Premium
A Trinuclear Iron(III) Complex of a Triple Noninnocent Ligand for Spin‐Structured Molecular Conductors
Author(s) -
Hoshino Norihisa,
Akutagawa Tomoyuki
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201804280
Subject(s) - ligand (biochemistry) , electrical conductor , spin (aerodynamics) , chemistry , materials science , crystallography , physics , composite material , biochemistry , receptor , thermodynamics
N , N′,N′ ′, N ′′′, N ′′′′, N ‐(Triphenylene‐2,3,6,7,10,11‐hexayl)hexapicolinamide (H 6 hptp), a triangular ligand containing three noninnocent coordination sites, and its trinuclear iron(III) complex (PPh 4 ) 3 [Fe III 3 (hptp) 6 (CN) 6 ] were prepared. In this complex, three low‐spin Fe 3+ ions are coordinated by the triangular hptp 6− bridging ligand at its apices. Cyclic voltammetry of (PPh 4 ) 3 [Fe III 3 (hptp) 6 (CN) 6 ] in PhCN solution showed one reductive wave for 3 Fe 2+ /3 Fe 3+ and three oxidative waves for the hptp 6− ligand. The controlled‐potential electronic spectra of the solution presented broad absorption bands in the near‐IR (NIR) region for oxidations because a π‐radical is generated on the hptp 6− ligand. The EPR spectra of frozen solutions also showed large oxidization‐state dependent differences caused by the strong exchange interactions between the electrons in the d orbitals of the Fe 3+ ions and those of the π‐radicals in the hptp 6− ligand. The electronic and magnetic states of the oxidized species were investigated using density functional theory.