6377-82-8Relevant articles and documents
13C CP MAS NMR, FTIR, X-ray diffraction and PM3 studies of some N-(ω-carboxyalkyl)morpholine hydrohalides
Dega-Szafran,Ga?szczyk,Maciejewska,Szafran,Tykarska,Wawer
, p. 261 - 273 (2007/10/03)
N-(ω-carboxyalkyl)morpholine hydrochlorides, OC4H8N(CH2)nCOOH·HCI, n = 1-5, were obtained and analyzed by 13C cross polarization (CP) magic angle spinning (MAS) NMR, FTIR and PM3 calculations. The structure of N-(3-carboxy-propyl)morpholine hydrochloride (n = 3) has been solved by X-ray diffraction method at 100 K and refined to the R = 0.031. The crystals are monoclinic, space group P21/c, a = 14.307(3), b = 9.879(2), c = 7.166(1) A?, β = 93.20(3)°, V = 1011.3(3) A?3, Z = 4. In this compound the nitrogen atom is protonated and two molecules form a centrosymmetric dimer, connected by two N+-H···Cl- (3.095(1) A?) and two O-H···Cl- (3.003(1) A?) hydrogen bonds. 13C CP MAS NMR spectra, contrary to the solution, showed non-equivalence of the ring carbon atoms. The PM3 calculations predict a molecular dimer without proton transfer for an HCl complex, while for an HBr complex an ion pairs with proton transfer, and reproduces correctly the conformation of both dimers but overestimates H-bond distances. Shielding constants calculated from the PM3 geometry of ion pairs gave a linear correlation with the 13C chemical shifts in solids.
TRIMETHYLSILYL ω-(DIORGANOAMINO)ALKANOATES
Voronkov, M. G.,Vvedenskii, V. Yu.
, p. 1266 - 1267 (2007/10/02)
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