Dreidimensionale Tomographie im mittleren Infrarotbereich von endogenen und exogenen Molekülen in einer einzelnen Zelle mit subzellulärer Auflösung

Acetoxymethyl Concept for Intracellular Administration of Carbon Monoxide with Mn(CO)3 -Based PhotoCORMs

Targeted administration of carbon monoxide with CO releasing molecules (CORMs) inside of cells proved to be very challenging. Consequently, there are only very few reports on intracellular uptake of CORMs requiring high extracellular CORM loading because an equilibrium between extra- and intracellular concentrations can be assumed. Here we present a strategy for a targeted intracellular administration of manganese(I)-based CORMs that are altered inside of cells to trap these complexes. Thereafter, carbon monoxide can be liberated by irradiation (photoCORMs). To achieve this innovative task, acetoxymethyl (AM) groups are attached at the periphery of the hydrophobic manganese(I) carbonyl complexes to not influence the CO release behavior. Inside of cells these AM substituents are cleaved by esterases yielding hydrophilic manganese(I) carbonyl compounds which are captured inside of cells. This objective is realized by using the bidentate bases 4-(acetoxymethoxycarbonyl)phenyl-bis(3,5-dimethylpyrazolyl)methane (1) and 4-(acetoxymethoxy)phenyl-bis(3,5-dimethylpyrazolyl)methane (4) at facial (OC)₃ MnBr fragments yielding CORM-AM1 (2) and CORM-AM2 (5), respectively. Besides synthesis, crystal structures and spectroscopic properties we present targeted administration and intracellular accumulation of these AM-containing CORMs.

Design, Synthesis, and Reactivity of Multidentate Ligands with Rhenium(I) and Rhenium(V) Cores

Synthetic pathways to a range of potentially N3O‐tetradentate ligands designed to coordinate to rhenium cores, as well as their coordination behaviors towards different rhenium cores (oxidation states +I and +V) are investigated. Two functionalized N‐{[1‐(4‐R)‐1H‐1,2,3‐triazol‐4‐yl]methyl}‐2‐(pyridin‐2‐ylmethoxy)aniline derivatives L1H (R = methyl acetate) and L2H (R = 4‐nitrophenyl) act exclusively as bidentate ligands and lead to the formation of mononuclear tricarbonylrhenium(I) complexes of the general formula [(LH)Re(CO)3Cl] with L = L1 or L2. Both complexes are characterized by 1H NMR and 13C NMR, FTIR spectroscopy, electrospray ionization mass spectrometry, and in the case of [(L2H)Re(CO)3Cl], single‐crystal X‐ray diffraction. The rhenium is coordinated by three carbonyl groups, a chlorine atom and two nitrogen atoms of a triazole group, and a nitrogen of the aniline ring of the ligand, respectively. A theoretical study shows complex [(L2H)Re(CO)3Cl] is the most stable structural isomer. In addition, the oxorhenium(V) complex [(L3)ReO] is isolated and fully characterized after the reaction of the ReV precursor [ReOCl3(PPh3)2] with L3H3 [methyl 2‐(4‐{[2‐(2‐hydroxyphenylamino)‐2‐oxoethylamino]methyl}‐1H‐1,2,3‐triazol‐1‐yl)acetate]. Its corresponding 99mTc complex was achieved with a good radiochemical yield (> 90 %). The convenient synthesis of this ligand, coupled with its high affinity for [ReO]3+ and [99mTcO]3+ cores, make it a promising chelator for biomedical applications.