Metal complexes with a chiral N4 symmetrical Schiff base. Crystal structures of the ligand and its Cu(ii) and Ni(ii) “mono-helicates”
作者:Miguel Vázquez、Manuel R. Bermejo、Jesús Sanmartín、Ana M. García-Deibe、Carlos Lodeiro、José Mahía
DOI:10.1039/b107116p
日期:——
The N4 Schiff base ligand N,Nâ²-bis(2-tosylaminobenzylidene)-1,2-diaminocyclohexane (H2cyTs) and its divalent metal (Fe, Co, Ni, Cu, Zn and Cd) complexes have been prepared. Of these compounds only Zn(trans-cyTs)·3H2O can be considered as blue luminescent (λ
= 435 nm, Ï
= 0, 12). Either demetallation or the absence of the tosyl groups, results in a loss of fluorescence. The X-ray crystal structures of a diastereoisomeric mixture of H2cyTs and its (1R,2R)-enantiomer, as well as those corresponding to Cu(trans-cyTs)·MeCN and Ni(trans-cyTs)·MeCN have been solved. The Cu(II) and Ni(II) ions assume tetrahedrally distorted square planar coordination geometries, involving the four donor N-atoms of the dianionic ligand. The spatial disposition of both tosyl groups prevents global consideration as
an usual symmetric helicand.
我们制备了 N4 希夫碱配体 N,Nâ²-双(2-对甲苯磺酸氨基亚苄基)-1,2-二氨基环己烷(H2cyTs)及其二价金属(铁、钴、镍、铜、锌和镉)配合物。在这些化合物中,只有 Zn(反式-cyTs)Â-3H2O 可被视为蓝色发光体(δ" = 435 纳米,Ï = 0,12)。无论是脱金属还是缺少甲苯基团,都会导致荧光消失。H2cyTs 及其 (1R,2R)-非对映异构体的非对映异构混合物,以及与 Cu(trans-cyTs)Â-MeCN 和 Ni(trans-cyTs)Â-MeCN 相对应的晶体的 X 射线晶体结构已经解决。Cu(II)和 Ni(II)离子呈四面体畸变方平面配位,涉及二阴离子配体的四个供体 N 原子。由于两个甲苯基团的空间分布,无法将其整体视为通常的对称螺旋体。