ELECTROSPRAY MASS-SPECTROMETRY OF HIGHLY MOISTURE-SENSITIVE METAL ALKOXIDES

Electrospray mass spectra of the metal alkoxides Zr(OEt)(4), Ti(OEt)(4 ), Al(OEt)(3) and Si(OEt)(4) and of Zr(OEt)(4) after reaction with che lating agents have been recorded in dry ethanol. By adding sodium etho xide to enhance the formation of ions, well resolved. isotope patterns were obtained for each major peak, allowing identification of species . The dominant ions detected in the spectra of Zr(OEt)(4) were [Zr-n(O Et)(4n+1)](-) (n = 1-5). Minimal fragmentation was observed at low con e voltages, and the molecular complexity n of the dominant species agr eed with the previously established polymeric nature of the alkoxides. Fragmentation of the polymeric Ti and Zr species at high cone voltage s occurred by loss of neutral Ti(OEt)(4) and Zr(OEt)(4). Complexation of Zr(OEt)(4) with acetylacetone [CH3COCH2COCH3] (Hacac) yields the mo nomeric ions [Zr(OEt)(4-n)(acac)(n)](-) (n = 1-3) as the dominant spec ies. Hydrolysis and condensation products were observed for 3-sulfanyl propyltrimethoxysilane [HS(CH2)(3)Si(OC2H5)(3)] reacted with water. Th e reaction of Zr(OEt)(4) with 3-sulfanylpropyltrimethoxysilane resulte d in the detection of zirconium alkoxide-silane complexes containing Z r-O-Si links. ESMS is applicable to the study of transition-metal alko xide compounds and solution species formed in reactions of these with chelating ligands. The results reveal further opportunities for develo pment of metal alkoxide chemistry.