Electronic coupling of two [Cp*ClM]+/[Cp*M] reaction centers via π conjugated bridging ligands: similarities and differences between rhodium and iridium analogues
作者:Wolfgang Kaim、Sascha Berger、Stefan Greulich、Ralf Reinhardt、Jan Fiedler
DOI:10.1016/s0022-328x(98)01027-4
日期:1999.6
identified via long-wavelength bands from intervalence charge transfer (IVCT) transitions. All complexes containing at least one chloride-free Cp*M group display intense long-wavelength absorption bands. The iridium complexes are distinguished by more negative potentials of the [Cp*Ir]-containing forms, by slower formation of the M2I,II mixed-valent intermediate, by larger g anisotropy of the paramagnetic
双核络合物[Cp * ClM(μ- L)MClCp *](PF 6)2,M = Rh或Ir,L = 3,6-双(2-吡啶基)-1,2,4,5-四嗪( bptz)或2,5-双(phenyliminoethyl)吡嗪(BPIP),在几个化学可逆步骤,通过多达六个电子到物种的[Cp * M(还原μ -L)MCP *] ñ - 。紫外-可见/近红外光谱电化学和顺磁态的EPR用于鉴定各种中间体。该配合物清楚地显示出在第一氯离解金属还原步骤(EC)之前可逆的,以配体为中心的单电子还原(E)。通过桥接的π受体配体L的金属-金属相互作用导致两个Cl的电势之间产生310-710 mV的分裂--分离步骤。对于L = bpip,第二种氯化物释放以EC + E方式发生,而对于L = bptz,则以双电子过程发生。M II M I混合价物质[Cp * M(μ- L)MCp *] +可以通过间隔电荷转移(IVCT)跃