Roberto Menzel

Light-triggered NO release from a nanofibrous non-woven

Light-controlled NO delivery systems promise new applications in phototherapies. For this purpose, a ruthenium nitrosyl complex [(2)Ru(NO)(Cl)] with the novel ligand N,N′-(1,2-phenylene)bis(1-methyl-1H-imidazole-2-carboxamide) (2) has been synthesised and characterised in detail. The photoactive {Ru–NO}6 nitrosyl released NO in DMSO upon exposure to low-intensity UV-A light (λ = 366 nm). In order to create an applicable system the water-insoluble [(2)Ru(NO)(Cl)] was embedded into poly(L-lactide-co-D/L-lactide) nanofibrous non-wovens by electrospinning. Exposure of a 25 wt% non-woven of [(2)Ru(NO)(Cl)] to UV-A light resulted in a continuous release of NO into an aqueous solution. The cytoxicity of the non-woven against 3T3 mouse fibroblasts was very low.

Light-harvesting of polymerizable 4-hydroxy-1,3-thiazole monomers by energy transfer toward photoactive Os(II) metal complexes in linear polymers

A polymer library consisting of a series of three fluorescing monomers (i.e., blue, yellow and red-emitting) based on 4-hydroxy-1,3-thiazole chromophores as well as an Os(II) metal complex containing monomer was synthesized. These materials were characterized using 1H NMR spectroscopy, size-exclusion chromatography (SEC) as well as TGA and DSC measurements. The optical properties were investigated utilizing UV-vis absorption and emission measurements. The tailor-made optical properties of the monomer units facilitate energy transfer from the blue over the yellow and red chromophores to the photoactive Os(II) polypyridyl moiety. For this purpose, the energy transfer was monitored using excitation–emission correlation spectroscopy.

A Surprising Formation of Novel Bridged Bis-Benzimidazoles by Oxidation of Diaminoquinoxalines

A synthesis of novel hexacyclic bis-benzimidazoles 6 starting from 2,3-diarylamino-quinoxalines via an oxidative cyclization cascade is described. These very stable and high-melting derivatives are featured by their strong fluorescence in the blue region of the visible spectrum. The cyclization reaction between 2,3-dichloroquinoxaline and 1,2-phenylenediamine did not lead to derivatives of type 6. In this case, only fluoflavine 7 was isolated quantitatively. Graphical Abstract A Surprising Formation of Novel Bridged Bis-Benzimidazoles by Oxidation of Diaminoquinoxalines

Bis{4-[(3-phenyl­allyl­idene)amino]cyclo­hexyl}methane trichloro­methane solvate

The title compound, C31H38N2, was prepared from bis(4-aminocyclohexyl)methane and two equivalents of cinnamaldehyde. The cyclohexyl groups each show a chair conformation and the α,β-unsaturated imine side chains are all-trans configured. Two molecules of the title compound as well as two trichloromethane solvent molecules are present in the asymmetric unit. The solvent molecules interact with the diimines via weak C—H⋯N hydrogen bonds.