Four new complexes, [PdX(κ2-2-C6R4PPh2)(PPh2Fc)] [X = Br, R = H (1), R = F (2); X = I, R = H (3), R = F (4)], containing ferrocenyldiphenylphosphine (PPh2Fc) have been prepared and fully characterised. The X-ray structures of complexes trans-1, cis-2 and cis-4, and that of a decomposition product of 4, [Pd(κ2-2-C6F4PPh2)(μ-I)(μ-2-C6F4PPh2)PdI(PPh2Fc)] (5), have been determined. These complexes show a distorted square planar geometry about the metal atom, the bite angles of the chelate ligands being about 69°, as expected. The cis/trans ratio of 1–4 in solution is strongly dependent on solvent. The new complexes and the uncoordinated PPh2Fc ligand were electrochemically characterised by cyclic and rotating disk voltammetry, UV-visible spectroelectrochemistry, and bulk electrolysis in dichloromethane and acetonitrile. In both cases, oxidation occurs at both the ferrocene and phosphine centres, but the complexes oxidise at more positive potentials than uncoordinated PPh2Fc; subsequently, the metal–phosphorus bond is cleaved, leading to free PPh2Fc+, which undergoes further chemical and electrochemical reactions.
制备并全面表征了包含
二茂铁二苯膦([PPh2Fc])的四种新型络合物:[PdX(κ2-2-C6R4PPh2)(PPh2Fc)] [X = Br, R = H (1), R = F (2); X = I, R = H (3), R = F (4)]。测定了反式-1、顺式-2、顺式-4和4的分解产物[Pd(κ2-2-C6F4PPh2)(μ-I)(μ-2-C6F4PPh2)PdI(PPh2Fc)] (5)的X射线结构。这些络合物显示出扭曲的四方平面几何构型,螯合
配体的咬合角度约为69°,符合预期。1-4在溶液中的顺/反比例强烈依赖于溶剂。通过循环伏安法、旋转圆盘伏安法、紫外-可见光谱电
化学和
二氯甲烷及
乙腈中的整体电解对新型络合物和未配位的PPh2Fc
配体进行了电
化学表征。在这两种情况下,氧化发生在
二茂铁和膦中心,但络合物的氧化电位比未配位的PPh2Fc更正;随后,
金属-
磷键断裂,导致自由的PPh2Fc+,它可以进一步发生
化学和电
化学反应。