Samanta S, Demesko S, Dechert S, Meyer F. A two-in-one pincer ligand and its diiron(II) complex showing spin state switching in solution through reversible ligand exchange.
Angew Chem Int Ed Engl 2015;
54:583-7. [PMID:
25412962 DOI:
10.1002/anie.201408966]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Indexed: 11/09/2022]
Abstract
A novel pyrazolate-bridged ligand providing two {PNN} pincer-type compartments has been synthesized. Its diiron(II) complex LFe2(OTf)3(CH3CN) (1; Tf = triflate) features, in solid state, two bridging triflate ligands, with a terminal triflate and a MeCN ligand completing the octahedral coordination spheres of the two high-spin metal ions. In MeCN solution, 1 is shown to undergo a sequential, reversible, and complete spin transition to the low-spin state upon cooling. Detailed UV/Vis and (19)F NMR spectroscopic studies as well as magnetic measurements have unraveled that spin state switching correlates with a rapid multistep triflate/MeCN ligand exchange equilibrium. The spin transition temperature can be continuously tuned by varying the triflate concentration in solution.
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