Synthesis and Characterization of Diiron(II) Complex with the Asymmetric Ligand Fixed into Internal Surface of Mesoporous Silica
A new diferrous complex with asymmetric coordination sites, [Fe2(μ-OBz)(L)](ClO4)2 (1) (L = N,N-bis(6-methyl-2-pyridylmethyl)-N’,N’-bis(6-pivalamido-2-pyridylmethyl)-1,3-diaminopropan- 2-ol), was synthesized, which was immobilized in the internal surface of mesoporous silica (FSM-16) to construct a functional material (1A). The reaction of 1 with O2 in acetone at –50°C generated a peroxo complex 2 [λmax = 589 nm (ε = 2200 M-1 cm-1), ν16O-16O = 890 and 908 cm-1 (ν18O-18O = 852 cm-1)]. The μ-peroxo complex 2 was decomposed by bubbling of Ar gas without releasing O2, but the reaction of 1A with O2 at ambient temperature also formed a peroxo complex (2A) without decomposition. The reflectance spectrum of 2A showed a band assignable to the LMCT band from peroxo to a Fe(III) ion at 588 nm. Compound 2A is very stable, whose half-life time is 45 min, in contrast to a short life of 2 (310 sec). 2A released dioxygen by heating up to 75°C in vacuo, which was regenerated by bubbling of dioxygen at ambient temperature.
Masayuki Nogami, Riguang Jin, Toshihiro Kasuga and Wantai Yang
Y. Kajita, R. Tsujimura, H. Arii, M. Konaka, T. Okumura, Y. Funahashi, T. Ozawa, H. Masuda, "Synthesis and Characterization of Diiron(II) Complex with the Asymmetric Ligand Fixed into Internal Surface of Mesoporous Silica", Advanced Materials Research, Vols. 11-12, pp. 285-290, 2006