Structural Diversity and Multielectron Reduction Reactivity of Samarium(II) Iodido-β-diketiminate Complexes Dependent on Tetrahydrofuran Content

Abstract

The molecular structures of complexes [Sm(Nacnac)I-(thf) n ] (Nacnac = HC(C(Me)Ndipp) 2 − , dipp = 2,6-diisopropylphenyl, thf = tetrahydrofuran) depending on the number of thf ligands are studied. The complete removal of thf from a known complex [Sm(Nacnac)I(thf) 2 ] leads to a tetranuclear product [Sm(Nacnac)I] 4 (4). The partial removal of thf results in mixtures of dinuclear [Sm 2 (Nacnac) 2 I 2 (thf)] (2), trinuclear [Sm 3 (Nacnac) 3 I 3 (thf)] (3), and tetranuclear [Sm 4 (Nacnac) 4 I 4 (thf) 2 ] (4*) complexes and 4, depending on the conditions. The reaction of solvent-free SmI 2 with 1 equiv of K(Nacnac) results mainly in [Sm(Nacnac) 2 ] (1), while the interaction of 4 with certain amounts of thf allows obtaining pure 2 and 3 (with the admixture of 4*). Complex 4* is the exact dimer of 2, and both compounds are stable in solutions. Reactions with 3 and 4 as reductants are studied. 4 is oxidized by I 2 to stoichiometrically yield two products, mixed-valent tetranuclear [Sm 4 (Nacnac) 4 I 5 ] (5) and binuclear [Sm(Nacnac)I 2 ] 2 (6) complexes. In the reaction of 4 with n Bu 3 PTe, a trinuclear complex [Sm 3 (Nacnac) 3 (μ-I) 3 (μ 3 -E) 2 ] (8, E = I or Te) is formed in small amounts, with the formation of 6 as the second product. 3 serves as a two-electron reductant in the reaction with n Bu 3 PTe to yield a trinuclear complex [Sm 3 (Nacnac) 3 I 3 (μ-Te 2 )] (7). Complexes 2, 4, 4*, 5, 6, and 8 possess a unique flat Sm x I y core of heavy atoms, which is assumed to be a consequence of the Nacnac ligand geometry.

A Series of Cyclopentadienyl Lanthanum Complexes with Metalloid Germanium Clusters

“…Typically, the angle at the La atom is noticeably smaller than that at the I atom (I1–La1–I′ 77.82°; La1–I–La1′ 102.19°). Such bridging La–(μ-I)–La fragments are very common for rare-earth iodide clusters . The La1–O1 distance [251.0(2) pm] to the coordinated THF molecule in [Cp ttt LaI 2 (THF)] 2 is slightly shorter than those in LaI 3 (THF) 4 [251.5(8)–257.5(8) pm] …”

Low-Coordinate Mixed Ligand NacNac Complexes of Rare Earth Metals

“…Recently, a series of 2,6-diisopropylphenyl-substituted β-diketiminato-diiodides [(NacNac dipp )LnI 2 (THF) n ] (NacNac dipp = 2,6- i Pr 2 C 6 H 3 -NC(Me)CHC(Me)N-2,6- i Pr 2 C 6 H 3 ); Ln = Dy, Gd, Tb [ 51 ], Nd, Sm [ 52 ]) was involved in the salt metathesis reactions with potassium phenyl- and 2-pyridylthiolates resulting in β-diketiminato-thiolato complexes. A comprehensive study of divalent samarium β-diketiminato-supported iodides [(NacNac dipp )SmI(THF) n ] revealed a series of polynuclear compounds with different structures depending on the THF content [ 53 ].…”

Revealing unbound β-diketiminate anions: structural dynamics from caesium complexes

“…1A). 3 BDI ligands are known for their ability to stabilise a broad array of metal ions from the s, 4 p, 5 d 6 and f-blocks 7 in diverse oxidation states by forming strong coordination complexes. Moreover, they have been shown to enhance catalytic activity, selectivity, and stability in several processes, including olefin polymerisation 8 and copolymerization, 9 transfer hydrogenation, 10 and cross-coupling reactions.…”