二甲基双（2-吡啶基）硼酸镍（II）配合物的合成与表征：围绕镍（II）的单分子平面正方形到平面正方形旋转

Synthesis and Characterization of Dimethylbis(2-pyridyl)borate Nickel(II) Complexes: Unimolecular Square-Planar to Square-Planar Rotation around Nickel(II).

作者信息

Celaje Jeff A, Pennington-Boggio Megan K, Flaig Robinson W, Richmond Michael G, Williams Travis J

机构信息

Loker Hydrocarbon Institute and Department of Chemistry, University of Southern California , Los Angeles, California, 90089-1661, United States.

Department of Chemistry, University of North Texas , Denton, Texas, 76203-5017, United States.

出版信息

Organometallics. 2014 Apr 28;33(8):2019-2026. doi: 10.1021/om500173j. Epub 2014 Apr 7.

DOI:10.1021/om500173j

PMID:24882919

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC4034079/

Abstract

The syntheses of novel dimethylbis(2-pyridyl)borate nickel(II) complexes and are reported. These complexes were unambiguously characterized by X-ray analysis. In dichloromethane solvent, complex undergoes a unique square-planar to square-planar rotation around the nickel(II) center, for which activation parameters of Δ = 12.2(1) kcal mol and Δ = 0.8(5) eu were measured via NMR inversion recovery experiments. Complex was also observed to isomerize via a relatively slow ring flip: Δ = 15.0(2) kcal mol; and Δ = -4.2(7) eu. DFT studies support the experimentally measured rotation activation energy (cf. calculated Δ = 11.1 kcal mol) as well as the presence of a high-energy triplet intermediate (Δ = 8.8 kcal mol).

摘要

报道了新型二甲基双（2-吡啶基）硼酸镍（II）配合物的合成。通过X射线分析对这些配合物进行了明确表征。在二氯甲烷溶剂中，配合物围绕镍（II）中心经历独特的平面正方形到平面正方形的旋转，通过核磁共振反转恢复实验测量其活化参数为Δ = 12.2(1) kcal/mol和Δ = 0.8(5) eu。还观察到配合物通过相对较慢的环翻转进行异构化：Δ = 15.0(2) kcal/mol；Δ = -4.2(7) eu。密度泛函理论研究支持实验测量的旋转活化能（计算得到的Δ = 11.1 kcal/mol）以及高能三重态中间体的存在（Δ = 8.8 kcal/mol）。