On the Road to MM鈥瞂 Polymers: Redox Properties of Heterometallic Ni路路路Pt Paddlewheel Complexes

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• 作者：Marcello Gennari ; Gonzalo Givaja ; Oscar Castillo ; Laura Hermosilla ; Carlos J. G贸mez-Garc铆a ; Carole Duboc ; Agust铆 Lled贸s ; Ruben Mas-Ballest茅 ; Felix Zamora
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：October 6, 2014
• 年：2014
• 卷：53
• 期：19
• 页码：10553-10562
• 全文大小：493K
• ISSN：1520-510X

文摘

On the quest of heterometallic mixed-valence MM鈥瞂 chains, we have prepared two stable discrete bimetallic compounds: the reduced (PPN)[ClNi(渭-OSCPh)<sub>4sub>Pt] (PPN = bis(triphenylphosphine)iminium; OSCPh = benzothiocarboxylato) and the oxidized [(H<sub>2sub>O)Ni(渭-OSCPh)<sub>4sub>PtCl] species. The role of the aqua and chlorido axial ligands is crucial to facilitate oxidation of the {Ni(渭-OSCPh)<sub>4sub>Pt} core. Experimental and theoretical analyses indicate that a NiPt-Cl/Cl-NiPt isomerization process occurs in the oxidized species. The electronic structure of the reduced system shows two unpaired electrons, one located in a d<sub>xsub><sup><sub>2sub>sup><sub>鈥?i>ysub><sup><sub>2sub>sup> orbital of the Ni(II) ion and a second in the antibonding d<sub>zsub><sup><sub>2sub>sup>鈥揹<sub><sub>zsub><sup>2sup>sub> combination from the Ni(II) and Pt(II) centers. Oxidation occurs by removing one electron from this second multicenter molecular orbital. Although the mixed-valence character of the oxidized species makes the isolation of MM鈥瞂 chains very attractive, such polymeric structure is prevented by the low Pt鈥揅l路路路Ni interaction energy and the high tendency of Ni centers to coordinate water molecules. Thus, this work offers valuable insights and hints to engage the production of heterometallic mixed-valence MM鈥瞂 chains, which still is a challenging task.