The influence of metals on the electronic system of biologically important ligands. Spectroscopic study of benzoates, salicylates, nicotinates and isoorotates. Review

Lewandowski, W.; Kalinowska, Monika; Lewandowska, Hanna

doi:10.1016/j.jinorgbio.2005.04.010

Cited by 159 publications

(90 citation statements)

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“…54,[60][61][62][63][64] IR and Raman spectroscopy have shown that formic acid forms a bridging ligand with titania. 55,[65][66][67][68] Previous reports have shown that similar chelating agents remain bound to the central titanium atom, while the isopropoxy (OR) groups are preferentially hydrolyzed. The bridging ligands remain throughout much of the condensation process, 54,56 altering the condensation pathway and promoting the formation of linear polymers composed of edge sharing octahedral.…”

Section: Resultsmentioning

confidence: 99%

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂

et al. 2010

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Anatase to rutile transition in an unmodified synthetic titania usually occurs at a temperature range of 600-700°C. Various methods such as addition of metallic and nonmetallic dopants and modifying the precursor have previously been reported to influence the anatase to rutile transition temperature. In the current study, the effect of addition of increasing amounts of silver to the extent of chelation of a formate group to a titanium precursor and the resulting effects on the transformation of anatase to rutile has been studied. The addition of silver (0, 1, 3, and 5 mol %) on the anatase to rutile transformation temperature has been systematically followed by Fourier transform infrared (FTIR), Raman, X-ray diffraction (XRD), differential scanning calorimetry, and X-ray photoelectron spectroscopy (XPS) studies. From the FTIR and Raman spectroscopy studies it was observed that the incorporation of silver caused a reduction in the intensity of the COO -stretches indicating that the titania formate bridging complex is becoming weaker in the presence of silver. XRD studies indicated an early rutile formation for the silver-doped samples. XRD of the samples calcined at 700°Cshowed that 5 mol % Ag TiO 2 contained both anatase (46%) and rutile (54%), whereas the undoped sample primarily consists of anatase (95%). At 800°C all silver doped samples converted to 100% rutile and the undoped TiO 2 consisted of both anatase (55%) and rutile (45%). XPS analysis showed that Ag 0 and Ag 2 O has been formed on the surface of the titania formate complex without calcination (>100°C) indicating that photo-oxidation has occurred. FTIR, Raman, and XPS studies confirmed that the presence of silver in the xerogel before calcination may be responsible for the reduction of the titanium formate bridge. It was concluded that the presence of silver (Ag 2 O and Ag 0 ) hindered bridging ligands, which resulted in a weakened titanium gel network. This structurally weakened gel network could easily be collapsed during calcination, and it favors an early rutile formation.

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Section: Resultsmentioning

confidence: 99%

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂

et al. 2010

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“…The current studies on copper(II) based compounds containing benzoate ligands are varied, either focusing on magneto-structural studies [14][15][16] or on complexes with different structural features [17][18][19]. To the best of our knowledge, no other physical and chemical studies, except on magnetic property have been done on copper(II) benzoate, having this structure.…”

Section: Introductionmentioning

confidence: 99%

Thermal stability and electrochemical behaviour of Tetrakis-μ-benzoatodicopper(II)

Mohamadin

Abdullah

2010

Open Chemistry

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“…Usually, their anti-tumor activities can increase more or less compared with those of either the free ligands or metal ions alone, which may be due to the different binding properties of these complexes to DNA. [10][11][12][13] It is necessary to understand the DNA binding properties for developing new potential DNA targeting anti-tumor drugs. In general, metal complexes interact with double helix DNA in either non-covalent or covalent way, the former including three binding modes, namely, intercalation, groove binding and external static electronic effects.…”

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Two New Co(II) and Ni(II) Complexes with 3-(2-Pyridyl)pyrazole-Based Ligand: Synthesis, Crystal Structures, and Bioactivities

et al. 2007

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Over the past decades, investigations on DNA interactions with transition metal complexes, especially for those containing multidentate aromatic ligands, have aroused considerable interests owing to their potential applications as new therapeutic agents and interesting properties that make them as possible probes of DNA structure and conformation. 1,2) The studies on DNA metallointercalators, which can react at specific sites along a DNA strand as reactive models for proteinnucleic acid interactions, have provided us with some effective routes toward rational drug design as well as approaches to develop sensitive chemical probes for DNA.3-9) Among them, a number of transition metal complexes with planar aromatic heterocyclic ligands have been used as the probes for DNA secondary structure and therapeutic agents. Usually, their anti-tumor activities can increase more or less compared with those of either the free ligands or metal ions alone, which may be due to the different binding properties of these complexes to DNA. [10][11][12][13] It is necessary to understand the DNA binding properties for developing new potential DNA targeting anti-tumor drugs. In general, metal complexes interact with double helix DNA in either non-covalent or covalent way, the former including three binding modes, namely, intercalation, groove binding and external static electronic effects. In these interactions, it should be pointed out that intercalation is a significantly important binding mode to DNA. In fact, DNA intercalators are some small molecules that contain a heterocyclic functional group with the structure of planar aromatic ring, which can insert and stack between the base pairs of doublehelical DNA. Meanwhile, the intercalative capability of DNA metallointercalators appears to be influenced by several factors such as the planarity of ligand, atom type of ligand donor and the coordination geometry.14-16) Moreover, the types of different metal ions and their flexible valences, which usually are responsible for the coordination geometry of complexes, also have significant influences on the intercalating ability of transition metal complexes to DNA. 17,18) In our previous work, a new 3-(2-pyridyl)pyrazole-based ligand L (see Chart 1) and its Cu(II), Zn(II) and Cd(II) com- 19,20) Obviously, the Cu(II) complexes were found to possess higher affinity to DNA and cytotoxic activity against different tested cancer cell lines (such as HL-60, BGC-823 and MDA-MB-435) as compared with Zn(II) and Cd(II) complex as well as the free ligand L. In attempt to further touch more insights into the relationship between structures and DNA-binding properties of such transition metal complexes, as well as to develop new useful DNA probes, herein, we report the synthesis and crystal structures of another two new complexes with L ligand, [Co(L) 3 ](ClO 4 ) 2 (1) and [Ni(L) 3 ](ClO 4 ) 2 (2). Moreover, the binding behaviors of these compounds with calf thymus DNA (CT-DNA) have been investigated in detail by thermal denaturation, viscosity measuremen...

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The influence of metals on the electronic system of biologically important ligands. Spectroscopic study of benzoates, salicylates, nicotinates and isoorotates. Review

Cited by 159 publications

References 132 publications

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂

Thermal stability and electrochemical behaviour of Tetrakis-μ-benzoatodicopper(II)

Two New Co(II) and Ni(II) Complexes with 3-(2-Pyridyl)pyrazole-Based Ligand: Synthesis, Crystal Structures, and Bioactivities

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The influence of metals on the electronic system of biologically important ligands. Spectroscopic study of benzoates, salicylates, nicotinates and isoorotates. Review

Cited by 159 publications

References 132 publications

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO2

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO2

Thermal stability and electrochemical behaviour of Tetrakis-μ-benzoatodicopper(II)

Two New Co(II) and Ni(II) Complexes with 3-(2-Pyridyl)pyrazole-Based Ligand: Synthesis, Crystal Structures, and Bioactivities

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A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂

A Systematic Study of the Effect of Silver on the Chelation of Formic Acid to a Titanium Precursor and the Resulting Effect on the Anatase to Rutile Transformation of TiO₂