Interactions of cobalt tetrasulfophthalocyanine with thiolate anions in dimethylformamide

2001 ◽  
Vol 05 (04) ◽  
pp. 405-414 ◽  
Author(s):  
EDUARD M. TYAPOCHKIN ◽  
EVGUENII I. KOZLIAK
Keyword(s):  
Axial Ligand ◽  
Anaerobic Conditions ◽  
Binding Studies ◽  
H Nmr ◽  
Dead End ◽  
End Products ◽  
Thiolate Complexes ◽  
Thiolate Anions ◽  
Equatorial Ligand ◽  
Phthalocyanine Ring

Thiolate complexes of cobalt tetrasulfophthalocyanine ( CoTSPc ), possible intermediates of the industrial removal of mercaptans from oil fractions (Merox process), were studied in dimethylformamide, dimethylsulfoxide, and other polar aprotic solvents by UV-vis, 1 H NMR, and ESR spectroscopy. All thiolates react with Co II TSPc under anaerobic conditions with 1:1 stoichiometry. All tested aliphatic thiolates, regardless of their basicity, reduce Co II TSPc to form Co I TSPc derivatives. Low-basicity thiolates also form unstable non-reduced ( RS -) Co II TSPc complexes as dead-end products. Indirect kinetic evidence was obtained for electron transfer from the axial ligand to metal via the phthalocyanine equatorial ligand. 1 H NMR and binding studies revealed sulfur–cobalt interactions in the Co I TSPc product, thus indicating an axial ligand attachment to Co I TSPc . Low-basicity aromatic thiolates (pentachloro- and pentafluorobenzenethiolate) form ( RS -) Co II TSPc complexes, which are stable toward intramolecular metal reduction. This effect is indicative of possible π-stacking between the aromatic thiolate and phthalocyanine ring.

scholarly journals Synthesis, Spectroscopy and Electrochemistry of Cobalt(III) Schiff Base Complexes

2005 ◽  
Vol 2005 (3) ◽  
pp. 190-193 ◽  
Author(s):  
Ali Hossein Sarvestani ◽  
Abdollah Salimi ◽  
Sajjad Mohebbi ◽  
Rahman Hallaj
Keyword(s):  
Schiff Base ◽  
Structural Model ◽  
Ligand Substitution ◽  
Axial Ligand ◽  
Schiff Base Complexes ◽  
H Nmr ◽  
Reduction Potentials ◽  
Axial Ligands ◽  
D Orbitals ◽  
Equatorial Ligand

Three Co(III) complexes of the type [Co(chel)(PBu3)]ClO4.H2O, (chel = 5-BrSalen, 5-MeOSalen and 4-MeOSalen), were synthesised and characterised by elemental analysis, IR, UV-Vis and 1H NMR spectroscopy. In their electronic spectra, the absorptions between 550 and 750 nm of these complexes are attributable to the lowest d–d transition. The axial ligands affect this transition through a σ-intraction with the dz2 orbital and the equatorial ligands affect it by π-interaction with populated d-orbitals. On the basis of an electronic structural model, in which the dz2 orbital is populated in forming cobalt(II), it is suggested that equatorial ligand substitution affects the reduction potentials less than axial ligand substitution.

scholarly journals Synthesis, Characterization, and BSA Binding Studies of Some New Benzamides Related to Schiff Base

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
M. K. Prashanth ◽  
M. Madaiah ◽  
H. D. Revanasiddappa ◽  
K. N. Amruthesh
Keyword(s):  
Schiff Base ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Binding Constants ◽  
Spectral Studies ◽  
Spectroscopic Techniques ◽  
Binding Studies ◽  
Mass Spectral ◽  
H Nmr

Condensation of amine 1 with aldehyde 2 gives Schiff base, N-(4-((benzofuran-2-ylmethylene) amino)phenyl)acetamide 3. Schiff base on N-acylation with different substituted acid chlorides in the presence of triethylamine gives the corresponding benzamides, N-acetyl-N-(4-((benzofuran-2-ylmethylene)amino)phenyl)substitutedbenzamide (NABP) 5a–j. The structures of newly synthesized compounds were characterized by elemental analysis, 1H NMR, 13C NMR FT-IR, and mass spectral studies. Compounds 3 and 5a–j have been screened for their antimicrobial activity using the disc diffusion and minimum inhibitory concentration (MIC) method against the selected bacterial and fungal strain. Compounds 5a, 5e, 5g, and 5h were found to be more active against all tested strains. The antioxidant properties were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging methods. Compounds 5i and 5j showed predominant antioxidant activities among the synthesized analogues. The interaction between NABP and bovine serum albumin (BSA) was investigated using fluorescence and ultraviolet spectroscopic techniques at 298 K under imitated physiological conditions. The results revealed that NABP caused the fluorescence quenching of BSA through a static quenching procedure. The binding constants and the number of binding sites were calculated. The binding distance between the donor (BSA) and acceptor (NABP) was determined based on Forster’s theory.

Host-guest interactions of cyclodextrins and metalloporphyrins: supramolecular building blocks toward artificial heme proteins

2004 ◽  
Vol 08 (02) ◽  
pp. 125-140 ◽  
Author(s):  
Huchen Zhou ◽  
John T. Groves
Keyword(s):  
Binding Constant ◽  
Molecular Design ◽  
Covalent Binding ◽  
Binding Constants ◽  
Building Blocks ◽  
Binding Pocket ◽  
Axial Ligand ◽  
Pyridyl Nitrogen ◽  
H Nmr ◽  
Self Assembled

Cyclodextrins are versatile building blocks for a variety of macromolecules due to the inclusion complexes that are formed with hydrophobic organic molecules. Cyclodextrin-porphyrin interactions are of particular interest since cyclodextrins can serve as a non-covalent binding pocket while metalloporphyrins could serve as the heme analogs in the construction of heme protein model compounds. Various approaches to the design and assembly of biomimetic porphyrin constructs are compared and contrasted in this minireview with a particular emphasis on self-assembled and porphyrin-cyclodextrin systems. Several recent advances from our laboratories are described in this context. A sensitive fluorescent binding probe, 6A-N-dansyl-permethylated-β-cyclodextrin (Dan-NH-TMCD), was found to form 2:1 complexes with the meso-tetraphenylporphyrins Mn(III)TCPP , Mn(III)TPPS and Mn(III)TF 4 TMAP with high binding constants. A perPEGylated cyclodextrin, heptakis(2,3,6-tri-O-2-(2-(2-methoxyethoxy)ethoxy)ethyl)-β-cyclodextrin (TPCD), has been shown by 1 H NMR spectroscopy to form a 1:1 complex with H 2 TCPP with a binding constant above 108M-1. Such a strong binding constant is the largest found for a 1:1 complex between a monomeric cyclodextrin and a guest. TPCD was also found to bind Mn(III)TCPP with a binding constant of 1.2 × 106 M -1. A novel, self-assembled hemoprotein model, hemodextrin is also described. The molecular design is based on a PEGylated cyclodextrin scaffold that bears both a heme-binding pocket and an axial ligand that binds an iron porphyrin. The binding constant for Fe (III) TPPS (iron(III) meso-tetra(4-sulfonatophenyl)porphyrin) by py-PPCD was determined to be 2 × 106 M -1. The pyridyl nitrogen of py-PPCD was shown to ligate to the iron center by observing signal changes in the Fe(II) -porphyrin 1 H NMR spectrum. This hemodextrin ensemble, a minimalist myoglobin, was shown to bind dioxygen reversibly and to form a stable ferryl species.

The Respiratory Metabolism of Dendrostomum cymodoceae Edmonds (Sipunculoidea)

1957 ◽  
Vol 8 (1) ◽  
pp. 55 ◽  
Author(s):  
SJ Edmonds
Keyword(s):  
Carbon Dioxide ◽  
Lactic Acid ◽  
Dissolved Oxygen ◽  
Blood Volume ◽  
Sea Water ◽  
Respiratory Metabolism ◽  
Anaerobic Conditions ◽  
Paraffin Oil ◽  
End Products ◽  
Wet Weight

The consumption of oxygen of Dendrostomum cymodoceae at 22'C in aerated sea-water varied from 4-5-5.5 μl/g (wet weight)/hr for adults to 20-31 μ/g/hr for juveniles. The production of carbon dioxide was 13-17 μ/g/hr (juveniles) and the R.Q. varied from 0.55 to 0.67 (juveniles). The rate of consunlption of oxygen decreased as the tension of the dissolved oxygen decreased. The oxygen combined with the pigment of the blood was 2.1 vols. of oxygen per 100 vols. of blood and the ratio of blood volume (ml) to total weight (g) of the animal was 0.47. D. cymodoceae was able to live under anaerobic conditions in sea-water for as long as 5 days and in paraffin oil for 4 days. The haemerythrin in the blood of animals kept under oil was found to be reduced after about 6 hr. Lactic acid was identified as one of the end-products of anaerobiosis. The concentration of lactic acid in the blood of animals living under anaerobic conditions increased after 60 hr from 7-12 to 46-61 μg/ml of blood. The ability to revert to anaerobiosis may have survival value for the species.

scholarly journals Synthesis and Spectroscopic Characterization of Some New Axially Ligated Indium(III) Macrocyclic Complexes and Their Biological Activities

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Gauri D. Bajju ◽  
Altaf Ahmed ◽  
Deepmala Gupta ◽  
Ashu Kapahi ◽  
Gita Devi
Keyword(s):  
Biological Activities ◽  
Spectroscopic Characterization ◽  
Axial Ligand ◽  
Free Base ◽  
H Nmr ◽  
Pyramidal Geometry ◽  
The Stability ◽  
Square Pyramidal Geometry ◽  
C Nmr

The synthesis and spectroscopic characterization of new axially ligated indium(III) porphyrin complexes were reported. Chloroindium(III) porphyrin (TPPIn-Cl) was obtained in good yield by treating the corresponding free base with indium trichloride. The action of the different phenols on chloroderivatives (TPPIn-Cl) led to the corresponding phenolato complexes (TPPIn-X). These derivatives were characterized on the basis of mass spectrometry,1H-NMR, IR, and UV-visible data. The separation and isolation of these derivatives have been achieved through chromatography. The spectral properties of free base porphyrin and its corresponding metallated and axially ligated indium(III) porphyrin compounds were compared with each other. A detailed analysis of UV-Vis,1H-NMR, and IR suggested the transformation from free base porphyrin to indium(III) porphyrin. Besides,13C-NMR and fluorescence spectra were also reported and interpreted. The stability of these derivatives has also been studied through thermogravimetry. The complexes were also screened for anticancerous activities. Among all the complexes, 4-MePhO-InTPP shows highest anticancerous activity. The title complexe, TPPIn-X (where X = different phenolates), represents a five-coordinate indium(III) porphyrin complex in a square-pyramidal geometry with the phenolate anion as the axial ligand.

scholarly journals One Pathway Can Incorporate either Adenine or Dimethylbenzimidazole as an α-Axial Ligand of B12 Cofactors in Salmonella enterica

2007 ◽  
Vol 190 (4) ◽  
pp. 1160-1171 ◽  
Author(s):  
Peter J. Anderson ◽  
Jozsef Lango ◽  
Colleen Carkeet ◽  
Audrey Britten ◽  
Bernhard Kräutler ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Axial Ligand ◽  
Vitamin B ◽  
Wild Type ◽  
Aerobic Growth ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Axial Ligands ◽  
And Control ◽  
Coenzyme B

ABSTRACT Corrinoid (vitamin B12-like) cofactors contain various α-axial ligands, including 5,6-dimethylbenzimidazole (DMB) or adenine. The bacterium Salmonella enterica produces the corrin ring only under anaerobic conditions, but it can form “complete” corrinoids aerobically by importing an “incomplete” corrinoid, such as cobinamide (Cbi), and adding appropriate α- and β-axial ligands. Under aerobic conditions, S. enterica performs the corrinoid-dependent degradation of ethanolamine if given vitamin B12, but it can make B12 from exogenous Cbi only if DMB is also provided. Mutants isolated for their ability to degrade ethanolamine without added DMB converted Cbi to pseudo-B12 cofactors (having adenine as an α-axial ligand). The mutations cause an increase in the level of free adenine and install adenine (instead of DMB) as an α-ligand. When DMB is provided to these mutants, synthesis of pseudo-B12 cofactors ceases and B12 cofactors are produced, suggesting that DMB regulates production or incorporation of free adenine as an α-ligand. Wild-type cells make pseudo-B12 cofactors during aerobic growth on propanediol plus Cbi and can use pseudo-vitamin B12 for all of their corrinoid-dependent enzymes. Synthesis of coenzyme pseudo-B12 cofactors requires the same enzymes (CobT, CobU, CobS, and CobC) that install DMB in the formation of coenzyme B12. Models are described for the mechanism and control of α-axial ligand installation.

Preparation, Infrared and Raman Spectra, and Stereochemistries of Pentacoordinate Trimethylphosphine Complexes, MX4•P(CH3)3 and MX4•P(CD3)3 where M = Ge or Sn and X = Cl or Br

1973 ◽  
Vol 51 (16) ◽  
pp. 2697-2709 ◽  
Author(s):  
D. K. Frieson ◽  
G. A. Ozin
Keyword(s):  
Solid State ◽  
Raman Spectra ◽  
Axial Ligand ◽  
Axial Position ◽  
Infrared And Raman Spectra ◽  
Normal Coordinate ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Equatorial Ligand

The 1:1 adducts MX4•PMe3 (M = Ge or Sn; X = Cl or Br) are prepared by recrystallization of the respective 1:2 complexes from excess MX4 acceptor. Solid state infrared and Raman Spectra and X-ray powder photographs suggest that these adducts are all trigonal bipyramidal with the ligand in an axial position. Normal coordinate calculations in C3v symmetry (axial ligand) and Cs symmetry (equatorial ligand) support this assignment. The rather high ν(MP) frequencies indicate unusually strong metal–phosphorus donor bonds in these compounds.

Study ofTrichoderma viridemetabolism under conditions of the restriction of oxidative processes

2005 ◽  
Vol 51 (10) ◽  
pp. 853-862 ◽  
Author(s):  
Peter Chovanec ◽  
Michal Kaliňák ◽  
Tibor Liptaj ◽  
Naďa Pronayová ◽  
Tibor Jakubík ◽  
...  
Keyword(s):  
Mycelial Growth ◽  
Trichoderma Viride ◽  
Anaerobic Conditions ◽  
Developmentally Regulated ◽  
H Nmr ◽  
Fermentative Metabolism ◽  
Yeast Autolysate ◽  
Oxidative Processes ◽  
High Concentrations ◽  
Aerobic And Anaerobic

Trichoderma viride was capable of growth and conidiation in the presence of high concentrations of the uncoupler 3,3′,4′,5-tetrachlorosalicylanilide (up to 100 µmol·L–1) and of the respiration inhibitor mucidin (up to 100 µmol·L–1) in both submerged and surface cultivation. When vegetative mycelia were cultivated on the solid Czapek-Dox medium with yeast autolysate under an anaerobic and CO2-containing atmosphere, the growth was observed only rarely but the microorganism survived as long as 3 months under these conditions. Major products of metabolism of both aerobic and anaerobic submerged mycelia were identified by means of1H-NMR measurements. Major products excreted to the medium under aerobic conditions were succinic and citric acids. Major metabolites present in the submerged mycelia were γ-aminobutyric (and glutamic) acid and alanine. Under anaerobic conditions, citric acid was not excreted into the medium but ethanol appeared. Its production could not be increased upon increasing the sugar concentration. The appearance of secondary metabolites was found to be modified by oxygen availability during the mycelial growth. Results suggest that the vegetative form of T. viride is capable of fermentative metabolism characterized by the production of ethanol and succinate and that the excretion of carboxylic acids is developmentally regulated and modified by oxygen availability.Key words: Trichoderma, mycelia, anaerobiosis, citrate, succinate, ethanol, GABA.

Design, Synthesis, Photophysics, and Anion-Binding Studies of Bis(dicyclohexylphosphino)methane-Containing Dinuclear Gold(I) Thiolate Complexes with Urea Receptors

2010 ◽  
Vol 16 (30) ◽  
pp. 9123-9131 ◽  
Author(s):  
Xiaoming He ◽  
Fernando Herranz ◽  
Eddie Chung-Chin Cheng ◽  
Ramon Vilar ◽  
Vivian Wing-Wah Yam
Keyword(s):  
Anion Binding ◽  
Binding Studies ◽  
Design Synthesis ◽  
Thiolate Complexes
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