The Relationship between Structure and Properties in Zn
II
Complexes of Bulky
N
,
N′
‐Diarylformamidinate
N
‐Oxides
摘要:
AbstractHomoleptic zinc(II) complexes (3a–3d) of the bulky N,N′‐diarylformamidinate N‐oxide ligands N‐hydroxy‐N,N′‐bis(2,6‐diisopropylphenyl)formamidine (2a), N‐hydroxy‐N,N′‐bis(2,6‐dimethylphenyl)formamidine (2b), N‐hydroxy‐N,N′‐bis(2‐isopropylphenyl)formamidine (2c) and N‐hydroxy‐N,N′‐bis(2‐biphenyl)formamidine (2d) were synthesized and characterized. Their solid‐state structures are presented together with their solution properties, as examined by NMR and UV/Vis spectroscopy, and cyclic voltammetry. Theoretical calculations [DFT and time‐dependent DFT (TD‐DFT)] were performed to assess and to rationalize the influence of ligand modification on the properties of the complexes: the highest occupied molecular orbital (HOMO), localized on the NCNO moiety, is less influenced by the substitution pattern, whereas the lowest unoccupied molecular orbital (LUMO), localized on the aryl ring with the O–N moiety, is directly affected; therefore, the optical band gap can be fine‐tuned for potential applications.
Influence of Ligand Substitution Pattern on Structure in Cobalt(II) Complexes of Bulky
<i>N</i>
,
<i>N′</i>
‐Diarylformamidinate
<i>N</i>
‐Oxides
作者:Mihaela Cibian、Sophie Langis‐Barsetti、Fernanda Gomes De Mendonça、Sammy Touaibia、Sofia Derossi、Denis Spasyuk、Garry S. Hanan
DOI:10.1002/ejic.201402895
日期:2015.1
Cobalt(II) complexes of bulky N,N′-diarylformamidinate N-oxide ligands were synthesized and structurally characterized. The cobalt(II) bis(chelates) are square-planar (low spin) in the solid state, according to XRD and magnetic measurements (μeff = 1.8 to 2.1 μB), but show square-planar (low spin) to tetrahedral (high spin: μeff = 3.5 to 4.7 μB) isomerization in solutions of noncoordinating solvents
合成了庞大的 N,N'-二芳基甲脒N-氧化物配体的钴 (II) 配合物并对其进行了结构表征。根据 XRD 和磁性测量(μeff = 1.8 至 2.1 μB),钴(II)双(螯合物)在固态下是方形平面(低自旋),但显示方形平面(低自旋)到四面体(高spin: μeff = 3.5 to 4.7 μB) 在非配位溶剂溶液中异构化,如不同光谱技术所证明的。由于空间和电子影响的组合,异构化平衡对配体上的取代模式高度敏感。