High spin iron(ii) complexes based on imidazolyl- and 1,2,3-triazolyl-thione ligands and NCE (E = S, Se or BH₃) co-ligands: effect of the S-functional group on the structural and magnetic properties

Abstract

To study the effect of the thione functional group embedded in two different types of heterocycles, imidazolyl and 1,2,3-triazolyl, on the magnetic properties of iron(II) octahedral complexes, two bidentate thione-containing...

Enantioselective Imine Reduction of Dihydro-β-carbolines by Fe-Thiosquaramide Catalyst

“…Online reaction monitoring by ESI-MS gave a very clean spectrum displaying two Fe-containing cationic species, which were easily identified by their isotopic pattern, as well as the ions [ 1c + H] + ( m / z 213) and the proton-bound dimer of 1c ( m / z 425) (Figure A). When NaCNBH 3 was added into the reaction flask followed by online ESI-MS monitoring (Figure B), a new intermediate species [ 5a + Na] + and product 2c ( m / z 215) were identified and characterized by MS/MS experiments (Figure B). Furthermore, formation of NaCNBH 3 cluster 6 (n = 4–12) was also observed in the DCE reaction media.…”

“…Furthermore, formation of NaCNBH 3 cluster 6 (n = 4–12) was also observed in the DCE reaction media. Species 6 might explain why imines 1 were not concomitantly reduced by free borohydride in a non Fe-catalytic manner, which would afford racemic amines and decreasing ee, but in fact 6 might be acting as a hydride source for formation of active Fe-complex intermediate 5 …”