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1.
《Electroanalysis》2004,16(19):1642-1646
The strategy for electrochemical detection of HBV DNA PCR product (181 bps) was designed by covalently immobilizing single‐stranded HBV DNA on preoxidized glassy carbon electrode surface. The immobilization of single stranded DNA was verified by AC impedance spectra. The following hybridization reaction on surface was evidenced by electrochemical methods using [Os(bpy)2Cl2]+ as an electroactive indicator. The interactions of [Os(bpy)2Cl2]+ with calf thymus single and double stranded DNA immobilized on preoxidized glassy carbon electrodes were studied. [Os(bpy)2Cl2]+ could bind preferentially to the duplex DNA by intercalating to base pairs. The intrinsic binding constant of [Os(bpy)2Cl2]+ with calf thymus DNA was calculated to be 1.21×104 M?1. Using [Os(bpy)2Cl2]+ as an electrochemical hybridization indicator, the HBV DNA sensor has been used to detect qualitatively target HBV DNA in solution with high sensitivity and selectivity. 相似文献
2.
Qian‐Xiong Zhou Dr. Wan‐Hua Lei Jing‐Rong Chen Chao Li Yuan‐Jun Hou Xue‐Song Wang Prof. Bao‐Wen Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(10):3157-3165
Ruthenium(II) polypyridyl complexes with long‐wavelength absorption and high singlet‐oxygen quantum yield exhibit attractive potential in photodynamic therapy. A new heteroleptic RuII polypyridyl complex, [Ru(bpy)(dpb)(dppn)]2+ (bpy=2,2′‐bipyridine, dpb=2,3‐bis(2‐pyridyl)benzoquinoxaline, dppn=4,5,9,16‐tetraaza‐dibenzo[a,c]naphthacene), is reported, which exhibits a 1MLCT (MLCT: metal‐to‐ligand charge transfer) maximum as long as 548 nm and a singlet‐oxygen quantum yield as high as 0.43. Steady/transient absorption/emission spectra indicate that the lowest‐energy MLCT state localizes on the dpb ligand, whereas the high singlet‐oxygen quantum yield results from the relatively long 3MLCT(Ru→dpb) lifetime, which in turn is the result of the equilibrium between nearly isoenergetic excited states of 3MLCT(Ru→dpb) and 3ππ*(dppn). The dppn ligand also ensures a high binding affinity of the complex towards DNA. Thus, the combination of dpb and dppn gives the complex promising photodynamic activity, fully demonstrating the modularity and versatility of heteroleptic RuII complexes. In contrast, [Ru(bpy)2(dpb)]2+ shows a long‐wavelength 1MLCT maximum (551 nm) but a very low singlet‐oxygen quantum yield (0.22), and [Ru(bpy)2(dppn)]2+ shows a high singlet‐oxygen quantum yield (0.79) but a very short wavelength 1MLCT maximum (442 nm). 相似文献
3.
d‐ Versus l‐Glucose Conjugation: Mitochondrial Targeting of a Light‐Activated Dual‐Mode‐of‐Action Ruthenium‐Based Anticancer Prodrug
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Lucien N. Lameijer Dr. Samantha L. Hopkins Tobias G. Brevé Sven H. C. Askes Dr. Sylvestre Bonnet 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18484-18491
Light‐activated ruthenium polypyridyl anticancer prodrugs often suffer from poor water solubility, poor selectivity, and/or ill‐defined intracellular targets. Coordination of the d ‐ or l ‐glucose thioether ligand 3 (2‐(2‐(2‐(methylthio)ethoxy)ethoxy)ethyl‐β‐glucopyranoside) to the highly lipophilic ruthenium complex [Ru(tpy)(dppn)(H2O)]2+ ([ 1 ]2+; dppn=benzo[i]dipyrido‐[3,2‐a:2′,3′‐c]phenazine, tpy=2,2′:6′,2′′‐terpyridine) solved all these problems at once. The two enantiomers of [Ru(tpy)(dppn)( 3) ][PF6]2, [d ‐ 2 ][PF6]2 and [l ‐ 2 ][PF6]2, were soluble in water, which allowed the influence of the chirality of the glucose moiety on uptake, toxicity, and intracellular localization of the prodrug to be probed without changing any other physicochemical properties. Both compounds showed mild, but different, cytotoxicity in A549 (human lung carcinoma) and MCF‐7 (human breast adenocarcinoma) cancer cells in the dark, whereas following low doses of visible light irradiation (3.1 J cm?2 at λ = 454 nm), a similar, but high cytotoxicity (EC50 < 1 μm ), was observed. Irrespective of the chirality, both slightly emissive Ru complexes were found in the mitochondria, and two modes of action may contribute to light‐induced cell death: 1) the glucose thioether ligand is photosubstituted by water, thus [ 1 ]2+, which interacts with DNA at an exceptionally high 400:1 base pair/Ru ratio, is released; 2) both [ 1 ]2+ and [ 2 ]2+ produce massive amounts of singlet oxygen, which leads to very efficient photodynamic DNA cleavage. 相似文献
4.
《Electroanalysis》2005,17(17):1517-1522
In this paper, we report the first attempt to use humic acid (HA) as modifiers to prepare the organic‐inorganic hybrid modified glassy carbon electrodes based on HA‐silica‐PVA (poly(vinyl alcohol)) sol‐gel composite. Electroactive species of tris(2,2′‐bipyridyl)ruthenium(II) (Ru(bpy) ) can easily incorporate into the HA‐silica‐PVA films to form Ru(bpy) modified electrodes. The amount of Ru(bpy) incorporated in the composite films strongly depends on the amount of HA in the hybrid sol. Electrochemical and electrogenerated chemiluminescence (ECL) of Ru(bpy) immobilized in HA‐silica composite films coated on a glassy carbon electrode have been studied with tripropylamine (TPA) as the coreactant. The analytical performance of this modified electrode was evaluated in a flow injection analysis (FIA) system with a homemade flow cell. The as‐prepared electrode showed good stability and high sensitivity. The detection limits (S/N=3) were 0.050 μmol L?1 for TPA and 0.20 μmol L?1 for oxalate, and the linear ranges were from 0.10 μmol L?1 to 1.0 mmol L?1 for TPA and from 1.0 μmol L?1 to 1.0 mmol L?1 for oxalate, respectively. The resulting electrodes were stable over two months. 相似文献
5.
《Electroanalysis》2006,18(2):186-194
The complex of osmium tetroxide with 2,2′‐bipyridine has been utilized as a probe of DNA structure and an electroactive marker of DNA in DNA hybridization sensors. It produces several voltammetric signals, the most negative of them has been observed only at mercury electrodes. This signal is of catalytic nature affording a high sensitivity of DNA determination. The catalytic current due to evolution of hydrogen in voltammetry of DNA modified by complex of osmium tetroxide with 2,2′‐bipyridine (DNA‐Os,bipy) was studied. Solid amalgam electrodes (modified with mercury menisci) of silver (m‐AgSAE), copper (m‐CuSAE), gold, and of combined bismuth and silver, were used as possible substitutes for mercury electrodes. Besides the hanging mercury drop electrode (HMDE), the catalytic current was observed only on m‐AgSAE and m‐CuSAE. Electrodes of gold and bismuth amalgams did not give the catalytic current. The detection limit of DNA‐Os,bipy on HMDE was 0.1 ng mL?1 (RSD=2.3 %, N=11), and on m‐AgSAE 0.2 ng mL?1 (RSD=3.1%, N=11). The m‐AgSAE was successfully applied as a detection electrode in double‐surface DNA hybridization experiments offering highly specific discrimination between complementary (target) and nonspecific DNAs, as well as determination of the length of a repetitive DNA sequence. The m‐AgSAE has proved a convenient alternative to the HMDE or carbon electrodes used for similar purposes in previous work. 相似文献
6.
Prof. Dr. Qingxiang Wang Yingtao Ding Liheng Wang Jiancong Ni Zhanglong Yu Haibin Lin Feng Gao 《化学:亚洲杂志》2013,8(7):1455-1462
An electrically neutral cobalt complex, [Co(GA)2(phen)] (GA=glycollic acid, phen=1,10‐phenathroline), was synthesized and its interactions with double‐stranded DNA (dsDNA) were studied by using electrochemical methods on a glassy carbon electrode (GCE). We found that [Co(GA)2(phen)] could intercalate into the DNA duplex through the planar phen ligand with a high binding constant of 6.2(±0.2)×105 M ?1. Surface studies showed that the cobalt complex could electrochemically accumulate within the modified dsDNA layer, rather than within the single‐stranded DNA (ssDNA) layer. Based on this feature, the complex was applied as a redox‐active hybridization indicator to detect 18‐base oligonucleotides from the CaMV35S promoter gene. This biosensor presented a very low background signal during hybridization detection and could realize the detection over a wide kinetic range from 1.0×10?14 M to 1.0×10?8 M , with a low detection limit of 2.0 fM towards the target sequences. The hybridization selectivity experiments further revealed that the complementary sequence, the one‐base‐mismatched sequence, and the non‐complementary sequence could be well‐distinguished by the cobalt‐complex‐based biosensor. 相似文献
7.
Xue‐Wen Liu Jin‐Can Chen Xia Hu Hong Li Kang‐Cheng Zheng Liang‐Nian Ji 《Helvetica chimica acta》2008,91(7):1374-1388
The ligand pteridino[6,7‐f] [1,10]phenanthroline‐11,13‐diamine (ppn) and its RuII complexes [Ru(bpy)2(ppn)]2+ ( 1 ; bpy=2,2′‐bipyridine) and [Ru(phen)2(ppn)]2+ ( 2 ; phen=1,10‐phenanthroline) were synthesized and characterized by elemental analysis, electrospray MS, 1H‐NMR, and cyclic voltammetry. The DNA‐binding behaviors of 1 and 2 were studied by spectroscopic and viscosity measurements. The results indicate that both complexes strongly bind to calf‐thymus DNA in an intercalative mode, with DNA‐binding constants Kb of (1.7±0.4)?106 M ?1 and (2.6±0.2)?106 M ?1, respectively. The complexes 1 and 2 exhibit excellent DNA‐‘light switch’ performances, i.e., they do not (or extremely weakly) show luminescence in aqueous solution at room temperature but are strongly luminescent in the presence of DNA. In particular, the experimental results suggest that the ancillary ligands bpy and phen not only have a significant effect on the DNA‐binding affinities of 1 and 2 but also have a certain effect on their spectral properties. [Ru(phen)2(ppn)]2+( 2 ) might be developed into a very prospective DNA‐‘light switch’ complex. To explain the DNA‐binding and spectral properties of 1 and 2 , theoretical calculations were also carried out applying the DFT/TDDFT method. 相似文献
8.
Dr. Chad M. Shade Dr. Robert D. Kennedy Dr. Jessica L. Rouge Dr. Mari S. Rosen Mary X. Wang Soyoung E. Seo Dr. Daniel J. Clingerman Prof. Chad A. Mirkin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(31):10983-10987
We report the design and synthesis of small molecules that exhibit enhanced luminescence in the presence of duplex rather than single‐stranded DNA. The local environment presented by a well‐known [Ru(dipyrido[3,2‐a:2′,3′‐c]phenazine)L2]2+‐based DNA intercalator was modified by functionalizing the bipyridine ligands with esters and carboxylic acids. By systematically varying the number and charge of the pendant groups, it was determined that decreasing the electrostatic interaction between the intercalator and the anionic DNA backbone reduced single‐strand interactions and translated to better duplex specificity. In studying this class of complexes, a single RuII complex emerged that selectively luminesces in the presence of duplex DNA with little to no background from interacting with single‐stranded DNA. This complex shows promise as a new dye capable of selectively staining double‐ versus single‐stranded DNA in gel electrophoresis, which cannot be done with conventional SYBR dyes. 相似文献
9.
Duha Jawad Awad Andreas Koch Wulfhard Mickler Uwe Schilde Prof. Dr. Peter Strauch 《无机化学与普通化学杂志》2012,638(6):965-975
A series of new heteroleptic MN2S2 transition metal complexes with M = Cu2+ for EPR measurements and as diamagnetic hosts Ni2+, Zn2+, and Pd2+ were synthesized and characterized. The ligands are N2 = 4, 4′‐bis(tert‐butyl)‐2, 2′‐bipyridine (tBu2bpy) and S2 =1, 2‐dithiooxalate, (dto), 1, 2‐dithiosquarate, (dtsq), maleonitrile‐1, 2‐dithiolate, or 1, 2‐dicyanoethene‐1, 2‐dithiolate, (mnt). The CuII complexes were studied by EPR in solution and as powders, diamagnetically diluted in the isostructural planar [NiII(tBu2bpy)(S2)] or[PdII(tBu2bpy)(S2)] as well as in tetrahedrally coordinated[ZnII(tBu2bpy)(S2)] host structures to put steric stress on the coordination geometry of the central CuN2S2 unit. The spin density contributions for different geometries calculated from experimental parameters are compared with the electronic situation in the frontier orbital, namely in the semi‐occupied molecular orbital (SOMO) of the copper complex, derived from quantum chemical calculations on different levels (EHT and DFT). One of the hosts, [NiII(tBu2bpy)(mnt)], is characterized by X‐ray structure analysis to prove the coordination geometry. The complex crystallizes in a square‐planar coordination mode in the monoclinic space group P21/a with Z = 4 and the unit cell parameters a = 10.4508(10) Å, b = 18.266(2) Å, c = 12.6566(12) Å, β = 112.095(7)°. Oxidation and reductions potentials of one of the host complexes, [Ni(tBu2bpy)(mnt)], were obtained by cyclovoltammetric measurements. 相似文献
10.
The one-pot hydrothermal reaction of CuCl2 with H2CPOA and 4,4'-bpy results in two new coordination polymers, [Cu(CPOA)(4,4'-bpy)(H2O)2]·1.5H2O (1) and [Cu2(HCPOA)4(4,4'-bpy)4] (2) (H2CPOA=4-carboxyphenoxy acetic acid, 4,4'-bpy=4,4'-bipyridine) since CPOA^2- anions reach equilibrium with HCPOA^- anions in the reaction system. The crystal structure of 1 shows a triple interpenetration CdSO4-like net with 1D channel, in which lattice water molecules are located. Complex 2 is a ladder-like 1D double chain structure assembled through coordination bonds and O—H…N hydrogen bonds. 相似文献
11.
Feng Gao Hui Chao Feng Zhou Lian‐Cai Xu Kang‐Cheng Zheng Liang‐Nian Ji 《Helvetica chimica acta》2007,90(1):36-51
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). 相似文献
12.
Champaka Gurudevaru Mohan Gopalakrishnan Kabali Senthilkumar Hridya Hemachandran Ramamoorthy Siva Thothadri Srinivasan Devadasan Velmurugan Swaminathan Shanmugan Nallasamy Palanisami 《应用有机金属化学》2018,32(2)
Mononuclear and dinuclear copper(II) complexes with thiophenecarboxylic acid, [Cu(3‐TCA)2(2,2′‐bpy)] ( 1 ), [Cu(3‐Me‐2‐TCA)2(H2O)(2,2′‐bpy)] ( 2 ), [Cu(5‐Me‐2‐TCA)2(H2O)(2,2′‐bpy)] ( 3 ) and [Cu2(2,5‐TDCA)(DMF)2(H2O)2(2,2′‐bpy)2](ClO4)2 ( 4 ) (where 3‐TCA = 3‐thiophenecarboxylic acid; 3‐Me‐2‐TCA = 3‐methyl‐2‐thiophenecarboxylic acid; 5‐Me‐2‐TCA = 5‐methyl‐2‐thiophenecarboxylic acid; 2,5‐TDCA = thiophene‐2,5‐dicarboxylic acid; 2,2′‐bpy = 2,2′‐bipyridyl; DMF = N,N‐dimethylformamide), were synthesized. Compounds 1 – 4 were extensively characterized using both analytical and spectroscopic methods. Additionally, the solid‐state structures of 1 and 4 were unambiguously established from single‐crystal X‐ray diffraction studies. The hexacoordinated Cu(II) centre in 1 (CuO4N2) is a distorted octahedral geometry whereas the pentacoodinated 4 (CuO3N2) has distorted square pyramidal geometry. Compounds 1 and 4 exhibit intermolecular hydrogen bonding which leads to the formation of two‐ and three‐dimensional supramolecular architectures, respectively. Spectrophotometric and computational investigations suggest that these compounds bind with DNA in minor groove binding such that Kb = 4.9 × 105 M?1 and Ksv = 3.4 × 105 M?1, and binding score of ?5.26 kcal mol?1. The binding affinity of these complexes to calf thymus DNA is in the order 2 > 3 > 4 > 1 . Methyl‐substituted thiophene ring increases the DNA binding affinity whereas unsubstituted thiophene ring DNA binding rate is reduced. The methyl group on the thiophene ring would sterically hinder π–π stacking of the ring with DNA base pairs, and subsequently they are involved in hydrophobic interaction with the DNA surface rather than partial intercalative interaction. Compounds 1 – 4 show pronounced activity against B16 mouse melanoma skin cancer cell lines as measured by MTT assay yielding IC50 values in the micromolar concentration range. The compounds could prove to be efficient anti‐cancer agents, since at a concentration as low as 2.1 μg ml?1 they exerted a significant cytotoxic effect in cancer cells whereas cell viability was not affected in normal cells. 相似文献
13.
Double‐stranded DNA and multiwalled carbon nanotube (MWNT) complex modified glassy carbon electrodes (DNA‐MWNT‐GCE) were employed to discriminate penicillamine (PA) enantiomers. Cyclic voltammetry, electrochemical impedance spectroscopy, atomic force microscopy and ultraviolet‐visible spectroscopy were used to characterize the enantioselective phenomenon. The results indicated that the binding effect between L ‐PA and DNA‐MWNTs was stronger than that of D ‐PA and DNA‐MWNTs. In addition, the influencing factors of the modified electrodes were systematically investigated. The modified electrodes exhibited a linear response towards PA enantiomers from 1.0×10?1 to 1.0×10?8 mol L?1 and detection limits of 3.1×10?9 and 3.3×10?8 mol L?1 for L ‐PA and D ‐PA, respectively. 相似文献
14.
An Easy One‐Pot Synthesis of Diverse 2,5‐Di(2‐pyridyl)pyrroles: A Versatile Entry Point to Metal Complexes of Functionalised,Meridial and Tridentate 2,5‐Di(2‐pyridyl)pyrrolato Ligands
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Alex McSkimming Dr. Mohan M. Bhadbhade Dr. Martin P. Bucknall Hon. Assoc. Prof. Roger W. Read Assoc. Prof. Stephen B. Colbran 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(36):11445-11456
A wide variety of 2,5‐di(2‐pyridyl)pyrroles (dppHs) substituted at the C3 and C4 positions of the pyrrole core were obtained by direct condensation of a 2‐pyridylcarboxaldehyde (2 equiv), an α‐methylene ketone with at least one electron‐withdrawing substituent and ammonium acetate. A novel 2,5‐di(1,10‐phenanthrolin‐2‐yl)pyrrole was also characterised. The dppHs provide a direct, quick entry to dipyridylpyrrolato (dpp?)–metal complexes. The meridial tridentate dpp? ligand is a useful anionic analogue of the terpyridyl ligand. The first (dpp)Ru complexes are described; the 3,4‐substitution of the central pyrrole significantly perturbs the potentials of the redox processes of these complexes. A [(dpp)Ru(bpy)(MeCN)]+ (bpy=2,2′‐bipyridine) complex is an electrocatalyst for the reductive disproportionation of carbon dioxide to carbon monoxide and the carbonate ion. 相似文献
15.
Chang‐Yan Sun Dr. Xin‐Xin Li Shui‐Feng Wang Wen‐Jun Li Xiang‐Jun Zheng 《无机化学与普通化学杂志》2008,634(5):950-955
Four new transition metal coordination polymers, [Co(bpndc)(phen)(H2O)]n ( 1 ), [Co3(bpndc)3(2,2′‐bpy)2]n·0.5n(i‐C3H7OH) ( 2 ), and [M(bpndc)(2,2′‐bpy)2]n (M = Zn, 3 ; Cu, 4 ; H2bpndc = benzophenone ‐4,4′‐dicarboxylic acid; phen = 1,10‐phenanthroline; 2,2′‐bpy = 2,2′‐bipyridine) have been synthesized by the hydrothermal reactions and characterized by single crystal X‐ray diffraction, elemental analysis, and IR spectrum. Because of the introduction of different terminal auxiliary ligands, bpndc ligands in complexes 1 and 2 adopt different coordination modes. In complex 1 , bpndc ligands act as tridentate ligand and bridge CoII ions into 1D double‐stranded chains; while complex 2 possesses 2D (4,4) grids, where bpndc ligands adopt tetradente and pentadentate modes. Two such grids interpenetrate to form a novel catenane‐like layer. Complexes 3 and 4 are isostructural. Bpndc ligands adopt tetradentate mode and bridge metal ions forming 1D helical chains. 相似文献
16.
Yun‐Jun Liu Hui Chao Jun‐Hua Yao Hong Li Yi‐Xian Yuan Liang‐Nian Ji 《Helvetica chimica acta》2004,87(12):3119-3130
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. 相似文献
17.
Two new nickel(II) complexes, [Ni(4, 4′‐bpy)(H2O)4]n · n(cpp) · 0.5nH2O ( 1 ) and [Ni(cpp)(4, 4′‐bpy)(H2O)2]n ( 2 ) [4, 4′‐bpy = 4, 4′‐bipyridine, H2cpp = 3‐(4‐carboxyphenyl)propionic acid] were synthesized and characterized by single‐crystal X‐ray diffraction, elemental analysis, IR spectroscopy, and thermal analysis. In complex 1 , NiII ions are bridged by 4, 4′‐bpy into 1D chains, and cpp ligands are not involved in the coordination, whereas in complex 2 , cpp ligands adopt a bis(monodentate) mode and link NiII ions into 2D (4, 4) grids with the help of 4, 4′‐bpy ligands. Triple interpenetration occurs, which results in the formation of a complicated 3D network. The difference in the structures of the two complexes can be attributed to the different reaction temperatures and bases. 相似文献
18.
The Equally Important Role of Adenine Derivatives to That of Pyrimidine Derivatives in Near‐0 eV Electron‐Induced DNA Lesions
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The role of adenine (A) derivatives in DNA damage is scarcely studied due to the low electron affinity of base A. Experimental studies demonstrate that low‐energy electron (LEE) attachment to adenine derivatives complexed with amino acids induces barrier‐free proton transfer producing the neutral N7‐hydrogenated adenine radicals rather than conventional anionic species. To explore possible DNA lesions at the A sites under physiological conditions, probable bond ruptures in two models—N7‐hydrogenated 2′‐deoxyadenosine‐3′‐monophosphate (3′‐dA(N7H)MPH) and 2′‐deoxyadenosine‐5′‐monophosphate (5′‐dA(N7H)MPH), without and with LEE attachment—are studied by DFT. In the neutral cases, DNA backbone breakage and base release resulting from C3′?O3′ and N9?C1′ bond ruptures, respectively, by an intramolecular hydrogen‐transfer mechanism are impossible due to the ultrahigh activation energies. On LEE attachment, the respective C3′?O3′ and N9?C1′ bond ruptures in [3′‐dA(N7H)MPH]? and [5′‐dA(N7H)MPH]? anions via a pathway of intramolecular proton transfer (PT) from the C2′ site of 2′‐deoxyribose to the C8 atom of the base moiety become effective, and this indicates that substantial DNA backbone breaks and base release can occur at non‐3′‐end A sites and the 3′‐end A site of a single‐stranded DNA in the physiological environment, respectively. In particular, compared to the results of previous theoretical studies, not only are the electron affinities of 3′‐dA(N7H)MPH and 5′‐dA(N7H)MPH comparable to those of hydrogenated pyrimidine derivatives, but also the lowest energy requirements for the C3′?O3′ and N9‐glycosidic bond ruptures in [3′‐dA(N7H)MPH]? and [5′‐dA(N7H)MPH]? anions, respectively, are comparable to those for the C3′?O3′ and N1‐glycosidic bond cleavages in corresponding anionic hydrogenated pyrimidine derivatives. Thus, it can be concluded that the role of adenine derivatives in single‐stranded DNA damage is equally important to that of pyrimidine derivatives in an irradiated cellular environment. 相似文献
19.
Cristiano Zuccaccia Gianfranco Bellachioma Giuseppe Cardaci Alceo Macchioni Barbara Binotti Carla Carfagna 《Helvetica chimica acta》2006,89(8):1524-1546
Palladacyclic compounds [Pd(C6H4(C6H5C?O)C?N? R)(N? N)] [X] (R = Et, iPr, 2,6‐iPr2C6H3; N? N = bpy = 2,2′‐bipyridine, or 1,4‐(o,o′‐dialkylaryl)‐1,4‐diazabuta‐1,3‐dienes; [X]? = [BF4]? or [PF6]?) were synthesized from the dimers [{Pd(C6H4(C6H5C?O)C?N? R)(μ‐Cl)}2] and N? N ligands. Their interionic structure in CD2Cl2 was determined by means of 19F,1H‐HOESY experiments and compared with that in the solid state derived from X‐ray single‐crystal studies. [Pd(C6H4(C6H5C?O)C?N? R)(N? N)] [X] complexes were found to copolymerize CO and p‐methylstyrene affording syndiotactic or isotactic copolymers when bpy or 1,4‐(o,o′‐dimethylaryl)‐1,4‐diazabuta‐1,3‐dienes were used, respectively. The reactions with CO and p‐methylstyrene of the bpy derivatives were investigated. Two intermediates derived from a single and a double insertion of CO into the Pd? C bonds were isolated and completely characterized in solution. 相似文献
20.
Enhanced Photostability of a Ruthenium(II) Polypyridyl Complex under Highly Oxidizing Aqueous Conditions by Its Partial Inclusion into a Cyclodextrin
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Dr. Pau Farras Dr. Helen Waller Prof. Andrew C. Benniston 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(3):1133-1140
The complex [Ru(bpy)2L]2+, where bpy=2,2′‐bipyridine, L=4‐(phenylethynyl)‐2,2′‐bipyridine, was prepared in its racemic and resolved forms (Δ and Λ). The phenylethynyl unit on the bipyridine for the complex acts as a binding site for α‐cyclodextrin in water (1:1 complex, K=3390 L mol?1) or β‐cyclodextrin (2:1 complex, K1=887 L mol?1, K2=8070 L mol?1). The presence of the cyclodextrin provides partial protection to the complex under light‐activated water oxidation conditions. 相似文献