A series of novel heterobimetallic bis(acetylide) ferrocene complexes
featuring a bis[1,2-bis(diphenylphosphino)methane]ruthenium centre and
seven variously substituted aromatic acetylene ligands have been
synthesised and characterised. The crystal structure of
trans-[Ru(dppm)
2
CC(C
5
H
4
)Fe(C
5
H
5
)}
2
]
shows the ruthenium centre in a distorted-octahedral environment bound to
two ferrocene units in a linear fashion by ‘rigid-rod’-like
acetylene linkages. The conformation is stabilised by strong intramolecular
CH· · ·π(CC) interactions.
Electrochemical studies showed that incorporation of donor-substituted
aromatic acetylide ligands causes a cathodic shift in the
Ru
II/III
redox potential. Conversely, an anodic shift is
observed when electron-withdrawing substituents are present in the
acetylide systems. Electronic spectral measurements indicated that the
systems belong to the Robin and Day ‘Class II’ mixed-valence
species and suggest that greater electronic interaction occurs in the
bis(acetylide) complexes than in the corresponding monoacetylide
chloro-complex.
我们合成并表征了一系列新型杂多
金属双(
乙炔)
二茂铁配合物,这些配合物以双[1,2-双(
二苯基膦)
甲烷]
钌中心和七个不同取代的芳香族
乙炔配体为特征。反式-[Ru(dppm) 2 CC(C 5 H 4 )Fe(C 5 H 5 )} 2 ]的晶体结构显示,
钌中心处于扭曲的八面体环境中,通过 "刚性杆 "状的
乙炔连接与两个
二茂铁单元线性结合。电
化学研究表明,加入供体取代的芳香族乙酰
配体会导致 Ru II/III 氧化还原电位发生阴极移动。相反,当乙酰化体系中存在抽电子取代基时,则会出现阳极移动。电子光谱测量结果表明,这些体系属于罗宾和戴的 "第二类 "混价物种,并表明双(乙酰化)络合物比相应的单乙酰化
氯络合物发生了更大的电子相互作用。