Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, 2780-157 Oeiras, Portugal.
Dalton Trans. 2013 May 7;42(17):6149-60. doi: 10.1039/c2dt32363j. Epub 2013 Jan 18.
Two new cyclen derivatives, H(2)do2nph and H(2)cb-do2nph, containing two trans-2-methyl-4-nitrophenol pendant arms and the latter including also an ethylene cross-bridge, were prepared in good yields using the bisaminal synthetic route. The two ligands were studied comparatively regarding their metal complexation behaviour. The copper(II) and zinc(II) complexes of H(2)do2nph and H(2)cb-do2nph were studied in dimethylsulfoxide-water (9 : 1 v/v) solution by a range of spectroscopic techniques. Copper(II) complexes were also studied in solid state by X-ray single crystal diffraction. These studies showed that the copper(II) and zinc(II) complexes of H(2)do2nph exhibited a distorted square pyramidal coordination environment with the four nitrogen atoms of the cyclen ring defining the basal plane, and that one of the nitrophenolate arms did not coordinate to the metal, independently of its protonation state. On the other hand, depending on the protonation state of one of the nitrophenolic arms, the cross-bridged derivative forms copper(II) complexes with distorted square pyramidal or octahedral geometries with one or two arms coordinated to the metal centre, respectively. In the complex with distorted octahedral geometry, the two phenolic oxygen atoms are coordinated to the metal centre in a cis-fashion. Acid-assisted dissociation assays in 1 mol dm(-3) HCl DMSO-H(2)O (9 : 1 v/v) solution at 298.2 K allowed one to determine the half-life of both copper(II) complexes, which is lower for the derivative without a cross-bridge as expected, while for the other one it is quite high and in line with similar cross-bridged cyclen derivatives from the literature.
两种新的环戊二烯衍生物，H(2)do2nph 和 H(2)cb-do2nph，含有两个反式-2-甲基-4-硝基苯甲醛侧臂，后者还包括一个乙烯交叉桥，使用双亚胺合成路线以良好的产率制备。这两种配体在比较研究中比较了它们的金属络合行为。通过一系列光谱技术研究了 H(2)do2nph 和 H(2)cb-do2nph 的铜(II)和锌(II)配合物在二甲亚砜-水（9：1 v/v）溶液中的性质。还通过 X 射线单晶衍射研究了铜(II)配合物在固态中的性质。这些研究表明，H(2)do2nph 的铜(II)和锌(II)配合物具有扭曲的四方锥配位环境，环戊二烯环的四个氮原子定义了基平面，并且一个硝基苯甲酰基臂不与金属配位，独立于其质子化状态。另一方面，取决于一个硝基酚臂的质子化状态，交叉桥衍生物形成具有扭曲的四方锥或八面体几何形状的铜(II)配合物，分别有一个或两个臂与金属中心配位。在具有扭曲的八面体几何形状的配合物中，两个酚氧基原子以顺式方式与金属中心配位。在 298.2 K 的 1 mol dm(-3) HCl DMSO-H(2)O（9：1 v/v）溶液中的酸辅助解离测定允许确定两种铜(II)配合物的半衰期，预期没有交叉桥的衍生物的半衰期较低，而对于另一种配合物，半衰期相当高，与文献中类似的交叉桥环戊二烯衍生物一致。
