Synthesis of rhodium(III), iridium(III) and osmium(III) complexes with tris(2-aminoethanethiolato)cobalt(III)

Polynuclear sulfur bridged complexes where the neutral complex tris(2-aminoethanethiolato)cobalt(III) acts as a tridentate ligand to rhodium(III), iridium(III) and osmium(III) have been prepared. These complexes have been characterized by electronic spectroscopy, vibrational spectroscopy and nuclear magnetic resonance spectroscopy. Along with the previously prepared complexes of iron(III), ruthenium(III) and cobalt(III), these complexes form two series of complexes with the group 8 and group 9 elements from all three transition series.     

New complexes of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III) and Gd(III) ions with morin

New solid complex compounds of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III) and Gd(III) ions with morin were synthesized. The molecular formula of the complexes is Ln(C₁₅H₉O₇)₃ · nH₂O, where Ln is the cation of lanthanide and n = 6 for La(III), Sm(III), Gd(III) or n = 8 for Ce(III), Pr(III), Nd(III) and Eu(III). Thermogravimetric studies and the values of dehydration enthalpy indicate that water occurring in the compounds is not present in the inner coordination sphere of the complex. The structure of the complexes was determined on the basis of UV-visible, IR, MS, ¹H NMR and ¹³C NMR analyses. It was found that in binding the lanthanide ions the following groups of morin take part: 3OH and 4CO in the case of complexes of La, Pr, Nd, Sm and Eu, or 5OH and 4CO in the case of complexes of Ce and Gd. The complexes are five- and six-membered chelate compounds.     

Diphosphinoazine rhodium(III) and iridium(III) octahedral complexes

Rhodium(III) and iridium(III) octahedral complexes of general formula [MCl₃{R₂PCH₂C(Bu^t)NNC(Bu^t)CH₂PR₂}] (M = Rh, Ir; R = Ph, c-C₆H₁₁, Prⁱ, Bu^t; not all the combinations) were prepared either from the corresponding diphosphinoazines and RhCl₃ · 3H₂O or by the oxidation of previously reported bridging complexes [{MCl(1,2-η:5,6-η-CHCHCH₂CH₂CHCHCH₂CH₂)}₂{μ-R₂PCH₂C(Bu^t)NNC(Bu^t)CH₂PR₂}] with chlorine-containing solvents. Depending on the steric properties of the ligands, complexes with facial or meridional configuration were obtained. Crystal and molecular structures of three facial and two meridional complexes were determined by X-ray diffraction. Hemilability of ligand in the complex fac-[RhCl₃{(C₆H₁₁)₂PCH₂C(Bu^t)NNC(Bu^t)CH₂P(C₆H₁₁)₂}] consisting in reversible decoordination of the phosphine donor group in the six-membered ring was observed as the first step of isomerization between fac and mer isomers.     

Nature and composition of La(III), Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Dy(III) and Ho(III) complexes of embelin

The isolation and characterization of nine polymeric complexes of the general formula [M(L)_1.5S₂]_n (where M is the metal ion, L the ligand and S the solvent, C₂H₅OH) of La(III) and Ce(III), Pr(III), Nd(III), Sm(III), Gd(III), Tb(III), Dy(III), Ho(III) with.the biologically active compound embelin using elemental and thermal analysis, infrared and electronic spectral studies is reported.     

Reactions of tetrabromoaurate(III) and dicyanodibromoaurate(III) with uracil

The reactions of AuBr^?₄ and Au(CN)₂Br^?₂ with uracil in water produce gold(I) and 5-bromouracil and/or 5-bromo-6-hydroxy-5,6-dihydrouracil. The observed kinetics of the reactions are consistent with a mechanism involving a fast redox pre-equilibrium followed by bromination of the pyrimidine (X^?= Br^? or CN^?):

The calculated equilibrium constant K = k₁/k_?1 is 1.6 × 10^?10 M for AuBr^?₄ and 1.7 × 10^?11 M for Au(CN)₂Br^?₂. Specific rates for the reduction of AuBr^?₄ are correspondingly greater than those for the reduction of Au(CN)₂Br^?₂.     

Bromodeoxyuridine (BrdU) immunocytochemistry by exonuclease III (Exo III) digestion

Summary A new procedure is described to generate single-stranded DNA by exonuclease III (Exo III) digestion for bromodeoxyuridine (BrdU) immunocytochemistry on tissue sections. We compared this procedure with the most widely used procedure of DNA denaturation with 2 N HCl. In vivo and in vitro pulse and continuous labelling of tissues and cells were used. The specimens were fixed in formalin, ethanol, glutaraldehyde, Carnoy's, Bouin's or Zamboni's fixative and embedded in paraffin or used unfixed as cryostat sections or cytospin preparations. After Exo III digestion, BrdU substituted DNA was detected irrespective of the fixation procedure applied. The optimal protocol for nuclease digestion appeared to be simultaneous incubation, of 10 Units Exo III per ml EcoRI buffer and anti-BrdU monoclonal antibody at 37° C. The advantages of Exo III digestion for BrdU immunocytochemistry compared to acid denaturation were: less non-specific nuclear background reactivity, no DNA renaturation, less DNA loss, optimal nuclear morphology, increase in antibody efficiency and the possibility for simultaneous detection of acid-sensitive tissue constituents. Disadvantages of the Exo III digestion are decreased sensitivity and the need for more rigorous pepsin pretreatment. We conclude that Exo III digestion of DNA is an appropriate alternative for acid denaturation for BrdU immunocytochemistry on sections of pulse-labelled specimens.     

Bromodeoxyuridine (BrdU) immunocytochemistry by exonuclease III (Exo III) digestion.

A new procedure is described to generate single-stranded DNA by exonuclease III (Exo III) digestion for bromodeoxyuridine (BrdU) immunocytochemistry on tissue sections. We compared this procedure with the most widely used procedure of DNA denaturation with 2 N HCl. In vivo and in vitro pulse and continuous labelling of tissues and cells were used. The specimens were fixed in formalin, ethanol, glutaraldehyde, Carnoy's, Bouin's or Zamboni's fixative and embedded in paraffin or used unfixed as cryostat sections or cytospin preparations. After Exo III digestion, BrdU substituted DNA was detected irrespective of the fixation procedure applied. The optimal protocol for nuclease digestion appeared to be simultaneous incubation, of 10 Units Exo III per ml EcoRI buffer and anti-BrdU monoclonal antibody at 37 degrees C. The advantages of Exo III digestion for BrdU immunocytochemistry compared to acid denaturation were: less non-specific nuclear background reactivity, no DNA renaturation, less DNA loss, optimal nuclear morphology, increase in antibody efficiency and the possibility for simultaneous detection of acid-sensitive tissue constituents. Disadvantages of the Exo III digestion are decreased sensitivity and the need for more rigorous pepsin pretreatment. We conclude that Exo III digestion of DNA is an appropriate alternative for acid denaturation for BrdU immunocytochemistry on sections of pulse-labelled specimens.     

微生物氧化As(III)和Sb(III)的研究进展

砷(Arsenic,As)和锑(Antimony,Sb)属于同族元素,具有相似的化学性质,是公认的有毒类金属(metalloid),广泛存在于自然界中。随着人类的发展,环境中砷和锑的污染日益严重,类金属污染环境的修复已经刻不容缓。现已表明,自然界中的微生物在砷和锑的生物地球化学循环中发挥着重要的作用,尤其是微生物的氧化作用,可以将毒性较强的亚砷酸盐[Arsenite,As(III)]和亚锑酸盐[Antimonite,Sb(III)]氧化为毒性较低的砷酸盐[Arsenate,As(V)]和锑酸盐[Antimonate,Sb(V)],被认为是一种潜在的类金属污染环境修复方法。本文就国内外对As(III)氧化菌和Sb(III)氧化菌的多样性、As(III)和Sb(III)微生物氧化调控机制和应用的研究进展进行总结,旨在为深入了解和探索微生物介导的砷和锑生物地球化学循环及污染环境的微生物修复提供参考。     

Chromium(III) interactions with nucleotides. III

Some new derivatives of Cr(III) with 5′AMP, 5′ATP, 5′CMP, 5′GMP, 5′IMP and 5′UMP have been obtained by reaction of the starting complexes cis and trans-[Cr(en)₂Cl₂]Cl with the above nucleotides.The complexes were characterized by elemental analysis, conductivity, infrared and electronic spectroscopy, and EPR for the 5′UMP derivative.In all cases, chlorine has been substituted and one ethylenediamine eliminated. The interaction of Cr(III) with the nucleotide seems to occur through the phosphate group and additional interaction through the heterocyclic ring especially for the 5′GMP and 5′IMP derivatives.The 5′UMP complex seems to be a dimer and the other complexes are polymer.     

Tris(pentachlorophenyl) gold(III) complexes

By reaction of Tl(C₆Cl₅)₂Cl with Au(C₆Cl₅)(tht) (tht = tetrahydrothiophen) or [N(PPh₃)₂] [Au(C₆- Cl₅)Cl] the gold(III) complexes [Au(C₆Cl₅)₃(tht)] or [N(PPh₃)₂][Au(C₆Cl₅)₃Cl] respectively, can be prepared. They are the first tris(pentachlorophenyl)- gold(III) complexes to be reported. The ready displacement of tht by other neutral or anionic ligands leads to the synthesis of Au(C₆Cl₅)₃(Ph₂PCH₂PPh₂) or Q[Au(C₆Cl₅)₃X] (Q=N(PPh₃)₂, PPh₃Me or PPh₂Me₂; X=C₆F₅, SCN, Br or I).     

Adhesion of Dissimilatory Fe(III)-Reducing Bacteria to Fe(III) Minerals

The metabolism of dissimilatory iron-reducing bacteria (DIRB) may provide a means of remediating contaminated subsurface soils. The factors controlling the rate and extent of bacterial F(III) mineral reduction are poorly understood. Recent research suggests that molecular-scale interactions between DIRB cells and Fe(III) mineral particles play an important role in this process. One of these interactions, cell adhesion to Fe(III) mineral particles, appears to be a complex process that is, at least in part, mediated by a variety of surface proteins. This study examined the hypothesis that the flagellum serves as an adhesin to different Fe(III) minerals that range in their surface area and degree of crystallinity. Deflagellated cells of the DIRB Shewanella algae BrY showed a reduced ability to adhere to hydrous ferric oxide (HFO) relative to flagellated cells. Flagellated cells were also more hydrophobic than deflagellated cells. This was significant because hydrophobic interactions have been previously shown to dominate S. algae cell adhesion to Fe(III) minerals. Pre-incubating HFO, goethite, or hematite with purified flagella inhibited the adhesion of S. algae BrY cells to these minerals. Transposon mutagenesis was used to generate a flagellum-deficient mutant designated S. algae strain NF. There was a significant difference in the rate and extent of S. algae NF adhesion to HFO, goethite, and hematite relative to that of S. algae BrY. Amiloride, a specific inhibitor of Na + -driven flagellar motors, inhibited S. algae BrY motility but did not affect the adhesion of S. algae BrY to HFO. S.algae NF reduced HFO at the same rate as S. algae BrY. Collectively, the results of this study support the hypothesis that the flagellum of S. algae functions as a specific Fe(III) mineral adhesin. However, these results suggest that flagellum-mediated adhesion is not requisite for Fe(III) mineral reduction.     

Cellular impact and selectivity of half-sandwich organorhodium(III) anticancer complexes and their organoiridium(III) and trichloridorhodium(III) counterparts

Half-sandwich organorhodium(III) complexes and their trichloridorhodium(III) counterparts are potent anticancer agents that enhance the formation of reactive oxygen species and invoke a strong induction of apoptosis in leukemia cells. The antiproliferative activity towards human MCF-7 and HT-29 adenocarcinoma cells of novel nonintercalating complexes containing the 5-substituted phenanthroline ligands 5,6-dimethylphenanthroline, 5-chlorophenanthroline, and 5-nitrophenanthroline (phen*) increases dramatically in the order [(η(5)-C(5)Me(5))IrCl(phen*)](CF(3)SO(3)) < [(η(5)-C(5)Me(5))RhCl(phen*)](CF(3)SO(3)) < mer-[RhCl(3)(DMSO)(phen*)] (DMSO is dimethyl sulfoxide). Improved activity was also achieved by attaching a cell-penetrating peptide to the dipyrido[3,2-a:2',3'-c]phenazine (dppz) ligand of an organorhodium(III) complex. Whereas 5-substitution led to significant improvements in the activity of the organoiridium(III) and trichloridorhodium(III) compounds in comparison with the parent phenanthroline complex, the IC(50) values of their organorhodium(III) counterparts remained effectively invariable. The high activities of the trichloridorhodium(III) complexes (IC(50) = 0.06-0.13 μM) were accompanied by pronounced selectivity towards human cancer cells in comparison with immortalized HEK-293 cells. In contrast, [(η(5)-C(5)Me(5))RhCl(5,6-Me(2)phen)](CF(3)SO(3)) (phen is phenanthroline) was markedly more active towards BJAB lymphoma cells than ex vivo healthy leukocytes and caused an immediate decrease in cellular adhesion possibly associated with interactions with membrane proteins. Its dppz analogue invoked an initial increase in glycolysis to compensate for reduced respiration before inducing a delayed onset of cell death. Strong antimitochondrial activity with respiration impairment and release of cytochrome c was established for both complexes.     

Spectroscopic studies of aqueous gallium(III) and aluminum(III) citrate complexes

Aqueous gallium(III) citrate complexes have been studied in the 10(-2) M concentration range with extended X-ray absorption fine structure (EXAFS) and FTIR techniques. From EXAFS data, one mononuclear and one oligomeric species were identified at different Ga(III) to citrate ratios. The first shell of the mononuclear complex was found to be distorted, with average Ga-O bond lengths of 1.95 and 2.06 A, in agreement with the solid-state structure of Ga(Cit)2(3-) (Cit=citrate). Also the oligomeric species was found to have a distorted first shell, with average Ga-O bond lengths of 1.95 and 2.04 A. This complex was found to contain two Ga-Ga distances at 3.03 and 3.56 A, typical for edge and corner sharing GaO6 octahedra, respectively. The gallium(III) and aluminum(III) citrate systems were compared by means of FTIR, and were found to be analogous. The IR results suggest that the bond lengths derived from EXAFS for the 1:2 gallium(III) citrate complex also provide a good estimate of the corresponding distances in the mononuclear 1:1 complex. Direct coordination of citrate to the metal ions in the oligomeric gallium(III) citrate complex was indicated from both EXAFS and IR results, and this complex is stoichiometrically analogous to the Al3(H-1Cit)3(OH)(H2O)4- complex, which has been structurally determined. However, while the formation of the aluminum trimer has been shown to be slow, the gallium trimer was significantly more labile with a rate of formation indicated to be in the order of seconds or faster.     

Secondary ligand-metal interactions in rhodium(III) and iridium(III) phosphoramidite complexes

The synthesis, characterization, and application in asymmetric catalytic cyclopropanation of Rh(III) and Ir(III) complexes containing (S_a,R_C,R_C)-O,O′-[1,1′-binaphthyl-2,2′-diyl]-N,N′-bis[1-phenyl-ethyl]phosphoramidite (1) are reported. The X-ray structures of the half-sandwich complexes [MCl₂(C₅Me₅)(1,κP)] (M = Rh, 2a; M = Ir, 2b) show that the metal-phosphoramidite bond is significantly shorter in the Ir(III) analog. Chloride abstraction from 2a (with CF₃SO₃SiMe₃ or with CF₃SO₃Me) and from 2b (with AgSbF₆) gives the cationic species [MCl(C₅Me₅)(1,2-η-1,κP)]⁺ (M = Rh, 3a; M = Ir, 3b), which display a secondary interaction between the metal and a dangling phenethyl group (NCH(CH₃)Ph) of the phosphoramidite ligand, as indicated by NMR spectroscopic studies. Complexes 3a and 3b slowly decompose in solution. In the case of 3b, the binuclear species [Ir₂Cl₃(C₅Me₅)₂]⁺ is slowly formed, as indicated by an X-ray study. Preliminary catalytic tests showed that 3a cyclopropanates styrene with moderate yield (35%) and diastereoselectivity (70:30 trans:cis ratio) and with 32% ee (for the trans isomer).     

Absorption and emission spectra of neodymium(III) and europium(III) complexes

The absorption and emission spectra of several complexes of neodymium(III) and europium(III) ions have been examined in order to obtain reliable information relating to coordination number, nature of bonding and symmetry around the lanthanide ion. It has been found that steric factors may force the polyhedron of coordination towards geometries less favourable by ligand–ligand repulsion. In general, no correlation has been found to exist between the low intensity of the hypersensitive transitions and high symmetry or low symmetry and high intensity. The results have pointed out the role of covalency in hypersensitivity.     

Water-soluble cationic gallium(III) and indium(III) phthalocyanines for photodynamic therapy

The new tetra-non-peripheral and peripheral 2-mercaptopyridine substituted gallium(III) and indium(III) phthalocyanine complexes (np-GaPc, p-GaPc, np-InPc and p-InPc) and their quaternized derivatives (Qnp-GaPc, Qp-GaPc, Qnp-InPc and Qp-InPc) have been synthesized and characterized. The quaternized complexes show excellent solubility in water, which makes them potential photosensitizer for use in photodynamic therapy (PDT) of cancer. Photophysical and photochemical properties of these phthalocyanines were investigated. General trends are described for quantum yields of photodegradation, fluorescence and fluorescence lifetimes as well as singlet oxygen quantum yields of these compounds. In this study, the effects of the position of the substituents, the nature of the metal ion and quaternization of the substituents on the photophysical and photochemical parameters of the gallium(III) and indium(III) phthalocyanines are also reported. This study also presented the ionic gallium(III) and indium(III) phthalocyanines strongly bind to bovine serum albumin (BSA).     

Intensity of cooperative vibronic transitions in the Eu(III), Gd(III) and Tb(III) formates spectra

The luminescence and absorption spectra of the lanthanide ions in solids and coordination compounds are characterized by sharp pure electronic lines, which are accompanied by much weaker lines of vibronic transitions. The vibronic spectroscopy is a good probing tool for investigations of the properties of surrounding ion ligands. The lanthanides formates are efficient luminescent crystals and can be viewed as the elementary type in the whole class of the oxygen-containing lanthanide coordination compounds. The intensity of vibronic transitions in spectra of luminescence and excitation europium (⁵D₀→⁷F₂, ⁷F₀→⁵D₂), terbium (⁷F₆→⁵D₄), gadolinium (⁶P_7/2→⁸S_7/2) in anhydrous formates of the type Ln(HCOO)₃ (Ln = Eu, Tb, Gd) and Y(HCOO)₃.2H₂O doped with Eu³⁺ and Tb³⁺ (C ~1 mol%) are reported. Also, the infrared and Raman spectra were obtained for the same compounds. Related integral intensity vibronic sidebands depend on the type of electronic transition of the same ion and varies for the same electronic transitions in different crystals. The obtained experimental data referring to the rate constants of vibronic transitions and intensity distribution in vibronic spectra on normal vibrations of the formate groups are in agreement with the predictions based on the Stavola–Dexter theory of cooperative vibronic transitions.     

Photophysical properties of Pr(III) and Er(III) complexes of poly(pyrazolyl)borates.

The complexes [M(L(1))(2)(NO(3))] and [M(L(2))(NO(3))(2)](M = Pr, Er; L(1)= the tetradentate ligand dihydrobis-[3-(2-pyridyl)pyrazolyl]borate; L(2)= the hexadentate ligand hydrotris-[3-(2-pyridyl)pyrazolyl]borate) were prepared and their structural and photophysical properties studied. All complexes are 10-coordinate. Crystallographic analysis of [M(L(1))(2)(NO(3))](M = Pr, Er) showed that for the smaller Er(iii) ions steric congestion at the metal centre results in two of the Er-N(pyridyl) distances being particularly long, which does not occur with the larger Pr(iii) ion that is better able to accommodate 10-fold coordination. On UV irradiation, both Pr(iii) complexes show, in the visible region of their luminescence spectra, transitions originating from both the (3)P(0) level (at ca. 21,000 cm(-1)) and the (1)D(2) level (at ca. 17,000 cm(-1)), a consequence of the fact that the lowest triplet state of the coordinated pyrazolylborate ligands lies at ca. 24,000 cm(-1) in each case so is high enough in energy to populate both levels. This contrasts with Pr(iii) complexes based on diketonate ligands in which the lower triplet energies of the ligands result in emission from the (1)D(2) level only. At longer wavelengths, near-infrared luminescence arising from the (1)D(2) emissive level is observed with lifetimes (in both the solid state and solution) being in the range 50-110 ns. For both Er(iii) complexes, luminescence at 1530 nm occurs following UV excitation of ligand-centred transitions. In CH(2)Cl(2) both complexes gave dual-exponential luminescence, with the major component having a lifetime characteristic of an intact Er(iii) complex (approximately 1.5 micros) and the minor component being much shorter lived (0.2-0.5 micros), suggestive of a species in which a ligand is partially detached and the metal is solvated, with the two forms interconverting slowly. This behaviour is consistent with the steric congestion and long M-N(pyridyl) bonds that were observed in [Er(L(1))(2)(NO(3))]. In the solid state both Er(iii) complexes gave very weak luminescence, which could be fitted to a single exponential decay with a lifetime similar to the longer-lived of the solution components.     

Carbohydrate-bearing 3-hydroxy-4-pyridinonato complexes of gallium(III) and indium(III)

Gallium and indium complexes with pendant carbohydrates have been prepared and examined for their potential as radiopharmaceuticals. Carbohydrate-bearing 3-hydroxy-4-pyridinone ligand precursors and their tris(ligand)gallium(III) and -indium(III) complexes were synthesized and characterized by mass spectrometry, elemental analysis, and (1)H and (13)C NMR spectroscopy, and in the case of one intermediate, by X-ray crystallography. With three equivalents of ligand, neutral complexes formed with the bidentate hydroxypyridinone moiety complexing the gallium(III) and indium(III) metal centers.     

Chromium(III) and iron(III) inhibits replication of DNA and RNA viruses

The aim of this study was to examine the effect of treating of chromium(III) and iron(III) and their combinations on Herpes Simplex Virus type 1 (HSV-1) and Bovine Viral Diarrhoea virus (BVDV) replication. The antiviral efficacies of chromium(III) and iron(III) on HSV-1 and BVDV were evaluated using Real Time PCR method. Moreover, the cytotoxicity of these microelements was examined using the MTT reduction assay. The IC₅₀ (50% inhibiotory concentration) for the chromium chloride was 1100 μM for Hep-2 cells and 1400 μM for BT cells. The IC₅₀ for the iron chloride was 1200 μM for Hep-2 cells and more than1400 μM for BT cells. The concentration-dependent antiviral activity of chromium chloride and iron chloride against HSV-1 and BVDV viruses was observed. In cultures simultaneously treated with (1) 200 μM of CrCl₃ and 1000 μM of FeCl₃, (2) 1000 μM of CrCl₃ and 200 μM of FeCl₃, (3) 400 μM of CrCl₃ and 800 μM of FeCl₃, (4) 800 μM of CrCl₃ and 400 μM of FeCl₃ a decrease in number of DNA or RNA copies was observed compared with control cells and cells incubated with chromium(III) and iron(III) used separately. The synergistic antiviral effects were observed for chromium(III) and iron(III) against HSV-1 and BVDV.