Charge distributions in multiple-decker sandwich clusters of lanthanide-cyclooctatetraene: Application of Na-atom doping

In gas phase, Na-atom adducts were produced for organometallic lanthanide c omplexes of Ln(n)(C8H8)(n+1) [Ln = europium (Eu) and holmium (Ho); C8H8 = 1 ,3,5,7-cyclooctatetraene (COT)] by a combination of two-laser vaporization and a molecular beam method. The number of attached Na atoms can be reasona bly explained by charge distributions of the complex, where Eu and Ho atoms exist as Eu2+ and Ho3+, respectively, and C8H8 molecules as COT2-, accepti ng two excess electrons. The behavior of the Na adducts chemically demonstr ates that the organometallic lanthanide complex is formed through ionic bon ding implying that it is possible to be isolated as its Na salt. (C) 1999 E lsevier Science B.V. All rights reserved.