Search results for "Isostructural"
showing 10 items of 158 documents
Trinuclear Lanthanide Coordination Clusters: Single-Molecule-Magnet Behavior and Catalytic Activity in the Friedel-Crafts Alkylation Reaction.
2019
A new multidentate ligand (H3 L) was synthesized by the condensation reaction of 4-tert-butyl-2,6-diformylphenol and 2-amino-4-nitrophenol. The reaction of the ligand with hydrated lanthanide nitrate produced two isostructural trinuclear coordination clusters: [DyLn3 L3 (DMF)3 (H2 O)2 ] ⋅ 3.8DMFLn=Dy (1) and Nd (2) (DMF=N, N-dimethylformamide). Single-crystal X-ray diffraction analysis revealed that there are three lanthanide ions arranged in an almost perfect linear fashion in both complexes. Magnetic studies show single-molecule-magnet (SMM) behavior in the Dy derivative with τ0 =1.7×10-6 s and a thermal energy barrier of 7.0 cm-1 . Both complexes were used as catalysts towards the Fried…
Cyanido-bridged {FeIIILnIII} heterobimetallic chains assembled through the [FeIII{HB(pz)3}(CN)3]−complex as metalloligand: synthesis, crystal structu…
2021
A new series of cyanido-bridged {FeIIILnIII} heterobimetallic chains of general formula {[(NC)FeIII{HB(pz)3}(μ-CN)2LnIII(bpdo)(NO3)2(H2O)]·CH3CN}n [HB(pz)3− = hydrotris(pyrazol-1-yl)borate, bpdo = 2,2′-bipyridine-N,N′-dioxide and Ln = Gd (1), Tb (2), Dy (3) and Ho (4)], were obtained by using the low-spin [Fe{HB(pz)3}(CN)3]− complex as a metalloligand towards the preformed [Ln(bdpo)(NO3)2(H2O)]+ species. Single-crystal X-ray diffraction shows that 1–4 are isostructural compounds that crystallize in the monoclinic P21/c space group. Their crystal structure consists of neutral 1D coordination polymers where the [Fe{HB(pz)3}(CN)3]− fragment adopts a bis-monodentate coordination mode, through t…
Supramolecular architectures formed by co-crystallization of bile acids and melamine
2010
Supramolecular multicomponent crystals constructed from three different bile acids (viz. lithocholic, deoxycholic and cholic acid) and melamine have been prepared and the non-covalent interactions in the crystals studied. Both salts and co-crystals were found. While deoxycholic and cholic acid co-crystallized with melamine as a 1 : 1 isostructural molecular complexes in space group C2, lithocholic acid formed with melamine a 2 : 1 molecular complex in space group P21. This is the first report on a multicomponent crystal structure containing lithocholic acid.
Metal complexes of phenobarbituric acid. Chelating behavior of the phenobarbiturate ring. Anticonvulsant properties of the K2[Cu(N-methylphenobarbitu…
1992
Abstract Na2Ni(phenobarbiturato)4·3H2O, Na2Ni3(phenobarbiturato)2(OH)6·4H2O, and NaZn(phenobarbiturato)2(OH)·H2O derivatives were prepared from Ni(II) and Zn(II) and phenobarbital. The Na2Ni(phenobarbiturato)4·3H2O complex is diamagnetic and isostructural with the complex previously reported, Na2Cu(phenobarbiturato)4, suggesting a square-planar environment around the Ni(II) ion. The DMF solutions of this complex show the existence of two species. The EPR spectra of the Cu(II) doped complex show the hyperfine and superhyperfine structures. The covalence parameters α2, β2, and δ2 show a strong bonding in the equatorial plane and suggests the formation of a [CuN4] chromophore. The anticonvulsa…
Proton sponge lead halides containing 1D polyoctahedral chains
2021
Hybrid one-dimensional lead halides, containing the protonated 1,8-bis(dimethylamino)naphthalene moiety (C14H19N2, monoprotonated "proton sponge"), were prepared by simple one-pot methods and investigated in terms of crystal structure, morphology, thermal stability and electronic properties. The as-precipitated (C14H19N2)PbBr3 and (C14H19N2)PbI3 species are isostructural and crystallize in the orthorhombic Pbca space group, resulting in 1D crystal phases with ([PbX3](-))(infinity) chains (built by face-sharing [PbX6] octahedra; X = Br, I), among which the (C14H19N2)(+) cations are inserted. The two compounds display complete miscibility in the solid state: both (C14H19N2)PbI2Br and (C14H19N…
Covalent bonding and the nature of band gaps in some half-Heusler compounds
2005
Half-Heusler compounds \textit{XYZ}, also called semi-Heusler compounds, crystallize in the MgAgAs structure, in the space group $F\bar43m$. We report a systematic examination of band gaps and the nature (covalent or ionic) of bonding in semiconducting 8- and 18- electron half-Heusler compounds through first-principles density functional calculations. We find the most appropriate description of these compounds from the viewpoint of electronic structures is one of a \textit{YZ} zinc blende lattice stuffed by the \textit{X} ion. Simple valence rules are obeyed for bonding in the 8-electron compound. For example, LiMgN can be written Li$^+$ + (MgN)$^-$, and (MgN)$^-$, which is isoelectronic wi…
Rational Design of Copper(II)-Uracil Nanoprocessed Coordination Polymers to Improve Their Cytotoxic Activity in Biological Media
2021
This work is focused on the rational structural design of two isostructural Cu(II) nano-coordination polymers (NCPs) with uracil-1-acetic acid (UAcOH) (CP1n) and 5-fluorouracil-1-acetic acid (CP2n). Suitable single crystals for ꭕ-ray diffraction studies of CP1 and CP2 were prepared under hydrothermal conditions, enabling their structural determination as 1D-CP ladder-like polymeric structures. The control of the synthetic parameters allows their processability into water colloids based on nanoplates (CP1n and CP2n). These NCPs are stable in water at physiological pHs for long periods. However, interestingly, CP1n is chemically altered in culture media. These transformations provoke the part…
Hopping Conductivity in Hydrogen-Bonded Antiferroelectric Compounds
1991
Antiferroelectric betaine phosphate (BP: (CH3)3NCH2COO · H3PO4) and ferroelectric betaine phosphite (BPI: (CH3)3NCH2COO · H3PO3) are molecular crystals of the amino acid betaine and the phosphoric or phosphorous acids, respectively. In both compounds the inorganic components are linked by hydrogen bonds to one-dimensional chains. The two isostructural compounds form solid solutions BPxBPI1-x at any concentration. Here we report measurements of the dielectric permittivity for concentrations 0.85 ≤ × ≤ 1 at frequencies 10−2 ≤ v ≤ 109 Hz and temperatures 2 K ≤ T ≤ 300 K. The dielectric response in BP:BPI (x = 0.95) is dominated by contributions from pure hopping conductivity which we ascribe t…
Syntheses, crystal structures, and solid state NMR investigations of K4M2P6S25 and K3M2P5S18 (M=Ti, Sn)
2002
Abstract Reaction of K 2 S 5 with P 4 S 10 and Ti at 450 °C results in the formation of K 4 Ti 2 P 6 S 25 , a new titanium thiophosphate, whose crystal structure was solved by single-crystal X-ray diffraction. The title compound crystallizes in the orthorhombic space group Fdd2, with the lattice constants a =33.819(7), b =35.508(7), and c =6.251(1) A ( Z =8). The structure contains a layered arrangement of crosslinked quasi-one-dimensional Ti 2 P 6 S 4− 25 chains. The K + ions are situated between the layers. The Ti atoms within the chains are octahedrally coordinated by P 2 S 4− 7 and P 2 S 4− 9 ligands. Reaction of K 2 S with P 4 S 10 , S and Ti at 600 °C results in the formation of K 3 T…