TY - JOUR
T1 - Relative and absolute bond dissociation energies of sodium cation complexes determined using competitive collision-induced dissociation experiments
AU - Amicangelo, Jay C.
AU - Armentrout, P. B.
N1 - Funding Information:
Funding for this work was provided by the National Science Foundation under Grant CHE-9877162. The authors thank Kent Ervin and Vince DeTuri for providing us with the least squares minimization program and for valuable discussion concerning hindered rotors. J. A. thanks Rohana Liyanage, Hideya Koizumi, and Felician Muntean for enlightening discussion regarding this work.
PY - 2001/11/15
Y1 - 2001/11/15
N2 - Absolute L1Na+-L2 and relative Na+-L bond dissociation energies are determined experimentally by competitive collision-induced dissociation of L1Na+L2 complexes with xenon in a guided ion beam mass spectrometer. The ligands examined include H2O, C6H6, CH3OH, CH3OCH3, NH3, and C2H5OH, which cover a range in Na+ affinities of only 20 kJ/mol. Dissociation cross sections for formation of Na+L1 + L2 and Na+L2 + L1 are simultaneously analyzed with a model that uses statistical theory to predict the energy dependent branching ratio. The use of independent and common scaling factors for each channel in this analysis is evaluated and discussed, as is the importance of properly handling ligand internal rotors. The cross section thresholds thus determined are interpreted to yield the 0 K L1Na+-L2 bond dissociation energies and the relative 0 K Na+-L binding affinities. The relative binding affinities are converted to absolute 0 K Na+-L binding energies by using the absolute bond energy for Na+-NH3, determined previously in our laboratory, as an anchor value. Comparisons are made to previous experimental and theoretical Na+-L thermochemistry from several sources. The absolute L1Na+-L2 bond dissociation energies were also calculated using ab initio theory at the MP2(full)/6-311+G(2d, 2p)//MP2(full)/6-31G* level (corrected for zero-point energies and basis set superposition errors) and are in good agreement with the experimentally determined values.
AB - Absolute L1Na+-L2 and relative Na+-L bond dissociation energies are determined experimentally by competitive collision-induced dissociation of L1Na+L2 complexes with xenon in a guided ion beam mass spectrometer. The ligands examined include H2O, C6H6, CH3OH, CH3OCH3, NH3, and C2H5OH, which cover a range in Na+ affinities of only 20 kJ/mol. Dissociation cross sections for formation of Na+L1 + L2 and Na+L2 + L1 are simultaneously analyzed with a model that uses statistical theory to predict the energy dependent branching ratio. The use of independent and common scaling factors for each channel in this analysis is evaluated and discussed, as is the importance of properly handling ligand internal rotors. The cross section thresholds thus determined are interpreted to yield the 0 K L1Na+-L2 bond dissociation energies and the relative 0 K Na+-L binding affinities. The relative binding affinities are converted to absolute 0 K Na+-L binding energies by using the absolute bond energy for Na+-NH3, determined previously in our laboratory, as an anchor value. Comparisons are made to previous experimental and theoretical Na+-L thermochemistry from several sources. The absolute L1Na+-L2 bond dissociation energies were also calculated using ab initio theory at the MP2(full)/6-311+G(2d, 2p)//MP2(full)/6-31G* level (corrected for zero-point energies and basis set superposition errors) and are in good agreement with the experimentally determined values.
UR - http://www.scopus.com/inward/record.url?scp=0035891927&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035891927&partnerID=8YFLogxK
U2 - 10.1016/S1387-3806(01)00494-8
DO - 10.1016/S1387-3806(01)00494-8
M3 - Article
AN - SCOPUS:0035891927
VL - 212
SP - 301
EP - 325
JO - International Journal of Mass Spectrometry
JF - International Journal of Mass Spectrometry
SN - 1387-3806
IS - 1-3
ER -