File Name: schiff base ligands and their metal complexes .zip
The efficiency of such a process is strongly dependent on the various molecular interactions occurring between components. Thermodynamic properties of these systems can provide valuable information about structural interactions.
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The complexes show enhanced antibacterial activity against S. Developing metal-based drugs is emerging as an active area of research. Many organic ligands particularly tridentate Schiff base ligands show enhanced antibacterial, antifungal, and carcinostatic activity when complexed to transition metal ions [ 1 — 7 ]. Heterocyclic systems bearing the pyrazolyl moiety show antibacterial, antifungal, anti-inflammatory and enzyme-inhibitory activity [ 8 — 11 ]. Synthesis and characterization of metal complexes of 4-acylpyrazoles are well documented [ 12 — 14 ].
The magnetic susceptibility measurements and low conductance data provide evidence for the monomeric and neutral natures of the complexes respective ly. The antimicrobial activities of the ligands and their complexes have been studied by screening the compounds against the bacteria E. The DNA cleavage experiments, performed using gel electrophoresis with the corresponding metal complexes in the presence of H 2 0 2 showed all the complexes afford a pronounced discernible DNA cleavage evidenced by the disappearance of Form I supercoiled of plasmid and the production of Form III linear. The metal ions are also known to accelerate drug action. The interaction of metal ions with nucleic acids and nucleic acid constituents has been actively studied in the recent years 2,3. The interaction of metal complexes with DNA has long been the subject of intense investigation in relation to the development of new reagents for biological and medicinal fields. DNA can be cleaved by hydrolytic or oxidative pathways.
Transition metal complexes of bidentate Schiff base ligands
The Schiff bases coordinate to the metal atoms through the phenolate O and imine N atoms. The Ni atom in 1 is in an octahedral coordination, and the Cu atom in 2 is in a square planar coordination. Keywords: Schiff base; nickel complex; copper complex; crystal structure. Schiff bases have been widely used as versatile ligands in coordination chemistry. Materials and Methods: All organic chemicals were purchased from Fluka.
New Schiff base ligands derived from vanillin HL 1 , 4-dimethylaminobenzaldehyde HL 2 and 3,5-di-t-butylhydroxybenzaldehyde HL 3 with N- pyridyl methoxyhydroxyaminobenzylamine 2 and their copper II , cobalt II , nickel II , oxovanadium IV and zinc II transition metal complexes have been synthesized and characterized by elemental analyses, electronic and i. The results indicate that the ligands coordinate through azomethine nitrogen and phenolic oxygen to the metal ions. In like manner, it was found that the pyridine and amine nitrogen atoms are not coordinated to the metal ions. The antimicrobial activity properties of the ligands and their metal complexes have been studied.
Their spectral properties and electrochemical behavior were investigated. During the past two decades, considerable attention has been paid to the chemistry of the metal complexes of Schiff bases containing nitrogen and other donors [ 1 , 2 , 3 , 4 ]. This may be attributed to their stability, biological activity [ 5 ] and potential applications in many fields such as oxidation catalysis [ 6 ], electrochemistry [ 7 ], etc. The ligand H 2 L was prepared as outlined in Figure 1. The disappearance of the OH band of the free ligand in the IR of the metal complexes indicates that the OH group is deprotonated and coordinated to the metal ion as —O -. According to the aforementioned data, we propose for the complexes prepared the structure shown in Figure 2.
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Он уходил корнями в давние времена. В эпоху Возрождения скульпторы, оставляя изъяны при обработке дорогого мрамора, заделывали их с помощью сеrа, то есть воска. Статуя без изъянов, которую не нужно было подправлять, называлась скульптурой sin cera, иными словами - без воска. С течением времени это выражение стало означать нечто честное, правдивое. Английское слово sincere, означающее все правдивое и искреннее, произошло от испанского sin сега - без воска.
Действительно хорошая новость. ГЛАВА 54 - Пусти. А потом раздался нечеловеческий крик. Это был протяжный вопль ужаса, издаваемый умирающим зверем.
Уран природный элемент, плутоний - искусственный. Для урана используется ружейный детонатор, для плутония нужен взрыв. Это не числа, такие различия нас не касаются. - Работайте, - поторопил Фонтейн.
- Давайте попробуем кандзи. И словно по волшебству все встало на свое место.