Preparation and crystal structure of trans-dihydroxo-[tetrakis(2,6-dichlorophenyl)porphinato]ruthenium(IV)·2toluene

Trans-dihydroxo-[tetrakis(2,6-dichlorophenyl)porphinato]ruthenium(IV) ([Ru(OH)₂(TDCPP)]) was prepared by meta-chloroperbenzoic acid oxidation of [Ru(CO)(TDCPP)] in dichloromethane-toluene, and its crystal structure is reported. Crystal data for [Ru(OH)₂(TDCPP)]·2toluene:C₄₄H₂₂N₄O₂Cl₈Ru·2C₇H₈, orthorhombic, space group Pbca a = 13.149(1), B = 19.893(2), C = 21.093(2)Å, U = 55.17.3(2) ų, Z = 4. The short axial Ru---O bond distance, 1.790(7) Å, is in the range expected for a double Ru(IV)-oxygen bond. Both hydroxo ligands are approximately located in the mean plane of two opposite dichlorophenyl groups. Full-matrix least-squares refinement of positional and thermal parameters, using 2368 unique reflections with F > 2.5 σ (F) led to R(F) = 0.063; R_w = 0.066.     

Biotransformations of ortho-, meta- and para-aromatic nitrocompounds by strains of Aspergillus terreus: Reduction of ketones and deracemization of alcohols

Seven strains of the fungus Aspergillus terreus isolated from several provenances in Brazil, catalyzed biotransformations of ortho-, meta- and para-nitrophenyl compounds at different pH values. ortho-Nitroacetophenone and meta-nitroacetophenone were transformed into (S)-(+)-1-(ortho-nitrophenyl)ethanol and (S)-(−)-1-(meta-nitrophenyl)ethanol with high enantiomeric excess (e.e. ≥98%) and conversion (≥98%) by all the strains used. Deracemization of (RS)-1-(meta-nitrophenyl)ethanol was obtained with high selectivity (e.e. up to ≥98%) and good conversion (c 98%). The biotransformations in acidic medium using these fungus strains were more efficient than under basic or neutral conditions.     

Two coordinatively linked supramolecular assemblies constructed from highly electron deficient porphyrins

The synthesis of a pair of electron-deficient porphyrin building blocks and their resulting coordinatively linked supramolecular assemblies are described. The perfluorophenyl substituted porphyrins feature pendant pyridines which, upon reaction with Re(CO)₅Cl assemble into discrete dimers and tetramers, as dictated by the geometry of the porphyrin monomer. The resulting supramolecular complexes as well as their constituent porphyrins display several interesting and potentially useful properties owing to the electron-withdrawing nature of the perfluorophenyl funtionalities. Structural, spectroscopic, and electrochemical data indicate that the electron-deficient porphyrins remain planar, allowing for modulation of spectral and redox properties, as well as for enhancement of the affinity of the porphyrins for Lewis-basic ligands.     

The synthesis and reactions of A-ring aromatic steroid complexes of manganese tricarbonyl

Treatment of the A-ring aromatic steroids estrone 3-methyl ether and β-estradiol 3, 17-dimethyl ether with Mn(CO)₅⁺BF₄⁻ in CH₂Cl₂ yields the corresponding [(steroid)Mn(CO)₃]BF₄ salts 1 and 2 as mixtures of and β isomers. The X-ray structure of [(estrone 3-methyl ether)Mn(CO)₃]BF₄ · CH₂Cl₂ (1) having the Mn(CO)₃ moiety on the side of the steroid is reported: space group P2₁ with a=10.3958(9), b=10.9020(6), c=12.6848(9) Å, β=111.857(6)°, Z=2, V=1334.3(2) ų, _calc=.481 cm⁻³, R=0.0508, and wR=0.0635. The molecule has the traditional ‘piano stool’ structure with a planar arene ring and linear Mn---C---O linkages. The nucleophiles NaBH₄ and LiCH₂C(O)CMe₃ add to [(β-estradiol 3,17-dimethyl ether)Mn(CO)₃]BF₄ (2) in high yield to give the corresponding - and β-cyclohexadienyl manganese tricarbonyl complexes (3). The nucleophiles add meta to the arene -OMe substituent and exo to the metal. The and β isomers of 3 were separated by fractional crystallization and the X-ray structure of the β isomer with an exo-CH₂C(O)CMe₃ substituent is reported (complex 4): space group P2₁2₁2₁ with a=7.5154(8), b=15.160(2), c=25.230(3) Å, Z=4, V=2874.4(5) ų, _calc=1.244 g cm⁻³, R=0.0529 and wR2=0.1176. The molecule 4 has a planar set of dienyl carbon atoms with the saturated C(1) carbon being 0.592 Å out of the plane away from the metal. The results suggest that the manganese-mediated functionalization of aromatic steroids is a viable synthetic procedure with a range of nucleophiles of varying strengths.     

Synthesis of tetraphenylsubstituted porphyrins by interaction of 5-aryldipyrromethanes with 4-substituted benzaldehydes

Synthesis of tetraphenyl substituted porphyrins with tert-butyl and methoxycarbonyl groups in meso-aryl radicals is described. It is shown that, during the condensation of dipyrromethanes with substituted benzaldehydes, a rearrangement occurs with the formation of a mixture of isomeric porphyrins. The character of these rearrangements depends on the position of substituents in the starting compounds.     

Production of substituted catechols from substituted benzenes by a Pseudomonas sp.

In the presence of a halobenzene or benzonitrile, Pseudomonas T-12 can produce substituted catechols from the corresponding substituted benzenes. A variety of monosubstituted benzenes with substituents containing up to four carbons, and some meta- and para- disubstituted benzenes, can serve as catechol precursors.     

Unusual kinetic and thermodynamic control in the formation of Pt(II)-complexes of a new C1-symmetric phosphine-phosphite

Versatile synthetic routes have been applied to prepare the new asymmetric phosphine-phosphite ligands 8 and 12. The chiral ligands have been designed so that the corresponding ligating groups have similar electronic properties and steric bulk, but 8 forms 6-, while 12 forms 7-membered chelate rings in their coordination compounds. The chelate size variation results in a markedly different coordination behavior towards Pt(II). In their reactions with Pt(PhCN)₂Cl₂ at 1:1 stoichiometry 12 forms the expected Pt(12)Cl₂ complex, while 8 gives the cation quantitatively. In the kinetically controlled reaction is the major product even at a 8:Pt(PhCN)₂Cl₂ = 1:2 ratio. Most interestingly, at 1:1 ligand to precursor ratio, cation rearranges to Pt(8)Cl₂ within one day, indicating that the neutral complex is thermodynamically more favorable.     

Characterization Studies of an Anaerobic, Pentachlorophenol-Dechlorinating Enrichment Culture

Dechlorination studies were conducted using microbial cultures developed in a fluidized-bed reactor (FBR) that dechlorinates pentachlorophenol (PCP) to 3,4-dichlorophenol (3,4-DCP) and 4-monochlorophenol (4-MCP). Electron donor experiments demonstrated that lactate, propionate, and H₂ can serve as electron donors for chlorophenol (CP) dechlorination in mixed, anaerobic, PCP-enriched cultures. Dechlorination did not proceed in the absence of an electron donor. Acetate, which resulted in little H₂ production, was a poor electron donor. The results of inhibition studies using vancomycin and 2-bromoethanesulfonic acid implicate members of the domain bacteria in the dechlorination of CPs, whereas methanogens do not appear to be involved in dechlorination. Brief heat treatment (80°C for 90 min) of the FBR enrichment cultures implicated endospore formers in the dechlorination of CPs, primarily at the ortho position, where PCP was dechlorinated to 3,4,5-trichlorophenol (3,4,5-TCP) (the sole TCP detected) and subsequently to 3,4-DCP. Both lactate and H₂ served as electron donors in the heat-and oxygen-treated cultures. In contrast, a lactate-fed anaerobic spread-plate enrichment culture exhibited solely meta-dechlorination, where PCP dechlorinated solely to 2,4,6-TCP. The separation of ortho- and meta-specific dechlorination reactions provides evidence that PCP dechlorination in the FBR enrichment culture was catalyzed by at least the following two separate groups of CP-dechlorinating bacteria: one meta-dechlorinating group and one primarily ortho-dechlorinating group.     

Bis-phenacetyl and phenoxyacetyl groups as substrates for penG and penV amidases

o-, m-, p-Bis-phenylacetic and -bis-phenoxyacetic acid esters with solketal are prepared and submitted to enzymatic hydrolysis with penicillin V (PVA) and G (PGA) amidases. While the para-isomers are recovered unchanged, ortho- and meta-bis-esters are completely hydrolysed. PVA shows a reversed substrate specificity, hydrolysing phenylacetates faster than its natural substrate. The use of the bis-acids as alcohol-protecting groups is proposed.     

Formylation of porphyrin platinum complexes

The formylation reaction of platinum complexes of -unsubstituted porphyrins was studied. The interaction of deuteroporphyrin IX derivatives with the Vilsmeyer reagent led to the selective formylation of their macrocycles in the position. The resulting formyl derivatives of the porphyrins are of interest for fluorescent immunoassay.Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 1, 2005, pp. 103–107.Original Russian Text Copyright © 2005 by Rumyantseva, Konovalenko, Nagaeva, Mironov.     

Nitrile biotransformation by Aspergillus niger

A nitrile-converting enzyme activity was induced in Aspergillus niger K10 by 3-cyanopyridine. The whole cell biocatalyst was active at pH 3–11 and hydrolyzed the cyano group into acid and/or amide functions in benzonitrile as well as in its meta- and para-substituted derivatives, cyanopyridines, 2-phenylacetonitrile and thiophen-2-acetonitrile. Amides constituted a significant part of the total biotransformation products of 2- and 4-cyanopyridine, 4-chlorobenzonitrile, 4-tolunitrile and 1,4-dicyanobenzene, while -substituted acrylonitriles gave amides as the sole products.     

Chloro and acetato complexes of platinum(II) with functionalized thioethers

The chloro complexes [PtCl₂(RSR′)₂] (1-10) (RSR′ = MeSCH₂C(O)OMe, 1; MeSCH₂C(O)OEt, 2; MeSCH₂C(O)Omenthyl(−), 3; MeSCH₂CH₂C(O)OMe, 4; , 5; EtSCH₂C(O)Me, 6; MeSCH(Me)C(O)Me, 7; MeSPh, 8; MeS-o-C₆H₄Me, 9; and MeS-o-C₆H₄Et, 10) are obtained in high yield (63-90%) by reaction of [PtCl₂(PhCN)₂] with the proper thioether in 1/2 molar ratio, in anhydrous chloroform, at reflux under argon for ca. 10 h. The X-ray crystal structure of [PtCl₂(MeS-o-C₆H₄Me)₂] (9) shows an almost regular trans square planar geometry (triclinic, space group , a 6.806(1), b 7.789(2), c 10.085(3) Å, α 101.80(2)°, β 69.55(2)°, γ 115.27(2)°, R(F_o) 0.023, ). The dichloro complexes react with silver acetate in a complex manner, which depends on the nature of the thioether, and only with RSR′ = MeSPh the simple diacetato complex [Pt(OAc)₂(RSR′)₂] is obtained as the major product.     

Photodynamic and light independent action of 8 to 2 carboxylic free porphyrins on some haem-enzymes

Backgrounds and aims: skin lesions in cutaneous porphyrias appear to be determined by the structural properties of the porphyrins accumulated. To better understand the relationship between the structure and physicochemical properties of porphyrins and their specific effect on protein configuration, the action of a whole range of 8 to 2 carboxylic porphyrins has been studied. Materials and methods: δ-aminolevulinic acid dehydratase (ALA-D) and porphobilinogen deaminase (PBG-D) partially purified from bovine liver, were exposed to 10 μM uroporphyrin (Uro), phyriaporphyrin (Phyria), hexaporphyrin (Hexa), pentaporphyrin (Penta), coproporphyrin (Copro) or protoporphyrin (Proto), either in the dark or under UV light. All experiments were performed in the enzyme solutions after removing the porphyrins. Results: under both illuminating conditions, all porphyrins inactivated the enzymes (20–70% under control values), indicating photodynamic action mediated by oxidative reactions and conformational changes due to direct binding of porphyrins to the protein. Total thiol content in ALA-D was not significantly changed by most porphyrins under UV light, while all porphyrins increase total sulfhydryl groups in PBG-D (23–52% over the control values) indicating changes in the redox status of SH residues. Free amino groups were reduced by all porphyrins in ALA-D (23–56% under controls), instead they were enhanced in PBG-D (23–51% over controls), suggesting protein fragmentation. The formation of molecular aggregates would be the consequence of cross-links between oxidation products, while fragmentation can be attributed to either rupture of disulphur bridges and/or enhancement of free amino groups on the protein enzyme. Conclusions: the effect of the porphyrins on enzyme activity, total SH groups and free amino groups content, was different for ALA-D and PBG-D, even under the same illuminating conditions. On the basis of these results, no correlation between enzyme alterations and the physico-chemical properties of porphyrins could be established.     

Physiological relevance of successive hydroxylations of toluene by toluene para-monooxygenase of Ralstonia pickettii PKO1

We have recently found that toluene para-monooxygenase (TpMO) of Ralstonia pickettii PKO1 (encoded by tbuA1UBVA2C) performs successive hydroxylations of benzene (Appl. Environ. Microbiol. 70: 3814, 2004) as well as hydroxylates toluene to a mixture of 90% p-cresol and 10% m-cresol which are then further oxidized to 100% 4-methylcatechol (J. Bacteriol. 186: 3117, 2004) whereas it was thought previously that TpMO forms 100% m-cresol and is not capable of successive hydroxylations. Here we propose a modification of the degradation pathway originally described by Olsen et al. (J. Bacteriol. 176: 3749, 1994) that now relies primarily on TpMO for conversion of toluene to 4-methylcatechol (instead of m-cresol) since both m-cresol and p-cresol are shown here to be good substrates for Escherichia coli expressing TpMO (V_max/K_m=0.046, 0.036, and 0.055 mL min^-1 mg^-1 protein for the oxidation of toluene, m-cresol, and p-cresol, respectively). In light of the broader activity of TpMO, phenol hydroxylase (encoded by tbuD) appears to facilitate conversion of any m-cresol or p-cresol formed from toluene oxidation by TpMO to 4-methylcatechol; hence, the cell has a redundant method for making this important intermediate 4-methylcatechol. Further, it is suggested that the physiological relevance of the 10% m-cresol formed from toluene oxidation by TpMO is needed for induction of the meta cleavage operon tbuWEFGKIHJ to enable full metabolism of toluene since p-cresol (and o-cresol) do not induce the meta-cleavage pathway. Therefore both the successive hydroxylation of toluene by TpMO and the product distribution are of physiological relevance to the cell.     

Determination of porphyrins and biliverdin in bile and excreta of birds by a single liquid chromatography-ultraviolet detection analysis

Methods developed for porphyrin analysis have low recoveries and/or poor precision for the less polar protoporphyrin IX. We describe a simple method of analysis of porphyrins and biliverdin in bile and excreta of birds based on extraction with HCl 3N: acetonitrile and HPLC/UV analyses. Recoveries were good for protoporphyrin IX and other porphyrins (>79%). Applications of this method showed that porphyrins and biliverdin in birds excreta are mainly of biliary-fecal origin rather than urinary origin. Biliverdin and protoporphyrin IX increased proportionately more than the rest of the porphyrins and coproporphyrin III increased more than coproporphyrin I in the bile of Pb-poisoned mallards.     

Porphyrin-sensitized photodynamic damage of isolated rat liver mitochondria

The respiration rates and the respiratory control ratios of isolated rat liver mitochondria have been measured following exposure to 0–160 kJ/m² of near-ultraviolet radiation (blacklight) in the presence of low concentrations of porphyrins (0.1–0.2 μmol/l).

Depending on the light dose, the concentration and the type of porphyrin, the following sequence of reactions occurred: uncoupling and inhibition of oxidative phosphorylation, energy dissipation, inhibition of respiration and swelling and disruption of the mitochondria.

The detrimental effects could not be elicited in the absence of oxygen, neither could they be elicited by porphyrins or light alone.

At equimolar concentrations, the effectiveness of the porphyrins as photosensitizers were: deuteroporphyrin > protoporphyrin coproporphyrin > murophorphyrin.

The results may be of importance to explain the skin lesions seen when porphyrins of different hydrophobicity accumulate in the skin.     

Properties of zinc uroporphyrin III produced from isopropanol by Arthrobacter hyalinus

In a large amount of porphyrins produced by a bacterium isolated from soil, Arthrobacter hyalinus, cultured in a medium containing isopropanol as the sole carbon source, zinc porphyrins, identified based on the coincidence between their m/z values in LC/MS and the molecular weight of porphyrins, were also found to be produced. Since zinc is easily separated from porphyrins in acid during the esterification of porphyrins, zinc uroporphyrin III was prepared from its octamethyl ester formed by incorporating zinc into the octamethyl ester of uroporphyrin III which was isolated from the culture broth. Its UV spectra, fluorometric spectra, fast atom bombardment (FAB)-mass spectra, and ¹H-NMR and ¹³C-NMR spectra were presented.     

Optical properties of porphyrin molecules immobilized in nano-porous silicon

The paper aims at studying optical properties of porous silicon powders and thin films which were impregnated with different porphyrin molecules. It has been shown that introducing porphyrins into porous silicon matrix results in quenching of luminescence from porous silicon, while luminescence of porphyrins survives, though its structure changes. At the same time, porphyrins in porous silicon matrix which was preliminarily oxidized does not alter luminescence from porphyrins. Generation of singlet oxygen by illuminated porphyrin/porous silicon composite is confirmed by additional oxidation of porous silicon and by the observation of characteristic 1270 nm luminescence band.     

Significance of the Excitonic Intensity Borrowing in the J-/H-aggregates of Bacteriochlorophylls/Chlorophylls

A quantitative analysis of the excitonic intensity borrowing for the J-/H-aggregates of the bacteriochlorophylls/chlorophylls (BChls/Chls) in specific, and of porphyrins in general, is presented. The analysis is based on the argument that the mixing between the two energetically well-separated bands, such as the Q and B bands of BChls/Chls, should be considered important if the aggregated system possesses an excitonic superstate. A remarkably simple explanation of the significance of the excitonic intensity borrowing is given: superhyperchromism is manifested by the mediation of interband coupling between the superstates in␣the two well-separated bands of such aggregates. A comprehensive discussion on the significance of superhyperchromism and on its size-dependence is provided in connection with its effects on the absorption spectra of the BChl/Chl J- and H-aggregates.     

Detection and quantification of phnE gene from oil-contaminated soil samples by competitive quantitative PCR

The phnE gene encoding catechol 2,3-dioxygenase belonging to the meta-cleavage pathway was selected as the marker gene and was detected and quantified from soil samples by competitive quantitative PCR. A PCR primer pair was designed based on the phnE gene to amplify the target DNA bands and competitor DNA bands. The phnE gene was detected in two samples of three. In samples S1 and S2, the phnE gene copy number was 6.2×10⁷/g soil and 5.8×10⁷/g soil, respectively. But no phnE gene was detected in sample S3. The target DNA bands were extracted and expressed. The results confirmed that the target DNA bands were the native phnE genes.