Simplifying the Complex1H NMR Spectra of Fluorine-Substituted Benzamides by Spin System Filtering and Spin-State Selection: Multiple-Quantum−Single-Quantum Correlation

2008 ◽  
Vol 112 (42) ◽  
pp. 10526-10532 ◽  
Author(s):  
Bikash Baishya ◽  
G. N. Manjunatha Reddy ◽  
Uday Ramesh Prabhu ◽  
T. N. Guru Row ◽  
N. Suryaprakash
Keyword(s):  
Spin State ◽  
Spin System ◽  
Quantum Correlation ◽  
Nmr Spectra ◽  
Multiple Quantum ◽  
Single Quantum ◽  
Substituted Benzamides ◽  
State Selection

Gerüstumlagerungen bei einem Yliddiylphosphan-Tetrameren

1998 ◽  
Vol 53 (11) ◽  
pp. 1285-1293 ◽  
Author(s):  
Skeletal Rearrangements ◽  
Ylidediylphosphane Tetramer ◽  
Hans-Peter Schrödel ◽  
Alfred Schmidpeter ◽  
Heinrich Nöth
Keyword(s):  
Spin System ◽  
Nmr Spectra ◽  
Amino Group ◽  
Counter Ion ◽  
Singly Charged

Condensation of the bis(trimethylsilyl)ylide Ph3PC(SiMe3)2 with PX3 (X = Cl, Br) yields the ionic tetramers 4a,b of ylidediyl-halophosphanes. Their cations (Ph3PC)4P4X3+ possess a tetraphosphabicyclo[2.2.2]octane (or tetraphospha-barrelane) skeleton ([AC]3BD spin system in 31P NMR spectra). Reaction of 4a with AlCl3 or GaCl3 converts the singly charged cation into the tetracation (Ph3PC)4P44+ having a cubane structure ([AB]4 spin system in the 31P NMR spectum). SbCl5 oxidizes 4a to give the dication (Ph3PC)4P4Cl42+ (counter ion: SbCl52-) with the barrelane skeleton either preserved (7) or rearranged into a tetraphospha-bicylco[3.3.0]- octane structure 8. In the latter case the dication contains a central diphosphanedionium bridge. Replacement of a chloro-substituent in 4a by an amino group also gives rise to a further dissociation and a concomitant rearrangement. The resulting dications (Ph3PC)4P4NR2Cl2+ possess a tetraphospha-bicyclo-[3.2.1]octane structure (with eight nonequivalent phosphorus atoms).

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