Mass spectrometric study of the overheated vapor over Ni(II), Cu(II), and Zn(II) N,N'-ethylenebis(acetylacetoniminato) complexes

A mass spectrometric study of the overheated vapor over the complexes Ni(acacen), Cu(acacen), and Zn(acacen) (H(2)acacen = N,N'-ethylenebis(acetylacetonimine)) has been carried out in the temperature range of 180-760A degrees C. Irrespective of the degree of overheating, the vapor phases over all of these compounds contain no ions heavier than the molecular ion [MO(2)N(2)C(12)H(18)](+). The existence of molecular ions in the overheated vapor in the double-chamber two-temperature effusion cell is evidence of the high thermal stability of the complexes. The onset temperature of the thermal decomposition of Ni(acacen), Cu(acacen), and Zn(acacen) is 690, 610, and 560A degrees C, respectively. The way of fragmentation of the chelates under electron impact ionization depends on the nature of the metal.