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51.
A Deadly Organometallic Luminescent Probe: Anticancer Activity of a ReI Bisquinoline Complex
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Dr. Igor Kitanovic Suzan Can Dr. Hamed Alborzinia Dr. Ana Kitanovic Vanessa Pierroz Anna Leonidova Dr. Antonio Pinto Priv. Doz. Dr. Bernhard Spingler Priv. Doz. Dr. Stefano Ferrari Roberto Molteni Dr. Andreas Steffen Prof. Dr. Nils Metzler‐Nolte Prof. Dr. Stefan Wölfl Prof. Dr. Gilles Gasser 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(9):2496-2507
The photophysical properties of [Re(CO)3(L ‐N3)]Br (L ‐N3=2‐azido‐N,N‐bis[(quinolin‐2‐yl)methyl]ethanamine), which could not be localized in cancer cells by fluorescence microscopy, have been revisited in order to evaluate its use as a luminescent probe in a biological environment. The ReI complex displays concentration‐dependent residual fluorescence besides the expected phosphorescence, and the nature of the emitting excited states have been evaluated by DFT and time‐dependent (TD) DFT methods. The results show that fluorescence occurs from a 1LC/MLCT state, whereas phosphorescence mainly stems from a 3LC state, in contrast to previous assignments. We found that our luminescent probe, [Re(CO)3(L ‐N3)]Br, exhibits an interesting cytotoxic activity in the low micromolar range in various cancer cell lines. Several biochemical assays were performed to unveil the cytotoxic mechanism of the organometallic ReI bisquinoline complex. [Re(CO)3(L ‐N3)]Br was found to be stable in human plasma indicating that [Re(CO)3(L ‐N3)]Br itself and not a decomposition product is responsible for the observed cytotoxicity. Addition of [Re(CO)3(L ‐N3)]Br to MCF‐7 breast cancer cells grown on a biosensor chip micro‐bioreactor immediately led to reduced cellular respiration and increased glycolysis, indicating a large shift in cellular metabolism and inhibition of mitochondrial activity. Further analysis of respiration of isolated mitochondria clearly showed that mitochondrial respiratory activity was a direct target of [Re(CO)3(L ‐N3)]Br and involved two modes of action, namely increased respiration at lower concentrations, potentially through increased proton transport through the inner mitochondrial membrane, and efficient blocking of respiration at higher concentrations. Thus, we believe that the direct targeting of mitochondria in cells by [Re(CO)3(L ‐N3)]Br is responsible for the anticancer activity. 相似文献
52.
Aryl–Phenyl Scrambling in Intermediate Organopalladium Complexes: A Gas‐Phase Study of the Mizoroki–Heck Reaction
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Lukas Fiebig Dr. Nils Schlörer Prof. Hans‐Günther Schmalz Priv.‐Doz. Dr. Mathias Schäfer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(17):4906-4910
The intramolecular aryl–phenyl scrambling reaction within palladium–DPPP–aryl complex (DPPP=1,3‐bis(diphenylphosphino)propane) ions was analyzed by state‐of‐the‐art tandem MS, including gas‐phase ion/molecule reactions. The Mizoroki–Heck cross‐coupling reaction was performed in the gas phase, and the intrinsic reactivity of important intermediates could be examined. Moreover, linear free‐energy correlations were applied, and a mechanism for the scrambling reaction proceeding via phosphonium cations was assumed. 相似文献
53.
Dr. Andreas Lerchen Dr. Narasimhulu Gandhamsetty Elliot H. E. Farrar Dr. Nils Winter Dr. Johannes Platzek Dr. Matthew N. Grayson Prof. Dr. Varinder K. Aggarwal 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(51):23307-23311
(−)-Finerenone is a nonsteroidal mineralocorticoid receptor antagonist currently in phase III clinical trials for the treatment of chronic kidney disease in type 2 diabetes. It contains an unusual dihydronaphthyridine core. We report a 6-step synthesis of (−)-finerenone, which features an enantioselective partial transfer hydrogenation of a naphthyridine using a chiral phosphoric acid catalyst with a Hantzsch ester. The process is complicated by the fact that the naphthyridine exists as a mixture of two atropisomers that react at different rates and with different selectivities. The intrinsic kinetic resolution was converted into a kinetic dynamic resolution at elevated temperature, which enabled us to obtain (−)-finerenone in both high yield and high enantioselectivity. DFT calculations have revealed the origin of selectivity. 相似文献
54.
Dilcan Dirican Nils Pfister Martin Wozniak Prof. Dr. Thomas Braun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(31):6945-6963
Binary sulfur fluorides exhibit an interesting reactivity towards transition metal complexes. They open up routes for the generation of sulfur-containing building blocks. Often ligands with particular properties can be constructed. This includes their ability to transfer sulfur atoms or polysulfide units as well as fluorination reactions. This Minireview provides an insight into the reactivity of the binary and ternary sulfur halides S2Cl2, SCl2, SF4, SF6 and SF5Cl towards transition-metal compounds. 相似文献
55.
Simon Ludwanowski Dr. Meral Ari Karsten Parison Somar Kalthoum Paula Straub Nils Pompe Prof. Dr. Stefan Weber Priv.-Doz. Dr. Michael Walter Prof. Dr. Andreas Walther 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(58):13203-13212
Arylazopyrazoles are an emerging class of photoswitches with redshifted switching wavelength, high photostationary states, long thermal half-lives and facile synthetic access. Understanding pathways for a simple modulation of the thermal half-lives, while keeping other parameters of interest constant, is an important aspect for out-of-equilibrium systems design and applications. Here, it is demonstrated that the thermal half-life of a water-soluble PEG-tethered arylazo-bis(o-methylated)pyrazole (AAP) can be tuned by more than five orders of magnitude using simple pH adjustment, which is beyond the tunability of azobenzenes. The mechanism of thermal relaxation is investigated by thorough spectroscopic analyses and density functional theory (DFT) calculations. Finally, the concepts of a tunable half-life are transferred from the molecular scale to the material scale. Based on the photochromic characteristics of E- and Z-AAP, transient information storage is showcased in form of light-written patterns inside films cast from different pH, which in turn leads to different times of storage. With respect to prospective precisely tunable materials and time-programmed out-of-equilibrium systems, an externally tunable half-life is likely advantageous over changing the entire system by the replacement of the photoswitch. 相似文献
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57.
The oxidation of cyclooctane (1) to cyclooctanone (3) with molecular oxygen and acetaldehyde (2) as a co-reductant occurs efficiently in the presence of compressed CO2. Up to 20% yields of 3 are obtained under optimised multiphase conditions. 相似文献
58.
59.
Monovacancy diffusion alone dominates over diffusion due to divacancies and interstitials in Al for all temperatures up to the melting point. Deviations from a single Arrhenius dependence are due to anharmonicity. The conclusion is based on a combination of theoretical methods, from density functional theory to thermodynamic integration, without fitting to experimental data. The calculated diffusion rate agrees with experimental data over 11 orders of magnitude. 相似文献
60.