2287-28-7Relevant academic research and scientific papers
Rare examples of diphenoxido-bridged trinuclear NiII2FeIII complexes with a reduced salen type Schiff base ligand: Structures and magnetic properties
Hazari, Alokesh,Gómez-García, Carlos J.,Drew, Michael G.B.,Ghosh, Ashutosh
, p. 145 - 153 (2017)
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.
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
Hazari, Alokesh,Giri, Sanjib,Diaz, Carmen,Ghosh, Ashutosh
, p. 70 - 80 (2016)
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.
Synthesis, crystal structure and urease inhibition of a trinuclear copper(II) complex with reduced Schiff base ligand
Duan, Mengmeng,Li, Yanmin,Xu, Luyao,Yang, Huailan,Luo, Fuwen,Guan, Yixing,Zhang, Bitong,Jing, Changling,You, Zhonglu
, p. 27 - 31 (2019)
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.
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
Atakol, Arda,Nazir, Hasan,Svoboda, Ingrid,Aksu, M. Levent,Atakol, Orhan
, p. 1863 - 1882 (2019/08/12)
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.
Two dinuclear NiII–CdII complexes of reduced ONNO-type Schiff bases: Synthesis, crystal structures, thermal kinetic analysis and DFT studies
S?nmez,Nazir,Emir,Svoboda,Aksu,Atakol
, p. 3077 - 3091 (2017/10/30)
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.
Rare trinuclear NiII2MII complexes (MII?=?Mn, Fe and Co) with a reduced Schiff base ligand: Synthesis, structures and magnetic properties
Hazari, Alokesh,Ghosh, Tanmoy Kumar,Gómez-García, Carlos J.,Ghosh, Ashutosh
, p. 168 - 175 (2017/11/16)
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).
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
Hazari, Alokesh,Diaz, Carmen,Ghosh, Ashutosh
, p. 16 - 24 (2018/01/17)
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.
An investigation of some Schiff base derivatives as chemosensors for Zn(II): The performance characteristics and potential applications
Ergun, Ece,Ergun, ümit,?leri, ?zgür,Kü?ükmüzevir, Muhammed Fatih
, p. 273 - 286 (2018/06/19)
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.
The investigations of thermal behavior, kinetic analysis, and biological activity of trinuclear complexes prepared ONNO-type Schiff bases with nitrito and nitrato μ-bridges
Acar, Nurcan,Atakol, Orhan,Sopac?, ?aziye Betül,Duman, Demet Cansaran,Svoboda, Ingrid,?z, Sevi
, p. 1319 - 1337 (2017/02/10)
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).
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
Acar,Atakol,Din?er Kaya,Svoboda,Yaz?c?o?lu,?z
, p. 463 - 472 (2017/07/18)
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.
