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81.
Nils Metzler‐Nolte 《Nachrichten aus der Chemie》2002,50(1):65-65
82.
Marco Felici Pablo Contreras‐Carballada Dr. Yolanda Vida Dr. Jan M. M. Smits Roeland J. M. Nolte Prof. Dr. Luisa De Cola Prof. Dr. René M. Williams Dr. Martin C. Feiters Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(47):13124-13134
Novel 2‐(1‐substituted‐1H‐1,2,3‐triazol‐4‐yl)pyridine (pytl) ligands have been prepared by “click chemistry” and used in the preparation of heteroleptic complexes of Ru and Ir with bipyridine (bpy) and phenylpyridine (ppy) ligands, respectively, resulting in [Ru(bpy)2(pytl‐R)]Cl2 and [Ir(ppy)2(pytl‐R)]Cl (R=methyl, adamantane (ada), β‐cyclodextrin (βCD)). The two diastereoisomers of the Ir complex with the appended β‐cyclodextrin, [Ir(ppy)2(pytl‐βCD)]Cl, were separated. The [Ru(bpy)2(pytl‐R)]Cl2 (R=Me, ada or βCD) complexes have lower lifetimes and quantum yields than other polypyridine complexes. In contrast, the cyclometalated Ir complexes display rather long lifetimes and very high emission quantum yields. The emission quantum yield and lifetime (Φ=0.23, τ=1000 ns) of [Ir(ppy)2(pytl‐ada)]Cl are surprisingly enhanced in [Ir(ppy)2(pytl‐βCD)]Cl (Φ=0.54, τ=2800 ns). This behavior is unprecedented for a metal complex and is most likely due to its increased rigidity and protection from water molecules as well as from dioxygen quenching, because of the hydrophobic cavity of the βCD covalently attached to pytl. The emissive excited state is localized on these cyclometalating ligands, as underlined by the shift to the blue (450 nm) upon substitution with two electron‐withdrawing fluorine substituents on the phenyl unit. The significant differences between the quantum yields of the two separate diastereoisomers of [Ir(ppy)2(pytl‐βCD)]Cl (0.49 vs. 0.70) are attributed to different interactions of the chiral cyclodextrin substituent with the Δ and Λ isomers of the metal complex. 相似文献
83.
Erik Schwartz Vincenzo Palermo Dr. Chris E. Finlayson Dr. Ya‐Shih Huang Matthijs B. J. Otten Andrea Liscio Dr. Sara Trapani Irene González‐Valls Patrick Brocorens Dr. Jeroen J. L. M. Cornelissen Dr. Kalina Peneva Dr. Klaus Müllen Prof. Dr. Frank C. Spano Prof. Dr. Arkady Yartsev Prof. Sebastian Westenhoff Dr. Richard H. Friend Prof. Dr. David Beljonne Dr. Roeland J. M. Nolte Prof. Dr. Paolo Samorì Prof. Dr. Alan E. Rowan Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(11):2536-2547
Exciton migration! Spectroscopic analyses and extensive molecular dynamics studies revealed a well‐defined 41 helix in which the perylene molecules (see figure) form four “helter‐skelter‐like” overlapping pathways along which excitons and electrons can rapidly migrate.
84.
The BioCD is a spinning-disc interferometric biosensor on which antibodies are immobilized to capture target antigens from
biological samples. In this work, BioCDs measured the interferometric response to prostate-specific antigen (PSA). The ideal
detection limit for PSA was determined using a BioCD with 12,500 printed target antibody spots with a corresponding number
of reference protein spots. Statistical analysis projects the detection limit of PSA as a function of the number of spots
included in the average. When approximately 10,000 spot pairs were averaged, the 3σ detection limit was 60 pg/ml in a 2 mg/ml simple protein background. A standard format for BioCD immunoassays uses 96 wells
with 32 target spots paired with reference spots. In serum, the detection limit for this format was 1 ng/ml in 3:1 diluted
female human serum using a sandwich assay with a nonfluorescent mass tag. 相似文献
85.
The two‐ and three‐dimensional mercurous cations [(Hg2)3(OH)2]4+ and [(Hg2)2O]2+ crystallize with channels and cages of roughly 1 nm diameter from aqueous solutions dependent upon the acidity of the solution. Crystal structures were determined, for example, for [Zn(H2O)6][(Hg2)3(OH)2](NO3)6 (trigonal, space group P321, a = 1183.5(2) pm, c = 534.8(1) pm, Z = 1, R1 = 0.0351 for I0 > 2σ(I0)) and for [(Hg2)2O][Pb(NO3)3]2 (cubic, space group , a = 1543.1(2) pm, Z = 8, R1 = 0.0534 I0 > 2σ(I0)). 相似文献
86.
Hüsken N G?bala M Battistel A La Mantia F Schuhmann W Metzler-Nolte N 《Chemphyschem》2012,13(1):131-139
Gold‐surface grafted peptide nucleic acid (PNA) strands, which carry a redox‐active ferrocene tag, present unique tools to electrochemically investigate their mechanical bending elasticity based on the kinetics of electron‐transfer (ET) processes. A comparative study of the mechanical bending properties and the thermodynamic stability of a series of 12‐mer Fc‐PNA?DNA duplexes was carried out. A single basepair mismatch was integrated at all possible strand positions to provide nanoscopic insights into the physicochemical changes provoked by the presence of a single basepair mismatch with regard to its position within the strand. The ET processes at single mismatch Fc‐PNA?DNA modified surfaces were found to proceed with increasing diffusion limitation and decreasing standard ET rate constants k0 when the single basepair mismatch was dislocated along the strand towards its free‐dangling Fc‐modified end. The observed ET characteristics are considered to be due to a punctual increase in the strand elasticity at the mismatch position. The kinetic mismatch discrimination with respect to the fully‐complementary duplex presents a basis for an electrochemical DNA sensing strategy based on the Fc‐PNA?DNA bending dynamics for loosely packed monolayers. In a general sense, the strand elasticity presents a further physicochemical property which is affected by a single basepair mismatch which may possibly be used as a basis for future DNA sensing concepts for the specific detection of single basepair mismatches. 相似文献
87.
Pinned water films in a microfluidic channel act as elastic membranes under tension that increase capillary pressures while preserving the mechanical work dissipated around capillary pressure-saturation, P(c)-S(w), hysteresis cycles. High-resolution two-photon laser micromachining of SU-8 photoresist was used to fabricate wedge-shaped microfluidic channels that included sharp edge features to pin wetting films during drainage. The films were measured using confocal fluorescence microscopy. The tension in the film acts as an elastic tether that shifts the P(c)-S(w) hysteresis cycle higher in pressure relative to the hysteresis cycle in the same sample when films are not pinned. The film tension is strongly nonlinear as the restoring force decreases with increasing displacement. The contribution of elastic forces to hysteresis has important consequences for pressure and saturation control in microfluidics. 相似文献
88.
Naether U Kartashov YV Vysloukh VA Nolte S Tünnermann A Torner L Szameit A 《Optics letters》2012,37(4):593-595
We study the gradual transition from one-dimensional (1D) to two-dimensional (2D) Anderson localization upon transformation of the dimensionality of disordered waveguide arrays. An effective transition from a 1D to a 2D system is achieved by increasing the number of rows forming the arrays. We observe that, for a given disorder level, Anderson localization becomes weaker with increasing numbers of rows-hence the effective dimension. 相似文献
89.
Naether U Meyer JM Stützer S Tünnermann A Nolte S Molina MI Szameit A 《Optics letters》2012,37(4):485-487
We investigate experimentally the light evolution inside a two-dimensional finite periodic array of weakly coupled optical waveguides with a disordered boundary. For a completely localized initial condition away from the surface, we find that the disordered boundary induces an asymptotic localization in the bulk, centered around the initial position of the input beam. 相似文献
90.
We present a practical method to determine femtosecond laser induced refractive index changes in transparent materials. Based on an iterative Fourier transform algorithm, this technique spatially resolves the refractive index of complex structures by combining the dimensions of the modified region with the corresponding phase change extracted from far-field intensity measurements. This approach is used to characterize optical waveguides written by a femtosecond laser in borosilicate glass. 相似文献