Dinuclear Complexes of Di-, Tri-, and Mixed-Valent Samarium Supported by the Calix-tetrapyrrole Ligand

SmCl 3 (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 {(μ-Cl) 2 [Li(THF) 2 ]} 2 ( 1 ). This species undergoes alkylation in diethyl ether resulting in the formation of the nearly isostructural (Et 8 -calix-pyrrole)Sm 2 {(μ-CH 3 ) 2 [Li(THF) 2 ]} 2 ( 2 ) Complex 1 is reduced by LiAlH 4 to produce either the mixed-valence (Et 8 -calix-pyrrole)Sm 2 (THF) 2 (μ-Cl) 2 [Li(THF) 2 ] ( 3 ) or the divalent (Et 8 -calix-pyrrole)Sm 2 (THF) 4 ( 4 ), depending on the reaction conditions employed. The alkyl compound 2 reacts with PhSiH 3 in THF, resulting in a complex mixture of products, from which a mixture of the trivalent, mononuclear hydride (Et 8 -calix-pyrrole)(THF)Sm(μ-H)Li 2 [LiOCH CH 2 ] 2 (THF) 2 ( 5 ) and (Et 8 -calix-pyrrole)Sm(H)Li 2 (THF) 6 ( 6 ) were isolated in modest yield. The structures of 1 − 5 were elucidated by X-ray crystallography.