Alkali Ion - Ce3+- DipicH2System : Coordination Networks and Water Clusters (original) (raw)
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Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 2009
a b s t r a c t 1 H NMR evidence for direct coordination between the Ln(III) ion and the oxygen atoms of the pentaethylene glycol (EO5) ligand and the picrate anion (Pic) in [Ln(Pic) 2 (EO5)][Pic] {Ln = Ce and Nd} complexes are confirmed by single X-ray diffraction. No dissociation of Ln-O bonds in dimethyl sulfoxide-d solution was observed in NMR studies conducted at different temperatures ranging 25-100 • C. The Ln(III) ion was chelated to nine oxygen atoms from the EO5 ligand in a hexadentate manner and the two Pic anions in each bidentate and monodentate modes. Both compounds are isostructural and crystallized in monoclinic with space group P2 1 /c. Coordination environment around the Ce1 and Nd1 atoms can be described as tricapped trigonal prismatic and monocapped square antiprismatic geometries, respectively. The crystal packing of the complexes have stabilized by one dimensional (1D) chains along the [0 0 1] direction to form intermolecular O-H· · ·O and C-H· · ·O hydrogen bonding. The molar conductance of the complexes in DMSO solution indicated that both compounds are ionic. The complexes had a good thermal stability. Under the UV-excitation, these complexes exhibited the red-shift emission. (E. Kusrini), midiris@usm.my (M.I. Saleh).
Linear, Zigzag, and Helical Cerium(III) Coordination Polymers
Crystal Growth & Design, 2012
Five novel one-dimensional cerium(III) carboxylate coordination polymers, [Ce(O 2 CCH 2 CHMe 2 ) 3 (EtOH) 2 ] n (1), {[Ce(O 2 CCH 2 Me) 3 (H 2 O)]· 0.5(4,4′-bpy)} n (2; 4,4′-bpy = 4,4′-bipyridine), {[Ce 2 (O 2 CCHMe 2 ) 6 (H 2 O) 3 ]} n (3), {[Ce 3 (O 2 CCHMe 2 ) 9 (nPrOH) 4 ]} n (4), and {[Ce 3 (O 2 CCHMe 2 ) 9 (HO 2 CCHMe 2 ) 2 -(H 2 O) 2 ]·2Me 2 CHCO 2 H} n , showcase the surprisingly consistent tendency of Ce(III) coordination network structures to adopt one-dimensional connection modes. The type of carboxylate as well as the reaction solvents determines the exact bridging versus end-on coordination modes for the carboxylates and, in turn, discriminate between linear, zigzag, and helical arrangements. Detailed magnetochemical analyses reveal pronounced single-ion effects and the expected weak antiferromagnetic coupling.
Polyhedron 24 (2005) 1487–1496, 2005
Reaction of dipicolinic acid with ammonium ceric nitrate and barium chloride produces, by self-assembly, three coordination polymers having similar stoichiometry but very different network structures. The structure of Ba(dipicH 2)(OH 2) 4 Ce(dipic) 3 AE 4.6H 2 O (1) is built up of 1-D alternating chains of nine-coordinate Ce and Ba polyhedra, each having tricapped trigonal prismatic geometry. The structure of Ba(OH 2) 6 Ce(dipic) 3 (2), wherein a chain of nine-coordinate aquo-Ba polyhedra is threaded through the channel formed by a trigonal arrangement of the CeðdipicÞ 3 2À anions, is analogous to that of SrCl 2 AE 6H 2 O AE Ba(OH 2) 4 Ce(dipic) 3 AE 2H 2 O (3), a polymorph of 2 (formally its hydrate isomer), exhibits a layered network in which Ce and Ba coordination polyhedra are linked by dipic ligands to form a corrugated sheet structure and may be considered as a metal-organic analog of the PbO lattice.
Synthesis, identification, crystal structure and theoretical study of a Ce(IV) complex
Journal of the Iranian Chemical Society, 2014
The compound (dienH 3) 2 (pydc) 3, 1; dien: diethyltriamine, pydcH 2 : pyridine-2,6-dicarboxylic acid, as a proton transfer ligand was applied to synthesize (dienH 3) 2 [Ce(pydc) 3 ] 3 Á16.75H 2 O, 2. The compounds were examined by elemental analysis, IR, UV and NMR spectroscopy. In addition, the compound 2 was studied by TG analysis, single crystal X-ray diffractometry and computational calculations. Geometry optimizations were carried out using B3PW91 hybrid density functional and quasirelativistic effective core potentials (ECP46MWB) to represent the atomic core of cerium and 6-311G(d, p) basis set that used to describe the electrons of oxygen, nitrogen, carbon and hydrogen atoms. Also, natural bond orbital (NBO) analysis at the B3 PW91/A level gives the natural electron population and the natural charge for each atom. Cerium atom in 2 is nine-coordinated with three (pydc) 2groups giving an anionic complex which is balanced by (dienH 3) 3? in the crystal structure. Several intermolecular interactions including O-HÁÁÁO and N-HÁÁÁO hydrogen bonds, face-to-face and edge-to-face stackings are responsible to stabilize the extended structure.
Zeitschrift für anorganische und allgemeine Chemie, 2005
This contribution gives an overview on the different subjects treated in our group. One of our fundamental interests lies in the synthesis and study of low-dimensional polymer and molecular solid state structures. We have chosen several synthetic approaches in order to obtain such compounds. Firstly, the concept of cutting out structural fragments from a solid state structure of a binary compound will be explained on behalf of BaI 2. Oxygen donor ligands, used as chemical scissors on BaI 2 , allow obtaining three-, two-, one-and zero-dimensional derived compounds depending on their size and concentration. Thus, a structural genealogy tree for BaI 2 can be established. This method, transferred to alkali halides using crown ethers and calix[n]arenes as delimiting ligands, leads us to the subject of one-dimensional ionic channels. A second chapter deals with the supramolecular approach for the synthesis of different dimensional polymer structures derived from alkaline earth metal iodides, and based on the combination of metal ion coordination with hydrogen bonding between the cationic complexes and their anions. Under certain circumstances, rules can be established for the prediction of the dimensionality of a given compound, thus contributing to the fundamental problem of structure prediction in crystal engineering. A third part describes a fundamentally new synthetic pathway for generating pure alkaline earth metal cage compounds as well as alkali and alkaline earth mixed metal clusters. In a first step, different molecular precursors, such as solvated alkaline earth metal hal
Inorganic Chemistry, 2001
There has been tremendous interest in the synthesis and crystal structure of open-framework materials due to their potential applications in catalysis, separations, and ion exchange processes. 1 A variety of organic molecules, including bi-, tri-, and tetradentate (diamondoid) ligands, 2 have been used in the construction of many fascinating structures. 1,4-Benzenedicarboxylic acid (H 2 bdc), a rodlike bifunctional ligand, has afforded a number of extended structures by virtue of an exodentate coordination mode. 3 An interesting lanthanide-bdc system has been reported recently that consists of a microporous structure generated upon removal of water from a condensed phase. This system is potentially important as a fluorescent probe. Our previous studies on dicarboxylic acids have shown that they are highly reactive toward metals under hydrothermal conditions. 5 In this work, 1,4-benzenedicarboxylic acid has been selected as a ligand and a water/ethanol solution as a solvent. Hydrated Er(NO 3 ) 3 (0.075 g), H 2 bdc (0.036 g), H 2 O (10 mL), and EtOH (1 mL) in the mole ratio of 1:1:2645:83 were placed in a 23 mL acid digestion bomb and heated at 160°C for 3 days. The pH of the final solution was 4.5. The pink crystals of Er 4 -(bdc) 6 ‚6H 2 O (1) (0.074 g, 74.2%) were collected after washing by water (3 × 10 mL) and by acetone (3 × 10 mL), respectively. 6a A microcrystalline sample of Er 4 (bdc) 6 (2) resulted after 1 (23 mg) was heated to 300°C under nitrogen gas. 6b A thermogravimetric (TG) curve indicated clearly the weight loss of six water molecules. Er 2 (bdc) 3 ‚4H 2 O (3) was obtained by allowing 2 to be exposed to saturated water vapor for 2 h. 6c This structural transformation was confirmed by PXRD, IR, and elemental microanalysis. 3 is isostructural to Tb 2 (bdc) 3 ‚4H 2 O 4 and can also be prepared using the same method described in ref 4. 6d The crystal structure of 1 is a condensed three-dimensional network. 7 There are four crystallographically independent erbium ions in this structure. The local coordination geometry around 10.
Polymers
Two-dimensional coordination polymers of [Pr(DMSO)2(OH2)3][Ru2(CO3)4(DMSO)(OH2)]·5H2O (Prα) and [Ln(OH2)5][Ru2(CO3)4(DMSO)]·xH2O (Ln = Sm (Smβ), Gd (Gdβ)) formulae have been obtained by reaction of the corresponding Ln(NO3)3·6H2O dissolved in dimethyl sulphoxide (DMSO) and K3[Ru2(CO3)4]·4H2O dissolved in water. Some DMSO molecules are coordinated to the metal atoms reducing the possibilities of connection between the [Ru2(CO3)4]3− and Ln3+ building blocks giving rise to the formation of two-dimensional networks. The size of the Ln3+ ion and the synthetic method seem to have an important influence in the type of two-dimensional structure obtained. Slow diffusion of the reagents gives rise to Prα that forms a 2D net that is built by Ln3+ ions as triconnected nodes and two types of Ru25+ units as bi- and tetraconnected nodes with (2-c)(3-c)2(4-c) stoichiometry (α structure). An analogous synthetic procedure gives Smβ and Gdβ that display a grid-like structure, (2-c)2(4-c)2, formed by b...