Abstract
Copper complexes of pyrazine (1,4-C 4H 4N 2), pyrimidine (1,3-C 4H 4N 2), and pyridazine (1,2-C 4H 4N 2) are produced in laser-vaporization supersonic molecular beams and studied by pulsed-field ionization zero electron kinetic energy (ZEKE) spectroscopy and second-order Møller-Plesset perturbation theory. Both σ and π complexes are considered by these ab initio calculations; only σ structures are identified in these experiments. Adiabatic ionization energies and metal-ligand vibrational frequencies of the σ complexes are measured from the ZEKE spectra. Metal-ligand bond dissociation energies of these complexes are obtained from a thermochemical cycle. The ionization energies follow the trend of Cu pyridazine (43 054 cm -1) < Cu pyrimidine (45 332 cm -1)<Cu pyrazine (46038 cm -1); the bond energies are in the order of Cu pyridazine (56.2 kJ mol -1) > Cu pyrazine (48.5 kJ mol -1) ∼Cu pyrimidine (46.4 kJ mol -1). The stronger binding of pyridazine is due to its larger electric dipole moment and possibly bidentate binding.
Original language | English |
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Article number | 014309 |
Journal | Journal of Chemical Physics |
Volume | 125 |
Issue number | 1 |
DOIs | |
State | Published - 2006 |
Bibliographical note
Funding Information:This work was supported by the Experimental Physical Chemistry Program of the National Science Foundation and the donors of the Petroleum Research Fund of the American Chemical Society.
ASJC Scopus subject areas
- General Physics and Astronomy
- Physical and Theoretical Chemistry