- Rare examples of diphenoxido-bridged trinuclear NiII2FeIII complexes with a reduced salen type Schiff base ligand: Structures and magnetic properties
-
Three new trinuclear hetero-metallic complexes, [(NiLR)2Fe(N3)3] (1), [(NiLR(H2O))2Fe(C6H5CH2CO2)2]·(HSO4) (2) and [(NiLR(H2O))2Fe(C6H5CO2)2]·(HSO4)·(H2O)·(CH2Cl2) (3) have been synthesized using [NiLR] as a “metalloligand” (where H2LR = N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine). All complexes have been characterized by elemental analysis, spectroscopic methods, single crystal XRD and magnetic study. In the angular trinuclear units of 1, the two terminals [NiLR] coordinate through double phenoxido bridges to the central FeIII ion which is penta-coordinated having terminally coordinated azide ion. The two terminal NiII centers are connected to each other and also to neighbouring units through μ1,3-azido bridges to form an alternating chain. On the other hand, complexes, 2 and 3 are linear discrete trinuclear species [NiII–FeIII–NiII] in which two terminal octahedral [NiLR] units coordinate to the central octahedral FeIII ion, located on a crystallographic centre of symmetry, through a μ2-phenoxido oxygen atom and a bridging carboxylato ion. Variable temperature magnetic susceptibility measurements show the presence of antiferromagnetic exchange interactions in 1 mediated through the phenoxido bridges (J1 = ?33.2 cm?1,) and μ1,3-N3 single bridges (J2 = ?19.9 cm?1 and J3 = ?16.7 cm?1). On the other hand, compounds 2 and 3 show ferromagnetic coupling interactions mediated through the double phenoxido bridges with J values of +4.9 and +3.0 cm?1 for 2 and 3, respectively.
- Hazari, Alokesh,Gómez-García, Carlos J.,Drew, Michael G.B.,Ghosh, Ashutosh
-
-
Read Online
- Unusual site selection of NCS?in trinuclear complexes of Cu(II) and Ni(II) with a reduced N2O2donor Schiff base: Structural, theoretical and magnetic studies
-
Four new trinuclear linear homo-metallic complexes [(CuLR)2Cu(NCS)2]·(CH3)2CO (1), [(CuLR)2Cu(NO3)2] (2), [(NiLR)2Ni(NCS)2·(CH3CN)2] (3), [(NiLR)2Ni(NO3)2·((CH3)2CO)2] (4) have been synthesized using [CuLR] and [NiLR] as metalloligands (where H2LR?=?N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine) along with polyatomic anions, thiocyanato or nitrato. All four complexes have been characterized by elemental analysis, spectroscopic methods, single crystal XRD, DFT and magnetic study. In all complexes, two units of metalloligands, [CuLR] or [NiLR] coordinate to the central copper or nickel atom through double phenoxido bridges forming a linear trinuclear structure. In the structures of 1 and 3, the N-bonded thiocyanato ion coordinates to the terminal metal centers of the trinuclear unit to complete the distorted square pyramidal and octahedral geometry, respectively; the central metal ions remain square planar in both structures. The coordination of thiocyanato to terminal Cu(II) and Ni(II) instead of central metal ion is unusual compared to the complexes of analogous unreduced species. On the other hand, complexes 2 and 4 possess usual structures in which the anionic coligand, nitrato bridges the central and terminal metal centers. The geometries of central metal ions are octahedral in both structures and those of terminal metal ions are square pyramidal in 2 and octahedral in 4. DFT calculations show that experimentally obtained structure 1 is the most stable compared with the possible other hypothetical isomers but complex 3 is energetically slightly disfavored and possibly packing forces stabilize it in the solid state. Variable temperature magnetic susceptibility measurements show the presence of strong antiferromagnetic exchange interactions mediated through the phenoxido bridges with J values of ?328.9, ?474.8, and ?11.13?cm?1for 1, 2, and 4, respectively. In complex 3, the central Ni(II) ion is diamagnetic, in agreement with its square planar geometry; however small antiferromagnetic interaction is found between the terminal Ni(II) ions with a J value equal to ?5.36?cm?1.
- Hazari, Alokesh,Giri, Sanjib,Diaz, Carmen,Ghosh, Ashutosh
-
-
Read Online
- Synthesis, crystal structure and urease inhibition of a trinuclear copper(II) complex with reduced Schiff base ligand
-
A trinuclear copper(II) complex, [Cu3L2]·2ClO4·2CH3CN, with the reduced Schiff base ligand 2,2′-((propane-1,3-diylbis(azanediyl))bis(methylene))diphenol (H2L) was prepared. The complex was characterized by elemental analysis, IR and UV–Vis spectra, and single crystal X-ray diffraction. The ligand coordinates to the Cu atoms through the amino nitrogen and phenolate oxygen, giving square planar geometry. The ligand and the complex were tested for their Jack bean urease inhibitory activities. The IC50 value of the complex on the urease inhibition is 1.6 ± 1.2 μmol·L?1. Molecular docking study of the complex was performed to study the inhibition.
- Duan, Mengmeng,Li, Yanmin,Xu, Luyao,Yang, Huailan,Luo, Fuwen,Guan, Yixing,Zhang, Bitong,Jing, Changling,You, Zhonglu
-
-
Read Online
- Synthesis, crystal structure, theoretical calculations and thermal characterization of two heterodinuclear NiII–ZnII complexes prepared from ONNO-type symmetrical Schiff base and its reduced derivative
-
Two complexes in NiII–ZnII heterodinuclear form were prepared in DMF medium by the use of an ONNO-type symmetrical Schiff base bis-N,N′(salicylidene)-1,3-diaminopropane (LH2) and the reduced derivative of this ligand bis-N,N′(2-hydroxybenzylidene)-1,3-diaminopropane (LHH2). The fact that the complexes are in [NiL·ZnCl2·DMF2] and [NiLH·ZnCl2·(DMF)2] stoichiometry was verified with elemental and thermogravimetric analyses and IR spectroscopy. The structures of the complexes were determined by the use of X-ray diffraction. The two complexes were very similar, almost isostructure, and it was observed that Ni(II) ions in both complexes coordinated with two phenolic oxygens and two iminic nitrogen of organic ligand and formed an octahedral coordination between two DMF molecules. On the other hand, the Zn(II) ion was observed to be located in a tetrahedral coordination sphere coordinated with two phenolic oxygens between two halides. Although the molecular structures of the complexes are very similar, their thermal properties are quite different from of each other. The decomposition of [NiL·ZnCl2·(DMF)2] was observed between 140 and 190?°C by the removal of coordinative DMF molecules, leaving a residue of a mixture of NiL and ZnCl2 behind. The complex of the reduced ligand [NiLH·ZnCl2·(DMF)2] was observed to be stable up to 250?°C. After this temperature, the coordinative DMF molecules rapidly leave the structure before the degradation of NiLH. That is why the activation energies of the thermal reactions were evaluated by the use of isothermal and nonisothermal kinetic models: Coats–Redfern, Ozawa, Ozawa–Flynn–Wall and Kissinger–Akahira–Sunose. Also the thermal differences between these two complexes were examined by the use of theoretical programs included in Gaussian 09 package. The ground-state energies calculations were carried out by the use of density functional theory method 631G(d) basis set. The calculated theoretical bond energies and angles were observed to be different compared with the experimental data. The HOMO and LUMO values of the complexes were also calculated. The difference between these two complexes was evaluated.
- Atakol, Arda,Nazir, Hasan,Svoboda, Ingrid,Aksu, M. Levent,Atakol, Orhan
-
p. 1863 - 1882
(2019/08/12)
-
- Two dinuclear NiII–CdII complexes of reduced ONNO-type Schiff bases: Synthesis, crystal structures, thermal kinetic analysis and DFT studies
-
Two ONNO-type Schiff bases, bis-N,N′-(salicylidene)-1,3-diaminopropane and bis-N,N′-(2-hydroxyacetophenylidene)-1,3-propanediamine, were reduced using NaBH4 and converted to two phenol–amine-type tetradentate ligands, bis-N,N′-(2-hydroxybenzyl)-1,3-diaminopropane (LHH2) and bis-N,N′-[1(2-hydroxyphenyl)ethyl]-1,3-diaminopropane (LACHH2). These ligands were used to prepare two NiII–CdII heterodinuclear complexes, namely [DMF·NiLH·CdI2·DMF] and [DMF·NiLACH·CdBr2·DMF] in DMF medium. The molecular structure and unit cells of these complexes have been elucidated by the use of X-ray diffraction data. The thermogravimetric analysis of the compounds revealed that as the temperature is increased, the first coordinative DMF molecule was removed from the structure followed by a second coordinative DMF molecule with the complete decomposition of the complex. The activation energies and Arrhenius pre-exponential factor of these thermal reactions were determined by the use of isothermal Coats–Redfern, nonisothermal Ozawa–Flynn–Wall and Kissinger–Akahira–Sunose methods. The results obtained for the first thermal reaction were similar since the structure of both complexes remained intact during this process. Also, the theoretical calculations of the bond lengths, bond angles and natural bond orbital analysis of both complexes were carried out using the algorithms embedded in Gaussian 09 software.
- S?nmez,Nazir,Emir,Svoboda,Aksu,Atakol
-
p. 3077 - 3091
(2017/10/30)
-
- Rare trinuclear NiII2MII complexes (MII?=?Mn, Fe and Co) with a reduced Schiff base ligand: Synthesis, structures and magnetic properties
-
Three new trinuclear hetero-metallic NiII2MII complexes with MII = Mn, Fe and Co have been synthesized using a [NiLR] “metalloligand”, where H2LR = N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine. All complexes have been characterized by elemental analysis, spectroscopic methods, single crystal XRD and magnetic and electrochemical studies. In the three complexes, in addition to the double phenoxido bridges, the two terminal NiII atoms are linked to the central MII [M = Mn(1), Fe(2) and Co(3)] ion by means of a bridging carboxylato co-anion, giving rise to a linear NiII-MII-NiII structure. Variable temperature magnetic susceptibility measurements show the presence of weak ferromagnetic and antiferromagnetic exchange interactions mediated through the double phenoxido bridges with J values of +8.5 and ?3.0 cm?1 for complexes 1 and 2, respectively. Compound 3 shows the presence of antiferromagnetic interactions. Cyclic voltammetry shows a common quasi-reversible one electron oxidation corresponding to the Ni(II)/Ni(III) process in 1–3 and an irreversible M(II)/M(III) oxidation for Mn(1) and Fe(2).
- Hazari, Alokesh,Ghosh, Tanmoy Kumar,Gómez-García, Carlos J.,Ghosh, Ashutosh
-
p. 168 - 175
(2017/11/16)
-
- H-bond assisted coordination bond formation in the 1D chains based on azido and phenoxido bridged tetranuclear Cu(II) complexes with reduced Schiff base ligands
-
Two new 1D chains [(CuL1R)2Cu2(N3)2(μ1,1,3-N3)2]n (1) and [{(CuL2R)2Cu2(N3)2(μ1,1,3-N3)2}·(CH3)2CO]n (2) based on rare μ1,1,3-N3 bridged tetranuclear Cu(II) complexes, have been synthesized using [CuL1R] and [CuL2R] as “metalloligands” [where H2L1R = N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine and H2L2R = N,N′-bis(2-hydroxybenzyl)-1,2-ethylenediamine]. Both complexes have been characterized by elemental analysis, spectroscopic methods, single crystal XRD, and magnetic study. In case of chain 1, the basic building block is a centrosymmetric tetranuclear unit whereas for 2, it is an asymmetric tetranuclear unit containing two types of square pyramidal Cu(II) centers (terminal and central). The μ1,1-N3 bridged central copper atoms of one tetranuclear unit are connected weakly to the axial position of the terminal copper atoms of neibouring units via the azide ions forming a rare μ1,1,3-N3 bridged novel 1D polymeric chain structure. Variable temperature magnetic susceptibility measurements show the presence of an overall strong antiferromagnetic exchange interactions mediated through the double phenoxido bridges with J values of ?123.8 and ?144.6 cm?1 for 1 and 2, respectively.
- Hazari, Alokesh,Diaz, Carmen,Ghosh, Ashutosh
-
-
- An investigation of some Schiff base derivatives as chemosensors for Zn(II): The performance characteristics and potential applications
-
The fluorescence properties of four simple Schiff bases (LH2, LDMH2, LH2 H and LDMHH2) and their potential application as chemosensors for the detection of zinc ion in aqueous solution have been investigated. While LH2 and LDMH2 have displayed specific recognition to Zn(II), the reduced derivatives (LH2 H and LDMHH2) of these ligands have shown no fluorescence response due to the lack of C[dbnd]N group. The Job plots, fluorescence titration experiments and ESI-MS results indicate the formation of 1:1 complexes between sensors and Zn(II). The analytic methods based on LH2 and LDMH2 as chemosensors have been proposed and optimized to detect Zn(II) ions in aqueous solution. The optimized methods have shown a good range of linearity, high precision, good accuracy and low detection limit. As an alternative to these methods, LH2 and LDMH2 have the capability to detect Zn(II) ions by naked eye under UV lamp. Moreover, LH2-Zn and LDMH2-Zn complexes have the ability to be a staining agent for identifying the radiation treatment of food by DNA comet assay.
- Ergun, Ece,Ergun, ümit,?leri, ?zgür,Kü?ükmüzevir, Muhammed Fatih
-
p. 273 - 286
(2018/06/19)
-
- The investigations of thermal behavior, kinetic analysis, and biological activity of trinuclear complexes prepared ONNO-type Schiff bases with nitrito and nitrato μ-bridges
-
By using bis-N,N′(salicylidene)-1,3-diaminopropane and reduced form of this ligand bis-N,N′(2-hydroxybenzylidene)-1,3-diaminopropane, we prepared eight trinuclear complexes in the core form of NiII–NiII–NiII and NiII–CuII–NiII. Complexes have been characterized with element analysis, IR spectroscopy and NMR spectroscopy methods and also investigated with Thermogravimetry (TG). It was observed that thermal characteristics of the complexes prepared by the reduced form of Schiff base are different from complexes prepared by the Schiff base. According to TG, two thermal reactions between 120 and 180?°C endothermic separation of coordinative dimethylformamide molecules and then around 300?°C exothermic decomposition of molecule were observed for Schiff base-prepared complexes. On the other hand, the complexes resulted from reduced Schiff base reactions were shown decomposed around 250–270?°C by exothermic thermal reaction. Kinetic parameters of decompositions were determined by isothermal and non-isothermal kinetic methods, Coats–Redfern (CR), Ozawa, Ozawa–Flynn–Wall (OFW) and Kissenger–Akahira–Sunose (KAS). Departing from these values, thermodynamic parameters were calculated and the results were interpreted. It was concluded that the complexes prepared with reduced Schiff bases are more strained structures. Biological activities of these complexes were also inspected, and antibacterial and antifungal activities were tested against four different bacterial strains (E. coli, P. aureginosa, S. aureus and E. feacalis) and a fungus species (C. albicans).
- Acar, Nurcan,Atakol, Orhan,Sopac?, ?aziye Betül,Duman, Demet Cansaran,Svoboda, Ingrid,?z, Sevi
-
p. 1319 - 1337
(2017/02/10)
-
- Synthesis, crystal structure, thermal decomposition, and XPS studies of homo and heterotrinuclear Cu(II)–Cu(II)–Cu(II) and Cu(II)–Ni(II)–Cu(II) complexes obtained from salpn type ligands
-
In this study, a mononuclear CuL complex was prepared by the use of bis-N,N′-(salicylidene)-1, 3-propanediamine (LH2) and Cu2+ ion. NiCl2 and NiBr2 salt were treated with this complex in dioxanewater medium and two new complexes [(CuL)2NiCl2(H2O)2] and [(CuL)2NiBr2(H2O)2)] with Cu(II)–Ni(II)–Cu(II) nucleus structure were obtained. In addition to this bis-N,N′-(2-hydroxybenzyl)-1,3-diaminopropane (LHH2) was prepared by the reduction of LH2 with NaBH4 in MeOH medium. The treatment of this reduced complex with Cu2+ ion resulted a complex [(CuLH)2CuCl2] with a structure of Cu(II)–Cu(II)–Cu(II). The complexes prepared were characterized by the use of elemental analysis, IR spectroscopy, thermogravimetric and X-ray diffraction methods. The crystal structures of [(CuL)2NiBr2(H2O)2] (СIF file CCDC 1448402) and [(CuLH)2CuCl2] (СIF file CCDC 1448401) complexes were elucidated. It was found that halogen ions are coordinated to terminal Cu2+ ions which are in a distorted square pyramid coordination sphere. It was determined that the central Cu(II), which joins terminal square pyramidal Cu(II), was coordinated only by the phenolic oxygens of the ligand while the central Ni(II) was coordinated by two phenolic oxygens of the organic ligand and two water molecules. These complexes were investigated by XPS and it was found that the terminal and central Cu2+ ions were different in Cu(II)–Cu(II)–Cu(II) complex. Also, the thermal degradation of the CuLH complex unit was observed to exothermic in contrast to the expectations.
- Acar,Atakol,Din?er Kaya,Svoboda,Yaz?c?o?lu,?z
-
p. 463 - 472
(2017/07/18)
-
- Mixed valence trinuclear cobalt (II/III) complexes: Synthesis, structural characterization and phenoxazinone synthase activity
-
Three new mixed valence trinuclear Co(II/III) compounds [Co3L2(μ2-C6H5CO2?)2(CH3CN)2](ClO4?)2·(CH3CN)3 (1) [Co3LR2(μ2-C6H5CO2?)2(C6H5CO2?)2]·(CH3CN)2 (2) and [Co3LR2(μ2-C6H5CH[dbnd]CH–CO2?)2(C6H5CH[dbnd]CH–CO2?)2]·((CH3)2CO)2 (3) have been synthesized by reacting the di-Schiff base ligand [H2L] or its reduced analog [H2LR] (where H2L?=?N,N′-bis(salicylidene)-1,3-propanediamine) and (H2LR?=?N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine) with cobalt perchlorate hexahydrate and sodium benzoate or sodium cinnamate. The complexes have been characterized by IR, UV–Vis and single crystal X-ray diffraction analyses. All the complexes are linear trinuclear species [CoIII–CoII–CoIII] in which two terminal octahedral CoIIIN2O2 cores coordinate to the central octahedral CoII ion through μ2-phenoxido oxygen atom and the bridging carboxylato ions. In addition, the complexes (2 and 3) derived from reduced Schiff base ligand have, rather unusually, a terminally coordinated carboxylato ion to CoIII, which is acetonitrile molecule in case of complex (1) with unreduced ligand. Complex 2 has been found to be an excellent functional model for the phenoxazinone synthase activity, in the aerial oxidation of 2-aminophenol to the corresponding 2-aminophenoxazine-3-one chromophore in acetonitrile solvent medium. Detailed kinetic data analysis of this oxidation reaction reveals a fairly high phenoxazinone synthase activity of 2 with kcat?=?153.60?h?1.
- Hazari, Alokesh,Das, Avijit,Mahapatra, Prithwish,Ghosh, Ashutosh
-
-
- Exploring the coordinative adaptation and molecular shapes of trinuclear Cu II 2 MII (M = Zn/Cd) complexes derived from salen type Schiff bases: Structural and theoretical studies
-
Three new trinuclear hetero-metallic complexes [(CuL)2Zn(NCS)2] (1), [(CuLR)2Zn(NCS)(μ1,1-NCS)] (2) and [(CuLR)2Cd(μ1,3-NCS)2] (4) have been synthesized using [CuL] and [CuLR] as "metalloligands" (where H2L = N,N′-bis(salicylidene)-1,3-propanediamine and H2LR = N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine). All three complexes are characterized by elemental analysis, spectroscopic methods and single crystal XRD. Complex 1 is an angular trinuclear species, in which two terminal four-coordinate square planar "metalloligands" [CuL] are coordinated to a central Zn(ii) through double phenoxido bridges along with two mutually cis nitrogen atoms of terminal isothiocyanate ions as is usually found in such complexes. In contrast, in complex 2, the two terminal "metalloligands" [CuLR] are square pyramidal, as one of the SCN- ions makes an unusual μ1,1-NCS bridge between copper centers while the other one coordinates to Zn(ii) through a N atom in a usual fashion making its geometry also square pyramidal. For 4 which possesses an angular trinuclear structure, in addition to double phenoxido bridges from two terminal [CuLR], both the SCN- ions are S-bonded to Cd(ii) and form a bridge (cis-μ1,3-SCN) between Cd(ii) and each of the terminal Cu(ii) ions. This structure is different from its unreduced analogue in which NCS- was N-terminal coordinated to Cd(ii) (3/3′). All the structures have been optimized using density functional theory (DFT) calculations. It has been found that for H2L, optimized structures like 1 and 2 differ only by 0.4 kcal mol-1 but the H2LR structure 2 is more stable by 5.5 kcal mol-1 than the structure resembling 1. For Cd(ii) complexes also, H2L optimized structures such as 3 and 4 do not differ significantly in energy (1.0 kcal mol-1) but the H2LR structure 4 is more stable than that of 3 by 4.6 kcal mol-1. In fact, structure 4 has been found to be the most stable one among the other possible isomers of H2LR.
- Hazari, Alokesh,Das, Lakshmi Kanta,Bauzá, Antonio,Frontera, Antonio,Ghosh, Ashutosh
-
p. 5730 - 5740
(2016/04/09)
-
- Unprecedented structural variations in trinuclear mixed valence Co(ii/iii) complexes: Theoretical studies, pnicogen bonding interactions and catecholase-like activities
-
Three new mixed valence trinuclear Co(ii/iii) compounds cis-[Co3L2(MeOH)2(N3)2(μ1,1-N3)2] (1), trans-[Co3L2(H2O)2(N3)2(μ1,1-N3)2]·(H2O)2 (2) and [Co3LR2(N3)3(μ1,3-N3)] (3) have been synthesized by reacting a di-Schiff base ligand (H2L) or its reduced form [H2LR] (where H2L = N,N′-bis(salicylidene)-1,3-propanediamine and H2LR = N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine) with cobalt perchlorate hexahydrate and sodium azide. All three products have been characterized by IR, UV-Vis and EPR spectroscopies, ESI-MS, elemental, powder and single crystal X-ray diffraction analyses. Complex 1 is an angular trinuclear species in which two terminal octahedral Co(iii)N2O4 centers coordinate to the central octahedral cobalt(ii) ion through μ2-phenoxido oxygen and μ1,1-azido nitrogen atoms along with two mutually cis-oxygen atoms of methanol molecules. On the other hand, in linear trinuclear complex 2, in addition to the μ2-phenoxido and μ1,1-azido bridges with terminal octahedral Co(iii) centres, the central Co(ii) is bonded with two mutually trans-oxygen atoms of water molecules. Thus the cis-trans configuration of the central Co(ii) is solvent dependent. In complex 3, the two terminal octahedral Co(iii)N2O4 centers coordinate to the central penta-coordinated Co(ii) ion through double phenoxido bridges along with the nitrogen atom of a terminal azido ligand. In addition, the two terminal Co(iii) are connected through a μ1,3-azido bridge that participates in pnicogen bonding interactions (intermolecular N-N interaction) as an acceptor. Both the cis and trans isomeric forms of 1 and 2 have been optimized using density functional theory (DFT) calculations and it is found that the cis configuration is energetically more favorable than the trans one. However, the trans configuration of 2 is stabilized by the hydrogen bonding network involving a water dimer. The pnicogen bonding interactions have been demonstrated using MEP surfaces and CSD search which support the counter intuitive electron acceptor ability of the μ1,3-azido ligand. Complexes 1-3 exhibit catecholase-like activities in the aerial oxidation of 3,5-di-tert-butylcatechol to the corresponding o-quinone. Kinetic data analyses of this oxidation reaction in acetonitrile reveal that the catecholase-like activity follows the order: 1 (kcat = 142 h-1) > 3 (kcat = 99 h-1) > 2 (kcat = 85 h-1). Mechanistic investigations of the catalytic behaviors by X-band EPR spectroscopy and estimation of hydrogen peroxide formation indicate that the oxidation reaction proceeds through the reduction of Co(iii) to Co(ii). This journal is
- Hazari, Alokesh,Kanta Das, Lakshmi,Kadam, Ramakant M.,Bauz, Antonio,Frontera, Antonio,Ghosh, Ashutosh
-
p. 3862 - 3876
(2015/03/04)
-
- Syntheses, structural characterization and biological activities of spiro-ansa-spiro-cyclotriphosphazenes
-
The replacement reactions of the Cl-atoms in partly substituted spiro-ansa-spiro-cyclotriphosphazenes (7 and 8) with excess pyrrolidine, 4-(2-aminoethyl)morpholine, and 1,4-dioxa-8-azaspiro[4,5]decane in dry THF led to the formation of heterocyclic amine substituted cyclotriphosphazenes (9a-c and 10a-c). All cyclotriphosphazene derivatives were characterized by elemental analysis, FTIR, MS, 1D 1H, 13C and 31P NMR and 2D HSQC, and HMBC techniques, and the crystal structure of partly substituted cyclotriphosphazene 8 was verified by X-ray diffraction analysis. Cyclotriphosphazene derivatives (5-8, 9a-c, and 10a-c) were subjected to antimicrobial activity against seven clinic bacteria and one yeast strain, and the interactions of the phosphazenes with plasmid pBR322 DNA were investigated. Phosphazene derivatives [(5, 7, 8, 9b and 9c) and (10a and 10b)] caused a slight increase and substantial decrease in the mobility of form I DNA, respectively, while 9a caused retardation on gel. Cytotoxic, apoptotic and necrotic effects against L929 fibroblast and A549 lung cancer cells were also evaluated. While the highest toxic effect was obtained for 9a in L929 fibroblast cells and for 9c in A549 lung cancer cells at 100 μg mL-1 concentration, the highest apoptotic effect was determined for 10a in L929 fibroblast cells and for 9a in A549 lung cancer cells at the same concentration. It was found that 9a and 10b exhibited the most necrotic effects against L929 fibroblast and A549 lung cancer cells, respectively. The toxic and necrotic effects of the phosphazenes against A549 lung cancer cells were greater than those against L929 fibroblast cells, whereas, the apoptotic effect of the compounds was greater in L929 fibroblast cells than in A549 lung cancer cells.
- Ba?terzi, Nisan Sevin,Bilge Ko?ak, Selen,Okumu?, Aytu?,Kili?, Zeynel,H?kelek, Tuncer,?elik, ?mer,Türk, Mustafa,Ko?, L. Yasemin,A?ik, Leyla,Aydin, Betül
-
p. 8825 - 8839
(2015/11/10)
-
- Structure, photochemistry and magnetic properties of tetrahydrogenated Schiff base chromium(III) complexes
-
Four mononuclear chromium(III) complexes [Cr(L(1))(en)]Br0.3Cl0.7 (1), [Cr(L(1))(pr)]Cl (2), [Cr(L(2))(en)]ClO4 (3), [Cr(L(2))(pr)]Cl (4) along with one dinuclear μ-methoxo [Cr(μ-OMe)(L1)]2 (5) were synthesized (en = 1,2-ethanediamine, pr = 1,3-diaminopropane H2L(1) = Tetrahydrosalen = H2[H4]salen = N,N′-bis(2-hydroxybenzyl)-1,2-ethanediamine, H2L(2) = Tetrahydrosalpr = H2[H4]salpr = N,N′-bis(2-hydroxybenzyl)-1,3-diaminopropane). The competitive reactions in the presence of EDTA were carried out and the first-order rate constants k(1) = (5.2 ± 0.2) × 10-3 h-1 -3 h-1 -3 h-1 -3 h-1 were obtained by spectroscopic measurements. In addition, photo-induced decomposition was monitored under irradiation of xenon lamp. The sequence of first-order rate constants is k′(1) = (4 ± 0.1) × 10-4 s-1 -4 s-1 -3 s-1 -3 s-1, which is in accordance with that of kinetics studies with EDTA. Dinuclear complex 5 exhibits a strong antiferromagnetic coupling with the J = -10.8 cm-1.
- Liu, Bin,Chai, Jie,Feng, Sisi,Yang, Binsheng
-
supporting information
p. 437 - 443
(2015/02/05)
-
- Phosphorus-nitrogen compounds. Part 29. Syntheses, crystal structures, spectroscopic and stereogenic properties, electrochemical investigations, antituberculosis, antimicrobial and cytotoxic activities and DNA interactions of ansa-spiro-ansa cyclotetrapho
-
A number of novel ansa-spiro-ansa (asa) cyclotetraphosphazenes (1a-5b) was prepared in the range of 63-90 % yields. The structures of the compounds were verified by MS, FTIR, 1H, 13C{1H} and 31P{1H} N
- Elmas, Gamze,Okumu?, Aytu?,Ko?, L.Yasemin,Soltanzade, Hossien,Kílí?, Zeynel,H?kelek, Tuncer,Dal, Hakan,A?ík, Leyla,üstünda?, Zafer,Dündar, Devrim,Yavuz, Makbule
-
p. 662 - 676
(2015/02/19)
-
- Salen and tetrahydrosalen derivatives act as effective inhibitors of the tumor-associated carbonic anhydrase XII - A new scaffold for designing isoform-selective inhibitors
-
Salen and tetrahydrosalen derivatives possess metal-chelating properties and have been used as ligands in organic synthesis and as scaffolds for developing therapeutic agents. Fourteen such compounds were synthesized in order to explore their ability to inhibit the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.1). Human (h) isoforms hCA I, hCA II, hCA IX and hCA XII were included in the investigation. Several aliphatic and aromatic spacers were introduced between the two chelating groups from salen/tetrahydrosalen in order to explore a diverse chemical space for designing CA inhibitors, which incorporate both phenol and polyamine fragments in their molecule. Some of these compounds showed CA inhibitory activity in the low micromolar-nanomolar range and a pronounced selectivity for inhibiting an isoform over-expressed in hypoxic tumors, hCA XII, over hCA I, II and IX.
- Carradori, Simone,De Monte, Celeste,D'Ascenzio, Melissa,Secci, Daniela,Celik, Gulsah,Ceruso, Mariangela,Vullo, Daniela,Scozzafava, Andrea,Supuran, Claudiu T.
-
supporting information
p. 6759 - 6763
(2014/01/06)
-
- Selective copper-mediated halogenation of aromatic rings under mild conditions
-
A mild copper-mediated halogenation reaction of phenolic rings is reported. The reaction of bis(2-hydroxybenzyl)-1,3-diaminopropane (H2bhbd) with copper(II) chloride in acetonitrile generates linear trinuclear [Cu 3(bhcbd)2Cl2](CH3CN), containing modified ligands, whose phenol moieties are selectively chlorinated at the 5-position. Under comparable experimental conditions with copper(II) bromide, bromination of the ligand is observed, albeit at a slower reaction rate. In the presence of trialkylorthoformates, which are used as dehydrating agents, a ring closure of the ligand is observed after removal of copper to yield a product with a six-membered ring. This product has been isolated and characterized by NMR spectroscopy and MS. Similarly, bromination of bis(2-hydroxybenzyl)-1,3- diiminopropane (H2bhbdi) occurs in the presence of copper(II) bromide, with concomitant formation of a linear trinuclear complex. Surprisingly, an asymmetric dinuclear copper(II) coordination compound without chlorination of the ligand is obtained when the related ligand bis(2-hydroxybenzyl)-1,3-diminopropane (H2bhbdi) reacts with copper(II) chloride. Copyright
- Gamba, Ilaria,Gamez, Patrick,Monzani, Enrico,Casella, Luigi,Mutikainen, Ilpo,Reedijk, Jan
-
experimental part
p. 4360 - 4368
(2011/12/13)
-
- Thermal decomposition of new mononuclear NiII complexes with ONNO type reduced Schiff bases and Pseudo halogens
-
Mononuclear nickel(II) complexes were prepared by reaction, of the three ONNO type reduced Schiff bases bis-N,N'-(2-hydroxybenzyl)-1,3-propanediamine (LHH2), bis-N,N'-(2-hydroxybenzyl)-2,2′-dimethyl-1, 3-propanediamine (LDMHH2), and bis-N,N'-[1-(2- hydroxyphenyl)ethyl]-1,3-propanediamine (LACHH2) with NiII ions in the presence of pseudo halides (OCN-, SCN- and N3-). The complexes were characterized with the use of elemental analyses, IR spectroscopy, and thermal analyses. The molecular structure of one of the complexes was obtained by single-crystal X-ray diffraction. The obtained complexes are mononuclear, and a pseudo halide molecule is attached. One of the oxygen atoms of the ligand is in phenolate and the other was in phenol form. According to the thermogravimetry results, it was thought that the pseudo halide thermally detaches from the structure as hydropseudo halide. In azide-containing complexes an endothermic reaction was observed although the azide group usually decomposes with an exothermic reaction.
- Ates, B. Meltem,Zeybek, Buelent,Aksu, Mecit,Ergun, Uemit,Ercan, Filiz,Aksu, M. Levent,Atakol, Orhan
-
experimental part
p. 840 - 845
(2010/09/04)
-
- Synthesis and antitubercular activity of substituted phenylmethyl- and pyridylmethyl amines
-
A total of 42 benzyl- and pyridylmethyl amines were synthesized either by reductive amination of aromatic/heteroaromatic aldehydes with amines or by conjugate addition of amines to the cinnamates followed by reduction of the ester group with lithium aluminium hydride to the respective propanolamines. All the synthesized compounds were evaluated against both avirulent and virulent strains of Mycobacterium tuberculosis. Many of the compounds exhibited MIC as low as 1.56 μg/mL. Few of potent compounds were also evaluated against clinical isolates of MDR TB and found to be active at one or other concentrations with MIC as low as 3.12 μg/mL.
- Tripathi,Saxena, Nisha,Tiwari,Verma,Chaturvedi, Vinita,Manju,Srivastva,Gaikwad,Sinha
-
p. 8186 - 8196
(2007/10/03)
-
- Synthesis, antiinflammatory and analgesic activity of new hexahydropyrimidine derivatives
-
A number of potentially active hexahydropyrimidine derivatives of pharmaceutical interest have been synthesized. Various diSchiff's bases prepared by reacting different aromatic aldehydes with 1,3-diaminopropane were suitably reduced to give their tetrahy
- Khan,Gupta
-
p. 377 - 383
(2007/10/03)
-
- Structure of μ-oxo-bis{{2,2′-[propane-1,3-diylbis (aminomethyl)]diphenolato}oxorhenium(V)}
-
In the title compound, C34H40N407Re 2, each of the two Re(V) atoms is hexacoordinated by two amine nitrogens, two phenol oxygens, and two axial oxygens. The compound is a binuclear complex with an O=Re-O-Re=O backbone and nearly octahedral coordination geometry at each Re atom. The Re=O bond distance is 1.720(14) A and the Re-O bridge bond distance is 1.938(12) A. The equatorial plane Re-O bond distances are 1.992(14) and 2.012(13) A, whereas the Re-N bond distances are 2.129(15) and 2.187(16) A.
- Huang, Wen-Tao,Yao, Hsueh-Hua,Chen, Bor-Hann,Liao, Fen-Ling,Lo, Jem-Mau
-
p. 465 - 468
(2007/10/03)
-
- Hydroxide-bridged Diiron(III) Complexes of Tetraaminodiphenol Macrocyclic Ligands: Structure and Properties
-
Some dinuclear iron(III) complexes derived from two tetraaminophenol macrocyclic ligands, one (H2L1) contains two -NH(CH2)3NH- and the other (H2L2) one -NH(CH2)3NH- and one -NH(CH2)2NH- units, and an acyclic tetradentate ligand 3 N,N'-bis(2-hydroxybenzyl)-1,3-diaminopropane> have been synthesised and studied.In all of the macrocyclic complexes 1)2>2 1, 12>*2H2O 2, 1)(H2O)2>3*H2O 3, 2)2>4*2H2O 4, 22>*2H2O 5 and 32> 6 only N2O2 donation to the metal centres occurs, while the two unco-ordinated amino nitrogens either remain singly protonated (2 and 5) or one (1) or both of these (3 and 4) is doubly protonated.Variable-temperature magnetic susceptibility data for 1, 4 and 6 indicate weak antiferromagnetic-exchange interactions in each case with J values of: -5.5 (1), -7.3 (4) and -11.8 cm-1 (6).The isomer-shift and quadrupole-splitting values for 1 at 77 K are 0.46 and 0.43 mm s-1, respectively.The redox chemistry of 1 has been studied by cyclic voltammetry and its crystal structure has been determined: monoclinic, space group P21/c, a = 13.448(1), b = 14.847(1), c = 13.442(1) Angstroem, β = 91.48(1) deg, Z = 2, R = 0.048 and R' = 0.050.The two edge-sharing FeO4N2 octahedra are distorted and connected by a centre of inversion.
- Nanda, Kausik K.,Dutta, Sujit K.,Baitalik, Sujoy,Venkatsubramanian, Krishnan,Nag, Kamalaksha
-
p. 1239 - 1244
(2007/10/02)
-
- Studies on antiamoebic compounds: Part IV - Synthesis of hexahydopyrimidines and tetrahydroimidazoles
-
Several compounds containing o-alkylaminomethylenephenolic group (Mannich group) incorporating heterocycles such as hexahydropyrimidines and tetrahydroimidazoles have been synthesiszed.Compound 18 has been found to be active against hepatic amoebiasis.Effect of substituents on the conformations of hexahydropyrimidines is discussed.
- Kalyanam, N,Parthasarathy, P C,Ananthan, L,Manjunatha, S G,Likhate, M A
-
p. 243 - 247
(2007/10/02)
-
- Study of Binuclear Copper(II) Complexes Derived from Tetradentate Mannich Base Complexes
-
Several new mononuclear Cu(II) complexes of tetradentate mannich bases have been prepared.The mononuclear complexes have been used as bidentate ligands in the preparation of binuclear complexes of the types and (ClO4)2, where
- Patel, Kalpana V.,Bhattacharya, Pabitra K.
-
p. 527 - 529
(2007/10/02)
-
- Process for preparing chelating agents
-
A process for preparing in high yield an isolable orthohydroxydiaminodicarboxylic acid which is useful as a metal chelating agent. The process comprises reacting a phenol (or mixture of phenols), a diaminodicarboxylic acid (or acid source), and a formaldehyde source in a medium having an acidic pH.
- -
-
-
- N,N-di-(hydroxybenzyl)-trimethylene diaminediacetic acids
-
A novel chelating agent having the formula STR1 in whichA. EACH OF X1, X2, X3, and X4 is a member selected from the group consisting of (i) hydrogen; (ii) an alkyl group having 1-4 carbon atoms; (iii) --CN; (iv) --So3 M1 ; (v) --COOM1 ; (vi) --OM3 ; (vii) --NO2 ; (viii) --OH; and (ix) STR2 in which each of R1 and R2 is an alkyl group having 1-4 carbon atoms; B. each of M1, M2, M3, and M4 is a member selected from the group consisting of (i) a hydrogen ion; (ii) an alkali metal ion; (iii) one-half an alkaline earth metal ion; and (vi) an ammonium ion having the formula STR3 in which each of R3, R4, R5, and R6 is a member selected from the group consisting of (A) hydrogen; (B) an alkyl group having 1-4 carbon atoms; and (C) a hydroxyalkyl group having 1-4 carbon atoms; and C. Z is a member selected from the group consisting of (i) hydrogen; and (ii) hydroxyl.
- -
-
-