Search results for "Square pyramidal molecular geometry"
showing 10 items of 116 documents
Dinuclear, tetranuclear and one-dimensional pyrazine-based copper(II) complexes: preparation, X-ray structure and magnetic properties.
2009
The preparation, crystal structures and magnetic properties of the copper(II) complexes of formula [Cu(2)(tppz)(H(2)O)(2)(CF(3)SO(3))(4)] (1), [Cu(tppz)(CrO(4))](n) x 3nH(2)O (2) and [Cu(4)(tppz)(4)(H(2)O)(4)(MoO(4))(2)](CF(3)SO(3))(4) x 7 H(2)O (3) [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine] are reported. Complex 1 is a dinuclear species where tppz adopts a bis-tridentate bridging mode with an intramolecular copper-copper separation of 6.5221(6) A. Each copper(II) ion in 1 has an elongated octahedral geometry with three tppz nitrogen atoms and a water molecule in the equatorial positions and two triflate oxygen atoms occupying the axial sites. Complex 2 is a uniform copper(II) chain where…
Metal complexes of sulfanilamide derivatives. Spectroscopic characterization of the dichloro disulfathiazole methanol copper(II) complex
1993
The synthesis and spectral characterization of the [Cu(Hstz)2(MeOH)Cl2] complex are described. Both polycrystalline powder EPR and single crystal EPR spectra recorded at room temperature show rhombic distortion with values of g1=2.25, g2=2.09 and g3=2.03 in agreement with a copper polyhedron, intermediate between trigonal bipyramid and square pyramidal.
Crystal Structure and Magnetic Properties of 3,5-Pyridinedicarboxylate-Bridged Re(Ii)M(Ii) Heterodinuclear Complexes (M = Cu, Ni and Co)
2021
Abstract The use of the mononuclear rhenium(II) precursor NBu4[Re(NO)Br4(H2pydc)]·i-PrOH (1) (H2pydc = 3,5-pyridinedicarboxylic acid) as a metalloligand towards Cu(II), Ni(II) and Co(II) afforded three new heterobimetallic complexes [Re(NO)Br4(μ-Hpydc)Cu(4,4′-dmbipy)2]·(CH3)2CO·0.25MeCN (2), [Re(NO)Br4(μ-Hpydc)Ni(dmphen)2]·MeCN (3) and [Re(NO)Br4(μ-Hpydc)Co(dmphen)2]·2H2O (4), respectively [4,4′-dmbipy = 4,4′-dimethyl-2,2′-bipyridine, dmphen = 2,9-dimethyl-1,10-phenanthroline and Bu4N+ = tetra-n-butylammonium]. The crystal structures of 1 and 2 are reported herein together with the cryomagnetic investigation of 1–4 in the temperature range of 2.0–300 K. 1 is a mononuclear compound whose str…
Structural chemistry of complexes of ( ? 1)d s metal ions with ?-N-donor substituted thiolate ligands (=0, 2)
2005
Abstract The molecular structures of several d 10 metal ion complexes with 2-amino or 2-imino substituted thiolate ligands, derived from 2-aminoethanethiol, 2-(mercaptomethyl)pyridine, 2-aminobenzenethiole, and 8-mercaptoquinoline, are presented. Since ligand field stabilization energy is absent, the complexes display a large variety of co-ordination numbers and geometries around the metal centers. Distortions from ideal tetrahedral or trigonal bipyramidal configurations are discussed in terms of special structural parameters. In contrast to thiolate ligands that lack additional donor atoms and thus form oligo- or poly-nuclear complexes, the β-N donor group stabilizes mono-nuclear complexes…
Dimeric Mn(ii), Co(ii), Ni(ii) and Cu(ii) complexes of a common carboxylate-appended (2-pyridyl)alkylamine ligand: structure, magnetism and DFT study
2021
Four new complexes of composition [MII2(L3)2(CH3OH)2](ClO4)2 (M = Mn, 1; Co, 2; Ni, 3) and [CuII2(L3)2](ClO4)2 (4) (L3(−) = 3-[2-(((6-methyl)pyridin-2-yl)methyl){(dimethylamino)ethyl}-amino]propionate) have been synthesized and characterized. Structural analysis reveals that 1–4 are discrete syn–anti carboxylate-bridged binuclear coordination complexes with a {MII2(–O–C–O–)2}2+ structural motif. In 1–3 distorted octahedral MN3O3 and in 4 distorted square pyramidal CuN3O2 coordination is satisfied at each M(II) center by three N (a pyridyl and two tertiary aliphatic amines) and a carboxylate O of the ligand, and an O of the carboxylate group. In 1–3 the M(II) center is also coordinated by a …
Synthesis, crystal structure and magnetic properties of the first single azido-bridged copper(II) chain [Cu(bpym)(N3)2]n (bpym = 2,2′-bipyrimidine)
1998
Abstract Single crystals of the copper(II) chain of formula [Cu(bpym) (N32]n (bpym = 2,2′-bipyrimidine) were prepared and characterized by X-ray diffraction methods. The structure consists of neutral chains of copper (II) ions bridged by a single azide group exhibiting the asymmetric end-to-end coordination mode. A terminally bound azide ligand and a didentate bpym group complete the square pyramidal geometry of the metal atom. The intrachain copper-copper separation is 5.063(1)A. The magnetic behaviour was investigated in the temperature range 2.0–290 K. The susceptibility curve exhibits a maximum at .9 K showing the occurrence of a weak intrachain antiferromagnetic coupling. Analysis of t…
New symmetrical dinucleating ligand based assembly of bridged dicopper(II) and dizinc(II) centers: Synthesis, structure, spectroscopy, magnetic prope…
2015
Two dinuclear copper(II) complexes Li(H2O)(3)(CH3OH)](4)Cu2Br4]Cu-2(cpdp)(mu-O2CCH3)](4)(OH)(2) (1), Cu (H2O)(4)]Cu-2(cpdp)(mu-O2CC6H5)](2)Cl-2 center dot 5H(2)O (2), and a dinuclear zinc(II) complex Zn-2(cpdp)(mu-O2CCH3)] (3) have been synthesized using pyridine and benzoate functionality based new symmetrical dinucleating ligand, N, N'-Bis2-carboxybenzomethyl]-N, N'-Bis2-pyridylmethyl]-1,3-diaminopropan-2-ol (H(3)cpdp). Complexes 1, 2 and 3 have been synthesized by carrying out reaction of the ligand H3cpdp with stoichiometric amounts of Cu-2(O2CCH3)(4)(H2O)(2)], CuCl2 center dot 2H(2)O/C6H5COONa, and Zn(CH3COO)(2)center dot 2H(2)O, respectively, in methanol in the presence of NaOH at amb…
Bis(μ-alkoxo) bridged dinuclear CuII2 and ZnII2 complexes of an isoindol functionality based new ligand: Synthesis, structure, spectral characterizat…
2014
Abstract Two new dinuclear copper(II) and zinc(II) complexes of an isoindol functionality based new dinucleating ligand, H3hdpa (H3hdpa = 2-({[2-hydoxyethyl]-[2-hydroxy-3-(1-oxo-1,3-dihydro-isoindol-2-yl)-propyl]-amino}-methyl)-benzoic acid) have been synthesized and characterized. In methanol, the reaction of stoichiometric amounts of Cu(OAc)2·H2O and the ligand H3hdpa in the presence of NaOH at ambient temperature afforded a new dinuclear copper(II) complex, [Cu2(Hhdpa)2]·2CH3OH·6H2O (1). Similarly, in methanol, the reaction of stoichiometric amounts of Zn(OAc)2·2H2O and H3hdpa in the presence of NaOH yielded a new dinuclear zinc(II) complex, Na4[Zn2(hdpa)2](OAc)2 (2). Characterization of…
Equilibrium and kinetics studies on bibrachial lariat aza-crown/Cu(II) systems reveal different behavior associated with small changes in the structu…
2014
Abstract The high-yield synthesis of a new bibrachial lariat azacrown constituted by two tris(2-aminoethyl)amine (tren) units functionalized in one of its arms with a 4-methylquinoline group linked by dimethylene pyridine spacers (L2) is reported for the first time. The speciation studies show formation of mono- and binuclear Cu2+ complexes of similar stability. Comparisons are established with the complexes formed by the precursor tren-quinoline derivative (L4) and with the previously reported ligands containing naphthalene instead of quinoline as the fluorophore (L1, L3). The kinetics of formation and decomposition of Cu2+ complexes with L1 and L2 has been studied. For L1, the acid-promot…
Polyaza and azaoxa macrocyclic receptors functionalised with fluorescent subunits; Hg2+ selective signalling
2000
A polyazacycloalkane containing naphthyl groups, 1,4,8,11-tetrakis(naphthylmethyl)-1,4,8,11-tetraazacyclotetradecane (L1), and the azaoxa cycloalkane receptors containing anthracenyl groups, 7,13-bis(anthracenylmethyl)-1,4,10-trioxa-7,13-diazacyclopentadecane (L2) and 10-anthracenylmethyl-1,4,7-trioxa-10-azacyclododecane (L3), have been synthesized and their activity as fluorescent chemosensors studied towards the metal cations Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ in THF–water (70∶30 v/v, 0.1 mol dm−3 tetrabutylammonium perchlorate, 25 °C) for L1 and 1,4-dioxane–water (70∶30 v/v, 0.1 mol dm−3 potassium nitrate, 25 °C) for L2 and L3. The crystal structure of the complex [Cd(L1)(Cl)][PF6] has been…