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Synthesis of Well‐Defined Bicapped Octahedral Iron Clusters [( tren L) 2 Fe 8 (PMe 2 Ph) 2 ] n ( n =0, −1)
Author(s) -
Sánchez Raúl Hernández,
Willis Alexander M.,
Zheng ShaoLiang,
Betley Theodore A.
Publication year - 2015
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201505671
Subject(s) - chemistry , crystallography , octahedron , amide , ligand (biochemistry) , antiferromagnetism , crystal structure , redox , electron paramagnetic resonance , amine gas treating , cluster (spacecraft) , hydrothermal synthesis , ferrous , octahedral molecular geometry , magnetic susceptibility , inorganic chemistry , stereochemistry , hydrothermal circulation , nuclear magnetic resonance , biochemistry , physics , receptor , organic chemistry , computer science , programming language , condensed matter physics , seismology , geology
The synthesis of polynuclear clusters with control over size and cluster geometry remains an unsolved challenge. Herein, we report the synthesis and characterization of open‐shell octairon clusters supported by two heptaamine ligands [ o ‐H 2 NC 6 H 4 NH(CH 2 ) 2 ] 3 N ( tren LH 9 ). The crystal structure of the all‐ferrous species ([ tren L) 2 Fe 8 (PMe 2 Ph) 2 ] ( 1 ) displays a bicapped octahedral geometry with FeFe distances ranging from 2.4071(6) to 2.8236(5) Å, where the ligand amine units are formally in amine, amide, and imide oxidation states. Several redox states of the octairon cluster are accessible, as ascertained using cyclic voltammetry. The one‐electron‐reduced clusters [M] + [( tren L) 2 Fe 8 (PMe 2 Ph) 2 ] − (M=Bu 4 N ( 2 a ); (15‐crown‐5)Na(thf) ( 2 b )) were isolated and characterized. Variable‐temperature magnetic susceptibility data indicates that the exchange coupling within the [Fe 8 ] core is antiferromagnetic which is attenuated upon reduction to the mixed valent anion.