Search results for "Square pyramidal molecular geometry"
showing 10 items of 116 documents
Double azido-bridged and mixed-bridged binuclear copper(II) and nickel(II) compounds with N,N,O-donor Schiff bases: Synthesis, structure, magnetic an…
2015
Abstract Two dinuclear complexes μ1,1-azido bridged [Cu(L1)(N3)]2 (1) and μ-phenoxo, μ1,1-azido bridged [Ni2(L2)2(μ1,1-N3)(N3) H2O] (2) bearing HL1 and HL2 as a blocking co-ligands produced by the 1:1 condensation of N-benzyl ethylenediamine with ortho-hydroxy acetophenone and N-methyl propanediamine with 3-methoxy salicylaldehyde respectively, have been synthesized and successfully characterized by elemental analyses, IR and electronic spectroscopy, single-crystal X-ray diffraction, variable temperature magnetic study and DFT studies. X-ray crystal structures of 1 reveal that the Cu(II) ion displays a five-coordinate square pyramidal coordination with a centro-symmetric μ1,1-azido bridging…
Coordination abilities of l-glutamic acid γ-monohydroxamic acid towards copper(II) in the absence and presence of some aliphatic amines
2012
Abstract Solution equilibrium studies on the Cu 2+ –(A)–(Glu-γ-ha) ternary systems ((A) = polyamine: ethylenediamine (en), diethylenetriamine (dien), N , N , N ′, N ″, N ″-pentamethyldiethylenetriamine (Me 5 dien); (Glu-γ-ha) = l -glutamic-γ-hydroxamic acid) have been performed by pH-potentiometry, UV–Vis spectrophotometry and EPR methods. The obtained results suggest the formation of the heteroligand complexes with [Cu(A)(Glu-γ-ha)] + stoichiometry in all studied systems. Our spectroscopic results indicate the tetragonal geometry for the [Cu(en)(Glu-γ-ha)] + species in which Glu-γ-ha acts as a tridentate ligand, the geometry slightly deviated from square pyramidal for [Cu(dien)(Glu-γ-ha)]…
DNA cleavage reaction induced by dimeric copper(II) complexes of N-substituted thiazole sulfonamides
2005
A new dinuclear copper(II) complex has been synthesised and structurally characterised: [Cu2(tz-ben)4] (Htz-ben = N-thiazol-2-yl-benzenesulfonamide). Its crystal structure, magnetic properties and electronic paramagnetic resonance (EPR) spectra were studied in detail. In the compound the metal centres are bridged by four non-linear triatomic NCN groups. The coordination geometry of the copper ions in the dinuclear entity is distorted square pyramidal (4+1). Two thiazole N and two sulfonamido N atoms occupy the equatorial positions and one sulfonamido O atom is in the axial position. Magnetic susceptibility data show a strong antiferromagnetic coupling, -2J = 114.1 cm(-1). The EPR spectra of…
Aromatic dicarboxylate incorporated new di- and tetranuclear cobalt(II) complexes: Synthetic and structural aspects, and evaluation of properties and…
2020
Abstract The synthetic and structural aspects as well as evaluation of magnetic properties and catalytic activity toward aerial oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylbenzoquinone of three new, two di- and one tetranuclear cobalt(II) complexes, [Co2(cpdp)(Hphth)]∙5H2O (1), [Co2(cpdp)(Hisophth)] (2) and [Co4(cpdp)2(terephth)]∙4.5CH3OH·5.5H2O (3), based on a symmetrical multidentate ligand, N,N'-Bis[2-carboxybenzomethyl]-N,N'-Bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol (H3cpdp) in combination with exogeneous aromatic dicarboxylic acids, such as phthalic acid (H2phth), isophthalic acid (H2isophth) and terephthalic acid (H2terephth) are reported. All three coordination compl…
Synthesis, characterization, crystal structures and magnetic exchange in dinuclear copper complexes with 3-amino-1-propanol as terminal and bridging …
1990
Abstract The synthesis, X-ray structures and spectroscopic and magnetic properties are described for two groups of dinuclear Cu(II) compounds with the ligand 3-amino-1-propanol (Hap). The formulae of the compounds are for group A: [Cu(ap)(anion)]2, in which ap is the dehydronated Hap and the anions are formate, nitrate, chloride and bromide and for group B: [Cu(ap)(Hap)]2(anion)2, with anion = iodide, bromide, chloride, nitrate and tetrafluoroborate. The structure of group A compounds consists of dinuclear units with the co-planar centrosymmetric chromophore ANCuOO′CuNA, in which the A ligands (anions) bridge to neighbouring units as axial ligands, thereby forming infinite chains. Dimer Cu……
Structural basis and effect of copper(II) complexes with 4-oxo-thiazolidine ligands on DNA binding and nuclease activity
2020
Abstract Seven novel Copper(II) complexes, namely [Cu(Am4DHotaz)(H2O)2](ClO4) (1), [Cu(Am4DHotaz)(NO3)(MeOH)]·H2O (2), [Cu(Am4Motaz)2(H2O)](ClO4)2·0.83H2O (3), [Cu(Am4Motaz)2(NO3)]NO3·MeOH (4), [Cu(Am4Eotaz)2(NO3)]3(NO3)3·2H2O (5), [Cu(Am4Eotaz)2(ClO4)](ClO4) (6) and [Cu(Am4Eotaz)(ClO4)(H2O)](ClO4) (6a) (HAm4DHotaz = N′-(4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide, Am4Motaz = N′-(3-methyl-4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide and Am4Eotaz = N′-(3-ethyl-4-oxothiazolidin-2-ylidene)pyridine-2-carbohydrazonamide), have been successfully synthesized and characterized by several physicochemical techniques and, for 1–6 complexes, single crystal X-ray diffraction. Ha…
Syntheses, crystal structures and magnetic properties of copper(II) polynuclear and dinuclear compounds with 2,3-bis(2-pyridyl)pyrazine (dpp) and pse…
2001
Abstract The preparation, crystal structures and magnetic properties of four heteroleptic copper(II) complexes with 2,3-bis(2-pyridyl)pyrazine (dpp) and azide, cyanate or thiocyanate as ligands are reported, [Cu(dpp)(N3)2]n (1), [Cu(dpp)(NCO)2]n (2), [Cu(dpp)(NCS)2]2 (3) and [Cu(H2O)(dpp)(NCS)2]2·2H2O (4). Compounds 1 and 2 are isomorphous, triclinic, space group P1, and consist of mononuclear building blocks featuring copper atoms with close to square planar coordination geometries. The mononuclear units are, however, associated into chains through weak axial Cu–N bonds formed by end-on asymmetrically bridging azido/cyanato groups and by pyridyl nitrogen atoms. Taking these contacts into a…
Coordinative Versatility of Guanazole [3,5‐Diamino‐1,2,4‐triazole]: Synthesis, Crystal Structure, EPR, and Magnetic Properties of a Dinuclear and a L…
2006
New complexes with guanazole (3,5-diamino-1,2,4-triazole = Hdatrz), [Cu 2 (Hdatrz) 2 (μ-OH 2 )(H 2 O) 4 (SO 4 )](SO 4 )·3.5H 2 O (1) and [Cu 3 (Hdatrz) 4 (μ-Cl) 2 (H 2 O) 4 (SO 4 ) 2 ]·11.4H 2 O (2), have been prepared and structurally characterized. Complex 1 is a noncentrosymmetric dinuclear compound in which the cop-per(II) ions are bridged by two triazole ligands and one μ-OH 2 molecule, with a Cu(1)···Cu(2) distance of 3.4945(8) A. The chromophores are Cu(1)N 2 O 2 O' (square pyramidal), and Cu(2)N 2 O 2 O'O" (octahedral). Complex 2 has a linear trinuclear copper(II) structure, with two crystallographically independent copper(II) atoms. Neighboring copper(II) ions are linked by two tri…
Ferromagnetic copper(II)–copper(II) interaction in a single chlorido and dicyanamido bridged mixed–valence copper(I/II) 2D polymer generated by in si…
2015
A mixed-valence 2-D Cu(I/II) complex, [{Cu(II)(dmen)(μ-Cl)(μ1,5-dca)}{Cu(I)(μ1,5-dca)}]n (1) (dmen = N,N-dimethylethylenediamine, dca = dicyanamide = [N(CN)2]−), has been synthesized by in situ partial reduction of Cu(II) to Cu(I) using benzoin (2-hydroxy-1,2-di(phenyl)ethanone) as reductant. Complex 1 was characterized by spectroscopic techniques, single crystal X-ray diffraction, and low temperature magnetic measurements. Structural investigation reveals that 1 represents a mixed-valence 2-D coordination polymer formed by parallel 1-D [Cu(II)(dmen)(Cl)Cu(I)(μ1,5-dca)2]n chains running along the b axis, where chloride bridges Cu(II) ions of adjacent polymers through long connections (2.840…
Coordination Chemistry of Cu2+ Complexes of Small N-Alkylated Tetra-azacyclophanes with SOD Activity
2018
A new tetraaza-pyridinophane macrocycle (L1) N-alkylated with two isopropyl and one methyl groups symmetrically disposed has been prepared and its behavior compared with those of the unsubstituted pyridinophane (L3) and the related compound with three methyl groups (L2). The protonation studies show that, first, a proton binds to the central methylated amine group of L1, while, second protonation leads to a reorganization of the protons that are at this stage attached to the lateral isopropylated amines. The X-ray structure of [HL1]+ agrees with the UV–vis and NMR studies as well as with the results of DFT calculations. The stability of the Cu2+ complexes decreases on increasing the bulkine…