Bryan Aimee M, Long Gary J, Grandjean Fernande, Power Philip P
Department of Chemistry, University of California , Davis, One Shields Avenue, Davis, California 95616, United States.
Inorg Chem. 2014 Mar 3;53(5):2692-8. doi: 10.1021/ic403098p. Epub 2014 Feb 17.
Treatment of the cobalt(II) amide, [Co{N(SiMe3)2}2]2, with four equivalents of the sterically crowded terphenyl phenols, HOAr(Me6) (Ar(Me6) = C6H3-2,6(C6H2-2,4,6-Me3)2) or HOAr(iPr4) (Ar(iPr4) = C6H3-2,6(C6H3-2,6-Pr(i)2)2), produced the first well-characterized, monomeric two-coordinate cobalt(II) bisaryloxides, Co(OAr(Me6))2 (1) and Co(OAr(iPr4))2 (2a and 2b), as red solids in good yields with elimination of HN(SiMe3)2. The compounds were characterized by electronic spectroscopy, X-ray crystallography, and direct current magnetization measurements. The O-Co-O interligand angles in 2a and 2b are 180°, whereas the O-Co-O angle in 1 is bent at 130.12(8)° and its cobalt(II) ion has a highly distorted pseudotetrahedral geometry with close interactions to the ipso-carbons of the two flanking aryl rings. The Co-O distances in 1, 2a, and 2b are 1.858(2), 1.841(1), and 1.836(2) Å respectively. Structural refinement revealed that 1, 2a, and 2b have different fractional occupations of the cobalt site in their crystal structures: 1, 95.0%, 2a, 93.5%, and 2b, 84.6%. Correction of the magnetic data for the different cobalt(II) occupancies showed that the magnetization of 2a and 2b was virtually identical. The effective magnetic moments for 1, 2a, and 2b, 5.646(5), 5.754(5), and 5.636(3) μB respectively, were indicative of significant spin-orbit coupling. The differences in magnetic properties between 1 and 2a/2b are attributed to their different cobalt coordination geometries.
用四当量空间位阻较大的三联苯酚HOAr(Me6)（Ar(Me6) = C6H3-2,6(C6H2-2,4,6-Me3)2）或HOAr(iPr4)（Ar(iPr4) = C6H3-2,6(C6H3-2,6-Pr(i)2)2）处理钴（II）酰胺[Co{N(SiMe3)2}2]2，首次得到了表征良好的单体二配位钴（II）双芳氧基化合物Co(OAr(Me6))2（1）和Co(OAr(iPr4))2（2a和2b），它们为红色固体，产率良好，同时消除了HN(SiMe3)2。通过电子光谱、X射线晶体学和直流磁化率测量对这些化合物进行了表征。2a和2b中的O-Co-O配体间夹角为180°，而1中的O-Co-O角呈130.12(8)°的弯曲状，其钴（II）离子具有高度扭曲的伪四面体几何结构，与两个相邻芳基环的本位碳有紧密相互作用。1、2a和2b中的Co-O距离分别为1.858(2) Å、1.841(1) Å和1.836(2) Å。结构精修表明，1、2a和2b在其晶体结构中钴位点的占有率不同：1为95.0%，2a为93.5%，2b为84.6%。对不同钴（II）占有率的磁数据进行校正后表明，2a和2b的磁化率几乎相同。1、2a和2b的有效磁矩分别为5.646(5) μB、5.754(5) μB和5.636(3) μB，表明存在显著的自旋-轨道耦合。1与2a/2b之间磁性质的差异归因于它们不同的钴配位几何结构。
