Synthesis, spectroscopic, and electrochemical properties of rare earth double-deckers with tetra(tert-butyl)-2,3-naphthalocyaninato ligands

A series of rare earth(III) double-deckers RE[Nc(tBu)(4)](2) [RE = La, Ce, Pr, Nd, Eu, Gd, Tb, Y, Er; Nc(tBu)(4) = dianion of tetra(tert-butyl)-2,3-na phthalocyanine] (1-9) have been prepared by treating RE(acac)(3) . n H2O (a cac = acetylacetonate) with 6-tert-butylnaphthalonitrile in refluxing n-oct anol in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). These nov el sandwich-type complexes have been spectroscopically characterized. The e lectrochemical studies show that the first oxidation and the first reductio n potentials increase with the size of the central metal ions with a relati vely small separation (0.28-0.33 V), reflecting the narrow HOMO-LUMO gap.