Diastereoselective fragmentation of chiral α-aminophosphonic acids/metal ion aggregates

✍ Scribed by Antonello Filippi; Maurizio Speranza; Alessandra Paladini; Roberta De Carolis; Anna Giardini Guidoni; Aldo Laganà; Mauro Satta

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 163 KB
• Volume: 41
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/jms.970

✦ Synopsis

Abstract

Diastereomeric clusters of general formula [MAB~2~]^+^ and [MA~2~B]^+^ (M = Li(I), Na(I), Ag(I), Ni(II)‐H, or Cu(II)‐H; A = (R)‐(−)‐ and (S)‐(+)‐(1‐aminopropyl)phosphonic acid; B = (1__R__)‐(−)‐ and (1__S__)‐(+)‐(1‐aminohexyl)phosphonic acid) have been readily generated in the electrospray ionization (ESI) source of a triple‐quadrupole mass spectrometer and their collision‐induced dissociation (CID) investigated. CID of diastereomeric complexes, e.g. [MA~S~(B~S~)~2~]^+^ and [MA~R~(B~S~)~2~]^+^, leads to fragmentation patterns characterized by R~homo~ = [MA~S~B~S~]^+^/[M(B~S~)~2~]^+^ and R~hetero~ = [MA~R~B~S~]^+^/[M(B~S~)~2~]^+^ abundance ratios, which depend upon the relative stability of the diastereomeric [MA~S~B~S~]^+^ and [MA~R~B~S~]^+^ complexes in the gas phase. The chiral resolution factor R~chiral~ = R~homo~/R~hetero~ is found to depend not only on the nature of the M ion but also on that of the fragmenting species, whether [MAB~2~]^+^ or [MA~2~B]^+^. The origin of this behavior is discussed. Copyright © 2005 John Wiley & Sons, Ltd.