With
different transition metal (TM) complexes as structure-directing
agents or structure-building units, a series of new mercury thioantimonates
with abundant architectures ranging from one-dimensional (1D) ribbons
to two-dimensional (2D) layers have been solvothermally synthesized
and structurally characterized. Compounds [Co(en)3]Hg2Sb2S6 (1) (en = ethylenediamine)
and [Ni(1,2-dap)3]2HgSb3S7Cl (2, 1,2-dap = 1,2-diaminopropane) contain
a discrete 2D [Hg2Sb2S6]
n
2n– layer and
1D [HgSb3S7]
n
3n– chain, respectively. Compounds
[Ni(1,2-dap)3]HgSb2S5 (3) and [Mn(dien)2]HgSb2S5 (4, dien = diethylenetriamine) feature distinct 2D
[HgSb2S5]
n
2n– layer and 1D [HgSb2S5]
n
2n– ribbon, respectively, whereas the 1D [HgSb2S5]
n
2n– chains are attached by [TM(tren)]2+ complexes via TM–S
bonds to form 1D {[TM(tren)]HgSb2S5}
n
ribbons in compounds [TM(tren)]HgSb2S5 (TM = Mn (5), Fe (6), Co
(7), tren = tris(2-aminoethyl)amine). Compounds [TM(dien)2]Hg3Sb4S10 (TM = Mn (8), Co(9), Ni(10)) feature 2D [Hg3Sb4S10]
n
2n– anionic layers separated by
[TM(dien)2]2+ cations. The most interesting
structural feature of these compounds is the presence of three different
types of coordination environments of Hg centers including linear
[HgS2] unit, [HgS3] triangle, and [HgS4] tetrahedron. The optical properties and thermal stabilities of
the title compounds were studied by UV–vis spectra and thernogravimetric
analyses, respectively. The photocatalytic experiments indicated that 3, 4, and 10 were able to degrade
rhodamine B (RhB) under visible irradiation.
We describe a nonenzymatic electrochemical sensor for uric acid. It is based on a carbon nanotube ionic-liquid paste electrode modified with poly(β-cyclodextrin) that was prepared in-situ by electropolymerization. The functionalized multi-walled carbon nanotubes and the surface morphology of the modified electrodes were characterized by transmission electronic microscopy and scanning electron microscopy. The electrochemical response of uric acid was studied by cyclic voltammetry and linear sweep voltammetry. The effects of scan rate, pH value, electropolymerization cycles and accumulation time were also studied. Under optimized experimental conditions and at a working voltage of 500 mV vs. Ag/ AgCl (3 M KCl), response to uric acid is linear in the 0.6 to 400 μΜ and in the 0.4 to 1 mΜ concentration ranges, and the detection limit is 0.3 μΜ (at an S/N of 3). The electrode was successfully applied to the detection of uric acid in (spiked) human urine samples.
Two new isostructural quaternary
tin(IV) antimony(III) sulfides,
[TM(en)3][SnSb4S9] [TM = Ni
(1), Co (2); en = ethylenediamine], and
one mixed-valent thioantimonate (III and V), [Mn(dien)2]2Sb4S9 (3, dien
= diethylenetriamine), have been solvothermally synthesized and structurally
characterized. In the structures of 1 and 2, four neighboring SbS3 trigonal pyramids are condensed
via corner-sharing to form bow-like Sb4S9 tetramers,
which are further interconnected by SnS6 octahedra into
the three-dimensional (3D) chiral [SnSb4S9]2– framework with two types of one-dimensional (1D)
chiral channels along the c axis. Compound 3 features a 3D network composed of 1D anionic [Sb4S9]4– chains and [Mn(dien)2]2+ complexes interconnected via various hydrogen
bonds. The most interesting structural feature of 3 is
the presence of two different oxidation states of antimony centers
in the 1D [Sb4S9]4– chain
with three different types of coordination environments, respectively.
The optical absorption spectra indicate that the band gaps of compounds 1, 2, and 3 are 2.07, 2.04, and
2.29 eV, respectively. The thermal stabilities and magnetic properties
of the title compounds are also studied.
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