Reversible switching of coordination mode of ansa bis(amidinate) ligand in ytterbium complexes driven by oxidation state of the metal atom.
Reversible switching of coordination mode of ansa bis(amidinate) ligand in ytterbium complexes driven by oxidation state of the metal atom.
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DOI：
10.1021/ic402530w
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发表时间：
2014-01
影响因子：
4.6
通讯作者：
A. Tolpygin;A. Cherkasov;G. K. Fukin;A. Trifonov
中科院分区：
文献类型：
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作者：
A. Tolpygin;A. Cherkasov;G. K. Fukin;A. Trifonov
双脒C6 H4 - 1，2-{NC（t-Bu）NH（2，6-Me 2C 6 H3）}2（1）和[（Me 3Si）2N] 2 Yb（THF）2（THF =四氢呋喃）（甲苯;室温）以1：1的摩尔比反应，以65%的产率得到双脒基Yb（II）配合物[C6 H4 - 1，2-{NC（t-Bu）N（2，6-Me 2C 6 H3）}2]Yb（THF）（2）。配合物2的特征是两个脒基片段与镱离子的不寻常的κ（1）酰胺、η（6）-芳烃配位，导致形成弯曲的双（芳烃）结构。以Ph 3SnCl（1：1摩尔比）或（PhCH 2S）2（1：0.5摩尔比）氧化2得到Yb（III）物种[C6 H4 - 1，2-{NC（t-Bu）N（2，6-Me 2C 6 H3）}2]YbCl（1，2-二甲氧基乙烷）（3）和{[C6 H4 - 1，2-{NC（t-Bu）N（2，6-Me 2C 6 H3）}2]Yb（μ-SCH 2 Ph）}2（4），表现为经典的柄型双脒基配体κ（2）N，N'-螯合配位模式。用等摩尔量的萘钠[C10 H8（·-）][Na（+）]在THF中还原配合物3，可将配合物2还原为弯曲的双（芳烃）结构。配合物3也通过等摩尔量的YbCl 3和1的二锂衍生物在THF中的盐复分解反应合成。
Reaction of bisamidine C6H4-1,2-{NC(t-Bu)NH(2,6-Me2C6H3)}2 (1) and [(Me3Si)2N]2Yb(THF)2 (THF = tetrahydrofuran) (toluene; room temperature) in a 1:1 molar ratio afforded a bis(amidinate) Yb(II) complex [C6H4-1,2-{NC(t-Bu)N(2,6-Me2C6H3)}2]Yb(THF) (2) in 65% yield. Complex 2 features unusual κ(1)amide, η(6)-arene coordination of both amidinate fragments to the ytterbium ion, resulting in the formation of a bent bis(arene) structure. Oxidation of 2 by Ph3SnCl (1:1 molar ratio) or (PhCH2S)2 (1:0.5) leads to the Yb(III) species [C6H4-1,2-{NC(t-Bu)N(2,6-Me2C6H3)}2]YbCl(1,2-dimethoxyethane) (3) and {[C6H4-1,2-{NC(t-Bu)N(2,6-Me2C6H3)}2]Yb(μ-SCH2Ph)}2 (4), performing "classic" κ(2)N,N'-chelating coordination mode of ansa bis(amidinate) ligand. By the reduction of 3 with equimolar amount of sodium naphthalide [C10H8(•-)][Na(+)] in THF, complex 2 can be recovered and restored to a bent bis(arene) structure. Complex 3 was also synthesized by the salt metathesis reaction of equimolar amounts of YbCl3 and the dilithium derivative of 1 in THF.