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Investigation of the Self‐Assembly Pathway of Pentanuclear Helicates by Electrospray Mass Spectrometry
Author(s) -
MarquisRigault Annie,
DupontGervais Annick,
Van Dorsselaer Alain,
Lehn JeanMarie
Publication year - 1996
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.19960021111
Subject(s) - electrospray mass spectrometry , chemistry , mass spectrometry , steric effects , electrospray , ion , crystallography , stereochemistry , chromatography , organic chemistry
The self‐assembly of the pentanuclear double helicates Hh, Ha and He from the corresponding oligobipyridine strands Lh, La and Le and Cu 1 ions has been investigated by NMR and electrospray mass spectrometry (ESMS). Where as Hh is assembled rapidly (in less than 20 min), He (about 20 h) and especially Ha (about 60 h) form much more slowly. The rate decreases strongly with increasing steric bulk of the substituents in the 4,4′‐positions on the bipyridine units; this indicates that the search processes (wrapping, unwrapping) that lead to the final helicate are strongly hindered by the size of the substituents. The ESMS data give information about the species present in solution under different conditions and allow the formulation of possible formation pathways, which may involve, in particular, helicates of hairpin type.