ic951253+_si_001.pdf (1.4 MB)
Synthesis, Reactivity, and Stability of Di- and Trivalent Samarium Amides
journal contribution
posted on 1996-03-27, 00:00 authored by Ravinder K. Minhas, Yinlin Ma, Jae-Inh Song, Sandro GambarottaSmCl3(THF)3 (THF =
tetrahydrofuran) reacts with anionic dialkylamides
R2N- [R = Cy (cyclohexyl),
i-Pr
(isopropyl), Ph (phenyl)] to give different products, depending on the
nature of the R substituents. Reaction with
Cy2NLi in a 1:2 molar ratio formed
[(Cy2N)2Sm(μ-Cl)(THF)]2
(1) in 80% yield, whereas reaction with
(i-Pr)2NLi
under similar conditions gave
[(i-Pr2N)2SmCl3(Li(TMEDA))2]
(2). Partial loss of THF from complex 1
reorganized
the molecule into the tetranuclear
(Cy2N)6Sm4Cl6(THF)2
(3). Attempts to reduce complex 1 with a
number of
reagents gave
[(Cy2N)3SmTHF]·toluene
(5), while
[(Cy2N)4SmLi(THF)] (4)
was isolated upon alkylation reactions
carried out with either NpLi or NfLi [Np =
CH2C(CH3)3; Nf =
CH2C(CH3)2Ph]. Direct
synthesis of Sm(II)
amides from SmI2(THF)2 starting material
was successful only in the case of diphenylamide anion
(Ph2N-).
Depending on the stoichiometry, -ate
(Ph2N)4Sm[Na(TMEDA)]2
(6) or neutral
[(Ph2N)2Sm(THF)4]·THF
(7) was
obtained. The crystal structures of 1−7
were demonstrated by X-ray diffraction analysis. Crystal data are
as
follows. 1:
C56H105N4O2Sm2Cl2,
triclinic, P1̄, a = 14.344(1) Å,
b = 23.897(2) Å, c = 10.2031(9)
Å, α =
88.479(9)°, β = 121.83(1)°, γ = 93.73(1)°,
Z = 2. 2:
C24H60N6SmCl3Li2
triclinic, P1̄, a = 11.552(1) Å,
b =
15.483(1) Å, c = 11.330(1) Å, α =
101.69(1)°, β = 106.13(1)°, γ = 88.89(2)°.
3:
C80H148N6Cl6O2Sm4,
triclinic,
P1̄, a = 16.508(1) Å, b
= 16.7795(9) Å, c = 16.4030(8) Å, α =
89.794(1)°, β = 88.688(2)°, γ =
79.531(1)°,
Z = 2. 4:
C56H106N4O2LiSm,
orthorhombic, Pna21, a =
16.6145(9) Å, b = 17.5858(9) Å, c
= 19.7754(9) Å,
V = 5778.0(9) Å3, Z = 4.
5:
C47H82N3OSm, monoclinic,
P21/c, a =
10.250(2) Å, b = 23.305(2) Å, c =
19.088(1) Å, β = 100.90(1)°, Z = 4.
6:
C60H72N8SmNa2,
tetragonal, I41/acd, a =
18.0004(9) Å, c = 34.106(1) Å,
Z
= 8. 7:
C44H60N2O5Sm,
monoclinic, C2, a = 19.066(1) Å,
b = 11.932(1) Å, c = 9.200(1) Å,
β = 93.89(1)°,
Z = 2.