英语翻译
Two New One-Dimensional Chain-Like Compounds
Constructed from the Sandwich-Type Polyoxotungstate
Clusters
Introduction
Polyoxometalates (POMs),as metal–oxygen cluster ions,have been attracting
extensive interests due to their enormous structural varieties and the accompanying
multitude of potential applications in the field of catalysis,electrochemistry,
electrochromism and magnetism [1,2].The evolution of POM chemistry is
dependent upon the synthesis of novel polyoxoanions possessing unique structures
and physicochemical versatilities.With the aim of producing novel polyoxoanions,
much attention has focused on the self-assembly of preformed building
units.In this subfamily,lacunary POMs represent one of the excellent inorganic
precursors to construct new compounds with diverse nuclearities and structural
features combined with interesting catalytic,electrochemical and magnetic
properties,which have attracted considerable attention worldwidely [3].Up to
now,numerous sandwich-type polyoxoanions have been synthesized by the
reactions of the lacunary polyoxoanions with the transition metal cations,and
mostly belong to the well-known Weakley-,Herve´-,Krebs- and Knoth-type
sandwich structures [4,5].They each accommodated a paramagnetic transition
metal-set between two lacunary polyoxoanions,which make them exhibit
interesting catalytic,magnetic,electrochemical properties.It is known to all that
the sandwich-type polyoxoanions have a larger volume and a more-negative
charge than that of the commonly used polyoxovanadate/-molybdate in constructing
the extended structure materials,which allow the formation of higher
coordination numbers with transition-metal cations.These sandwich-type clusters
should be the excellent precursors,but are used scarcely for constructing the
extended structure materials [6].In this article,we reported two new onedimensional
chain-like compounds constructed from the M4-sandwiched
polyoxoanions.
Materials and Methods
All chemicals were commercially purchased and used without further purification.
K8[b-GeW11O39] \1 14H2O and K8[c-SiW10O36] \1 12H2O were synthesized according
to the literatures [7] and characterized by IR spectra.Elemental analyses (H)
were performed on a Perkin-Elmer 2400 CHN elemental analyzer; Si,Ge,W,Mn,
Cu,Na and K were analyzed on a PLASMA-SPEC(I) ICP atomic emission
spectrometer.IR spectra were recorded in the range 400–4,000 cm-1 on an Alpha
Centaurt FT/IR Spectrophotometer using KBr pellets.TG analyses were performed
on a Perkin-Elmer TGA7 instrument in flowing N2 with a heating rate of
10 \2C min-1.Electrochemical measurements were carried out on a CHI 660A
electrochemical workstation at room temperature (25–30 \2C) under nitrogen
atmosphere.A pHS-25B type pH meter was used for pH measurement.