			15min:

ZEKE SPECTROSCOPY OF METAL COMPLEXES WITH A MULTIDENTATE LIGAND: M(H₂NCH₂CH₂NH₂) (M = Al, Ga, In).

SHENGGANG LI, JASON F. FULLER, PARAGRANJITA BHOWMIK, XU WANG, BRADFORD R. SOHNLEIN AND DONG-SHENG YANG, Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055.

Metal coordination to an ethylenediamine ligand may form a chain-like or a cyclic structure. The complex is expected to be a chain if the metal atom is bound to a single nitrogen atom or a five-member ring if the metal is attached to both nitrogen atoms. ZEKE (zero-electron-kinetic-energy) spectra show that M(H₂NCH₂CH₂NH₂) and M⁺(H₂NCH₂CH₂NH₂) (M = Al, Ga, In) complexes have a cyclic conformation. These cyclic complexes have significantly lower adiabatic ionization potentials (AIPs) and metal-nitrogen stretching frequencies than simple metal-primary amines. For example, the AIP of Ga(H₂NCH₂CH₂NH₂) was determined to be 33322 cm^-1, 6008 cm^-1 less than that of Ga(H₂NCH₃). The Ga⁺-N stretching frequency was measured to be 204 cm^-1 in gallium-ethylenediamine and 299 cm^-1 in gallium-methylamine.