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Computed coupling constants in X(CH 3 ) n H (4– n ) moieties where X = 13 C and 15 N + , and n = 0–4: comparisons with experimental data
Author(s) -
Jimeno MaríaLuisa,
Alkorta Ibon,
Elguero José,
Del Bene Janet E.
Publication year - 2006
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.1840
Subject(s) - chemistry , coupling constant , ab initio , ab initio quantum chemistry methods , coupling (piping) , spin (aerodynamics) , computational chemistry , ion , molecule , ammonium , atomic physics , crystallography , molecular physics , thermodynamics , physics , quantum mechanics , mechanical engineering , organic chemistry , engineering
Seventy‐three unique spin–spin coupling constants have been analyzed for the ten species in the two series X(CH 3 ) n H 4– n , where the central atom X is 13 C or 15 N + . Thirty‐seven experimental values have been obtained from the literature, and several new coupling constants have been measured for the methyl‐substituted ammonium ions. Both DFT with the B3LYP functional and ab initio EOM‐CCSD calculations have been carried out on these same systems. Coupling constants computed by these two methods are in agreement with experimental values. Some problems related to coupling constants for the cationic ammonium systems have been resolved when these were recomputed at EOM‐CCSD for complexes in which NH 4 + is hydrogen‐bonded to H 2 O molecules. Copyright © 2006 John Wiley & Sons, Ltd.