TY - JOUR
T1 - Closed-shell molecules that ionize more readily than cesium
AU - Cotton, F. Albert
AU - Gruhn, Nadine E.
AU - Gu, Jiande
AU - Huang, Penglin
AU - Lichtenberger, Dennis L.
AU - Murillo, Carlos A.
AU - Van Dorn, Laura O.
AU - Wilkinson, Chad C.
PY - 2002/12/6
Y1 - 2002/12/6
N2 - We report a class of molecules with extremely low ionization enthalpies, one member of which has been determined to have a gas-phase ionization energy (onset, 3.51 electron volts) lower than that of the cesium atom (which has the lowest gas-phase ionization energy of the elements) or of any other known closed-shell molecule or neutral transient species reported. The molecules are dimetal complexes with the general formula M2(hpp)4 (where M is Cr, Mo, or W, and hpp is the anion of 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine), structurally characterized in the solid state, spectroscopically characterized in the gas phase, and modeled with theoretical computations. The low-energy ionization of each molecule corresponds to the removal of an electron from the delta bonding orbital of the quadruple metal-metal bond, and a strong interaction of this orbital with a filled orbital on the hpp ligands largely accounts for the low ionization energies.
AB - We report a class of molecules with extremely low ionization enthalpies, one member of which has been determined to have a gas-phase ionization energy (onset, 3.51 electron volts) lower than that of the cesium atom (which has the lowest gas-phase ionization energy of the elements) or of any other known closed-shell molecule or neutral transient species reported. The molecules are dimetal complexes with the general formula M2(hpp)4 (where M is Cr, Mo, or W, and hpp is the anion of 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine), structurally characterized in the solid state, spectroscopically characterized in the gas phase, and modeled with theoretical computations. The low-energy ionization of each molecule corresponds to the removal of an electron from the delta bonding orbital of the quadruple metal-metal bond, and a strong interaction of this orbital with a filled orbital on the hpp ligands largely accounts for the low ionization energies.
UR - https://www.scopus.com/pages/publications/2242466603
UR - https://www.scopus.com/pages/publications/2242466603#tab=citedBy
U2 - 10.1126/science.1078721
DO - 10.1126/science.1078721
M3 - Article
C2 - 12471252
AN - SCOPUS:2242466603
SN - 0036-8075
VL - 298
SP - 1971
EP - 1974
JO - Science
JF - Science
IS - 5600
ER -