Chinese Chemical Letters
journal homepage: www.elsevier.com/locate/cclet
Original article
Efficient photocatalytic properties of a dinuclear iron complex with
bis[2-hydroxybenzaldehyde]hydrazonate ligand
a
a
a,
b
Jing-Wen Ran , Shao-Wen Liu , Peng Wu *, Jun Pei
a
Chemical Engineering College, Huanggang Normal University, Huanggang 438000, China
b
Education Science and Technology College, Huanggang Normal University, Huanggang 438000, China
A R T I C L E I N F O
A B S T R A C T
Article history:
A novel photooxidative system for degrading toxic organic pollutants is reported. A new complex of
Received 13 December 2012
Received in revised form 1 February 2013
Accepted 27 February 2013
Available online 11 April 2013
Fe
2
L
3
(L = bis[2-hydroxybenzaldehyde]hydrazone) synthesized can efficiently activate hydrogen perox-
) to oxidize and mineralize the target complexes rhodamine B (RhB) and methyl orange (MO) in
ide (H
2 2
O
aqueous media under ambient temperature and normal pressure and with visible light irradiation.
ß 2013 Peng Wu. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
Keywords:
Synthesis
Catalysis
Degradation
Mechanism
1
. Introduction
2. Experimental
Some water-soluble metal complexes can mimic peroxidase
and P450 enzymes to catalytically activate oxidants such as H
, and KHSO for the degradation of toxic organic pollutants.
Generally speaking, people focus on dyes because the pollutants
from manufacturing plants are difficult to degrade under natural
conditions and can lead to cancers. Zhao and co-workers [1–4]
reported an aqueous system containing test compounds such as
salicylic acid, p-hydroxybenzoic acid, RhB, Orange II, [Fe(PcS)] and
Ligand H
dehyde (30 mmol) and hydrazine hydrate (15 mmol) in 50 mL
methanol. [Fe O(OOCCH (H O) ] was prepared according to the
following procedure [5,6]. FeCl O (0.1 mol), sodium acetate
Á4H
2
L was readily prepared by mixing 2-hydroxybenzal-
2 2
O ,
O
2
5
3
3
)
6
2
3
2
2
(0.24 mol) and glacial acetic acid (1 mol) were dissolved in 100 mL
of water. The reaction mixture was heated at 70–80 8C under reflux
for 2 h, while bubbling a constant stream of air. The mixture was
cooled to room temperature and the dark-brown precipitate was
filtered, washed with ethanol and ethyl ether, and then dried under
vacuum.
H
2
O
2
. The degradation of organic pollutants is significantly
accelerated with visible-light. With a catalyst/substrate/H
2 2
O
molar ratio of 4:1:100, the degradation time is 160 min and the
removal of total organic carbon (TOC) of RhB in the aqueous RhB/
The synthesis of the complex proceeded as follows: [Fe
(OOCCH (H O) ] (150 mg) was added to a CH OH/H O (4:1)
solution of H L (2.5 mmol) and NaOH (5 mmol) while being stirred,
affording pale sediment immediately. The sediment was dissolved
in CH OH/pyridine (4:1) at 50 8C and filtered. The filtrate was
3
O
3
)
6
2
3
3
2
[
Fe(PcS)]/H
2
O
2
system was about 30% after 8 h of reaction.
(L = bis[2-
2
In this experiment we find a dinuclear complex Fe
2 3
L
hydroxybenzaldehyde]hydrazone) which plays an important role
in mimicking enzymes like peroxidase and P450 enzymes with the
3
allowed to stand in air for a week and brown crystals were formed
at the bottom of the vessel with slow evaporation of the solvent.
2 2
help of environmentally friendly oxidants (H O ). The degradation
and mineralization rates are higher than in the natural enzymes.
Further, the complex was used to explore the structural
characteristics of such enzymes. Herein, we carried out the
experiments to test its catalytic potential in detail.
Yield: 21.2%. Anal. Calcd. for C42
H
32
N
6
Fe
2
O
7
: C 59.74, H 3.82, N
À1
9.95. Found: C 60.02, H 4.01, N 10.03. Selected IR data (cm ):
3446(w), 3044(w), 1624(s), 1536(s), 1203(m), 903(m), 753(s).
During the catalysis process, a 500 W Xe lamp (Lansheng Co.,
Ltd., Shanghai) used as a visible light source was positioned inside a
cylindrical Pyrex vessel [7,8]. Meanwhile, a cutoff filter (diameter
3
cm) was used to completely remove the light of their
wavelengths less than 400 nm and to ensure irradiation only by
visible light ( > 400 nm). The distance between the reaction
*
l