Isopropyltetramethylcyclopentadienyl samarium chemistry: structural studies of divalent (C 5Me 4iPr) 2Sm(THF) and mixed valent [(C 5Me 4iPr) 2Sm] 2( μ-Cl)

Abstract

The isopropyltetramethylcyclopentadienyl samarium complexes (C 5Me 4 i Pr) 2Sm(THF), 1, and [(C 5Me 4 i Pr) 2Sm] 2( μ-Cl), 2, have been isolated and structurally characterized. Divalent 1 crystallizes from hot toluene as a monosolvate in space group P3 121 with a= b=15.494(2) Å, c=9.7724(7) Å, α= β=90°, γ=120°, V=2031.6(5) Å 3 and D calcd=1.346 g⧹cm 3, Z=3 and T=163 K. 1 has a 141.6° ring centroid–Sm–ring centroid angle and an average Sm–C distance of 2.80(3) Å. 2 crystallizes from hot toluene in space group P1 with a=9.616(2) Å, b=15.479(2) Å, c=17.844(1) Å, α=111.671(4)°, β=93.488(8)°, γ=107.494(9)°, V=2309.3(5) Å 3 and D calcd=1.423 g⧹cm 3, Z=2 and T=163 K. The two bent metallocene units in 2 are connected by an asymmetrical chloride bridge which has a 169.88(4)° Sm(1)–Cl–Sm(2) angle and 2.678(1) Å Sm(1)–Cl and 2.891(1) Å Sm(2)–Cl distances. The 2.69(2) Å average Sm(1)–C(C 5Me 4 i Pr) distance is characteristic of Sm(III) and the 2.80(2) Å average Sm(2)–C(C 5Me 4 i Pr) distance is characteristic of Sm(II).