Lorenz Michael Reith

Synthesis and Characterization of a Stable Bismuth(III) A3–Corrole

An efficient metalation procedure for bismuth complexes with meso-substituted corrole ligands is presented. Reaction of 5,10,15-tris-pentafluorophenylcorrole H(3)(TpFPC) with Bi{N(SiMe(3))(3)} converts the free ligand H(3)(TpFPC) to a neutral low-valent species Bi(TpFPC), which has been characterized by different spectroscopic techniques. (Spectro)electrochemical studies were performed in order to describe the redox potentials of the Bi(TpFPC) complex and to ascribe the sites of electron transfer. The first crystal structure of a bismuth corrole is presented and compared to the geometry-optimized molecular structure obtained with density functional theory (DFT) calculations. We show an example of a 4-coordinate metallocorrole with a very large out-of-plane displacement and significant doming. The electronic structure of the novel bismuth corrole system is discussed in detail. Time-dependent DFT results support the proposed assignment of electronic transitions observed for the Bi(TpFPC) derivative. To account for the reactivity we investigated the photocatalytic properties of the Bi(TpFPC) complex.

Spectroscopic STM Studies of Single Gold(III) Porphyrin Molecules

Low-temperature scanning tunneling microscopy, a well-established technique for single-molecule investigations in an ultrahigh vacuum environment, has been used to study the electronic properties of Au(III) 5,10,15,20-tetraphenylporphyrin (AuTPP) molecules on Au(111) at the submolecular scale. AuTPP serves as a model system for chemotherapeutically relevant Au(III) porphyrins. For the first time, real-space images and local scanning tunneling spectroscopy data of the frontier molecular orbitals of AuTPP are presented. A comparison with results from density functional theory reveals significant deviations from gas-phase behavior due to a non-negligible molecule/substrate interaction. We identify the oxidation state of the central metal ion in the adsorbed AuTPP as Au(3+).

Asymmetrically substituted cationic indole- and fluorene porphyrins inhibit tumor proliferation in small intestinal neuroendocrine tumors and medullary thyroid carcinomas.

In this study we demonstrate anticancer activity of novel fully water soluble cationic porphyrins. The two cationic porphyrins 5,10,15-tris(N-methylpyridinium-4-yl)-20-[1-phenyl-4-(3-N-phenylsulfonylindolyl)]-21H,23H-porphyrin chloride (TMPy(3)PhenIndolprot(1)P-Cl(3)) and 5-{5-[2-(9,9-Dimethyl)fluorenyl]-N-methylpyridinium-3-yl}-10,15,20-tris(N-methyl-pyridinium-4-yl)-21H,23H-porphyrin chloride (TMPy(3)PyFluorenyl(1)P-Cl(4)) were prepared and their antiproliferative effects were studied in two human tumor cell lines and a normal human fibroblast cell line. Effects of the novel porphyrin compounds were evaluated in the small intestinal neuroendocrine tumor cell line KRJ-I, the medullary thyroid carcinoma cell line MTC-SK and the normal human fibroblast cell line HF-SAR by cell counting, cell proliferation assays and cell cytotoxicity analyses. TMPy(3)PhenIndolprot(1)P-Cl(3) and TMPy(3)PyFluorenyl(1)P-Cl(4) showed antiproliferative effects in the tumor cell lines MTC-SK and KRJ-I; cell viability was decreased and cytotoxic effects were quantified, while no significant alterations of the human fibroblasts were noted. With the advantage of full water solubility and antiproliferative effects in tumor cell lines, the novel porphyrin compounds TMPy(3)PhenIndolprot(1)P-Cl(3) and TMPy(3)PyFluorenyl(1)P-Cl(4) could be a new therapeutic option in anticancer treatment.

A water soluble tri-cationic porphyrin–EDTA conjugate induces apoptosis in human neuroendocrine tumor cell lines

Graphical abstract Highlights ► Synthesis of tri-cationic porphyrin–EDTA conjugate (TMPy3PhenEDTA-P-Cl4). ► Treatment of small-intestinal neuroendocrine tumor cells with TMPy3PhenEDTA-P-Cl4. ► Treatment of medullary thyroid carcinoma cell lines with TMPy3PhenEDTA-P-Cl4. ► Apoptotic cell death on MTC cells after treatment with TMPy3PhenEDTA-P-Cl4.

The evolution of corrole synthesis — from simple one-pot strategies to sophisticated ABC-corroles

This review highlights synthesis procedures to obtain A3-, cis- and trans- A2B- and ABC-corroles. Synthesis methods from the early beginning of “corrole chemistry”, acid-catalyzed condensation methods of various building blocks (pyrrole, aldehyde, dipyrromethane, dipyrromethane-carbinol, and dipyrromethane-dicarbinol etc.), possible side reaction during Bronsted acid catalyzed reactions (scrambling), one-pot synthesis of corroles, and post-macrocyclization modification reactions of meso-substituted A3-corroles are discussed.

Tight binding of transition-state analogues to a peptidyl-aminoacyl-L/D-isomerase from frog skin.

d-Amino acids in peptide linkage are a noteworthy exception from the universal homochirality of proteins and peptides.[1] The first animal peptide that was found to contain a d-amino acid as the second residue was dermorphin, isolated from the skin of a South American tree frog.[2] This peptide binds with high affinity to μ-opiate receptors. The d-residue in this and related amphibian opioid peptides is essential for the biological function, whereas the all-L-isomers lack activity.

Determination of 3J(1H3′31P) couplings in a DNA oligomer with enhanced sensitivity employing a constant‐time TOCSY difference experiment

A constant‐time TOCSY difference experiment for the determination of 3J(1H3′31P) coupling constants in non‐isotope‐labelled DNA oligonucleotides is presented. The method is tested on a DNA octamer and compared with the established constant‐time NOESY difference method. Each 3J(1H3′31P) coupling constant is determined from amplitude changes caused by phosphorous decoupling, which are observable on multiple cross‐peaks, thus leading to a high accuracy of the value of the 3J(1H3′31P) coupling constant. The new experiment delivers up to three times the sensitivity compared with previously reported methods. Copyright