Department of Chemistry and Biochemistry , Loyola University Chicago , Chicago , Illinois 60660 , United States.
Department of Chemistry , Grand Valley State University , Allendale , Michigan 49401 , United States.
Inorg Chem. 2018 Jul 16;57(14):8307-8316. doi: 10.1021/acs.inorgchem.8b00958. Epub 2018 Jul 3.
A series of four- and five-coordinate Ni(II) complexes Cz (Pyr )NiX (1-3 and 1·THF-3·THF), where X = Cl, Br, and I, were synthesized and fully characterized by NMR and UV-vis spectroscopy, X-ray crystallography, cyclic voltammetry, and density functional theory calculations. The solid-state structures of 1-3 reveal rare examples of seesaw Ni(II) complexes. In solution, 1-3 bind reversibly to a THF molecule to form five-coordinate adducts. The electronic transitions in the visible region (630-680 nm), attributed to LMCT bands, for 1 → 3 exhibit a bathochromic shift. The thermochromic tendency of the five-coordinate complexes implies the loss of THF coordination at elevated temperatures. Finally, the electronic properties of all Ni(II) complexes were studied by time-dependent density functional theory calculations to characterize the nature of the excited states.
一系列四配位和五配位 Ni(II) 配合物 Cz(Pyr)NiX(1-3 和 1·THF-3·THF)，其中 X = Cl、Br 和 I，通过 NMR 和 UV-vis 光谱、X 射线晶体学、循环伏安法和密度泛函理论计算进行了充分的表征。1-3 的固态结构揭示了罕见的跷跷板 Ni(II) 配合物实例。在溶液中，1-3 可逆地与 THF 分子结合形成五配位加合物。可见光区（630-680nm）的电子跃迁归因于 LMCT 带，对于 1→3 表现出红移。五配位配合物的热致变色趋势表明在较高温度下失去 THF 配位。最后，通过时间依赖的密度泛函理论计算研究了所有 Ni(II) 配合物的电子性质，以表征激发态的性质。
