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[M(bpy) 3 ] (M = Fe, Ru, Os): New Crystalline Materials from the reductive electrocrystallization of [M(bpy) 3 ](PF 6 ) 2
Author(s) -
PérezCordero Eduardo,
Buigas Rosanna,
Brady Nancy,
Echegoyen Luis,
Arana Claudia,
Lehn JeanMarie
Publication year - 1994
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19940770504
Subject(s) - chemistry , crystallography , x ray crystallography , inorganic chemistry , diffraction , optics , physics
Reductive electrocrystallization at a constant current density (11.0–11.5 μA/cm 2 ) of millimolar solutions of [M(bpy) 3 ](PF 6 ) 2 , where M = Fe, Ru, or Os, and bpy = 2,2′‐bipyridine in acetonitrile containing 0.1 M Bu 4 NPF 6 results in the formation of dark crystals on the Pt cathode. The crystals grow as long, thin, and shiny needles having a hexagonal cross section of 0.1–0.5 mm in diameter. Combustion microanalyses results are consistent with the composition for [Fe(bpy) 3 ], [Ru(bpy) 3 ], and [Os(bpy) 3 ]. In addition, the chromophores are conserved, as confirmed by recording both the electronic and the 1 H‐NMR spectra after reoxidation of the electrocrystals in humid air. The spectra are identical to those for authentic samples of [Fe(bpy) 3 ] 2+ , [Ru(bpy) 3 ] 2+ , and [Os(bpy) 3 ] 2+ . A ratio of 2.0 ± 0.1 e − /molecule is observed upon completion of the controlled potential electrolysis of a solution of [M(bpy) 3 ] 2+ , which results in the precipitation of a dark solid and the almost complete fading of the color of the original solution. Unexpectedly, the crystals do not exhibit an ESR signal. These data indicate the formation of novel materials, crystalline [Fe(bpy) 3 ], [Ru(bpy) 3 ], and [Os(bpy) 3 ].