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14 N nuclear quadrupole resonance study of the protonation of thiourea
Author(s) -
Murgich Juan,
Magaly Santana R.,
Abanero Jose A.
Publication year - 1987
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260250206
Subject(s) - chemistry , protonation , thiourea , nuclear quadrupole resonance , hydrogen bond , perchloric acid , hexamethylenetetramine , crystallography , inorganic chemistry , molecule , nuclear magnetic resonance , organic chemistry , ion , physics
Abstract 14 N NQR frequencies of thiourea complexes with HCIO 4 , HCI and H 2 SO 4 obtained at 77 K are reported. Comparison of NQR data previously obtained in hexamethylenetetramine‐2thiourea showed that the perchloric acid complex was a hydrogen‐bonded complex. A similar comparison with uronium salts showed that the other complexes were thiouronium salts. The protonation site in thiouronium salts was shown to be the S atom. S protonation produced decreases of the N non‐bonding orbital occupation number and increases in those of the NN and NC sigma bonds. Changes in the N non‐bonding orbital produced by protonation were larger in thiourea than in urea.