Dinuclear complexes of di-, tri-, and mixed-valent samarium supported by the calix-tetrapyrrole ligand

SmCl3(THF)(3) reacts with 1/2 equiv of (Et-8-calix-pyrrole)[Li(THF)](4) to yield the dinuclear, trivalent complex (Et-8-calix-pyrrole)Sm-2{(mu-Cl)(2)[ Li(THF)(2)]}(2) (1). This; species undergoes alkylation in diethylether res ulting in the formation of the nearly isostructural (Et-8-calix-pyrrole)Sm- 2{mu-CH3)(2)[Li(THF)(2)]}(2) (2) Complex 1 is reduced by LiAlH4 to produce either the mixed-valence (Et-8-calix-pyrrole)Sm-2(THF)(2)(mu-Cl)(2) [Li(THF )(2)] (3) or the divalent (Et-8-calix-pyrrole)Sm-2(THF)(4) (4), depending o n the reaction conditions employed. The alkyl compound 2 reacts with PhSiH3 in THF, resulting in a complex mixture of products, from which a mixture o f the trivalent, mononuclear hydride (Et-8-calix-pyrrole)(THF)Sm(mu-H)Li-2[ LiOCH= CH2](2)(THF)(2) (5) and (Et-8-calix-pyrrole)Sm(H)Li-2(THF)(6) (6) we re isolated in modest yield. The structures of 1-5 were elucidated by X-ray crystallography.