Recent Developments in Radical Photoinitiator Chemistry

Radiation curing is an established technology used in many industrial manufacturing processes. New applications and technical specifications stimulate the continuous development of tailor-made photoinitiators which can efficiently meet specific requirements. A new class of radical photoinitiators, bisacylphosphine oxides (BAPO), give four initiating radicals per photoinitiator molecule and undergo photo-bleaching of the low-energy absorption band. These features make the compounds highly efficient for radiation curing of highly opaque white pigmented systems, thick coatings, or fiber-reinforced formulations

Light-based 3D printing of functional polydimethylsiloxane- based microfluidic chips

The objective of the work is to fabricate and functionalize 3D printed PDMS-based microfluidic chips through digital light processing DLP-3D printing

Synthesis, structural characterization, antimicrobial and cytotoxic effects of aziridine, 2-aminoethylaziridine and azirine complexes of copper(II) and palladium(II).

The synthesis, spectroscopic and X-ray structural characterization of copper(II) and palladium(II) complexes with aziridine ligands as 2-dimethylaziridine HNCH2CMe2 (a), the bidentate N-(2-aminoethyl)aziridines C2H4NC2H4NH2 (b) or CH2CMe2NCH2CMe2NH2 (c) as well as the unsaturated azirine NCH2CPh (d) are reported. Cleavage of the cyclometallated Pd(II) dimer [μ-Cl(C6H4CHMeNMe2-C,N)Pd]2 with ligand a yielded compound [Cl(NHCH2CMe2)(C6H4CHMe2NMe2-C,N)Pd] (1a). The reaction of the aziridine complex trans-[Cl2Pd(HNC2H4)2] with an excess of aziridine in the presence of AgOTf gave the ionic chelate complex trans-[(C2H4NC2H4NH2-N,N′)2Pd](OTf)2 (2b) which contains the new ligand b formed by an unexpected insertion and ring opening reaction of two aziridines (“aziridine dimerization”). CuCl2 reacted in pure HNC2H4 or HNCH2CMe2 (b) again by “dimerization” to give the tris-chelated ionic complex [Cu(C2H4NC2H4NH2-N,N′)3]Cl2 (3b) or the bis-chelated complex [CuCl(C2H2Me2NC2H2Me2NH2-N,N′)2]Cl (4c). By addition of 2H-3-phenylazirine (d) to PdCl2, trans-[Cl2Pd(NCH2CPh)2] (5d) was formed. All new compounds were characterized by NMR, IR and mass spectra and also by X-ray structure analyses (except 3b). Additionally the cytotoxic effects of these complexes were examined on HL-60 and NALM-6 human leukemia cells and melanoma WM-115 cells. The antimicrobial activity was also determined. The growth of Gram-positive bacterial strains (S. aureus, S. epidermidis, E. faecalis) was inhibited by almost all tested complexes at the concentrations of 37.5–300.0 μg mL−1. However, MIC values of complexes obtained for Gram-negative E. coli and P. aeruginosa, as well as for C. albicans yeast, mostly exceeded 300 μg mL−1. The highest antibacterial activity was achieved by complexes 1a and 2b. Complex 2b also inhibited the growth of Gram-negative bacteria. Graphical abstract: Synthesis, structural characterization, antimicrobial and cytotoxic effects of aziridine, 2-aminoethylaziridine and azirine complexes of copper(ii) and palladium(ii

Photochemisch induzierte Reaktionen von 3-Amino-2H-azirinen

Photochemically Induced Reactions of 3-Amino-2H-azirines. Irradiation of 3-(N-methylanilino)-2H-azirines with a mercury low pressure lamp induces the cleavage of the C(2),C (3)-ring bond thus affording nitrilio- methanide dipols, substituted by an amino group at C(1). Depending on the substitution pattern at C(3), these intermediates can be trapped by dipolarophiles to yield five-membered heterocycles with high regioselectivity, or they undergo a 1,4-H-shift forming 2-azabutadiene derivatives. Further, the dipol is protonated at C (1) even by weak CH-acids