Yumei Kong

Detection and analysis of reactive oxygen species (ROS) generated by nano-sized TiO2 powder under ultrasonic irradiation and application in sonocatalytic degradation of organic dyes

Recently, the sonocatalytic technology using various semiconductors combined with ultrasonic irradiation has been received much attention to solve the environmental problems. In this paper, nano-sized titanium dioxide (TiO(2)) powder as a sonocatalyst was irradiated by ultrasound and the generation of reactive oxygen species (ROS) during sonocatalytic reaction process has been estimated by the method of Oxidation-Extraction Photometry (OEP). That is, the 1,5-diphenylcarbohydrazide (DPCI) can be oxidized by ROS into diphenylcarbonzone (DPCO), which can be extracted by the mixed solution of benzene and carbon tetrachloride and show the great absorbance at 563 nm wavelength. The synergistic effect of TiO(2) and ultrasonic irradiation was estimated and some influencing factors, such as ultrasonic irradiation time and TiO(2) addition amount on the generation of ROS were reviewed. The results indicate that the quantities of generated ROS increase with the increase of ultrasonic irradiation time and TiO(2) addition amount. Moreover, the relationship between quantities of generated ROS and DPCI concentration was also studied. And then, several quenchers were used to determine the kind of the generated ROS. At last, the researches on the sonocatalytic degradation of organic dyes and the corresponding reaction kinetics have also been performed, which is found to follow the pseudo first-order kinetics approximately. This paper may offer some important subjects for broadening the applications of sonocatalytic technology.

Spectroscopic analyses on ROS generation catalyzed by TiO2, CeO2/TiO2 and Fe2O3/TiO2 under ultrasonic and visible-light irradiation.

In this work, the TiO2, CeO2/TiO2 and Fe2O3/TiO2 powders were irradiated, respectively, by ultrasound and visible-light, and the generation of reactive oxygen species (ROS) were estimated by the method of Oxidation-Extraction Photometry (OEP). That is, the 1,5-diphenyl carbazide (DPCI) can be oxidized by generated ROS into 1,5-diphenyl carbazone (DPCO), which can be extracted by mixed solvent of benzene and carbon tetrachloride. The DPCO extract liquor displays an obvious absorbance at 563 nm wavelength. In addition, some influencing factors, such as (ultrasonic or visible-light) irradiation time, catalyst addition amount and DPCI concentration, on the generation of ROS were also reviewed. The results indicated that the quantities of generated ROS increase with the increase of (ultrasonic or visible-light) irradiation time and catalyst addition amount. Moreover, the displayed quantities of ROS are also related with DPCI concentration. And then, several radical scavengers were used to determine the kinds of the generated ROS. At last, the researches on the sonocatalytic and photocatalytic degradation of several organic dyes have also been performed. It is wished that this paper might offer some important subjects for broadening the applications of sonocatalytic and photocatalytic technologies in future environment treatment.

Syntheses, structural determination, and binding studies of binuclear eight-coordinate (enH2)[GdIII 2(pdta)2(H2O)2] · 8H2O and mononuclear nine-coordinate (enH2)[GdIII(egta)(H2O)]2 · 6H2O

The (enH2)[GdIII 2(pdta)2(H2O)2] · 8H2O (1) (en = ethylenediamine and H4pdta = propylenediamine-N, N, N′, N′-tetraacetic acid) and (enH2)[GdIII(egta)(H2O)]2 · 6H2O (2) (H4egta = ethyleneglycol-bis-(2-aminoethylether)-N, N, N′, N′-tetraacetic acid) complexes were synthesized and characterized by infrared spectrum, thermal analysis, and single-crystal X-ray diffraction. The complex (enH2)[GdIII 2(pdta)2(H2O)2] · 8H2O has a binuclear eight-coordinate structure with pseudo square antiprism and crystallizes in the monoclinic crystal system with C2/c space group. Through a carboxylate bridge, an infinite 1-D zigzag polymeric binuclear [GdIII 2(pdta)2(H2O)2]2− complex anion is formed. All infinite zigzag polymeric complex anions link through hydrogen bonds, yielding a layer structure. (enH2)[GdIII(egta)(H2O)]2 · 6H2O has a mononuclear nine-coordinate structure with pseudo monocapped square antiprism and crystallizes in the monoclinic crystal system with P21/n space group. Each enH2 2+ cation, through hydrogen bonds, connects two adjacent [GdIII(egta)(H2O)]− complex anions.

Syntheses, structural determination, and binding studies of nine-coordinate mononuclear complexes (EnH2)3[EuIII(Etha)]2 · 11H2O and (EnH2)[EuIII(Egta)(H2O)]2 · 6H2O

Two novel ethylenediaminium salt of europium complexes with aminopolycarboxylic acid ligands, (EnH2)3[EuIII(Ttha)]2 · 11H2O (I) (En is ethylenediamine, H6Ttha is triethylenetetramine-N,N,N′,N″,N‴,N‴-hexaacetic acid) and (EnH2)[EuIII(Egta)(H2O)]2 · 6H2O (II) (H4Egta is ethyleneglycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid) complexes were synthesized, and their crystal structures were determined by single-crystal X-ray diffraction techniques. Both of the two complexes adopt nine-coordinate structures with the pseudo-monocapped square antiprism and crystallize in the monoclinic crystal system with the P21/n space group. The crystal data for complex I are as follows: a = 17.8262(8), b = 19.3137(5), c = 20.6233(8) Å, β = 111.301(2)°, V = 6615.3(4) Å3, Z = 8, ρc = 1.677 mg/m3, μ = 1.981 mm−1, F(000) = 3432, R = 0.0308, and wR = 0.0737 for 43622 observed reflections with I ≥ 2σ(I). The crystal data for complex II are as follows: a = 12.952(3), b = 12.618(2), c = 14.809(3) Å, β = 105.695(2)°, V = 2330.0(8) Å3, Z = 4, ρc = 1.800 mg/m3, μ = 2.765 mm−1, F(000) = 1276, R = 0.0297, and wR = 0.0638 for 18416 observed reflections with I ≥ 2σ(I). One remarkable feature of the two complexes is that the protonated [EnH22+] cations conjugating to [EuIII(Ttha)]26− and [EuIII(Egta)(H2O)]22− complex anions are reviewed, respectively, which open the path for the EuIII complexes conjugating with other various biomolecules.

Synthesis and structural determination of the first eight-coordinate rare earth metal complex with a six-member ring, (NH4)[EuIII(pdta)(H2O)] · H2O

(NH4)[EuIII(pdta)(H2O)] · H2O has been synthesized and characterized by infrared spectrum, fluorescence spectrum, elemental analyses and single-crystal X-ray diffraction techniques. It crystallizes in the monoclinic system with space group P21/n, a = 12.7700(15) Å, b = 9.3885(11) Å, c = 14.4070(18) Å, α = 90°, β = 95.950(2)°, γ = 90°, V = 1718.0(4) Å3, Z = 4, M = 508.28, D c = 1.965 g cm−3, μ = 3.708 mm−1, F(000) = 1108. The structure was refined to R 1 = 0.0238 for 3469 observed reflections (I > 2σ(I)). The EuIIIN2O6 part in the [EuIII(pdta)(H2O)]− complex anion has an eight-coordinate structure with a distorted square anti-prismatic conformation, in which six coordination positions, two nitrogen atoms and four oxygen atoms are from one pdta (=propylenediaminetetraacetic acid) ligand, the seventh position is an oxygen (O(8A)) from another pdta and the eighth coordination site is occupied by a water molecule. (NH4)[EuIII(pdta)(H2O)] · H2O is the first eight-coordinate complex with a six-member ring in the rare earth metal complexes with aminopolycarboxylic acid ligands.

Syntheses and Structures of Nine-Coordinate NH4|HoIII(Edta)(H2O)3] ·1.5H2O, (NH4)4[Ho2III(Dtpa)2]·9H2O, and (NH4)3[HoIII(Ttha)] ·5H2O Complexes

The three title complexes, NH4[HoIII(Edta)(H2O)3] · 1.5H2O (I) (H4Edta = ethylenedianine-N,N,N′,N′-tetraacetic acid), (NH4)4[Ho2III (Dtpa)2] · 9H2O (II) (H5Dtpa = diethylenetriamine-N,N,N′,N″,N″-entaacetic acid), and (NH4)3[HoIII(Ttha)] · 5H2O (III) (H6 Ttha = triethylenetetramine-N,N,N′,N″,N‴,N‴-hexaacetic acid), have been prepared and characterized by FT-IR, elemental analyses, and single-crystal X-ray diffraction technique. Complex I has a nine-coordinate mononuclear structure with distorted monocapped square antiprismatic conformation and its crystal structure belongs to orthorhombic system and Fdd2 space group. The crystal data are as follows: a = 19.343(9), b = 35.125(17), c = 12.364(6) Å, V = 8400(7) Å3, Z = 16, M = 552.26, ρcalcd = 1.747 g cm−3 μ = 3.828 mm−1, and F(000) = 4368. Complex II has a binuclear nine-coordinate pseudomonocapped square antiprismatic conformation and its crystal structure belongs to triclinic system and space P1 group. The crystal data are as follows: a = 9.7637(16), b = 9.9722(16), c = 12.945(2) Å, α= 85.853(2)°, β = 77. 140(2)°, γ = 77.140(2)°, V = 1198.4(3) Å3, Z = 1, M = 1340.80, ρcalcd = 1.858 g cm−3, μ = 3.380 mm−1, and F(000) = 674. As for complex III, it also has nine-coordinate mononuclear structure with distorted tricapped trigonal prism and its crystal structure belongs to monoclinic system andP21/c space group. The crystal data are as follows: a = 10.349(3), b = 12.760(4), c = 23.142(7) Å, β = 91.020(6)°, V = 3055.6(16) Å3, Z = 2, M = 797.55, ρcalcd = 1.734 g cm−3, μ = 2.674 mm−1, and F(000) = 1624. The results showed that although the ligands are different from one another in the shape and the numbers of coordination atoms, they all have nine-coordinate structures. However, one of them has binuclear structure and the other two have mononuclear structures because of the difference of the ligands.

The syntheses and structures of ten-coordinate K6[PrIII(ttha)]2 · 10H2O and nine-coordinate K4[ (Httha)2] · 14H2O complexes

The title complexes, K6[PrIII(ttha)]2 · 10H2O and K4[ (Httha)2] · 14H2O (H6ttha = triethylenetetraaminehexaacetic acid), have been prepared and characterized using IR, elemental analyses and single-crystal X-ray diffraction techniques. The crystal of K6[PrIII(ttha)]2 · 10H2O has a ten-coordinate mononuclear structure with a distorted bicapped square antiprismatic prism, belonging to the triclinic crystal system and P space group. The crystal data are as follows: a = 9.697(4) Å, b = 16.183(6) Å, c = 20.957(8) Å, V = 2963.0(19) Å3, Z = 2. The crystal of K4[ (Httha)2] · 14H2O belongs to the monoclinic crystal system and P21/n space group, with a = 11.2787(10) Å, b = 25.706(2) Å, c = 22.058(2) Å, V = 6231.5(10) Å3, Z = 4, and is a binuclear nine-coordinate pseudo-monocapped square antiprism. The results provide the dividing point of nine-coordinate and ten-coordinate rare earth complexes with ttha ligand.

Spectroscopic investigation on protein damage by ciprofloxacin under ultrasonic irradiation.

In recent years, sonodynamic activities of many drugs have attracted more and more attention of researchers. The correlative study will promote the development of sonodynamic therapy (SDT) in anti-tumor treatment. In this work, bovine serum albumin (BSA) was used as a protein model to investigate the intensifying effects of ciprofloxacin (CPFX) ultrasonically induced protein damage by UV-vis and fluorescence spectra. Meanwhile, the conformation of BSA is changed upon the addition of CPFX and metal ions under ultrasound (US) so that the damaging site of BSA is considered. Various influencing factors, such as US irradiation time, metal ions, solution temperature and ionic strength, on the ultrasonically induced BSA damage are discussed. It was showed that CPFX could enhance ultrasonically induced BSA damage. The damage degree of BSA was aggravated with the increasing of US irradiation time, solution temperature, ionic strength as well as the addition of metal ions. Furthermore, the reactive oxygen species (ROS) in reaction system were detected by oxidation-extraction photometry (OEP). Experimental results also showed that US could activate CPFX to produce ROS, which were mainly determined as superoxide radical anion (.O2-) and hydroxyl radical (.OH).

Syntheses and structures of six-coordinate K[GaIII(Cydta)] · 2H2O and K[GaIII(Pdta)] · 3H2O complexes

The title complexes, K[GaIII(Cydta)] · 2H2O(Cydta = trans-1,2-cyclohexanediaminetetraacetic acid) and K[GaIII(Pdta)] · 3H2O (Pdta = propylenediaminetetraacetic acid), were prepared, and their structures were studied by IR spectra, elemental analyses, NMR spectra, and single-crystal X-ray diffraction techniques. In the K[GaIII(Cydta)] · 2H2O complex, the Ga3+ is six-coordinated by the Cydta ligand yielding an octahedral conformation, and the complex crystallizes in the monoclinic system with the P21/c space group. The crystal data are as follows: a = 16.5039(19), b = 13.1499(16), c = 8.5204(10) Å, β = 101.650(2)°, V = 1811.0(4) Å3, Z = 4, ρ = 1.757 g/cm3, μ = 1.805 mm−1, F(000) = 984, R = 0.0291, and wR = 0.0698 for 3713 observed reflections with I ≥ 2σ(I). In the K[GaIII(Pdta)] · 3H2O complex, the Ga3+ is also six-coordinated by the Pdta ligand yielding an almost standard octahedral conformation, and the complex crystallizes in the orthorhombic system with P212121 space group. The crystal data are as follows: a = 8.8913(10), b = 11.6181(13), c = 17.0227(19) Å, V = 1758.4(3) Å3, Z = 4, ρ = 1.757 g/cm3, μ = 1.862 mm−1, F(000) = 952, R = 0.0288, and wR = 0.0724 for 3556 observed reflections with I ≥ 2σ(I).

Syntheses and structures of mononuclear eight-coordinate Na[ErIII(Cydta)(H2O2]·5H2O (Cydta = trans-1,2-cyclohexanediaminetetraacetic acid) and binuclear nine-coordinate Na2[SmIII(Cydta)][SmIII(Cydta)(H2O)3] · 11H2O

The title complexes, Na[ErIII(Cydta)(H2O)2] · 5H2O (I) and Na2[SmIII(Cydta)][SmIII(Cydta)(H2O)3] · 11H2O (II) (Cydta is trans-1,2-cyclohexanediaminetetraacetic acid), are prepared and characterized using IR, elemental analyses, and single-crystal X-ray diffraction techniques. Crystal I belongs to triclinic system (space group P1), which has a mononuclear eight-coordinate slightly distorted square antiprismatic conformation. The crystal data are as follows: a = 8.371(12) Å, b = 9.952(14) Å, c = 14.74(2) Å, α = 88.32(2)°, β = 76.30(2)°, γ = 87.87(2)°, V = 1192(3) Å3, Z = 1, ρ = 1.835 g/cm3, μ = 3.612 mm−1, F(000) = 658, R = 0.0194, and wR = 0.0520 for 4130 observed reflections with I≥2σ(I). Crystal II belongs to monoclinic system (space group P21/n), which has the binuclear nine-coordinate structure with tricapped trigonal prismatic conformation for Sm(1) and the pseudomonocapped square antiprismatic conformation for Sm(2). The crystal data are as follows: a = 12.283(6) Å, b = 15.626(7) Å, c = 25.875(12) Å, β = 97.962(7)°, V = 4919(4) Å3, Z = 4, ρ = 1.717 g/cm3, μ = 2.476 mm−1, F(000) = 2536, R = 0.0781, and wR = 0.1745 for 8554 observed reflections with I ≥ 2σ(I).