A wide range of new zirconium(IV) derivatives utilizing
the
N,N′-bis(trimethylsilyl)benzamidinato
ligand are reported. The previously reported dichloride,
L
2
ZrCl
2
[L = PhC(NSiMe
3
)
2
], reacted cleanly
with 1 equivalent of Me
2
Mg in Et
2
O to give
L
2
ZrMe
2
which was isolated as colorless crystals
from CH
2
Cl
2
or Et
2
O. Attempting to
prepare the methyl chloride derivative using 0.5 equivalent of
Me
2
Mg yielded mixtures of dichloride, dimethyl and methyl
chloride derivatives. The compound L
2
ZrCl
2
reacted
cleanly with 1 equivalent of the bulkier alkyl
LiCH
2
SiMe
3
giving
L
2
Zr(CH
2
SiMe
3
)Cl. Reactivity of methyl
derivatives with a variety of small molecules (CO, CO
2
or
acetone) is reported. The dimethyl compound,
L
2
ZrMe
2
, reacted cleanly with
B(C
6
F
5
)
3
to form the
methyltriarylborate complex
L
2
Zr[MeB(C
6
F
5
)
3
]Me which is
moderately active towards ethylene polymerization. Additionally, several
other derivatives are conveniently prepared by salt-metathesis reactions
with the dichloride including:
L
2
Zr(CH
2
Ph)
2
,
L
2
Zr(OSO
2
CF
3
)
2
,
L
2
Zr[NH(C
6
H
3
Pr
i
2
-2,6)]Cl, L
2
Zr(BH
4
)
2
,
L
2
Zr[ESi(SiMe
3
)
3
]Cl
(E = Se or Te). The 1% Na–Hg amalgam reduction of
L
2
ZrCl
2
in the presence of diphenylacetylene or
trimethylsilylacetylene yielded orange zirconacyclopentadienes
L
2
Zr(C
4
Ph
4
) and
L
2
Zr[C
4
H
2
(SiMe
3
)
2
-2,4] in moderate yields. The compound
L
2
Zr(C
4
Ph
4
) reacted readily with CO to
give the dark red η
2
-cyclopentadienone
L
2
Zr[η
2
-C(O)C
4
Ph
4
].
Analogous to the formation of the zirconacyclopentadienes, reduction in
the presence of ethylene gave the zirconacyclopentane,
L
2
Zr(C
4
H
8
), in good yield. When the
reduction is carried out in the absence of any trapping ligands,
however, a benzamidinate ligand is oxidatively cleaved and the dimeric
imido-iminoacyl compound,
[LZr(η
2
-PhCNSiMe
3
)(µ-NSiMe
3
)]
2
, is isolated as orange crystals in moderate yield.
Single-crystal X-ray diffraction data are reported for
L
2
ZrCl
2
, L
2
ZrMe
2
and
L
2
Zr(C
4
H
8
).
本研究报道了一系列利用 N,N′-双(三甲基
硅基)苯甲酰胺
配体的新型
锆(IV)衍
生物。之前报道过的二
氯化物 L 2 ZrCl 2 [L = PhC(NSiMe 3 ) 2 ] 与 1 个当量的 Me 2 Mg 在 Et 2 O 中发生了完全反应,得到了 L 2 ZrMe 2,并从 CH 2 Cl 2 或 Et 2 O 中分离出无色晶体。化合物 L 2 ZrCl 2 与 1 个当量的块状烷基 LiCH 2 SiMe 3 反应,得到 L 2 Zr(CH 2 SiMe 3 )Cl。据报道,甲基衍
生物可与多种小分子(CO、CO 2 或
丙酮)发生反应。二甲基化合物 L 2 ZrMe 2 与 B(C 6 F 5 ) 3 反应生成甲基三芳基
硼酸酯复合物 L 2 Zr[MeB(C 6 F 5 ) 3 ]Me,该复合物对
乙烯聚合具有中等活性。此外,还可以通过与二
氯化物的盐析反应方便地制备其他几种衍
生物,包括:L 2 Zr(CH 2 Ph) 2 、L 2 Zr(OSO 2 CF 3 ) 2 、L 2 Zr[NH(C 6 H 3 Pr i 2 -2,6)]Cl 、L 2 Zr(BH 4 ) 2 、L 2 Zr[ESi(SiMe 3 ) 3 ]Cl (E = Se 或 Te)。在
二苯基乙炔或三甲基
硅基
乙炔存在下,用 1%的 Na-Hg
汞齐还原 L 2 ZrCl 2,得到橙色的
锆环戊二烯 L 2 Zr(C 4 Ph 4 ) 和 L 2 Zr[C 4 H 2 (SiMe 3 ) 2 -2,4],收率中等。化合物 L 2 Zr(C 4 Ph 4 ) 很容易与 CO 发生反应,生成深红色的 η 2 -
环戊二烯酮 L 2 Zr[η 2 -C(O)C 4 Ph 4 ]。 与
锆环戊二烯的生成类似,在
乙烯存在下进行还原可生成
锆环戊烷 L 2 Zr(C 4 H 8 ) ,收率很高。然而,在没有任何捕获
配体的情况下进行还原时,苯甲酰胺
配体会被氧化裂解,从而分离出二聚体亚
氨基
酰亚胺化合物 [LZr(η 2 -PhCNSiMe 3 )(µ-NSiMe 3 )] 2,该化合物为橙色晶体,收率中等。 本文报告了 L 2 ZrCl 2、L 2 ZrMe 2 和 L 2 Zr(C 4 H 8 ) 的单晶 X 射线衍射数据。