Biomimetic Reagents for the Selective Free Radical and Acid–Base Chemistry of Glycans: Application to Glycan Structure Determination by Mass Spectrometry

2013 ◽  
Vol 135 (29) ◽  
pp. 10684-10692 ◽  
Author(s):  
Jinshan Gao ◽  
Daniel A. Thomas ◽  
Chang Ho Sohn ◽  
J. L. Beauchamp
Keyword(s):  
Mass Spectrometry ◽  
Free Radical ◽  
Structure Determination ◽  
Glycan Structure ◽  
Acid Base

Syntheses, Spectroscopy And Crystal Structures Of (R)-N-(1-Aryl-Ethyl)Salicylaldimines And [Rh{(R)-N-(1-Aryl-Ethyl)Salicylaldiminato}(η4-Cod)] Complexes

2007 ◽  
Vol 62 (6) ◽  
pp. 807-817 ◽  
Author(s):  
Mohammed Enamullah ◽  
A.K.M. Royhan Uddin ◽  
Anne-Christine Chamayou ◽  
Christoph Janiak
Keyword(s):  
Mass Spectrometry ◽  
Schiff Base ◽  
Schiff Bases ◽  
Structure Determination ◽  
Chelate Ring ◽  
Optical Rotation ◽  
X Ray ◽  
Mononuclear Complexes ◽  
Chiral Schiff Base ◽  
C Nmr

Condensation of salicylaldehyde with enantiopure (R)-(1-aryl-ethyl)amines yields the enantiopure Schiff bases (R)-N-(1-aryl-ethyl)salicylaldimine (HSB*; aryl = phenyl, 2-methoxyphenyl, 3- methoxyphenyl, 4-methoxyphenyl (4), 4-bromophenyl (5), 2-naphthyl). These Schiff bases readily react with dinuclear (acetato)(η4-cycloocta-1,5-diene)rhodium(I), [Rh(μ-O2CMe)(η4-cod)]2, to afford the mononuclear complexes, cyclooctadiene-((R)-N-(1-aryl-ethyl)salicylaldiminato-κ2N,O)- rhodium(I), [Rh(SB∗)(η4-cod)] (SB* = deprotonated chiral Schiff base = salicylaldiminate; aryl = phenyl (7), 2-methoxyphenyl, 4-methoxyphenyl, 4-bromophenyl, 2-naphthyl). The complexes have been characterized by IR, UV/vis, 1H/13C NMR and mass spectrometry, optical rotation as well as by single-crystal X-ray structure determination for 4, 5 and 7. The structure of 5 shows C-Br· · ·π contacts. Compound 7 is only the second example of a Rh(η4-cod) complex with a six-membered Rh-N,O-chelate ring

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