Felipe Vilhena - Academia.edu (original) (raw)
Papers by Felipe Vilhena
European Journal of Organic Chemistry, Aug 7, 2017
Vilhena, Felipe de Souza Dias dos Santos; Rey, Nicolás Adrián. Study of the formation of binary a... more Vilhena, Felipe de Souza Dias dos Santos; Rey, Nicolás Adrián. Study of the formation of binary and ternary complexes of Cu(II) ion with some dipeptides and amino acids. Rio de Janeiro, 2012. 165p. DSc. Thesis
Journal of the Brazilian Chemical Society, 2014
Two new synthetic melanin-like oligomers inspired by the synthesis of pheomelanin (cys-DOPA) were... more Two new synthetic melanin-like oligomers inspired by the synthesis of pheomelanin (cys-DOPA) were prepared using L-DOPA as a precursor and the amino acids serine (ser-DOPA) and threonine (thr-DOPA) for modifications. The products obtained exhibited appreciable antioxidant activity. The compounds were characterized by liquid chromatography-mass spectrometry (LC-MS), elemental analysis and infrared spectroscopy. The pKa values of the groups present in each melanin suspension were determined in aqueous solution by potentiometric and spectrophotometric titration. Cytotoxicity assays showed an IC 50 > 500 mg L-1 resulting in non-toxic compounds for living cells. Finally, cys-DOPA, ser-DOPA and thr-DOPA exhibited antioxidant activity determined by the DPPH scavenging assay, with EC 50 = 7.69, 1.02 and 27.60 mg L-1 , respectively.
Polyhedron, Apr 1, 2013
The ternary complexes of Cu(II) with some dipeptides and methionine were studied both in aqueous ... more The ternary complexes of Cu(II) with some dipeptides and methionine were studied both in aqueous solution and in solid state. The formation constants of copper(II) ternary complexes were calculated by potentiometric titration at 25°C and l = 0.1 mol L À1. The values of the constants for CuL 1 L 2 species (L 1-= GlyGly, GlyVal, GlyLeu or GlyPhe; L 2 = Met) were 15.66, 15.75, 15.69 and 16.31, respectively. The complexes [Cu(GlyGly)Met]K (1), [Cu(GlyVal)Met]KÁ2H 2 O (2), [Cu(GlyLeu)(Met)(H 2 O) 2 ]KÁH 2 O (3) and [Cu(GlyPhe)(Met)(H 2 O)]KÁ2H 2 O (4) were isolated in pH around 7 and characterized through microanalyses, thermogravimetry, UV-Vis, infrared and EPR spectroscopies. The presence of the sulfur noncoordinated to metal in these ternary complexes can exert reduction action in biological systems under stress conditions.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
![Research paper thumbnail of In vitro and in vivo activity of a new unsymmetrical dinuclear copper complex containing a derivative ligand of 1,4,7-triazacyclononane: catalytic promiscuity of [Cu2(L)Cl3]](https://attachments.academia-assets.com/92856074/thumbnails/1.jpg)
](Dalton Transactions, 2013
Inorganica Chimica Acta, 2012
Alzheimer's disease is characterized by the loss of synapses and by the presence of extra-cellula... more Alzheimer's disease is characterized by the loss of synapses and by the presence of extra-cellular amyloid b-peptide (Ab) plaques, and it has been associated to copper metabolism. The plasma of patients with Alzheimer's disease presents higher levels of the amino acid homocysteine (hCys). In this study, three new ternary complexes of copper(II) with homocysteine and three amino acids of Ab (aspartate, glutamate or methionine) were studied both in solution (pH-potentiometry and UV-Vis) and in the solid state (CHNS, AAS, TGA, EPR, and FT-IR). Molar conductance and electrochemical (CV) measurements were carried out as well. The binary complex [Cu(hCys) 2 ] was also synthesized and characterized. For the ternary complexes, the values of the stability constants (log b equal to 25.62 for CuAsphCys, 23.53 for CuGluhCys, and 18.61 for CuMethCys) are similar to those of the cysteine-containing ternary complexes CuAspCys and CuGluCys, recently reported by us, indicating a related N 2 OS coordination. The results found in the solid state are in agreement with the data found in solution studies whereby methionine, aspartic, and glutamic acids coordinate to copper(II) ion through the nitrogen atom of the amino group and one oxygen atom of the a-carboxylate group, and homocysteine coordinates through nitrogen and sulfur atoms. EPR data suggest that, in solution, the complexes are in a distorted tetrahedral geometry.
Adsorption
Anthropogenic CO 2 emissions are the major drivers of global warming and climate change. The adso... more Anthropogenic CO 2 emissions are the major drivers of global warming and climate change. The adsorption of CO 2 is one of the strategies to mitigate these emissions. In this sense, different materials have been used as adsorbents as is the case of zeolites. In this work,experimental infrared and X-ray analyses together with DFT (Density Functional Theory)theoretical calculations were employed to study the adsorption of CO 2 on mordenite zeolites (Na-MOR). Ion exchange followed by chemical analysis showed that the Na + of Na-MOR was not completely substituted under the experimental conditions employed. The XRD (X-ray Diffraction) analysis indicated that Na + exchanged for Li + did not affect the crystallinity of the materials. The infrared results showed that CO 2 interacted linearly with the sodium and lithium cations present in the main channel of the mordenite framework. Sodium in dry samples favored the formation of carbonates and hydroxycarbonate species, as did the presence of low water content in the Li x Na-MOR. The DFT periodical calculation of dehydrated mordenite models led to CO 2 adsorption energies in the range of − 31.6 to − 34.2 kJ mol −1 , with the highest adsorption energy found for sodium mordenite.The asymmetric stretching ν 3 (CO 2) vibration mode resulted intense and presented a shift which indicated a higher CO 2 interaction of Na-MOR. The presence of some water molecules in the mordenite framework caused a decrease in the adsorption energy.
Journal of Molecular Modeling
1,3-Dipolar cycloaddition (1,3-DC) reactions are powerful synthetic tool to obtain highly functio... more 1,3-Dipolar cycloaddition (1,3-DC) reactions are powerful synthetic tool to obtain highly functionalized 5-membered heterocycles, starting from a 1,3-dipole and a dipolarophile in a single step. The reactivity of these systems is usually rationalized in terms of Frontier Molecular Orbital Theory (FMOT), which neglects a possible contribution of an open-shell weakly coupled singlet-diradical specie. In this work, the broken-symmetry approach is used to estimate the singlet-diradical character of 18 dipoles of the second period of the periodic table, classified as allyl-type N-centered, allyl-type O-centered, and propargyl-type 1,3-dipoles, providing a rationalization for 1,3-DC reactivity. The intramolecular cyclization of bent allyl-type N- and O-centered dipoles into 3-membered rings was also analyzed, and revealed that the energetic change is associated with the spin densities of peripheral atoms. Finally, a close relationship between the energy for the ring-opening process of the cyclic configuration and the reactivity of 1,3-dipoles toward 1,3-dipolar cycloaddition reaction was also found. Graphical abstract Graphical abstract
Journal of Molecular Modeling
The Sn–Cl chemical bond of four organotin halides (Me3SnCl, Et3SnCl, Bu3SnCl, and Ph3SnCl) was st... more The Sn–Cl chemical bond of four organotin halides (Me3SnCl, Et3SnCl, Bu3SnCl, and Ph3SnCl) was studied by using relativistic density functional theory in combination with a quantitative energy decomposition analysis to explain the formation of charged species. The σ orbital is the dominant contributor to the stabilization of the Sn–Cl bond, and the π-orbital interactions also have a significant contribution to the stabilization of Ph3Sn+ cation when the aromatic groups are bonded to the tin atom. The aromaticity of the phenyl groups delocalizes the positive charge, donating electrons to tin atom by conjugation. Although Me3SnCl and Ph3SnCl are constituted by groups which the size of the substituents is different, the interaction energies obtained with the energy decomposition analysis present similar values, which also occur with the thermodynamic parameters. Graphical abstract Organotin compounds have widely studied as a potential antitumoral agent. The mechanism in triorganotin compounds includes the formation of cation species, R3Sn+. This article studies the influence of the R groups on the rupture of Sn–Cl bond using the fragment analysis and quantitative energy decomposition analysis. Organotin compounds have widely studied as a potential antitumoral agent. The mechanism in triorganotin compounds includes the formation of cation species, R3Sn+. This article studies the influence of the R groups on the rupture of Sn–Cl bond using the fragment analysis and quantitative energy decomposition analysis.
Journal of Molecular Structure, 2016
Abstract A large number of copper (II) complexes have been used as mimetic models for metalloprot... more Abstract A large number of copper (II) complexes have been used as mimetic models for metalloproteins and metalloenzymes. Due to the lack of structural information about copper (II) complexes in aqueous solution, the coordination environment of this metal is not well established. In this work, pK a values of the complexes in the Cu:GlyGly, Cu:Met and Cu:GlyGly:Met systems were calculated by potentiometric titration at 25 °C and ionic strength of 0.1 mol L −1 . The coordination modes of the ligands were explored for the main hydrolytic species throught RI-PBE/def2-SVP/COSMO level. In the Cu:GlyGly system, DFT results indicated that the N amine N pept coordination of dipeptide is 2.1 kcal mol −1 more stable than the tridentate N amine N pept O carboxy coordination moiety. The deprotonation of the peptide nitrogen is 13.7 kcal mol −1 more favorable than the hydrolysis of the water molecule coordinated to the metal. In the Cu:GlyGly:Met system, the sulfur atom does not belong to the copper (II) coordination sphere. Once the copper ion is incorporated into peptides, another ligand as methionine could bind to this system and carry an antioxidant site to different brain regions.
The ternary complexes of copper (II) with some dipeptides ( solution by potentiometric titration ... more The ternary complexes of copper (II) with some dipeptides ( solution by potentiometric titration at 25 oC and I spectra. The values of formation constants for CuL > Cu:GlyGly:His. The species distribution diagrams show at 77 K suggest that the copper(II) is in a square planar geometry. The infrared data indicated tridentate behavior of dipeptides (NamineNpeptOcarboxy) and monodentate of histidine suggesting that the heteroaromatic nitrogen can bind
Computational and Theoretical Chemistry, 2016
Abstract Mordenite is a type of zeolite used in catalysis processes and in the selective adsorpti... more Abstract Mordenite is a type of zeolite used in catalysis processes and in the selective adsorption of gases. The properties of this material are related to the presence of aluminium atoms and exchangeable cations in the structure. In this work, we performed DFT periodic calculations of cationic mordenites X8Al8Si40O96 and X4Al4Si44O96 (X = Li+ or Na+) and the corresponding hydrated species. Calculations of Li+ and Na+ mordenites indicated preference for the aluminium atoms to occupy T3 and T4 sites. In this configuration, the alkaline cations have preference for the two channels 8MRz and 12MRz along [0 0 1] crystallographic axis. In the hydrated structures, the alkaline cations have preference for the side pockets (8MRy along [0 1 0] direction). Hydrated structures with high aluminium content have a stability caused by interaction of the alkaline cations with water molecules and oxygen atoms of the framework.
Journal of Molecular Modeling
Polyhedron, 2008
... Angelica E. Graminha a , Felipe S. Vilhena b , Alzir A. Batista a , Sonia RW Louro c , Robert... more ... Angelica E. Graminha a , Felipe S. Vilhena b , Alzir A. Batista a , Sonia RW Louro c , Roberta L. Ziolli b , Letícia R. Teixeira b , Corresponding Author Contact Information , E-mail The Corresponding Author and Heloisa Beraldo d. ...
Journal of Solution Chemistry, Mar 1, 2013
![Research paper thumbnail of In vitro and in vivo activity of a new unsymmetrical dinuclear copper complex containing a derivative ligand of 1,4,7-triazacyclononane: catalytic promiscuity of [Cu2(L)Cl3]](https://attachments.academia-assets.com/49593589/thumbnails/1.jpg)
](Dalton Transactions, 2013
Here we present the synthesis of the dinuclear complex [Cu II 2 (L)Cl 3 ] (1), where L is the dep... more Here we present the synthesis of the dinuclear complex [Cu II 2 (L)Cl 3 ] (1), where L is the deprotonated form of the 3-[(4,7-diisopropyl-1,4,7-triazacyclononan-1-yl)methyl]-2-hydroxy-5-methylbenzaldehyde ligand. The complex was characterized by single crystal X-ray diffraction, potentiometric titration, mass spectrometry, electrochemical and magnetic measurements, EPR, UV-Vis and IR. Complex 1 is able to increase the hydrolysis rate of the diester bis-(2,4-dinitrophenyl)phosphate (2,4-BDNPP) by a factor of 2700, and also to promote the plasmidial DNA cleavage at pH 6 and to inhibit the formazan chromophore formation in redox processes at pH 7. Using Saccharomyces cerevisiae (BY4741) as a eukaryotic cellular model, we observed that 1 presents reduced cytotoxicity. In addition, treatment of wild-type and mutant cells lacking Cu/Zn-superoxide dismutase (Sod1) and cytoplasmic catalase (Ctt1) with 1 promotes increased survival after H 2 O 2 or menadione (O 2˙− generator) stress, indicating that 1 might act as a Sod1 and Ctt1 mimetic. Considered together, these results support considerations regarding the dynamic behaviour of an unsymmetrical dinuclear copper(II) complex in solid state and in aqueous pH-dependent solution.
European Journal of Organic Chemistry, Aug 7, 2017
Vilhena, Felipe de Souza Dias dos Santos; Rey, Nicolás Adrián. Study of the formation of binary a... more Vilhena, Felipe de Souza Dias dos Santos; Rey, Nicolás Adrián. Study of the formation of binary and ternary complexes of Cu(II) ion with some dipeptides and amino acids. Rio de Janeiro, 2012. 165p. DSc. Thesis
Journal of the Brazilian Chemical Society, 2014
Two new synthetic melanin-like oligomers inspired by the synthesis of pheomelanin (cys-DOPA) were... more Two new synthetic melanin-like oligomers inspired by the synthesis of pheomelanin (cys-DOPA) were prepared using L-DOPA as a precursor and the amino acids serine (ser-DOPA) and threonine (thr-DOPA) for modifications. The products obtained exhibited appreciable antioxidant activity. The compounds were characterized by liquid chromatography-mass spectrometry (LC-MS), elemental analysis and infrared spectroscopy. The pKa values of the groups present in each melanin suspension were determined in aqueous solution by potentiometric and spectrophotometric titration. Cytotoxicity assays showed an IC 50 > 500 mg L-1 resulting in non-toxic compounds for living cells. Finally, cys-DOPA, ser-DOPA and thr-DOPA exhibited antioxidant activity determined by the DPPH scavenging assay, with EC 50 = 7.69, 1.02 and 27.60 mg L-1 , respectively.
Polyhedron, Apr 1, 2013
The ternary complexes of Cu(II) with some dipeptides and methionine were studied both in aqueous ... more The ternary complexes of Cu(II) with some dipeptides and methionine were studied both in aqueous solution and in solid state. The formation constants of copper(II) ternary complexes were calculated by potentiometric titration at 25°C and l = 0.1 mol L À1. The values of the constants for CuL 1 L 2 species (L 1-= GlyGly, GlyVal, GlyLeu or GlyPhe; L 2 = Met) were 15.66, 15.75, 15.69 and 16.31, respectively. The complexes [Cu(GlyGly)Met]K (1), [Cu(GlyVal)Met]KÁ2H 2 O (2), [Cu(GlyLeu)(Met)(H 2 O) 2 ]KÁH 2 O (3) and [Cu(GlyPhe)(Met)(H 2 O)]KÁ2H 2 O (4) were isolated in pH around 7 and characterized through microanalyses, thermogravimetry, UV-Vis, infrared and EPR spectroscopies. The presence of the sulfur noncoordinated to metal in these ternary complexes can exert reduction action in biological systems under stress conditions.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Dalton Transactions, 2013
Inorganica Chimica Acta, 2012
Alzheimer's disease is characterized by the loss of synapses and by the presence of extra-cellula... more Alzheimer's disease is characterized by the loss of synapses and by the presence of extra-cellular amyloid b-peptide (Ab) plaques, and it has been associated to copper metabolism. The plasma of patients with Alzheimer's disease presents higher levels of the amino acid homocysteine (hCys). In this study, three new ternary complexes of copper(II) with homocysteine and three amino acids of Ab (aspartate, glutamate or methionine) were studied both in solution (pH-potentiometry and UV-Vis) and in the solid state (CHNS, AAS, TGA, EPR, and FT-IR). Molar conductance and electrochemical (CV) measurements were carried out as well. The binary complex [Cu(hCys) 2 ] was also synthesized and characterized. For the ternary complexes, the values of the stability constants (log b equal to 25.62 for CuAsphCys, 23.53 for CuGluhCys, and 18.61 for CuMethCys) are similar to those of the cysteine-containing ternary complexes CuAspCys and CuGluCys, recently reported by us, indicating a related N 2 OS coordination. The results found in the solid state are in agreement with the data found in solution studies whereby methionine, aspartic, and glutamic acids coordinate to copper(II) ion through the nitrogen atom of the amino group and one oxygen atom of the a-carboxylate group, and homocysteine coordinates through nitrogen and sulfur atoms. EPR data suggest that, in solution, the complexes are in a distorted tetrahedral geometry.
Adsorption
Anthropogenic CO 2 emissions are the major drivers of global warming and climate change. The adso... more Anthropogenic CO 2 emissions are the major drivers of global warming and climate change. The adsorption of CO 2 is one of the strategies to mitigate these emissions. In this sense, different materials have been used as adsorbents as is the case of zeolites. In this work,experimental infrared and X-ray analyses together with DFT (Density Functional Theory)theoretical calculations were employed to study the adsorption of CO 2 on mordenite zeolites (Na-MOR). Ion exchange followed by chemical analysis showed that the Na + of Na-MOR was not completely substituted under the experimental conditions employed. The XRD (X-ray Diffraction) analysis indicated that Na + exchanged for Li + did not affect the crystallinity of the materials. The infrared results showed that CO 2 interacted linearly with the sodium and lithium cations present in the main channel of the mordenite framework. Sodium in dry samples favored the formation of carbonates and hydroxycarbonate species, as did the presence of low water content in the Li x Na-MOR. The DFT periodical calculation of dehydrated mordenite models led to CO 2 adsorption energies in the range of − 31.6 to − 34.2 kJ mol −1 , with the highest adsorption energy found for sodium mordenite.The asymmetric stretching ν 3 (CO 2) vibration mode resulted intense and presented a shift which indicated a higher CO 2 interaction of Na-MOR. The presence of some water molecules in the mordenite framework caused a decrease in the adsorption energy.
Journal of Molecular Modeling
1,3-Dipolar cycloaddition (1,3-DC) reactions are powerful synthetic tool to obtain highly functio... more 1,3-Dipolar cycloaddition (1,3-DC) reactions are powerful synthetic tool to obtain highly functionalized 5-membered heterocycles, starting from a 1,3-dipole and a dipolarophile in a single step. The reactivity of these systems is usually rationalized in terms of Frontier Molecular Orbital Theory (FMOT), which neglects a possible contribution of an open-shell weakly coupled singlet-diradical specie. In this work, the broken-symmetry approach is used to estimate the singlet-diradical character of 18 dipoles of the second period of the periodic table, classified as allyl-type N-centered, allyl-type O-centered, and propargyl-type 1,3-dipoles, providing a rationalization for 1,3-DC reactivity. The intramolecular cyclization of bent allyl-type N- and O-centered dipoles into 3-membered rings was also analyzed, and revealed that the energetic change is associated with the spin densities of peripheral atoms. Finally, a close relationship between the energy for the ring-opening process of the cyclic configuration and the reactivity of 1,3-dipoles toward 1,3-dipolar cycloaddition reaction was also found. Graphical abstract Graphical abstract
Journal of Molecular Modeling
The Sn–Cl chemical bond of four organotin halides (Me3SnCl, Et3SnCl, Bu3SnCl, and Ph3SnCl) was st... more The Sn–Cl chemical bond of four organotin halides (Me3SnCl, Et3SnCl, Bu3SnCl, and Ph3SnCl) was studied by using relativistic density functional theory in combination with a quantitative energy decomposition analysis to explain the formation of charged species. The σ orbital is the dominant contributor to the stabilization of the Sn–Cl bond, and the π-orbital interactions also have a significant contribution to the stabilization of Ph3Sn+ cation when the aromatic groups are bonded to the tin atom. The aromaticity of the phenyl groups delocalizes the positive charge, donating electrons to tin atom by conjugation. Although Me3SnCl and Ph3SnCl are constituted by groups which the size of the substituents is different, the interaction energies obtained with the energy decomposition analysis present similar values, which also occur with the thermodynamic parameters. Graphical abstract Organotin compounds have widely studied as a potential antitumoral agent. The mechanism in triorganotin compounds includes the formation of cation species, R3Sn+. This article studies the influence of the R groups on the rupture of Sn–Cl bond using the fragment analysis and quantitative energy decomposition analysis. Organotin compounds have widely studied as a potential antitumoral agent. The mechanism in triorganotin compounds includes the formation of cation species, R3Sn+. This article studies the influence of the R groups on the rupture of Sn–Cl bond using the fragment analysis and quantitative energy decomposition analysis.
Journal of Molecular Structure, 2016
Abstract A large number of copper (II) complexes have been used as mimetic models for metalloprot... more Abstract A large number of copper (II) complexes have been used as mimetic models for metalloproteins and metalloenzymes. Due to the lack of structural information about copper (II) complexes in aqueous solution, the coordination environment of this metal is not well established. In this work, pK a values of the complexes in the Cu:GlyGly, Cu:Met and Cu:GlyGly:Met systems were calculated by potentiometric titration at 25 °C and ionic strength of 0.1 mol L −1 . The coordination modes of the ligands were explored for the main hydrolytic species throught RI-PBE/def2-SVP/COSMO level. In the Cu:GlyGly system, DFT results indicated that the N amine N pept coordination of dipeptide is 2.1 kcal mol −1 more stable than the tridentate N amine N pept O carboxy coordination moiety. The deprotonation of the peptide nitrogen is 13.7 kcal mol −1 more favorable than the hydrolysis of the water molecule coordinated to the metal. In the Cu:GlyGly:Met system, the sulfur atom does not belong to the copper (II) coordination sphere. Once the copper ion is incorporated into peptides, another ligand as methionine could bind to this system and carry an antioxidant site to different brain regions.
The ternary complexes of copper (II) with some dipeptides ( solution by potentiometric titration ... more The ternary complexes of copper (II) with some dipeptides ( solution by potentiometric titration at 25 oC and I spectra. The values of formation constants for CuL > Cu:GlyGly:His. The species distribution diagrams show at 77 K suggest that the copper(II) is in a square planar geometry. The infrared data indicated tridentate behavior of dipeptides (NamineNpeptOcarboxy) and monodentate of histidine suggesting that the heteroaromatic nitrogen can bind
Computational and Theoretical Chemistry, 2016
Abstract Mordenite is a type of zeolite used in catalysis processes and in the selective adsorpti... more Abstract Mordenite is a type of zeolite used in catalysis processes and in the selective adsorption of gases. The properties of this material are related to the presence of aluminium atoms and exchangeable cations in the structure. In this work, we performed DFT periodic calculations of cationic mordenites X8Al8Si40O96 and X4Al4Si44O96 (X = Li+ or Na+) and the corresponding hydrated species. Calculations of Li+ and Na+ mordenites indicated preference for the aluminium atoms to occupy T3 and T4 sites. In this configuration, the alkaline cations have preference for the two channels 8MRz and 12MRz along [0 0 1] crystallographic axis. In the hydrated structures, the alkaline cations have preference for the side pockets (8MRy along [0 1 0] direction). Hydrated structures with high aluminium content have a stability caused by interaction of the alkaline cations with water molecules and oxygen atoms of the framework.
Journal of Molecular Modeling
Polyhedron, 2008
... Angelica E. Graminha a , Felipe S. Vilhena b , Alzir A. Batista a , Sonia RW Louro c , Robert... more ... Angelica E. Graminha a , Felipe S. Vilhena b , Alzir A. Batista a , Sonia RW Louro c , Roberta L. Ziolli b , Letícia R. Teixeira b , Corresponding Author Contact Information , E-mail The Corresponding Author and Heloisa Beraldo d. ...
Journal of Solution Chemistry, Mar 1, 2013
Dalton Transactions, 2013
Here we present the synthesis of the dinuclear complex [Cu II 2 (L)Cl 3 ] (1), where L is the dep... more Here we present the synthesis of the dinuclear complex [Cu II 2 (L)Cl 3 ] (1), where L is the deprotonated form of the 3-[(4,7-diisopropyl-1,4,7-triazacyclononan-1-yl)methyl]-2-hydroxy-5-methylbenzaldehyde ligand. The complex was characterized by single crystal X-ray diffraction, potentiometric titration, mass spectrometry, electrochemical and magnetic measurements, EPR, UV-Vis and IR. Complex 1 is able to increase the hydrolysis rate of the diester bis-(2,4-dinitrophenyl)phosphate (2,4-BDNPP) by a factor of 2700, and also to promote the plasmidial DNA cleavage at pH 6 and to inhibit the formazan chromophore formation in redox processes at pH 7. Using Saccharomyces cerevisiae (BY4741) as a eukaryotic cellular model, we observed that 1 presents reduced cytotoxicity. In addition, treatment of wild-type and mutant cells lacking Cu/Zn-superoxide dismutase (Sod1) and cytoplasmic catalase (Ctt1) with 1 promotes increased survival after H 2 O 2 or menadione (O 2˙− generator) stress, indicating that 1 might act as a Sod1 and Ctt1 mimetic. Considered together, these results support considerations regarding the dynamic behaviour of an unsymmetrical dinuclear copper(II) complex in solid state and in aqueous pH-dependent solution.