Outer sphere perturbation of delocalized mixed-valence complexes
Outer sphere perturbation of delocalized mixed-valence complexes
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DOI：
10.1021/ic0349454
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发表时间：
2004-03-08
影响因子：
4.6
通讯作者：
Crutchley, RJ
中科院分区：
文献类型：
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作者：
Al-Noaimi, M;Yap, GPA;Crutchley, RJ
合成了配合物[{Ru(TTP)(Bpy)}(2)(u-adpc)][PF6](2)和[{Ru(Ttp)(Bpy)}(2)(Mudiyd)][PF6](2)，其中TTP为4-甲苯-2，2‘：6’，2“-联吡啶，bpy为2，2‘-联吡啶，adpc(2-)为偶氮(苯基氰胺)，diyd(2-)为1，4-二氰胺苯。配合物[{Ru(TTP)(Bpy)}(2)(Mu-adpc)][Pf6](2)(.)6DMF的晶体结构为平面桥联的adpc(2-)配体，氰基采用反构型。IR和同构化数据与离域混合价络合物一致，假定C-2H微对称性的光谱分析导致预测了多个MMCT跃迁，其最低能量跃迁等于Ru施主和受主轨道与桥联配体轨道混合的共振交换积分(首选的超交换途径)。[{Ru(TTP)(Bpy)}(2)(Mu-adpc)](3+)的MMCT能带与溶剂的依赖关系是由于溶剂给体与桥联配体上的偶氮基相互作用导致金属-金属耦合的基态减弱所致。
The complexes [{Ru(ttp)(bpy)}(2)(u-adpc)][PF6](2) and [{Ru(ttp)(bpy)}(2)(mu-dicyd)][PF6](2), where ttp is 4-toluene-2,2': 6',2"-terpyridine, bpy is 2,2'-bipyridine, adpc(2-) is azodi(phenylcyanamide), and dicyd(2-) is 1,4-dicyanamidebenzene, were prepared and characterized by IR and NIR, vis spectroelectrochemistry, and cyclic voltammetry. The crystal structure of the complex, [{Ru(ttp)(bpy)}(2)(mu-adpc)][PF6](2)(.)6DMF, revealed a planar bridging adpc(2-) ligand with the cyanamide groups adopting an anti configuration. IR and comproportionation data are consistent with delocalized mixed-valence complexes, and a spectroscopic analysis assuming C-2h microsymmetry leads to a prediction of multiple MMCT transitions with the lowest energy transition equal to the resonance exchange integral for the mixing of ruthenium donor and acceptor orbitals with a bridging ligand orbital (the preferred superexchange pathway). The solvent dependence of the MMCT band energy that is seen for [{Ru(ttp)(bpy)}(2)(mu-adpc)](3+) is due to a ground state weakening of metal-metal coupling because of solvent donor interactions with the acceptor azo group of the bridging ligand.