Abstract
Deuterium equilibrium isotope effects (EIE) for H2 and H-CH3 addition to Vaska-type complexes, transIr(PH3)2(CO)X (XM), have been determined using vibrational frequencies obtained from ab initio calculations on XM and on cis,trans-H2Ir(PH3)2(CO)X (XMH2). Inverse primary EIE values for H2/D2 addition to XM are computed to be 0.46 (X = Cl), 0.57 (X = CH3), and 0.33 (X = H; 0.66 after statistical normalization) at 300 K. The EIE values and the computed enthalpy and entropy terms are consistent with several experimental studies. Secondary thermodynamic deuterium isotope effects for H2 addition to XM are computed for X = H/D (α-EIE = 0.44; 0.88 after statistical normalization) and for X = CH3/CD3 (β-EIE = 0.86). Computations on the addition of CH4/CH3D or CH4/CD4 to HM reveal EIEs of 7.77 (1.94 per bond) and 3.64, respectively. These results are analyzed and discussed using equilibrium statistical mechanics.
| Original language | English |
|---|---|
| Pages (from-to) | 8019-8023 |
| Number of pages | 5 |
| Journal | Journal of the American Chemical Society |
| Volume | 115 |
| Issue number | 18 |
| Publication status | Published - Sep 8 1993 |
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Theoretical study of primary and secondary deuterium equilibrium isotope effects for H2 and CH4 addition to trans-Ir(PR3)2(CO)X. / Abu-Hasanayn, Faraj; Krogh-Jespersen, Karsten; Goldman, Alan S.
In: Journal of the American Chemical Society, Vol. 115, No. 18, 08.09.1993, p. 8019-8023.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Theoretical study of primary and secondary deuterium equilibrium isotope effects for H2 and CH4 addition to trans-Ir(PR3)2(CO)X
AU - Abu-Hasanayn, Faraj
AU - Krogh-Jespersen, Karsten
AU - Goldman, Alan S
PY - 1993/9/8
Y1 - 1993/9/8
N2 - Deuterium equilibrium isotope effects (EIE) for H2 and H-CH3 addition to Vaska-type complexes, transIr(PH3)2(CO)X (XM), have been determined using vibrational frequencies obtained from ab initio calculations on XM and on cis,trans-H2Ir(PH3)2(CO)X (XMH2). Inverse primary EIE values for H2/D2 addition to XM are computed to be 0.46 (X = Cl), 0.57 (X = CH3), and 0.33 (X = H; 0.66 after statistical normalization) at 300 K. The EIE values and the computed enthalpy and entropy terms are consistent with several experimental studies. Secondary thermodynamic deuterium isotope effects for H2 addition to XM are computed for X = H/D (α-EIE = 0.44; 0.88 after statistical normalization) and for X = CH3/CD3 (β-EIE = 0.86). Computations on the addition of CH4/CH3D or CH4/CD4 to HM reveal EIEs of 7.77 (1.94 per bond) and 3.64, respectively. These results are analyzed and discussed using equilibrium statistical mechanics.
AB - Deuterium equilibrium isotope effects (EIE) for H2 and H-CH3 addition to Vaska-type complexes, transIr(PH3)2(CO)X (XM), have been determined using vibrational frequencies obtained from ab initio calculations on XM and on cis,trans-H2Ir(PH3)2(CO)X (XMH2). Inverse primary EIE values for H2/D2 addition to XM are computed to be 0.46 (X = Cl), 0.57 (X = CH3), and 0.33 (X = H; 0.66 after statistical normalization) at 300 K. The EIE values and the computed enthalpy and entropy terms are consistent with several experimental studies. Secondary thermodynamic deuterium isotope effects for H2 addition to XM are computed for X = H/D (α-EIE = 0.44; 0.88 after statistical normalization) and for X = CH3/CD3 (β-EIE = 0.86). Computations on the addition of CH4/CH3D or CH4/CD4 to HM reveal EIEs of 7.77 (1.94 per bond) and 3.64, respectively. These results are analyzed and discussed using equilibrium statistical mechanics.
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M3 - Article
VL - 115
SP - 8019
EP - 8023
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 18
ER -