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Bulletin of the Korean Chemical Society (BKCS)

ISSN 0253-2964(Print)
ISSN 1229-5949(Online)
Volume 26, Number 11
BKCSDE 26(11)
November 20, 2005 

 
Title
Potential Energy Curves and Geometrical Structure Variations for ([MX4]2- : M=Ni(II), Pd(II), Pt(II); X=Cl-, Br-) Dissociating into ([MX3]- + X-) : Ab Initio Study
Author
Jong Keun Park*, Bong Gon Kim, In Sun Koo
Keywords
Potential energy curve, Geometrical structure, Dissociation reaction, Atomic charge, Density functional theory
Abstract
Potential energy curves and internuclear (M-X) distance variations for dissociation reactions of [MX4]2- into ([MX3]- + X-) have been calculated using ab initio Hartree-Fock (HF), second order Moller-Plesset perturbation (MP2), and Density Functional Theory (DFT) methods with a triple zeta plus polarization (TZP) basis set. The equilibrium geometrical structures of [MX4]2- are optimized to tetrahedral geometry for [NiX4]2- and square planar geometry for ([PdX4]2- and [PtX4]2-). The bond (M-X) distances of [NiCl4]2-, [NiBr4]2-, [PdCl4]2-, [PdBr4]2-, [PtCl4]2-, and [PtBr4]2- at the DFT level are 2.258, 2.332, 2.351, 2.476, 2.367, and 2.493 A, respectively. The dissociation energies for the bond dissociation of ([MX3]-…X-) at the DFT level are found to be 4.73 eV for [NiCl4]2-, 4.89 eV for [NiBr4]2-, 4.93 eV for [PdCl4]2-, 5.57 eV for [PdBr4]2-, 5.44 eV for [PtCl4]2-, and 5.87 eV for [PtBr4]2-. As the (M…X) distance of ([MX3]-X-) increases, the distance variation (Rt) of trans (M-X) bond at the trans-position is shorter than those (Rc) of two cis (M-X) bonds at the cisposition. Simultaneously the atomic charge variation of trans-X atom is more positive than those of equilibrium [MX4]2- structures, while the variation of leaving X group is more positive.
Page
1795 - 1802
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