Heterobimetallic complexes based on bis(hexafluoroacetylacetonato)magnesium or bis(hexafluoroacetylacetonato)barium and N,N '-bis(salicylidene)ethylenediiminonickel(II)

Two new heterobimetallic complexes [Ba(hfa)(2)(NiSalen)(2)] (I) and [Mg(hfa )(2)(NiSalen)] (II) were prepared by reacting bis(hexafluoroacetylacetonato )magnesium (Mg(hfa)(2)) or bis(hexafluoroacetylacetonato)barium (Ba(hfa)(2) ) with NiSalen (H(2)Salen is the Schiff base obtained from salicylaldehyde and ethylenediamine). The composition of complexes I and II was confirmed b y elemental analysis and X-ray powder diffraction. The crystal structure of complex I was determined by X-ray crystallography: space group P (1) over bar, a = 11.783(4) Angstrom, b = 14.626(4) Angstrom, c = 15.693(5) Angstrom , alpha = 81.93(3)degrees, beta = 69.13(3)degrees, gamma = 66.57(2)degrees, Z = 2, R-1 = 0.0484. The NiSalen molecules enter into the coordination sph ere of the central barium ion as ancillary donor ligands to form monomeric complex molecules. The composition of the gas phase over solid complexes I and II and initial magnesium and barium hexafluoroacetylacetonates was stud ied by mass spectrometry. Upon heating in a vacuum, the heterobimetallic co mplexes decompose into their constituent beta -diketonates and NiSalen. The rmodynamic characteristics of the decomposition processes were determined.