Diorganotin (IV) amino acid complexes as potential anticancer agents. Synthesis, structural characterization, and in vitro assays.

Nine new organotin (IV) derivatives from L-amino acids (l-lysine, L-ornithine, L-glutamic acid, and L-aspartic acid) were synthesized by one-pot ultrasound-assisted methodology. All compounds were characterized by ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared), LRMS (Low-Resolution Mass Spectrometry), and solution NMR (1H, 13C, 119Sn Nuclear Magnetic Resonance) spectroscopies. Complexes Bu2Sn(Lys) (1), Ph2Sn(Lys) (2), Bu2Sn(Orn) (3), and Ph2Sn (Glu-OMe) (6a) were crystallized, and the structures were established by single-crystal X-ray diffraction analysis. Diffraction results evidenced that complexes 1 to 3 were five-coordinated mononuclear species while the phenyl substituted derivative Ph2Sn (Glu-OMe) (6a) forms a polymeric network via Sn-O-Sn bridging whereby the tin atom is six-coordinated. In turn, 119Sn NMR results revealed that all tin complexes exist as mononuclear penta-coordinated species in solution. The tin derivatives were screened for ADME (Adsorption, Distribution, Metabolism, and Excretion) properties via the freely available tools SWISS ADME, and the results were analyzed hereafter. The antiproliferative activity of the complexes was tested against three human cancer cell lines: colorectal adenocarcinoma HT-29, breast adenocarcinoma MDA-MB-231, and chondrosarcoma SW-1353 using a non-tumoral cell line of human osteoblast as control, demonstrating selective inhibitory activities against cancer cells. Hence, these compounds could be a promising alternative to classical chemotherapy agents.

Halogen Bonding in Brominated BODIPY Crystals: a Crystallographic and Computational Study.

The study of halogen bonds (XBs) has been a subject of great interest in recent years due to its clear application in catalysis, liquid crystals, and crystal engineering. In this study, we analyzed the intermolecular interactions, in particular halogen bonds in BODIPYs with an increasing number of bromine atoms. The computational study included analyses through three different methods: the first approach of close contacts provided by mercury, then the expanded approach of the electron density partition of the molecules in the crystals provided by the analysis of Hirshfeld surfaces, and finally, the approach of the Quantum Theory of Atoms in Molecules (QT-AIM) to characterize the non-covalent interactions through finding electron density critical points between atoms and between neighboring molecules. The use of different computational methods allowed to gain insight into the interactions directing the crystal packing as the number of bromine atoms increased in the BODIPY moiety. Monocoordinated and bifurcated halogen bonds involving halide/halide were found. The penta-brominated BODIPY showed four-center cyclic nodes where each node is linked via XBs. This kind of motif can be useful in supramolecular chemistry and self-assembly.

Dibromo-BODIPY as an Organic Photocatalyst for Radical-Ionic Sequences.

A new dibrominated 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) is reported as a new metal-free photocatalyst. This BODIPY showed similar optoelectronic, electrochemical, and performance properties to those of Ru(bpy)3Cl2, one of the most common photocatalysts in a known radical-ionic transformation, such as the formation of 1,4-dicarbonyl compounds. Moreover, additional sequences in which the generated oxonium ion is trapped by an internal nucleophile were developed using this BODIPY photocatalyst. These new sequences allowed the straightforward preparation of γ-alkoxylactones, monoprotected 1,4-ketoaldehydes, and dihydrofurans. This new catalyst, the methodology, and the forged functional groups could be important tools in organic synthesis.