Chelation of UO22+ and ThIV by N,N′-bis(pyridoxylideneiminato)R (R=n-propyl, diethylamine), new dianionic Schiff bases derived from vitamin B6: Synthesis and structural features of [Th(pyr2pen)2] (pen=1,3-propylendiamine), [UO2(pyr2pen)(CH3OH)] and [UO2(pyr2dien)]·2H2O (dien=diethylenetriamine). Searching further modelings for heavy metals damage inhibition in living beings

2008 ◽  
Vol 102 (4) ◽  
pp. 666-672 ◽  
Author(s):  
Davi Fernando Back ◽  
Gelson Manzoni de Oliveira ◽  
Jaqueline Pinto Vargas ◽  
Ernesto Schulz Lang ◽  
Greice Tabarelli
2018 ◽  
Vol 34 (4) ◽  
pp. 2031-2042 ◽  
Author(s):  
Tahseen Saddam Fandi Al-Mathkuri ◽  
Hamid Mohammed Saleh Al-Jubori ◽  
Ali Taha Saleh

The compound 6-amino-5-mercapto-4H-1,2,4-triazol-3-yl)-9-fluoro-3-methyl-10-(4-methylpiperazin-1-yl)-2,3-dihydro-7H-[1,4] oxazino[2,3,4-ij] quinolin-7-one (M1) synthesize from the reaction of thiocarbohydrazide with levofloxacin acid by using ethanol as a solvent, phenolic Schiff bases (Z)-9-fluoro-6-(4-((4-hydroxybenzylidene) amino)-5-mercapto4H1,2,4-triazol-3-yl)-3-methyl-10-(4-methylpiperazin-1-yl)-2,3-dihydro-7H-[1,4]oxazino[2,3,4-ij] quinolin-7-one (M2), (Z)-6-(4-((2,4-dihydroxybenzylidene) amino)-5-mercapto-4H-1,2,4-triazol-3-yl)-9-fluoro-3-methyl-10-(4-methylpiperazin-1-yl)-2,3-dihydro-7H-[1,4] oxazino[2,3,4-ij]quinolin-7-one (M3) and (Z)-6-(4-((5-chloro-2-hydroxybenzylidene) amino)-5-mercapto-4H-1,2,4-triazol-3-yl)-9-fluoro-3-methyl-10-(4-methylpiperazin-1-yl)-2,3-dihydro-7H- [1,4] oxazino[2,3,4-ij] quinolin-7-one (M4) were prepared from the reaction of trizol derivative of [M1] compound with the appropriate phenolic aldehydes by using ethanol as a solvent. The synthetic Schiff bases used to prepare numbers of phenolic polymers [M5-M7] from the reaction of Schiff bases [M2-M4] with phenol formaldehyde. The analytical efficiency of the synthetic chelating polymers studied by the batch method with different transition metals ions (Cd2+, Fe3+, Cu2+), in terms of the effect of treatment time and the pH on the loading capacity of the polymers, controlling the other factors such as temperature, ions concentration and quantity of polymers. The result shows that the capacity of the polymer increased with increasing of the pH and treating time. The synthetic compounds were characterized by various instrumental techniques like FTIR, 1H-NMR, DTG and TGA studies.These spectral and thermal studies provide very valuable information about the structural features.


1992 ◽  
Vol 70 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Sudhindra N. Misra ◽  
Shaun O. Sommerer

The absorption difference, comparative absorption spectrophotometry, and quantitative analysis of 4f–4f spectra of praseodymium(III) complexes with ligands possessing varying structural features and binding capabilities have clearly indicated that the 3H4 → 3P2, 3H4 → 3P1, 3H4 → 3P0, and 3H4 → 1D2 transitions exhibit substantial intensification as well as a wide variation of oscillator strength. Since these transitions do not follow the selection rules they cannot be considered hypersensitive. Ligands such as β-diketones, Schiff bases, amino acids, diols, nucleic bases, nucleosides, nucleotides, alkoxides, and haloacetates with widely differing binding features in terms of coordinating ability, denticity, and normalized bite appear to induce, to varying degrees, high sensitivity in these non-hypersensitive transitions. The present article reports the high sensitivity of the 3H4 → 3P2, 3P1, 3P0, and 1D2, transitions of Pr(III) by considering the solution spectra of 173 species. This unique sensitivity is termed Ligand Mediated Pseudohypersensitivity. Keywords: praseodymium(III), 4f–4f transitions, hypersensitive transitions.


2007 ◽  
Vol 63 (a1) ◽  
pp. s169-s169
Author(s):  
S. Ide ◽  
N. Ancın ◽  
H. Malkaş ◽  
S. G. Öztaş

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Samik Gupta

Abstract Pyridoxal and Pyridoxal 5-phosphate are two among the six aqua soluble vitamers of vitamin B6. They can form Schiff bases readily due to the presence of aldehyde group. Schiff bases can offer diverse coordination possibilities for many transition metals as has been found in a large volume of research till now. The coordination complexes thus formed gives insight into the active core structure and enzymatic activities of vit B6 containing enzymes. Apart from that, these complexes have been found useful as catalysts for synthesis of fine chemicals, as sensors and for their diverse biological activities.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Kiran Singh ◽  
Parvesh Puri ◽  
Yogender Kumar ◽  
Chetan Sharma

This paper deals with the syntheses and structural features of some new diorganosilicon(IV) and diorganotin(IV) complexes having general formulae (CH3)2MCl(L1), (CH3)2MCl(L2), (CH3)2M(L1)2, and (CH3)2M(L2)2 with new Schiff bases (M = Si and Sn). The Schiff bases HL1 and HL2 have been derived from the condensation of 3-bromobenzaldehyde with 4-amino-3-ethyl-5-mercapto-1,2,4-triazole and 4-amino-5-mercapto-3-propyl-1,2,4-triazole, respectively. The compounds have been characterized by the elemental analyses, molar conductance, and spectral (UV, IR, 1H, 13C, 29Si, and 119Sn NMR) studies. The resulting complexes have been proposed to have trigonal bipyramidal and octahedral geometries. In vitro antimicrobial activities of the compounds have been carried out.


2015 ◽  
Vol 71 (7) ◽  
pp. 554-563 ◽  
Author(s):  
Yun-Na Liu ◽  
Shuang-Shuang Cheng ◽  
Chao Wang ◽  
Dian-Xiang Xing ◽  
Yun Liu ◽  
...  

A series of mono- and di-Schiff bases formed between benzil dihydrazone {BDH; systematic name: (1Z)-[(2E)-2-hydrazinylidene-1,2-diphenylethylidene]hydrazine} and three isomeric chlorobenzaldehydes were designed and synthesized to be used as model compounds to help to explain the reaction mechanisms for the formation of Schiff bases. These compounds are 1-(2-chlorobenzylidene)-2-{2-[2-(2-chlorobenzylidene)hydrazin-1-ylidene]-1,2-diphenylethylidene}hydrazine (BDHOCB), and the 3-chloro (BDHMCB) and 4-chloro (BDHPCB) analogues, all having the formula C28H20Cl2N4. Surprisingly, only di-Schiff bases were obtained; our attempts to push the reaction in favour of the mono-Schiff bases all failed. Density functional theory (DFT) calculations were performed to explain the trend in the experimental results. In the case of the systems studied, the type of Schiff base produced exhibits a clear dependence on the HOMO–LUMO energy gaps (ΔEHOMO–LUMO),i.e.the product is mainly governed by its stability. The compounds were characterized by single-crystal X-ray diffractometry, elemental analysis, melting point,1H NMR and13C NMR spectroscopy. The structural features of the three new Schiff bases are similar. For instance, they have the same chemical formula, all the molecules have a symmetrical double helix structure, with each Ph—C=N—N=C—Ph arm exhibiting ananticonformation, and their supramolecular interactions include intermolecular π–π and weak C—H...π stacking interactions. The crystal systems are different, however,viz.triclinic (space groupP\overline{1}) for BDHPCB, monoclinic (space groupP21/n) for BDHOCB and orthorhombic (space groupPnna) for BDHMCB.


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