Search results for "stacking"
showing 10 items of 215 documents
Growth and defect studies of CdTe particles
2013
The paper reports the epitaxial growth of cadmium telluride (CdTe) particles by thermal deposition on cleaved planes of (001)NaCl and (001)KBr. Using high resolution transmission electron microscopy and electron diffraction it was shown that CdTe particles could have different orientation and phase (cubic or hexagonal) depending on the substrate temperature. Their most common defects are twins and stacking faults.
Magneto-Structural Correlations in μ-Halo Bridged Copper(II) Chains
1987
To design synthetic pathways to systems of desired properties is a growing challenge for inorganic chemist. Our current interest in this area is focused on copper(II) chemistry. Besides to advance in the understanding of the factors determining the conformation around copper(II) in the solid state, we intend to gain insight into the chemical and structural effects that govern exchange coupling interactions in condensed species. In this context, we have approached the synthesis and characterization of a wide set of pentacoordinated Cu(LIII)XY complexes (LIII=tridentate ligand, X=coordinating anion, Y=coordinating or non-coordinating anion) showing a great structural diversity (including mono…
Bis(6-thioxo-1,6-dihydropurinium) tetrachlorozincate(II).
2006
The title salt, (C(5)H(5)N(4)S)(2)[ZnCl(4)], consists of two 6-thioxo-1,6-dihydropurinium (6mpH(2)(+)) cations (A and B) and a tetrachlorozincate anion, which are held together by N-H...Cl and C-H...Cl interactions. There is an anion-pi interaction between one Cl atom of the [ZnCl(4)](-) anion and the pyrimidine ring of the 6mpH(2)(+)(B) cation. Intermolecular pi-pi stacking interactions allow 6mpH(2)(+)(A) cations to form antiparallel pairs. One interesting structural feature is the double N-H...N intermolecular hydrogen bonds between two 6mpH(2)(+)(A) cations. This kind of interaction, mimicking that of natural nucleobases, can be very valuable in designing new therapeutic purine derivati…
Synthesis, structure and in vitro anticancer activity of Pd(II) complexes of mono- and bis-pyrazolyl-s-triazine ligands
2020
Abstract The square planar complexes [Pd(MPT)Cl2] (1) and [Pd(BPT)Cl]ClO4 (2) were synthesized by the reaction of the 4,4′-(6-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazine-2,4-diyl)dimorpholine (MPT) and N-methyl-N-phenyl-4,6-di(1H-pyrazol-1-yl)-1,3,5-triazin-2-amine (BPT) ligands with PdCl2 (1:1) in acetone under thermal conditions, respectively. In complex 1, the Pd(II) ion is coordinated with the MPT ligand as a bidentate NN-chelate, augmented with two chloride ligands in cis positions. In complex 2, the Pd(II) ion is coordinated with the BPT ligand as a tridentate N-chelate in a pincer fashion, together with one chloride ligand. Hirshfeld analysis indicated that complex 1 is packed with…
Novel Bimetallic-Dicyanamide Extended Two- and Three-Dimensional Networks through [Cu(rac-CTH)]2+ Cation Templation
2009
Reaction of [Cu(rac-CTH)]2+ with dicyanamide and Mn2+ or Fe2+ produces three bimetallic extended structures. Complexes 1 and 2, both obtained in the same reaction pot, consist of two different (4,4) two-dimensional (2D) layers, with the [Cu(rac-CTH)(dca)]+ cations noncoordinated and coordinated to the Mn(μ1,5-dca) network for 1 and 2, respectively (rac-CTH = racemic-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane). Complex 2 shows an unusual monodentate coordination mode through the central amide nitrogen of the dca ligand which is first reported for a polynuclear complex. The structure of 3 consists of a three-dimensional network which can be described as a stacking of layers m…
Heteropolymetallic Supramolecular Solid-State Architectures Constructed from [Cr(AA)(C2O4)2]- Tectons, and Sustained by Coordinative, Hydrogen Bond a…
2004
The paper reports on four novel solid-state architectures constructed by using tectons having the general formula: [Cr(AA)(C2O4)2]- [AA = 2,2‘-bipyridine (bipy) and 1,10-phenanthroline (phen)]. These building blocks are involved in various intermolecular interactions: coordinative, hydrogen bonds, and π−π contacts. Two new crystallohydrates in the Ba[Cr(AA)(C2O4)2]2·nH2O family have been characterized: [BaCr2(bipy)2(C2O4)4(H2O)2]·4H2O (1) and [BaCr2(phen)2(C2O4)4(H2O)2] (2). Because of the different numbers of water molecules, their crystal structures are completely different from those of two others previously reported, [BaCr2(bipy)2(C2O4)4(H2O)]·H2O and [BaCr2(phen)2(C2O4)4(H2O)2]·4H2O…
Synthesis, crystal structure and magnetic properties of [Cu(bipy)2(CH3COO)][Cu(bipy)2(Cr(C2O4)3)]·∼10.5H2O, the first compound containing the [Cr(C2O…
2001
Abstract The reaction between copper(II) acetate with 2,2′-bipyridine and K3[Cr(C2O4)3] leads to the novel salt [Cu(bipy)2(CH3COO)][Cu(bipy)2(Cr(C2O4)3)]·∼10.5H2O, 1 (bipy=2,2′-bipyridine). The crystal structure of 1 consists of mononuclear cationic species [Cu(bipy)2(CH3COO)]+ and heterobinuclear anionic units, [Cu(bipy)2(Cr(C2O4)3)]−. The tris-oxalato-chromium entity behaves as a monodentate ligand toward the copper(II) ion within the complex anion. The distance between Cr(III) and Cu(II) across the bridging oxalato group is 5.056(2) A. The copper(II) ions exhibit a distorted trigonal bipyramidal surrounding in both cationic and anionic species. The π–π stacking interaction between bipy l…
Synthesis, Structure, Spectroscopic Studies and Magnetic Properties of the Tetrakis(5,7‐dichloro‐8‐quinolinolato)gadolinium(III) Complex
2008
The synthesis and structural characterization of the neutral gadolinium tetrakis-type complex with 5,7-dichloro-8-quinolinolato (H5,7ClQ) ligands, [Gd(5,7ClQ)2(H5,7ClQ)2Cl], is reported. The GdIII ion is epta coordinated to one chloride ion and to four ligands: two N,O-chelated monoanions and two as zwitterionic (+NH and O–) monodentate oxygen donors. Electronic and vibrational spectra provide suitable markers to distinguish the presence of deprotonated and protonated ligands. The magnetic behaviour of this compound was investigated and explained by taking into account that π–π stacking interactions between the (H5,7ClQ) ligands give rise to a ferromagnetic interaction between the gadoliniu…
DNA binding, nuclease activity, DNA photocleavage and cytotoxic properties of Cu(II) complexes of N-substituted sulfonamides.
2013
Abstract Ternary copper(II) complexes [Cu(NST)2(phen)] (1) and [Cu(NST)2(NH3)2]·H2O (2) [HNST = N-(4,5-dimethylthiazol-2-yl)naphthalene-1-sulfonamide] were prepared and characterized by physico-chemical techniques. Both 1 and 2 were structurally characterized by X-ray crystallography. The crystal structures show the presence of a distorted square planar CuN4 geometry in which the deprotonated sulfonamide, acting as monodentate ligand, binds to the metal ion through the thiazole N atom. Both complexes present intermolecular π–π stacking interactions between phenanthroline rings (compound 1) and between naphthalene rings (compound 2). The interaction of the complexes with CT DNA was studied b…
Synthesis, crystal structure, electrochemical and magnetic properties of (NBu4)[ReCl5(L)] with L=pyrimidine and pyridazine
2008
Abstract Two novel rhenium(IV) compounds, namely (NBu4)[ReCl5(pym)] (1) and (NBu4)[ReCl5(pyd)] (2) (pym = pyrimidine, pyd = pyridazine and NBu4 = n-tetrabutylammonium cation), have been obtained by reaction of [ReCl6]2− and the diazine in dmf, and their crystal structures determined by single-crystal X-ray diffraction. The structures of 1 and 2 consist of [ReCl5(pym)]− or [ReCl5(pyd)]− anions and NBu 4 + cations held together by electrostatic forces and van der Waals interactions. Stacking interactions are present only in 1. The coordination sphere of the ReIV ion is defined by five chloride anions and one nitrogen atom of a monodentate diazine, resulting in a distorted octahedral environme…