共查询到20条相似文献,搜索用时 46 毫秒
1.
Shuang Qi Zhihui Jin Yuanjun Hou Chao Li Xuesong Wang Qianxiong Zhou 《Particle & Particle Systems Characterization》2021,38(11):2100193
Ru(II) complexes with weak ligand fields may undergo light-induced ligand dissociation, and the resulted Ru(II) aqua complexes may bind with biomolecules such as DNA, showing potential as photoactivated chemotherapy (PACT) agents. However, Ru(II) complexes with efficient PACT activity are still rare. Some Ru(II) complexes exhibit efficient photoinduced ligand dissociation but poor cytotoxicity. It is speculated that the low nuclear accumulation levels may account for their low PACT efficacy. In order to confirm this hypothesis, the almost noncytotoxic [Ru(7-OCH3-dppz)(4-OCH3-py)4](PF6)2 (Ru1) is loaded on nucleus-targeted C5N2 nanoparticles (NPs). Compared with the free Ru1, Ru1–C5N2 NPs exhibit significantly increased cellular uptake and nuclear accumulation. Therefore, Ru1–C5N2 NPs show efficient PACT activity toward various cancer cell lines (including cisplatin-resistant one) with half maximal inhibitory concentration (IC50) values of 0.18 × 10−6–0.29 × 10−6 m and phototoxicity index (IC50dark/IC50light) values above 137 under both normoxic and hypoxic conditions. Moreover, Ru1–C5N2 NPs also exhibit efficient PACT activity toward cisplatin-resistant 3D multicellular tumor spheroids upon two-photon irradiation (800 nm). The same strategy is also feasible to greatly improve the PACT activity of [Ru(7-OCH3-dppz)(py)4]2+, which itself only has a medium effect. The results may provide new sights for developing efficient Ru(II) PACT agents. 相似文献
2.
Qi Xiao Shan Huang Yushu Ge Zhike He Yi Liu Jiangong Liang 《Journal of fluorescence》2010,20(2):541-549
As one of nucleic acid molecular “light switch”, Ru(bipy)2(dppx)2+ is a good probe for the determination of double-helical DNA, which displays intense fluorescence when double-helical DNA
is present. However, the fluorescence of Ru(bipy)2(dppx)2+ is quenched when Ag+ is added to the Ru(bipy)2(dppx)2+-DNA system. Based on the quenching of the fluorescence of Ru(bipy)2(dppx)2+-DNA system by Ag+, a simple, rapid and specific method for Ag+ determination was proposed. In the optimum conditions, Ag+ concentration versus Ru(bipy)2(dppx)2+ fluorescence intensity gave a linear response in the range from 0.2 to 6.0 μM with a detection limit (3σ) of 3.2 × 10−8 M. The proposed method has been applied to determine the Ag+ in water samples and sulfadiazine silver cream successfully. Because of the intense fluorescence of Ru(bipy)2dppx2+ when DNA is present, the interaction between Ag+ and DNA was confirmed by fluorescence microscopy and the phenomenon of the fluorescence images agreed well with the results.
The possible mechanism of the reaction was also discussed by circular dichroism spectra and isothermal titration calorimetry. 相似文献
3.
制备了高折射率Tm3+/Yb3+共掺杂铋碲酸盐玻璃,利用棱镜耦合法测量出玻璃在632.8和1550nm波长处的折射率分别为2.0365和1.9795. 对玻璃的吸收、荧光和红外透过光谱展开了测试与分析,根据Judd-Ofelt理论对吸收光谱进行拟合,求得Tm3+的振子强度参数Ωt(t=2,4,6)分别为3.90×10-20, 2.03×10-20和9.03×10-2
关键词:
3+/Yb3+共掺')" href="#">Tm3+/Yb3+共掺
铋碲酸盐玻璃
光谱参数
上转换荧光 相似文献
4.
M. Atif 《Optics and Spectroscopy》2012,112(5):763-766
Experiments were carried out using the femtosecond laser to compare the fluorescence amplitude produced by two-photon excitation at 800 nm and 400 nm (i.e. to the strong absorption band in mTHPC). Using an experimental arrangement where the fluorescence sampling geometry was kept unchanged between the two exposure wavelengths a value for the two-photon cross-section of mTHPC at 800 nm of ?1.8 × 10?57 m4 s/molecule/photon was derived. This is larger than the value estimated using a simple theoretical model, probably because the calculation neglects ??resonant?? assistance provided by the real state at ??650 nm (S 0). In terms of order of magnitude the values are in agreement with the two-photon cross-section for other organic species. 相似文献
5.
R. Castro-Beltran G. Ramos-Ortiz C. K. W. Jim J. L. Maldonado M. H?u?ler D. Peralta-Dominguez M. A. Meneses-Nava O. Barbosa-Garcia B. Z. Tang 《Applied physics. B, Lasers and optics》2009,97(2):489-496
The nonlinear optical properties of a hyperbranched polyyne (hb-Polyyne) have been measured at infrared wavelengths by using femtosecond and nanosecond pulsed excitation. This hyperbranched
polyyne exhibited strong and intrinsic (simultaneous) two-photon absorption and upconverted blue fluorescent emission under
femtosecond excitation around 800 nm. The hb-Polyyne in chloroform solution is characterized by a large two-photon absorption cross section of 9068 GM (1GM=10−50 cm4 s) and a fluorescence quantum yield of 0.57. On the other hand, by third-harmonic generation (THG) spectroscopy with nanosecond
excitation, the measured third-order nonlinear susceptibility χ
(3) for solid films of hb-Polyyne ranged from 2.4×10−11 to 6.1×10−11 esu in the spectral range of 1100–1600 nm, with results comparable to the values exhibited by the well-known conjugated polymer
MEH:PPV, but with a much better transparency for visible wavelengths. 相似文献
6.
Zhu WeiLing Liu XueWen Wang Hui Yu HuiJuan Li AiZheng Chao Hui Zheng KangCheng Ji LiangNian 《中国科学G辑(英文版)》2008,51(2):133-139
The transient luminescence of three kinds of ruthenium complexes [Ru(bpy)2(7-CH3-dppz)]2+, [Ru(bpy)2(7-F-dppz)]2+ and [Ru(phen)2(7-F-dppz)]2+ bound to calf thymus DNA (ctDNA) has been studied by using the time-resolved spectroscopy. The results show that the luminescence
is due to the radiative decay from the charge-transfer states to the ground state. By the interaction with DNA, the radiativeless
rate of the photoexcited Ru complex molecules decreases, which results in the increase of luminescence lifetime and efficiency.
The structure of the Ru complex has an important impact on the interaction with DNA. The [Ru(bpy)2(7-CH3-dppz)]2+ shows the longest luminescence lifetime (about 382 ns), while the [Ru(bpy)2(7-F-dppz)]2+ shows the shortest lifetime (about 65 ns). The possible origin of the luminescence dynamics is discussed.
Supported by the National Natural Science Foundation of China (Grant Nos. 60478013 and 20571089), the Key Program of Natural
Science Foundation of Guangdong Province of China (Grant No. 05101819), the Doctoral Program Foundation of Institutions of
Higher Education of China (Grant No. 20040558031) and the Scientific Research Foundation of Maoming College (Grant No. 203346) 相似文献
7.
Ravi Kumar Vuradi Srishailam Avudoddi Venkat Reddy Putta Laxma Reddy Kotha Praveen Kumar Yata Satyanarayana Sirasani 《Journal of fluorescence》2017,27(3):939-952
Three ruthenium(II) polypyridyl complexes, [Ru(phen)2(mip)](ClO4)2 (1) (phen =1,10-Phenanthroline), [Ru(bpy)2(mip)](ClO4)2 (2) (bpy = 2,2’bipyridyl) and [Ru(dmb)2(mip)](ClO4)2 (3) (dmb = 4, 4′-dimethyl 2, 2′-bipyridine), were synthesized with an intercalative ligand mip (2-morpholino-1H-imidazo[4,5-f][1, 10]phenanthroline) and characterized by 1H, 13C–NMR, IR, UV-vis, mass spectra and elemental analysis. pH effect, ion selectivity (cations, anions) and solvent sensitivity of complexes were studied. The interaction of these complexes with DNA was performed using absorption, emission spectroscopy and viscosity measurements. The experimental results indicated that the two complexes interacted with calf thymus DNA (CT-DNA) by intercalative mode. BSA (Bovine Serum Albumin) protein binding of these complexes was studied by UV-visible and fluorescence techniques. The binding capacity of these complexes was explained theoretically by molecular docking method. 相似文献
8.
H. P. Liu Z. G. Sun S. D. Hogan N. Q. Lou 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(3):357-362
We report an experimental study of the multiphoton dissociation dynamics of
CF3I performed on a home-built femtosecond laser pump-probe system, with
time-of-flight mass spectrometer. The first repulsive A band and the
5pπ37sσ υ2=1 Rydberg state of CF3I were accessed
by one- and two-photon transitions at 267 nm, respectively, with the latter
two-photon absorption followed by a further two-photon probe transition at
401 nm to the
state of the parent ion. The observed signals
from the CF3
+ and I+ fragments show similar multi-component
exponential decay patterns but the former is 4 times stronger than the
latter. However, the parent CF3I+ signal was observed to evolve in a
very different manner, decreasing sharply when probed in the first 289 fs
following excitation and subsequently rising again after 860 fs to a
constant level below that measured at negative pump-probe delay times when the
pump and probe pulses exchange roles. This dip observed in the parent ion
profile, is very different from that previously reported at shorter pump
wavelengths of 264 nm or 265 nm, and is interpreted as the competition
between two different ionization channels. One from the vibrationally excited
υ2=1 of the irradiated Rydberg state and the other from the
dissociative vibrational origin of the same electronic state which is
populated by internal vibrational relaxation. 相似文献
9.
Andrew Frazer Alma R. Morales Adam W. Woodward Paul Tongwa Tatiana Timofeeva Kevin D. Belfield 《Journal of fluorescence》2014,24(1):239-250
The design, synthesis, and photophysical properties of a new fluorene-based fluorescent chemosensor, 4-((E)-2-(2-(benzo[d]thiazol-2-yl)-9,9-diethyl-9H-fluoren-7-yl)vinyl)-N,N-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)benzenamine (AXF-Al), is described for the detection of Al3+. AXF-Al exhibited absorption at 382 nm and strong fluorescence emission at 542 nm (fluorescence quantum yield, Φ F, of 0.80). The capture of Al3+ by the pyrazolyl aniline receptor resulted in nominal change in the linear absorption (372 nm) but a large hypsochromic shift of 161 nm in the fluorescence spectrum (542 to 433 nm, Φ F?=?0.88), from which Al3+ was detected both ratiometrically and colorimetrically. The addition of other metal ions, namely Mg2+, Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg 2+ and Pb2+, produced only minimal changes in the optical properties of this probe. The emission band of this probe was also accessed by two-photon excitation in the near-IR, as two-photon absorption (2PA) is important for potential applications in two-photon fluorescence microscopy (2PFM) imaging. The 2PA cross section of the free fluorenyl ligand AXF-Al was 220 GM at 810 nm and 235 GM at 810 nm for the Al-ligand complex, practically useful properties for 2PFM. 相似文献
10.
Igor Alperovich Dooshaye Moonshiram Alexander Soldatov Yulia Pushkar 《Solid State Communications》2012,152(20):1880-1884
Density functional theory (DFT)-based relativistic calculations were performed to model the Ru L-edge X-ray absorption near edge structure (XANES) spectra of the hexaammineruthenium complex [Ru(NH3)6]3+ and “blue dimer” water oxidation catalyst, cis,cis- [(bpy)2(H2O)RuIIIORuIII(OH2)(bpy)2]4+ (bpy is 2,2-bipyridine). Two computational approaches were compared: simulations without the core-hole and by modeling of the core-hole within the Z+1 approximation. Good agreement between calculated and experimental XANES spectra is achieved without including the core-hole. Simulations with algorithms beyond the Z+1 approximation were only possible in a framework of the scalar relativistic treatment. Time-dependent DFT (TD-DFT) was used to compute the Ru L-edge spectrum for [Ru(NH3)6]3+ model compound. Three different core-hole treatments were compared in a real-space full multiple scattering XANES modeling within the Green function formalism (implemented in the FEFF9.5 package) for the [Ru(Mebimpy)(bpm)(H2O)]2+ complex. The latter approaches worked well in cases where spin–orbit treatment of relativistic effects is not required. 相似文献
11.
Summary The spectral behaviour of the direct interband two-photon absorption coefficient α(2) in ZnO, CuCl and Bi4Ge3O12 has been investigated in a large excitation energy range. The experimental results have shown that the α(2) spectral behaviour is well described by a parametric formula containing terms with different energy dependence. In particular,
for 2ħω-E
g>≈400 meV, the first experimental evidence of 2ħω-E
g)5/2 dependence has been obtained. As a consequence, each of the various models proposed to predict the α(2) dispersion curve gives the correct energy dependence in a limited energy range, due to the poor approximation made in the
evaluation of dipole matrix elements. To explain the spectral dependence of the two-photon absorption coefficient, consideration
of all the intermediate states is required, with the energy dependence of the dipole matrix elements properly considered.
It is shown that the greatest contributions to the oscillator strength come from transitions totally allowed at the critical
points.
Work partially supported by M.P.I. 相似文献
12.
Guangyong Zhuo Xiaomei Wang Dong Wang Chun Wang Xian Zhao Zongshu Shao Minhua Jiang 《Optics & Laser Technology》2001,33(4)
A new organic dye trans-4-[p-(N-ethyl-N-hydroxyethylamino)styryl]-N-methylpyridinium iodide (abbreviated as HEASPI hereafter) with large two-photon absorption (TPA) cross section and excellent upconverted superradiance properties was synthesized in our group recently. The TPA cross section was measured to be σ2′=7.0×10−48 cm4 s/photon by using an open aperture Z-scan system. Linear absorption, single-photon induced fluorescence, two-photon induced fluorescence and two-photon pumped (TPP) upconverted superradiance properties were systematically studied. The highest net upconversion efficiency from the absorbed pump energy to the output upconverted superradiance energy is as high as 19.6% at the pump energy of 2.07 mJ from a mode-locked Nd : YAG picosecond laser. The dye solution also shows a clear optical power limiting effect. 相似文献
13.
Xiaobo Chen Guojian YangSong Li Masaaki OhtsukaSawanobori Naruhito Jinying LiuLuan Chen Gregory J. Salamo 《Optics Communications》2012,285(24):5247-5253
The infrared quantum cutting phenomenon, which is an international hot research field, of Ho3+Yb3+: oxyfluoride vitroceramics (FOV) was studied in the present paper. It was found from the fluorescence spectroscopy experiments that the excitation spectrum of 973.0 nm fluorescence of Yb3+ ion is very similar to the absorption and excitation spectra of Ho3+ ion. It suggests that the energy transfer from Ho3+ ion to Yb3+ ion is very efficient. Then, all the possible important energy transfer passages were analyzed. It was found that the energy transfers {5G4(Ho3+)→5F5(Ho3+), 2F7/2(Yb3+)→2F5/2(Yb3+)} and {5F5(Ho3+)→5I7(Ho3+), 2F7/2(Yb3+)→2F5/2(Yb3+)} result in the effective two-photon quantum cutting 973.0 nm fluorescence of Yb3+ ion when 5G4 or 3K7 or the above energy level of Ho3+ ion are excited. Finally, the quantum efficiency ηQE,1%Yb=43.0% and ηQE,5%Yb=171.7% of two-photon quantum cutting was calculated for Ho(0.5)Yb(1):FOV and Ho(0.5)Yb(5):FOV respectively. This research would be beneficial for the enhancement of solar cell efficiency. 相似文献
14.
以532nm皮秒脉冲作抽运光,采用单光束Z-扫描技术对具有激发态分子内质子转移效应的有机分子2-(2′-羟基苯基)苯并噻唑(HBT)在其双光子吸收区的非线性光学特性进行了研究.实验结果表明,对532nm波长的光,HBT分子存在明显的双光子吸收.通过拟合开孔Z-扫描实验数据,求解了HBT分子在其双光子吸收区的非线性吸收系数,并探讨了抽运光强度对介质双光子吸收效应的影响.采用高斯分解法,通过拟合闭孔Z-扫描除以开孔Z-扫描数据,理论推导并计算了在介质对抽运光存在非线性吸收的情况下HBT分子的非线性折射率,以及不同入射光强度时HBT分子的三阶非线性极化率实部和虚部的值.计算结果表明,理论分析与实验结果较好地符合,这些结果为进一步研究和开发此类材料的应用提供了理论与实验依据. 相似文献
15.
B. N. Murdin C. Merveille A. K. Kar C. R. Pidgeon D. A. Jaroszynski J.-M. Ortega R. Prazeres F. Glotin 《Optical and Quantum Electronics》1993,25(3):171-175
We have performed the first experiment on the free-electron laser (CLIO) at the Laboratoire pour l'Utilisation du Rayonnement Électromagnétique (LURE). In a transmission experiment we observed strong power limiting at wavelengths longer than the absorption edge associated with induced free carrier absorption produced by direct interband two-photon transitions in InSb. We have estimated the two-photon absorption (TPA) coefficient () of InSb at 8.9 m to be 2 cm MW-1, by fitting the power-limiting effect with a simple theoretical model. An important feature of this result is that we are utilizing the broad tunability of the FEL to explore the TPA theory to shorter wavelengths than hitherto available with CO2 lasers. The result is in broad agreement with the longer-wavelength measurements of Sheik-Bahae et al. 相似文献
16.
对一种低温易烧结的Yb:Y2-2xLa2xO3激光透明陶瓷的光谱性能进行了初步研究,Yb:Y2-2xLa2xO3激光透明陶瓷具有宽的吸收带和大的吸收截面,在最强的吸收峰977nm处吸收截面达4.0×10-20cm2;其荧光发射寿命为1.1ms,发射截面在1033nm处为1.0×10-20cm2,在1077nm处为0.7×10-20cm2.Yb:Y2-2xLa2xO3陶瓷的各项光学性能指标接近或达到单晶的指标.
关键词:
氧化镧钇
激光陶瓷
低温烧结
光谱性能 相似文献
17.
A. Srishailam Yata Praveen Kumar Nazar M. D. Gabra P. Venkat Reddy N. Deepika Nageti Veerababu S. Satyanarayana 《Journal of fluorescence》2013,23(5):897-908
Three Ruthenium(II) polypyridine complexes, [Ru(phen)2(mipc)]2+(1), [Ru(bpy)2(mipc)]2+ (2) and [Ru(dmb)2(mipc)]2+(3) [mipc?=?2-(6-methyl-3-(1H-imidazo[4, 5-f][1,10]-phenanthroline-2-yl)-4H-chromene-4-one, phen?=?1,10-phenanthroline,bpy?=?2, 2′bipyridine,dmb?=?4, 4′-dimethyl-2, 2′-bipyridine] have been synthesized and characterized by elemental analysis, IR, UV–Vis, 1H& 13C NMR and mass spectra. The DNA-binding properties of the Ruthenium(II) complexes were investigated by spectrophotometric methods, viscosity measurements and light switch studies. These three complexes have been focused on photo activated cleavage studies with pBR-322 and antimicrobial studies. Experimental results indicate that the three complexes intercalate into DNA base pairs and follows the order of 1?>?2?>?3 respectively. Molecular docking studies also support the DNA interactions with complexes through hydrogen bonding and vander Waal’s interactions. Cytotoxicity studies with Hela cell lines has been revealing about anti tumor activity of these complexes. 相似文献
18.
S. Shojaei 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,83(2):197-201
The present work investigates the nonlinear optical properties of a GaN quantum dot in the disk limit via the exciton and
biexciton states using the compact density matrix formalism. Based on this model, we calculate the ground state energy of
the exciton and biexciton states by the variation method, within envelope function and effective mass approximations. Linear
and nonlinear optical absorption (α
(1), α
(3)) and oscillator strengths attributed to the optical transitions are obtained. The details of the behaviour of α
(1) and α
(3) around the resonance frequencies and for different quantum dot geometries are presented. It is found that the size of quantum
dot and the optical intensity have a remarkable effect on the optical absorption, and the biexcitonic two-photon absorption
coefficient(K
2) has also been calculated in this system. The results show that this parameter is strongly affected by the size of the quantum
dot. 相似文献
19.
Seven different two-photon excitable dipyrrylmetheneboron difluoride labels (dipyrrylmethene-BF2 labels) and a frequently used TAMRA label were conjugated to mouse IgG against α-fetoprotein in variable substitution degrees. Altogether 40 IgG conjugates were prepared, and studied with respect to one-photon absorption and emission properties, and two-photon fluorescence efficiency using 1064 nm laser as illumination source. Performance of the IgG conjugates as tracers in a separation-free immunometric assay of α-fetoprotein was evaluated using two-photon excitation assay technology, ArcDiaTM TPX. The results show that the dipyrrylmethene-BF2 labels provide subpicomolar sensitivity, which is an order of magnitude better than that of TAMRA label. The effect of chromophore structure and substitution degree of IgG-label conjugates on the assay performance is discussed. 相似文献
20.
Photoinduced electron‐transfer reactions of tris(2,2′‐bipyridine)ruthenium(II)‐based carbonic anhydrase inhibitors tethering plural binding sites 下载免费PDF全文
Mikiko Suwa Narumi Imamura Pirika Awano Eiji Nakata Hiroshi Takashima 《Journal of Physical Organic Chemistry》2018,31(9)
Tris(2,2′‐bipyridine)ruthenium(II) complex‐based carbonic anhydrase (CA) inhibitors, [Ru(bpy)2(bpydbs)]2+ {bpy = 2,2′‐bipyridine and bpydbs = 2,2′‐bipyridinyl‐4,4′‐dicarboxilic acid bis[(2‐{2‐[2‐(4‐sulfamoylbenzoylamino)ethoxy]ethoxy}ethyl)amide]} and [Ru(bpydbs)3]2+, tethering plural benzenesulfonamide groups have been prepared. The CA catalytic activity was effectively suppressed by these synthetic [Ru(bpy)2(bpydbs)]2+ and [Ru(bpydbs)3]2+ inhibitors, and their dissociation constants at pH = 7.2 and at 25°C were determined to be KI = 0.93 ± 0.02 μM and KI = 0.24 ± 0.03 μM, respectively. Next, 2 photoinduced electron‐transfer (ET) systems comprising a Ru2+‐CA complex and an electron acceptor, such as chloropentaamminecobalt(III) ([CoCl(NH3)5]2+) or methylviologen (MV2+) were studied. In the presence of CA and a sacrificial electron acceptor, such as pentaamminechlorocobalt(III) complex, the photoexcited triplet state of 3([Ru(II)]2+)* was quenched through an intermolecular photoinduced ET mechanism. In case of the [Ru(bpydbs)3]2+‐CA‐MV2+ system, the photoexcited triplet state of 3([Ru(bpydbs)3]2+)* was quenched by sacrificial quencher through an intermolecular photoinduced ET mechanism, giving the oxidized [Ru(bpydbs)3]3+. Then the following intramolecular ET from the amino acid residue, Tyr6, near the active site of CA proceeded. We observed a transient absorption around at 410 nm, arising from the formation of a Tyr?+ in the [Ru(bpydbs)3]2+‐CA‐MV2+ system. These artificial Ru(II)‐CA systems may clearly demonstrate both intermolecular and intramolecular photoinduced ET reactions of protein and could be one of the interesting models of the ET proteins. Their photophysical properties and the detailed ET mechanisms are discussed in order to clarify the multistep ET reactions. 相似文献