Lanthanide Complexes with D-Penicillamine Methyl Ester: Formation Constants, Spectral and Thermal Properties

2006 ◽  
Vol 61 (2) ◽  
pp. 139-146 ◽  
Author(s):  
Shehab A. Sallam ◽  
Marwa A. Mahmoud
Keyword(s):  
Methyl Ester ◽  
Lanthanide Complexes ◽  
Formation Constants ◽  
Ester Formation ◽  
Elemental Analyses ◽  
Dta Analysis ◽  
Neutral Media ◽  
Tg And Dta Analysis ◽  
Atomic Radii ◽  
Solid Complexes

AbstractThe complex-formation of the lanthanide(III) cations with D-penicillamine methyl ester have been investigated in acidic and neutral media. The macroscopic protonation constants of the ligand and the formation constants of [Ln·Pme]2+, [Ln·(Pme)2]+, [Ln·Pme·OH]+ and [Ln·Pme·(OH)2] complexes have been determined from pH-metric data using BEST computer program. Species distribution diagrams of the complexes were obtained and plotted using SPE and SPEPLOT computer programs. Elemental analyses of the solid complexes indicate the formation of 1:1 metal:ligand species. Infrared spectra show that coordination takes place through the NH2, the SH and the C=O groups of the ligand. The complexes decompose in four steps as shown by their TG and DTA analysis with the formation of Ln2(SO4)3 as a final product. Activation energy values (ΔEa) are correlated with the atomic radii of the metal ions. The mechanism of the thermal decomposition is proposed.

Charge Transfer Molecular Complexes of 4-(Dimethylamino)pyridine with Some Conventional and Unconventional Acceptors Involving Fluoroarenes

2006 ◽  
Vol 71 (9) ◽  
pp. 1359-1370 ◽  
Author(s):  
Usama M. Rabie
Keyword(s):  
Charge Transfer ◽  
Nmr Spectra ◽  
Molecular Complexes ◽  
Outer Sphere ◽  
Formation Constants ◽  
Stoichiometric Ratio ◽  
Spectral Bands ◽  
Elemental Analyses ◽  
Ct Complexes ◽  
Solid Complexes

Charge transfer (CT) complexes of 4-(dimethylamino)pyridine (DMAP) with iodine as a typical σ-type acceptor and with typical π-type acceptor, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), have been synthesized and characterized. Octafluorotoluene (OFT), octafluoronaphthalene (OFN), perfluorophenanthrene (PFP), and 2,3,5,6-tetrafluoropyridine-4-carbonitrile (TFP) were also used as acceptors for interaction with DMAP. Properties of such CT complexes were investigated by UV/VIS and IR spectra, and elemental analyses of the isolated complexes. The systems DMAP-iodine and DMAP-DDQ are characterized by formation of triiodide ions (I3-) and DDQ•- anion radicals, respectively, which is proposed to occur via initial formation of outer-sphere CT complexes. The systems (DMAP-OFT, DMAP-OFN, DMAP-PFP and DMAP-TFP) are characterized by the appearance of new UV/VIS spectral bands assigned as CT bands; they also furnished the corresponding solid complexes with the stoichiometric ratio 1:1. 1H and 19F NMR spectra were used on confirming the formation of the DMAP-PFP CT complexes. The formation constants (KCT) and molar absorption coefficients (εCT) of the latter complex were obtained.

Two Novel One-dimensional Inorganic-Organic Hybrids Constructed from [H2W12O40]6– Clusters and Lanthanide-organic Complexes: [(C5H5N-CO2)2Ln(H2O)3]2[H2W12O40]·nH2O (C5H5N-CO2 = Pyridine-4-carboxylate; Ln = La3+, n = 5; Ce3+, n = 7)

2008 ◽  
Vol 63 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Hai-jun Pang ◽  
Ya-guang Chen ◽  
Fan-xia Meng ◽  
Dong-mei Shi
Keyword(s):  
Lanthanide Complexes ◽  
Rare Earth Compounds ◽  
Bidentate Ligands ◽  
X Ray Diffraction ◽  
Electrolytic Solution ◽  
One Dimensional ◽  
X Ray ◽  
Notable Effect ◽  
Organic Complexes ◽  
Elemental Analyses

Two novel polyoxotungstate-based rare earth compounds, [(C5H5N-CO2)2Ln(H2O)3]2- [H2W12O40] · nH2O (C5H5N-CO2 = pyridine-4-carboxylate; Ln = La3+ (1), n = 5; Ce3+ (2), n = 7), have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and TG analyses. The isostructural compounds 1 and 2 exhibit onedimensional (1D) zig-zag chains, in which the dinuclear lanthanide complexes act as bridging linkers and the [H2W12O40]6− groups serve as bidentate ligands. The results of cyclic voltammetry (CV) show that compounds 1 and 2 undergo two two-electron redox processes, similar to that of the parent (NH4)6[H2W12O40] ·3H2O, and also reveal that the pH of the supporting electrolytic solution has a notable effect on the electrochemical behavior of compound 2.

On Attempts to Synthesize Lanthanide Complexes of the Dianionic Fluorenyl-alkoxo Ligand [C13H8-cyclo-C6H10-O]2-. Crystal Structure of (C13H9-cyclo-C6H10-O)LaI2(DME)2

2003 ◽  
Vol 58 (5) ◽  
pp. 389-394 ◽  
Author(s):  
Alexander A. Trifonov ◽  
Mikhail N. Bochkarev ◽  
Herbert Schumann ◽  
Sebastian Dechert
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Ir Spectra ◽  
Single Crystal ◽  
Lanthanide Complexes ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Elemental Analyses ◽  
C Nmr

Racemic trans-2-(9(H)-fluoren-9-yl)cyclohexanol, C13H9-cyclo-C6H10-OH (1), reacts with two equivalents of potassium naphthalenide in THF to give the dipotassium salt [C13H8-cyclo-C6H10-O]- K2(THF) (2). Recrystallization of 2 from pyridine affords the solvent free salt [C13H8-cyclo-C6H10- O]K2 (3). The reactions of LaI3(THF)4 with one equivalent of 2 or of YbI2(THF)2 with equimolar amounts of 2 produce the alkoxolanthanum diiodide (C13H9-cyclo-C6H10-O)LaI2(DME)2 (4) and the ytterbium dialkoxide (C13H9-cyclo-C6H10-O)2Yb(THF)0.5(5), respectively. [(Me3Si)2N]3Y reacts with three equivalents of 1 with elimination of hexamethyldisilazane and formation of the yttrium trialkoxide (C13H9-cyclo-C6H10-O)3Y (6). The compounds 2 to 5 were characterized by elemental analyses, 1H NMR, 13C NMR and IR spectra. The molecular structure of 4 was determined by single crystal X-ray diffraction.

Lichen substances. V. Methylated derivatives of orsellinic acid, lecanoric acid, and gyrophoric acid from Pseudocyphellaria crocata

1975 ◽  
Vol 53 (10) ◽  
pp. 1031-1039 ◽  
Author(s):  
W. S. G. Maass
Keyword(s):  
Natural Products ◽  
Methyl Ester ◽  
Orsellinic Acid ◽  
Ester Formation ◽  
Lichen Substances ◽  
Fingerprint Pattern ◽  
Derivatives Of ◽  
Gyrophoric Acid

Two tridepsides (tenuiorin and methyl gyrophorate) have been identified as major constituents of Pseudocyphellaria crocata. Two similarly substituted didepsides (methyl evernate and methyl lecanorate) and the monomer methyl orsellinate have been isolated as new natural products. A number of additional orsellinic acid derivatives occur in the same lichen as identified by cochromatography with reference compounds, which reveals a biosynthetical fingerprint pattern based on methyl ester formation, 4-O-methylation, and condensation.

Synthesis and Properties of Novel Asymmetrical Porphyrin with [p-(4-Flourobenzoyloxy)-M-Ethyloxy]phenyl and its Lanthanide Complexes

2011 ◽  
Vol 308-310 ◽  
pp. 643-646
Author(s):  
Xiao Ling Cui ◽  
Xin Ming Shi ◽  
Shi You Li
Keyword(s):  
Lanthanide Complexes ◽  
Room Temperature ◽  
Molar Conductance ◽  
Bidentate Ligand ◽  
Quantum Yields ◽  
Luminescence Spectra ◽  
Tetradentate Ligand ◽  
Rare Earth Ion ◽  
Elemental Analyses ◽  
Band Fluorescence

A series of lanthanide complexes with acetylacetonate and a new asymmetrical 5-[p-(4-fluorobenzoyloxy)-m-ethyloxy]phenyl-10,15,20-triphenylporphyrin were prepared and characterized by elemental analyses, molar conductance, UV-Vis, IR, 1H NMR, luminescence spectra and themal analysis. Quantum yields of Q band fluorescence are in the region 0.073-0.097 at room temperature. Complexes have higher stability (decompose until 211°C). The structure that both the porphyrin behaved as a tetradentate ligand and acetylacetonate as a bidentate ligand are coordinated to a rare earth ion also has been proposed.

The dependence of vanadate phenyl ester formation on the acidity of the parent phenols

1988 ◽  
Vol 66 (10) ◽  
pp. 2565-2569 ◽  
Author(s):  
Bruno Galeffi ◽  
Alan S. Tracey
Keyword(s):  
Formation Constants ◽  
Resonance Spectroscopy ◽  
Resonance Effects ◽  
Linear Free Energy ◽  
Ester Formation ◽  
Inductive Effects ◽  
Energy Relationships ◽  
Parameter Approach ◽  
D Orbitals ◽  
Aqueous Acetone Solution

The condensation of vanadate (VO4H21−) with a variety of substituted phenols in aqueous acetone solution has been studied by 51V nuclear magnetic resonance spectroscopy. The formation constants for the various product esters were determined, as were their respective pKa values. Inductive and resonance contributions to vanadate ester formation were investigated using the dual substituent parameter approach. This procedure did not succeed particularly well, although trends were clearly observed. Correlations with Hammett constants were compared with those of the dual parameter approach. The observation of some linear free-energy relationships was interpreted to mean that the inductive and resonance parameters generally ascribed to the various phenols are not directly applicable to vanadate ester formation where d orbitals are probably involved. The results did indicate that resonance effects have a significantly greater influence on ester formation than do inductive effects.

scholarly journals Isolation of oligomers of 5,6-dihydroxyindole-2-carboxylic acid from the eye of the catfish

1974 ◽  
Vol 143 (1) ◽  
pp. 207-217 ◽  
Author(s):  
Shosuke Ito ◽  
J. A. Colin Nicol
Keyword(s):  
Carboxylic Acid ◽  
Methyl Ester ◽  
Methyl Esters ◽  
Tricarboxylic Acid ◽  
Oxidation Products ◽  
Molecular Weight Determination ◽  
Mushroom Tyrosinase ◽  
Natural Pigment ◽  
Elemental Analyses ◽  
Tapetum Lucidum

The reflecting material of the tapetum lucidum of the sea catfish (Arius felis) was chromatographed on Sephadex LH-20 in methanol–dimethyl sulphoxide–formic acid. Two components were present: one, showing an absorption maximum at 330nm, was tapetal pigment; the other, at 257nm, was an associated nucleoside. The tapetal pigment was extracted in methanol–HCl and isolated by adsorption chromatography on Sephadex LH-20. It yielded a methoxy methyl ester on treatment with diazomethane, and permanganate oxidation gave pyrrole-2,3,5-tricarboxylic acid. From the information provided by u.v. and i.r. spectra of the pigment and its methoxy methyl ester, from elemental analyses and from the oxidation products, we suggest that the tapetal pigment is derived from oxidative coupling of 5,6-dihydroxyindole-2-carboxylic acid. A molecular-weight determination and chromatography of the methoxy methyl ester indicate that the pigment is a mixture of oligomers, among which the tetramers probably predominate. We consider that the monomers are joined mainly by C-C linkages at positions 4 and 7. A synthetic pigment having spectral properties nearly identical with those of the natural pigment was prepared by enzymic oxidation of 5,6-dihydroxyindole-2-carboxylic acid with mushroom tyrosinase. The identity of the tapetal pigment with the synthetic pigment was further confirmed by comparing u.v. and i.r. spectra of their methoxy methyl esters. Formation of the tapetal pigment from tyrosine and relationships of the tapetal pigment to melanin are discussed.

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