稀土酞菁配合物的XPS研究

XPS Study on Rare Earth Phthalocyanine Complexes

我们合成了稀土单酞菁配合物LnPcCl和LnPc(OAc)_2(Ln=Tb,Ho,Tm,Lu,Pc为酞菁根,OAc为乙酸根)。用XPS研究了它们的电子结构。结果指出,稀土酞菁配合物的化学键具有一定程度的共价性,其强度与电荷转移程度有关。L→Ln电荷转移不同于冠醚配合物,前者既有配位也含取代,后者纯系配位。且酞菁环系吸电子基团,电负性较高,故LnPc(OAc)_2中乙酸根的配位氧原子的Ols比Ln(OAc)_3的Ols结合能高。由于电荷转移程度与电负性、配位数等因素有关,LnPc(OAc)_2中Ln的配位数较高,LnPcCl中Cl的电负性较高,故LnPc(OAc)_2中Ln4d_(5/2)结合能低于LnPcCl。并讨论了配合物的分子组成及结构。

The rare earth monophthalocyanine complexes, LnPeCl and LnPc(OAc)_2 (Ln=Tb Ho, Tm, Lu, Pc= Phthalocyanine, OAc=Acetate), were synthesized. The electronic structures of the complexes have been studied by moans of XPS. The experimental rosults of binding energies for the complexes indicate that the bonds of the complexes have a certain covalent character depending on L→Ln charge transfer. This L→Ln charge transfor process of phthalocyanine complexes differs from that of crown ether complexes. Both coordination and substitution are included in the former case, but only coordination in the latter. Phthalocyanine ring is an electrophilie group and its clectronegativity is large. So, the O1s binding energies of coordinating oxygen atoms of acetate in LnPc (OAc)_2 are larger than those of Ln (OAc)_3. The magnitude of valent charge delocalized from ligand onto metal atom is dependent on electronegativity, coordination number, valence state and so on. Because coordination number of Ln in LnPo(OAc)_2 is larger than that in LnPcCl and electronegativity of Clin LnPcCl is larger than that of O in LnPc(OAc)_2, the Ln4d_(5/2) binding energies of LnPc (OAc)_2 are less than those of LnPcCl.