Suppr超能文献

两坐标、拟两坐标和扭曲三坐标、T 型铬(II)酰胺配合物:配位几何对基态磁矩降低的影响。

Two-coordinate, quasi-two-coordinate, and distorted three coordinate, T-shaped chromium(II) amido complexes: unusual effects of coordination geometry on the lowering of ground state magnetic moments.

机构信息

Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.

出版信息

Inorg Chem. 2012 Mar 5;51(5):3212-9. doi: 10.1021/ic202661n. Epub 2012 Feb 22.

Abstract

The synthesis and characterization of the mononuclear chromium(II) terphenyl substituted primary amido-complexes Cr{N(H)Ar(Pr(i)(6))}(2) (Ar(Pr(i)(6)) = C(6)H(3)-2,6-(C(6)H(2)-2,4,6-(i)Pr(3))(2) (1), Cr{N(H)Ar(Pr(i)(4))}(2) (Ar(Pr(i)(4)) = C(6)H(3)-2,6-(C(6)H(3)-2,6-(i)Pr(2))(2) (2), Cr{N(H)Ar(Me(6))}(2) (Ar(Me(6)) = C(6)H(3)-2,6-(C(6)H(2)-2,4,6-Me(3))(2) (4), and the Lewis base adduct Cr{N(H)Ar(Me(6))}(2)(THF) (3) are described. Reaction of the terphenyl primary amido lithium derivatives Li{N(H)Ar(Pr(i)(6))} and Li{N(H)Ar(Pr(i)(4))} with CrCl(2)(THF)(2) in a 2:1 ratio afforded complexes 1 and 2, which are extremely rare examples of two coordinate chromium and the first stable chromium amides to have linear coordinated high-spin Cr(2+). The reaction of the less crowded terphenyl primary amido lithium salt Li{N(H)Ar(Me(6))} with CrCl(2)(THF)(2) gave the tetrahydrofuran (THF) complex 3, which has a distorted T-shaped metal coordination. Desolvation of 3 at about 70 °C gave 4 which has a formally two-coordinate chromous ion with a very strongly bent core geometry (N-Cr-N= 121.49(13)°) with secondary Cr--C(aryl ring) interactions of 2.338(4) Å to the ligand. Magnetometry studies showed that the two linear chromium species 1 and 2 have ambient temperature magnetic moments of about 4.20 μ(B) and 4.33 μ(B) which are lower than the spin-only value of 4.90 μ(B) typically observed for six coordinate Cr(2+). The bent complex 4 has a similar room temperature magnetic moment of about 4.36 μ(B). These studies suggest that the two-coordinate chromium complexes have significant spin-orbit coupling effects which lead to moments lower than the spin only value of 4.90 μ(B) because λ (the spin orbit coupling parameter) is positive. The three-coordinated complex 3 had a magnetic moment of 3.79 μ(B).

摘要

单核铬(II)三联苯取代的伯酰胺配合物 Cr{N(H)Ar(Pr(i)(6))}(2)(Ar(Pr(i)(6))=C(6)H(3)-2,6-(C(6)H(2)-2,4,6-(i)Pr(3))(2) (1),Cr{N(H)Ar(Pr(i)(4))}(2)(Ar(Pr(i)(4))=C(6)H(3)-2,6-(C(6)H(3)-2,6-(i)Pr(2))(2) (2),Cr{N(H)Ar(Me(6))}(2)(Ar(Me(6))=C(6)H(3)-2,6-(C(6)H(2)-2,4,6-Me(3))(2) (4)和路易斯碱加合物 Cr{N(H)Ar(Me(6))}(2)(THF)(3)的合成和表征。三联苯伯酰胺锂衍生物 Li{N(H)Ar(Pr(i)(6))}和 Li{N(H)Ar(Pr(i)(4))}与 CrCl(2)(THF)(2)以 2:1 的比例反应,得到了配合物 1 和 2,它们是两配位铬的极罕见例子,也是第一个具有线性配位高自旋 Cr(2+)的稳定铬酰胺。与 CrCl(2)(THF)(2)反应的空间位阻较小的三联苯伯酰胺锂盐 Li{N(H)Ar(Me(6))}得到了四氢呋喃(THF)配合物 3,它具有扭曲的 T 形金属配位。在约 70°C 下脱去 3 的溶剂得到了 4,它具有形式上为两配位的亚铬离子,具有非常强烈弯曲的核心几何形状(N-Cr-N=121.49(13)°),与配体的次级 Cr--C(芳基环)相互作用为 2.338(4)Å。磁测量研究表明,两个线性铬物种 1 和 2 在环境温度下具有约 4.20 μ(B)和 4.33 μ(B)的磁矩,低于通常观察到的六配位 Cr(2+)的自旋仅值 4.90 μ(B)。弯曲的配合物 4 在室温下具有类似的磁矩,约为 4.36 μ(B)。这些研究表明,两配位铬配合物具有显著的自旋轨道耦合效应,导致磁矩低于自旋仅值 4.90 μ(B),因为 λ(自旋轨道耦合参数)为正。三配位配合物 3 的磁矩为 3.79 μ(B)。

文献AI研究员

20分钟写一篇综述,助力文献阅读效率提升50倍。

立即体验

用中文搜PubMed

大模型驱动的PubMed中文搜索引擎

马上搜索

文档翻译

学术文献翻译模型,支持多种主流文档格式。

立即体验