N‐Thiophosphorylated Bis‐thioureas and 2,2′‐Bipyridine or 1,10‐Phenanthroline: Synthesis,Characterization, and Picrate Extraction Properties

Reaction of O,O′‐diisopropylthiophosphoric acid isothiocyanate (iPrO)₂P(S)NCS with 1,10‐diaza‐18‐crown‐6, 1,7‐diaza‐18‐crown‐6, or 1,7‐diaza‐15‐crown‐5 leads to the N‐thiophosphorylated bis‐thioureas N,N′‐bis[C(S)NHP(S)(OiPr)₂]‐1,10‐diaza‐18‐crown‐6 ( H₂L^I ), N,N′‐bis[C(S)NHP(S)(OiPr)₂]‐1,7‐diaza‐18‐crown‐6 ( H₂L^II ) and N,N′‐bis[C(S)NHP(S)(OiPr)₂]‐1,7‐diaza‐15‐crown‐5 ( H₂L^III ). Reaction of the potassium salts of H₂L^I–III with a mixture of CuI and 2,2′‐bipyridine ( bpy ) or 1,10‐phenanthroline ( phen ) in aqueous EtOH/CH₂Cl₂ leads to the dinuclear complexes [Cu₂(bpy)₂L^I–III] and [Cu₂(phen)₂L^I–III] . The structures of these compounds were investigated by ¹H, ³¹P{¹H} NMR spectroscopy, and elemental analysis. The crystal structures of H₂L^I and [Cu₂(phen)₂L^I] were determined by single‐crystal X‐ray diffraction. Extraction capacities of the obtained compounds in comparison to the related compounds 1,10‐diaza‐18‐crown‐6, N,N′‐bis[C(=CMe₂)CH₂P(O)(OiPr)₂]‐1,10‐diaza‐18‐crown‐6, N,N′‐bis[C(S)NHP(O)(OiPr)₂]‐1,10‐diaza‐18‐crown‐6 towards the picrate salts LiPic, NaPic, KPic. and NH₄Pic were also studied.     

Synthesis,characterization, and DNA-binding of [Co(phen)2(CPIA)]3+, [Co(phen)2(BIP)]3+, and [Co(phen)2(CIP)]3+

Three ligands, 2-(3-(carboxymethyl)-1,10-phenanthroline-[5,6-d]imidazole-1-yl)acetate (CPIA), 2-(benzo[d][1,3]dioxol-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (BIP), and 2-(9H-carbazol-3-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (CIP), and their complexes, [Co(phen)₂(CPIA)]³⁺ (1) (phen = 1,10-phenanthroline), [Co(phen)₂(BIP)]³⁺ (2), and [Co(phen)₂(CIP)]³⁺ (3), have been synthesized and characterized. Binding of the three complexes with calf thymus DNA (CT-DNA) has been investigated by spectroscopic methods, cyclic voltammetry, and viscosity measurements. The three complexes bind to DNA through an intercalative mode, and the size and shape of the intercalative ligands have significant effects on the binding affinity of complexes to CT-DNA.     

新型2-取代苯基-1H-咪唑[4,5-f][1,10]邻菲啰啉基Ru(II)配合物的光电性质

为获取具有活性官能团的接枝型、高性能荧光传感配合物,合成了2-(4-氨基苯基)-1H-咪唑[4,5-f][1,10]邻菲啰啉(CImPB-NH2)、2-(4-羟基苯基)-1H-咪唑[4,5-f][1,10]邻菲啰啉(CImPB-OH)、2-(4-羧基苯基)-1H-咪唑[4,5-f][1,10]邻菲啰啉(CImPB-COOH)和2-(4-硝基苯基)-1H-咪唑[4,5-f][1,10]邻菲啰啉(CImPB-NO2)四种配体,借助紫外-可见(UV-Vis)吸收光谱、荧光(PL)光谱、循环伏安法(CV)和含时密度泛函理论(TD-DFT)对上述四种配体与过渡金属元素钌(Ru)所形成的配合物的光电性能进行研究.结果表明:四种配合物均在可见光区域有较强吸收,发光范围覆盖绿色到红色光波段.在极性溶剂N,N-二甲基甲酰胺(DMF)中,以2-(4-氨基苯基)-1H-咪唑[4,5-f][1,10]邻菲啰啉为配体所构建的钌配合物([Ru(CImPB-NH2)(bpy)2]2+的荧光量子产率(Φ)较不含咪唑环的5-氨基邻菲啰啉合钌([Ru(phen-NH2)(bpy)2]2+)的提高了67%,以2-(4-羧基苯基)-1H-咪唑[4,5-f][1,10]邻菲啰啉所构建的钌配合物([Ru(CImPB-COOH)(bpy)2]2+)的Φ可达29.8%,是[Ru(phen-NH2)(bpy)2]2+的18倍.理论计算表明:配体中取代苯环、咪唑环和邻菲啰啉的稠环共平面,形成共价大π体系,其有效共轭长度较邻菲啰啉母体有显著增加,配合物是以Ru为中心的近似八面体构型,理论计算的电子吸收光谱和跃迁性质与实验结果相一致.上述研究有可能为接枝型、高性能荧光传感配合物的设计和筛选提供实验依据.     

Studies on the nuclease activity and interactions of the mixed‐polypyridyl [Ni2(1,3‐tpbd)(diimine)2(H2O)2]4+ complexes with thioredoxin reductase

Three new nickel(II) complexes formulated as [Ni₂(1,3‐tpbd)(diimine)₂(H₂O)₂]⁴⁺ [1,3‐tpbd = N,N,N′,N′‐tetrakis(2‐pyridylmethyl)benzene‐1,3‐diamine, where diimine is an N,N‐donor heterocyclic base like 1,10‐phenanthroline (phen),2,2′‐bipyridine (bpy), 4,5‐diazafluoren‐9‐one (dafo)], have been synthesized and structurally characterized by X‐ray crystallography: [Ni₂(1,3‐tpbd)(phen)₂(H₂O)₂]⁴⁺ (1), [Ni₂(1,3‐tpbd)(bpy)₂(H₂O)₂]⁴⁺(2) and [Ni₂(1,3‐tpbd)(dafo)₂(H₂O)₂]⁴⁺ (3). Single‐crystal diffraction reveals that the metal atoms in the complexes are all in a distorted octahedral geometry and in a trans arrangement around 1,3‐tpbd ligand. The interactions of the three complexes with calf thymus DNA (CT‐DNA) have been investigated by UV absorption, fluorescence spectroscopy, circular dichroism and viscosity. The apparent binding constant (K_app) values are calculated to be 1.91 × 10⁵ m ^?1 for 1, 1.18 × 10⁵ m ^?1 for 2, and 1.35 × 10⁵ m ^?1 for 3, following the order 1 > 3 > 2. The higher DNA binding affinity of 1 is due to the involvement in partial insertion of the phen ring between the DNA base pairs. A decrease in relative viscosities of DNA upon binding to 1–3 is consistent with the DNA binding affinities. These complexes efficiently display oxidative cleavage of supercoiled DNA in the presence of H₂O₂ (250 µ m ), with 3 exhibiting the highest nuclease activity. The rate constants for the conversion of supercoiled to nicked DNA are 5.28 × 10^?5 s^?1 (for 1), 6.67 × 10^?5 s^?1 (for 2) and 1.39 × 10^?4 s^?1 (for 3), also indicating that complex 3 shows higher catalytic activity than 1 and 2. Here the nuclease activity is not readily correlated to binding affinity. The inhibitory effect of complexes 1–3 on thioredoxin reductase has also been examined. The IC₅₀ values are calculated to be 26.54 ± 0.57, 31.03 ± 3.33 and 8.69 ± 2.54 µ m , respectively, showing a more marked inhibitory effect on thioredoxin reductase by complex 3 than the other two complexes. Copyright © 2012 John Wiley & Sons, Ltd.     

Stabilization of G‐Quadruplex DNA,Inhibition of Telomerase Activity and Live Cell Imaging Studies of Chiral Ruthenium(II) Complexes

Telomerase inhibition is an attractive strategy for cancer chemotherapy. In the current study, we have synthesized and characterized two chiral ruthenium(II) complexes, namely, Λ‐[Ru(phen)₂(p‐MOPIP)]²⁺ and Δ‐[Ru(phen)₂(p‐MOPIP)]²⁺, where phen is 1,10‐phenanthroline and p‐MOPIP is 2‐(4‐methoxyphenyl)‐imidazo[4,5f][1,10]phenanthroline. The chiral selectivity of the compounds and their ability to discriminate quadruplex DNA were investigated by using UV/Vis, fluorescence spectroscopy, circular dichroism spectroscopy, fluorescence resonance energy transfer melting assay, polymerase chain reaction stop assay and telomerase repeat amplification protocol. The results indicate that the two chiral compounds could induce and stabilize the formation of antiparallel G‐quadruplexes of telomeric DNA in the presence or absence of metal cations. We report the remarkable ability of the two complexes Λ‐[Ru(phen)₂(p‐MOPIP)]²⁺ and Δ‐[Ru(phen)₂(p‐MOPIP)]²⁺ to stabilize selectively G‐quadruplex DNA; the former is a better G‐quadruplex binder than the latter. The anticancer activities of these complexes were evaluated by using the MTT assay. Interestingly, the antiproliferative activity of Λ‐[Ru(phen)₂(p‐MOPIP)]²⁺ was higher than that of Δ‐[Ru(phen)₂(p‐MOPIP)]²⁺, and Λ‐[Ru(phen)₂(p‐MOPIP)]²⁺ showed a significant antitumor activity in HepG2 cells. The status of the nuclei in Λ/Δ‐[Ru(phen)₂(p‐MOPIP)]²⁺‐treated HepG2 cells was investigated by using real‐time living cell microscopy to determine the effects of Λ/Δ‐[Ru(phen)₂(p‐MOPIP)]²⁺ on intracellular accumulation. The results show that Λ/Δ‐[Ru(phen)₂(p‐MOPIP)]²⁺ can be taken up by HepG2 cells and can enter into the cytoplasm as well as accumulate in the nuclei; this suggests that the nuclei were the cellular targets of Λ/Δ‐[Ru(phen)₂(p‐MOPIP)]²⁺.     

Synthesis,characterization, DNA-binding and DNA-photocleavage studies of [Ru(bpy)2(BPIP)] and [Ru(phen)2(BPIP)] (BPIP = 2-(4′-biphenyl)imidazo[4,5-f][1,10]phenanthroline)

New ligand 2-(4′-biphenyl)imidazo[4,5-f][1,10]phenanthroline (BPIP) and its complexes [Ru(bpy)₂(BPIP)]²⁺ (1) (bpy = 2,2′-bipyridine) and [Ru(phen)₂(BPIP)]²⁺ (2) (phen = 1,10-phenanthroline) have been synthesized and characterized by mass spectroscopy, ¹H NMR and cyclic voltammetry. The interaction of two Ru(II) complexes with calf thymus DNA (CT-DNA) was investigated by spectroscopic and viscosity measurements. Results indicate that both complexes bind to DNA via an intercalative mode and the DNA-binding affinity of complex 2 is much greater than that of complex 1. Furthermore, when irradiated at 365 nm, both complexes have also been found to promote the photocleavage of plasmid pBR 322 DNA.     

Investigation of DNA/BSA binding of three Ru(II) complexes by various spectroscopic methods,molecular docking and their antimicrobial activity

An intercalative ligand, ppip (ppip = {2-(4-(piperidin-1-yl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline}), and its mononuclear Ru(II) polypyridyl complexes, [Ru(phen)₂(ppip)]²⁺ (1) (phen=1,10-phenanthrolene), [Ru(bpy)₂(ppip)]²⁺ (2) (bpy=2,2′-bipyridine) and [Ru(dmb)₂(ppip)]²⁺ (3) (dmb=4,4′-dimethyl-2,2′-bipyridine), have been synthesized and characterized by elemental analysis and spectroscopic techniques such as UV–vis, IR, ¹H, as well as ¹³C NMR and ESI-MS. The interaction of these complexes with DNA/BSA (bovine serum albumin) was investigated using absorption, emission spectroscopy, viscosity measurements and molecular docking studies. The docking study infers that the binding strength (K_b) of these complexes was in agreement with results from absorption and emission techniques. These studies reveal that these three Ru(II) polypyridyl complexes bind to DNA/BSA. The binding ability of these complexes in the presence of different ions and solvents were also reported. All complexes were effectively cleaving pBR322 DNA in different forms and follows order which is similar to absorption and emission studies. These complexes were effective exhibiting the antimicrobial activity against different microbes Bacillus subtilis, Escherichia coli and Staphylococcus aureus.     

Synthesis,Characterization, Antibacterial and Antifungal Activity of Yttrium(III) Complexes Including 1,10‐Phenanthroline

Two rare metal coordination complexes of yttrium(III) including 1,10‐phenanthroline, Y(phen)₂(NO₃)₃ and (phenH)₂[Y₂(pydc)₃(NO₃)₂·6H₂O] (phen=1,10‐phenanthroline, pydc=2,6‐pyridinedicarboxylate), and a proton transfer compound (phenH⁺)₂(pydc^2?) were synthesized and characterized by elemental analysis, molar conductance, infrared spectra (IR), nuclear magnetic resonance (NMR) and thermal analysis. The proposed structures of yttrium complexes were exhibited. The in vitro biological activities of the newly synthesized complexes have also been investigated against Bacillus coli, Staphylococcus aureus and Candida albicans. The results showed that yttrium(III) complexes including 1,10‐phenanthroline exhibited better antibacterial/antifungal activity than their ligands and corresponding compounds.     

Two Novel Three‐Dimensional Lead(II) Coordination Polymers Involving 16‐Membered Rings: [Pb2(Bs‐glu)2(bipy)2] and [Pb2(Bs‐glu)2(phen)2]

The reaction of Pb(CH₃COO)₂·3H₂O with N‐benzesulfonyl‐L‐glutamic acid in the presence of 2, 2′‐bipyridine (bipy) or 1,10‐phenanthroline (phen) produced two novel complexes [Pb₂(Bs‐glu)₂(bipy)₂] ( 1 ) and [Pb₂(Bs‐glu)₂(phen)₂] ( 2 ) (Bs‐glu = N‐benzesulfonyl‐L‐glutamic acid dianion). In 1 chains bearing alternative 16‐membered rings and Pb₂O₃ nodes are constructed from the interactions of Pb^II ions with the carboxylates of Bs‐glu ligands. To the best of our knowledge, this is the first lead(II) complex of carboxylates with the formation of chains of Pb₂O₃. In 2 the 16‐membered ring units are connected by centrosymmetric Pb₂O₂ nodes to form chains. Complexes 1 and 2 construct the 3‐D supramolecular architectures through versatile hydrogen bonds and π‐π stacking interactions.     

Synthesis, characterization and DNA-binding studies of ruthenium(II) mixed-ligand complexes containing dipyrido[1,2,5]oxadiazolo[3,4-b]quinoxaline

A novel ligand dipyrido[1,2,5]oxadiazolo[3,4-b]quinoxaline (dpoq) and its complexes [Ru(bpy)₂(dpoq)]²⁺ and [Ru(phen)₂(dpoq)]²⁺ (bpy = 2,2′-bipyridine; phen = 1,10-phenanthroline) have been synthesized and characterized by elemental analysis, electrospray mass spectra and ¹H NMR. The interaction of Ru(II) complexes with calf thymus DNA (CT-DNA) was investigated by absorption spectroscopy, fluorescence spectroscopy, thermal denaturation and viscosity measurements. Results suggest that two Ru(II) complexes bind to DNA via an intercalative mode.     

DNA Interactions of the Functionalized (Mixed Polypyridine)ruthenium(II) Complex Bis(2,2′‐bipyridine‐κN1,κN1′)(methyl dipyrido[3,2‐a : 2′,3′‐c]phenazine‐11‐carboxylate‐κN4,κN5)ruthenium(2+) ([Ru(bpy)2(dppz‐11‐CO2Me)]2+)

A novel polypyridine ligand, dipyrido[3,2‐a:2′,3′‐c]phenazine‐11‐carboxylic acid methyl ester (=dppz‐11‐CO₂Me), and its ruthenium(II) complex, [Ru(bpy)₂(dppz‐11‐CO₂Me)]²⁺ ( 1 ), were synthesized and characterized. The binding properties of this complex to calf‐thymus DNA (CT‐DNA) were investigated by different spectrophotometric methods and viscosity measurements. The results suggest that the complex binds to DNA in an intercalative mode and serves as a molecular ‘light switch’ for DNA. When irradiated at 365 nm, the complex 1 promoted the photocleavage of plasmid pBR‐322 DNA.