Materials Research Bulletin, Vol.37, No.4, 647-651, 2002
Silica-[Fe(bPY)(3)](2+) composite particles with photo-responsive change of color and magnetic property
Photo-induced complex formation of tris-2,2'-bipyridine iron(II) complex ([Fe(bpy)(3)](2+)) from the mixture of FeCl3 and 2,2'-bipyridine was achieved in silica gel containing 150-300 mum silica particles, derived from a complex emulsion with HCl aqueous solution and tetraethyl orthosilicate (TEOS). More than 95% of Fe(III) and 2,2'-bipyridine were incorporated in silica particles. Yellow-red color change, due to [Fe(bpy)(3)](2+), was observed by irradiation with 365 nm UV beam at 0.3 mW cm(-2) for 120 s. The complex formation accompanies simultaneous spin transition from the high-spin state of Fe(III) to the low-spin state of Fe(II). (C) 2002 Elsevier Science Ltd. All rights reserved.