ISSN:
0749-1581
Keywords:
1H NMR
;
1H spin-lattice relaxation
;
Nitramines
;
Inclusion complexes
;
Cyclodextrins
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Inclusion complex formation between the explosive molecules of the nitramine type, RDX, HMX and TNAZ, and cyclodextrins (α, β and γ) was studied in aqueous solution by means of 1H spin-lattice relaxation time (T1) measurements. The results show that nitramines bind to cyclodextrins in solution; RDX and HMX bind most strongly to γ-cyclodextrin whereas TNAZ binds most strongly to β-cyclodextrin. The dynamic coupling coefficient and dissociation constant were determined for the complex of TNAZ with β-cyclodextrin. The values obtained suggest that TNAZ forms a relatively weak complex with β-cyclodextrin (Kd = 1.8 × 10-2 M) that displays considerable motion in the complex with respect to cyclodextrin (coupling coefficient = 0.23). This method of using 1H T1 measurements for characterizing complex formation in solution, while limited to guest molecules containing a pair of protons having a fixed internuclear distance, is shown to be useful when complexation-induced chemical shifts are too small to be significant.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260310808
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