Theoretical evaluation of inter-ion and intra-ion isotope effects in fragmentation: insights into chlorine and bromine isotope effects of halogenated organic compounds occurring in electron ionization mass spectrometry

Abstract

A theoretical basis is proposed for elucidating the details and implications of chlorine and bromine isotope effects in dehalogenation reactions.

Design, quality and validation of the EU-OPENSCREEN fragment library poised to a high-throughput screening collection

“…We defined modification vectors as the number of hydrogens and aromatic halogen atoms contained in the fragment which could be substituted by a heavy atom with a single bond. Naturally, not all hydrogens and halogens can be easily modified by common synthetic routes to replace them with a heavy atom, so we practically rewarded those fragments possessing hydrogens attached to heteroatoms [O,N], aromatic chlorine or bromine (also useful for MS-driven screening 22 ) and number of fluorine atoms (for NMR-driven screening 23 ). Implicitly, this definition also smoothed the obvious tendency to reward larger fragments against smaller ones.…”