Organothallium compounds. IV. Carboxylatobis(pentafluorophenyl)thallium(III) compounds and their complexes with 1,10-phenanthroline and 2,3'-bipyridyl

Abstract

Carboxylatobis(pentafluorophenyl)thallium(III) compounds, Tl(OCOR)(C₆F₅)₂ (R = Ph, Me, or C₆F₅), have been prepared by a metathesis reaction between bromobis(pentafluorophenyl)thallium(III) and the appropriate sodium or ammonium carboxylate in aqueous ethanol. They are considered to have dimeric structures with bridging carboxylate groups. With 1,10- phenanthroline (phen), the complexes Tl(OCOR)(C₆F₅)₂ phen, which are monomeric in benzene and acetone, are obtained. The complexes, Tl(OCOR)(C6F6)2 bipy (bipy = 2,2'-bipyridyl; R = Ph or Me) can be prepared only by using excess ligand. They decompose to Tl(OCOR)(C₆F₅)₂ compounds on attempted recrystallization, partly dissociate into Tl(OCOR)(C₆F₅)₂ and bipyridyl in benzene and acetone, and undergo ligand exchange with 1,10-phenanthroline to give Tl(OCOR)(C₆F₅)₂ phen complexes. By contrast, Tl(OCOC₆F₅)-(C₆F₅)₂ bipy has been prepared without using excess ligand and can be recrystallized unchanged. It is monomeric in benzene, but dissociates slightly in acetone. The complexes, Tl(OCOR)(C₆F₅)₂(phen or bipy), are considered to contain five-coordinate thallium.