Influence of Central Metalloligand Geometry on Electronic Communication between Metals: Syntheses,Crystal Structures,MMCT Properties of Isomeric Cyanido‐Bridged Fe2Ru Complexes,and TDDFT Calculations |
| |
| Authors: | Dr Xiao Ma Dr Chen‐Sheng Lin Sheng‐Min Hu Dr Chun‐Hong Tan Dr Yue‐Hong Wen Prof?Dr Tian‐Lu Sheng Prof Xin‐Tao Wu |
| |
| Institution: | State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Science, Fuzhou, Fujian 350002 (China) |
| |
| Abstract: | To investigate how the central metalloligand geometry influences distant or vicinal metal‐to‐metal charge‐transfer (MMCT) properties of polynuclear complexes, cis‐ and trans‐isomeric heterotrimetallic complexes, and their one‐ and two‐electron oxidation products, cis/trans‐ Cp(dppe)FeIINCRuII(phen)2CN‐FeII(dppe)Cp]PF6]2 (cis/trans‐ 1 PF6]2), cis/trans‐Cp(dppe)FeIINCRuII(phen)2CNFeIII‐(dppe)Cp]PF6]3 (cis/trans‐ 1 PF6]3) and cis/trans‐Cp(dppe)FeIIINCRuII(phen)2CN‐FeIII(dppe)Cp]PF6]4 (cis/trans‐ 1 PF6]4) have been synthesized and characterized. Electrochemical measurements show the presence of electronic interactions between the two external FeII atoms of the cis‐ and trans‐isomeric complexes cis/trans‐ 1 PF6]2. The electronic properties of all these complexes were studied and compared by spectroscopic techniques and TDDFT//DFT calculations. As expected, both mixed valence complexes cis/trans‐ 1 PF6]3 exhibited different strong absorption signals in the NIR region, which should mainly be attributed to a transition from an MO that is delocalized over the RuII‐CN‐FeII subunit to a FeIII d orbital with some contributions from the co‐ligands. Moreover, the NIR transition energy in trans‐ 1 PF6]3 is lower than that in cis‐ 1 PF6]3, which is related to the symmetry of their molecular orbitals on the basis of the molecular orbital analysis. Also, the electronic spectra of the two‐electron oxidized complexes show that trans‐ 1 PF6]4 possesses lower vicinal RuII→FeIII MMCT transition energy than cis‐ 1 PF6]4. Moreover, the assignment of MMCT transition of the oxidized products and the differences of the electronic properties between the cis and trans complexes can be well rationalized using TDDFT//DFT calculations. |
| |
| Keywords: | cyanido‐bridged complexes density functional calculations electronic communication geometry isomers |
|
|
