Crystallochemical formula as a tool for describing metal–ligand complexes – a pyridine-2,6-dicarboxylate example

2009 ◽  
Vol 65 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Viktor N. Serezhkin ◽  
Anna V. Vologzhanina ◽  
Larisa B. Serezhkina ◽  
Ekaterina S. Smirnova ◽  
Elena V. Grachova ◽  
...  
Keyword(s):  
Dicarboxylic Acid ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystallochemical Formula ◽  
Structural Database ◽  
Acidic Ligands ◽  
Metal Ligand ◽  
Crystallochemical Analysis ◽  
Pentadentate Ligand

Compounds (299) containing 494 symmetrically independent pyridine-2,6-dicarboxylate moieties have been investigated. Among them the structures of Na3[Nd(Pydc)3]·14H2O and Na3[Er(Pydc)3]·11.5H2O, where H2Pydc is pyridine-2,6-dicarboxylic acid, were determined by single-crystal X-ray diffraction, while the others were taken from the Cambridge Structural Database. The characteristics of any complex by means of the `method of crystallochemical analysis' are described, and the coordination types of all the Pydc ions and crystallochemical formulae of all the compounds were determined. Although the ion can act as a mono-, bi-, tri-, tetra- and pentadentate ligand, 96% of Pydc ions are coordinated to the central A atom in the tridentate-chelating mode. The dependence of the denticity and geometry of pyridine-2,6-dicarboxylate, as well as of the composition of Pydc-containing complexes, was studied as a function of the nature of the A atom, the molar ratio Pydc:A and the presence of neutral or acidic ligands in the reaction mixture.

scholarly journals Interaction Study of Co-Crystallization or Salt Formation Between 5-Hydroxyisophthalic Acid and 4,4′-Bipyridine using NMR and Powder X-Ray Diffraction

2021 ◽  
Vol 33 (12) ◽  
pp. 3103-3107
Author(s):  
Balvinder Singh
Keyword(s):  
Proton Transfer ◽  
Molar Ratio ◽  
Organic Base ◽  
Salt Formation ◽  
Interaction Study ◽  
X Ray Diffraction ◽  
Transition Range ◽  
X Ray ◽  
Acid And Base ◽  
Structural Database

When an organic acid and an organic base are used for the study of potential co-crystallization then on the basis of differences in their pKa salt, co-crystal or proton transfer is possible. A study of the Cambridge Structural Database (CSD) revealed that no cocrystal or salt formation has been observed between 5-hydroxyisophthalic acid (5-HIPA) and 4,4′-bipyridine (4,4-BIPY). This fact provided motivation for the study of interaction between these two leading to co-crystallizations or salt formation. On comparing differences in their pKa values these two lays in transition range where three possibilities as mentioned above may be present. In this study, it is emphasized on exploring interaction between 5-HIPA and 4,4-BIPY, using solution state NMR and powder X-ray diffraction (PXRD) and find feasibility of cocrystal formation, salt formation or proton transfer. After studying this system, evidence were found in support of proton transfer between 5-HIPA and 4,4-BIPY and molar ratio for maximum interaction between acid and base was also mapped and found to be 1:1.

pH-Controlled Assembly of 3D and 2D Zinc-based Metal-Organic Frameworks with Tetrazole Ligands

2017 ◽  
Author(s):  
Felipe Herrera ◽  
Ignacio Chi-Duran ◽  
Javier Enriquez ◽  
Carolina Manquian ◽  
Kerry Wrighton-Araneda ◽  
...  
Keyword(s):  
Structural Diversity ◽  
Molar Ratio ◽  
Aqua Complex ◽  
Initial Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Metal Organic ◽  
Metal Ligand

<div> <div> <div> <p>We report the synthesis and structural diversity of Zn(II) MOF with in situ formation of tetrazole ligand 3-ptz [3-ptz = 5-(3-pyridyl)tetrazolate], as a function pH. By varying the initial reaction pH, we obtain high-quality crystals of the non-centrosymmetric 3D MOF Zn(3-ptz)2, mixed phases involving the zinc-aqua complex [Zn(H2O)4(3-ptz)2]·4H2O, and 2D MOF crystals Zn(OH)(3-ptz) with a tunable micro-rod morphology, keeping reaction time, temperature and metal-ligand molar ratio constants. Structures are characterized by X-ray diffraction, scanning electron microscopy, FTIR and UV-Vis spectroscopy. We discuss the observed structural diversity in terms of the relative abundance of hydroxo-zinc species in solution for different values of pH. </p> </div> </div> </div>

scholarly journals Synthesis zeolitic Imidazolate Framework-8 (Zif-8) In Solvothermal: The Effect Comparison of Metal-Ligand

2017 ◽  
Vol 17 (1) ◽  
pp. 53
Author(s):  
Muhammad Nadjib ◽  
Ratna Ediati ◽  
Yudi Aris Sulistiyo ◽  
Lutfiatun Nadifah
Keyword(s):  
Surface Morphology ◽  
Zinc Nitrate ◽  
Molar Ratio ◽  
Irregular Surface ◽  
Zeolitic Imidazolate Frameworks ◽  
X Ray Diffraction ◽  
Zeolitic Imidazolate Framework ◽  
X Ray ◽  
Ligand Ratio ◽  
Metal Ligand

Synthesis of ZIF-8 (zeolitic Imidazolate Frameworks-8) have been successfully carried out by the reaction of zinc nitrate and 2-methylimidazolate in DMF (N'N-dimethylformamide) solvent at a temperature of 120 °C for 24 hours. Synthesis of ZIF-8 has been conducted five times with variations molar ratio of metal (Zn2+):ligand (MeIM) consecutive 1:1; 1:1.5; 1:2; 1:2.5 and 1:3 to study the influence of metal-ligand ratio of the crystallinity and morphology of ZIF-8 that was produced. The results of characterization by X-ray diffraction, FTIR and SEM show that ZIF-8 is synthesized with a ratio of metal: ligand = 1:2 showed the highest crystallinity and has the most irregular surface morphology with form box. Keywords: ZIF-8, solvotermal, metal/ligand ratio 

pH-Controlled Assembly of 3D and 2D Zinc-based Metal-Organic Frameworks with Tetrazole Ligands

2017 ◽  
Author(s):  
Felipe Herrera ◽  
Ignacio Chi-Duran ◽  
Javier Enriquez ◽  
Carolina Manquian ◽  
Kerry Wrighton-Araneda ◽  
...  
Keyword(s):  
Structural Diversity ◽  
Molar Ratio ◽  
Aqua Complex ◽  
Initial Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Metal Organic ◽  
Metal Ligand

<div> <div> <div> <p>We report the synthesis and structural diversity of Zn(II) MOF with in situ formation of tetrazole ligand 3-ptz [3-ptz = 5-(3-pyridyl)tetrazolate], as a function pH. By varying the initial reaction pH, we obtain high-quality crystals of the non-centrosymmetric 3D MOF Zn(3-ptz)2, mixed phases involving the zinc-aqua complex [Zn(H2O)4(3-ptz)2]·4H2O, and 2D MOF crystals Zn(OH)(3-ptz) with a tunable micro-rod morphology, keeping reaction time, temperature and metal-ligand molar ratio constants. Structures are characterized by X-ray diffraction, scanning electron microscopy, FTIR and UV-Vis spectroscopy. We discuss the observed structural diversity in terms of the relative abundance of hydroxo-zinc species in solution for different values of pH. </p> </div> </div> </div>

Effect of Hydrated Metal Salts on the Coordination Product of Cobalt(II) halide and PNP Type Ligand, 2,6-bis(di-tertbutylphosphinomethyl) pyridine

2018 ◽  
Author(s):  
Tasneem Siddiquee ◽  
Abdul Goni
Keyword(s):  
Metal Salts ◽  
Molar Ratio ◽  
Pincer Complexes ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
Pincer Ligand ◽  
Tetrahedral Geometry ◽  
X Ray ◽  
Distorted Tetrahedral Geometry ◽  
Cobalt Center

Chemical treatment of CoX<sub>2</sub><b><sup>. </sup></b>6H<sub>2</sub>O (X = Cl, Br, I) with the potentially tridentate PNP pincer ligand 2,6-bis(di-<i>tert</i>-butylphosphinomethyl)pyridine in 1:1 molar ratio results in cobalt(II) halide-PNP pincer complexes. The effect of the hydrated metal source on molecular structure and geometry of the complexes was studied by single crystal X-ray diffraction analysis. The complexes are neutral and the cobalt center adopts a penta-coordinate system with potential atropisomerization. Within the unit cell there are two distinct molecules per asymmetric unit. One of the two phosphorus atoms in the PNP ligand was observed to be partially oxidized to phosphinoxide. Disorder in the structure reflects a mixture of square pyramidal and distorted tetrahedral geometry.

scholarly journals Photocatalytic Reduction of CO2 to Methanol Using a Copper-Zirconia Imidazolate Framework

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 346
Author(s):  
Sonam Goyal ◽  
Maizatul Shima Shaharun ◽  
Ganaga Suriya Jayabal ◽  
Chong Fai Kait ◽  
Bawadi Abdullah ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalyst Support ◽  
Oxidation Potential ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Optimum Parameters ◽  
Reduction Of Co2 ◽  
Enhanced Yield

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.

Crystal structures of (S)- and (R,S)-2,2′-bipyridine-3,3′-dicarboxylic acid 1,1′-dioxides and of their barium salts: absolute configuration and molecular distortion enforced by supramolecular self-assembly

1997 ◽  
Vol 212 (3) ◽  
Author(s):  
P. Vojtíšek ◽  
I. Císařová ◽  
J. Podlaha ◽  
Z. Žák ◽  
S. Böhm ◽  
...  
Keyword(s):  
Single Crystal ◽  
Dicarboxylic Acid ◽  
Crystal Structures ◽  
Absolute Configuration ◽  
Self Assembly ◽  
Barium Salt ◽  
X Ray Diffraction ◽  
X Ray

AbstractCrystal structures of the title compounds were determined by single crystal X-ray diffraction. Absolute configuration of the barium salt of (+)-(

Application of vermiculite and limestone to desulphurization and to the removal of dust during briquette combustion

2003 ◽  
Vol 67 (6) ◽  
pp. 1243-1251 ◽  
Author(s):  
A. Lu ◽  
D. Zhao ◽  
J. Li ◽  
C. Wang ◽  
S. Qin
Keyword(s):  
Electron Microscopy ◽  
Coal Combustion ◽  
Combustion Temperature ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Retention Ratio ◽  
X Ray ◽  
Major Factors ◽  
Chemical Reactant ◽  
Scanning Electron

AbstractSmall domestic cooking furnaces are widely used in China. These cooking furnaces release SO2 gas and dust into the atmosphere and cause serious air pollution. Experiments were conducted to investigate the effects of vermiculite, limestone or CaCO3, and combustion temperature and time on desulphurization and dust removal during briquette combustion in small domestic cooking furnaces. Additives used in the coal are vermiculite, CaCO3 and bentonite. Vermiculite is used for its expansion property to improve the contact between CaCO3 and SO2 and to convey O2 into the interior of briquette; CaCO3 is used as a chemical reactant to react with SO2 to form CaSO4; and bentonite is used to develop briquette strength. Expansion of vermiculite develops loose interior structures, such as pores or cracks, inside the briquette, and thus brings enough oxygen for combustion and sulphation reaction. Effective combustion of the original carbon reduces amounts of dust in the fly ash. X-ray diffraction, optical microscopy, and scanning electron microscopy with energy dispersive X-ray analysis show that S exists in the ash only as anhydrite CaSO4, a product of SO2 reacting with CaCO3 and O2. The formation of CaSO4 effectively reduces or eliminates SO2 emission from coal combustion. The major factors controlling S retention are vermiculite, CaCO3 and combustion temperature. The S retention ratio increases with increasing vermiculite amount at 950°C. The S retention ratio also increases with increasing Ca/S molar ratio, and the best Ca/S ratio is 2-3 for most combustion. With 12 g of the original coal, 1 to 2 g of vermiculite, a molar Ca/S ratio of 2.55 by adding CaCO3, and some bentonite, a S retention ratio >65% can be readily achieved. The highest S retention ratio of 97.9% is achieved at 950°C with addition of 2 g of vermiculite, a Ca/S ratio of 2.55 and bentonite.

The Crystal and Molecular Structures of Two Modifications of cis-Dichloro-mer-tris-(dimethylphenylphosphine)hydridoiridium(III)

1988 ◽  
Vol 41 (3) ◽  
pp. 283 ◽  
Author(s):  
GB Robertson ◽  
PA Tucker
Keyword(s):  
Heavy Atom ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
Metal Ligand ◽  
Ligand Bond

The structures of two crystalline modifications of mer -(Pme2Ph)3H-cis-Cl2IrIII, (1), have been determined from single-crystal X-ray diffraction data. Modification (A) is monoclinic, space group P21/c with a 12.635(1), b 30.605(3), c 14.992(2)Ǻ, β 110.01(2)° and Z = 8. Modification (B) is orthorhombic, space group Pbca with a 27.646(3), b 11.366(1), c 17.252(2)Ǻ and Z = 8. The structures were solved by conventional heavy atom techniques and refined by full-matrix least- squares analyses to conventional R values of 0.037 [(A), 8845 independent reflections] and 0.028 [(B), 5291 independent reflections]. Important bond lengths [Ǻ] are Ir -P(trans to Cl ) 2.249(1) av. (A) and 2.234(1) (B), Ir -P(trans to PMe2Ph) 2.339(2) av. (A) and 2.344(1), 2.352(1) (B), Ir-Cl (trans to H) 2.492(2), 2.518(2) (A) and 2.503(1) (B) and Ir-Cl (trans to PMe2Ph)2.452(2) av. (A) and 2.449(1)(B). Differences in chemically equivalent metal- ligand bond lengths emphasize the importance of non-bonded contacts in determining those lengths.

Synthese und Kristallstrukturen einiger Tetramethylstibonium-Hydrogendicarboxylate / Synthesis and Crystal Structures of Some Tetramethylstibonium Hydrogendicarboxylates

1982 ◽  
Vol 37 (11) ◽  
pp. 1393-1401 ◽  
Author(s):  
Beatrix Milewski-Mahrla ◽  
Hubert Schmidbaur
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Spectroscopic Data ◽  
Molar Ratio ◽  
Ionic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carboxylate Oxygen ◽  
Donor Acceptor ◽  
New Compounds

Reactions of pentamethylantimony (CH3)5Sb with carboxylic acids in the molar ratio 1:2 afford one equivalent of methane and essentially quantitative yields of crystalline tetramothylstibonium hydrogendicarboxylates. Six new compounds of this series have been synthesized using benzoic, o-phthalic, salicylic, 4-ethoxy-salicylic, oxalic, and malic acid, and characterized by analytical and spectroscopic data. An ionic structure with strong hydrogen bonds in the anionic components is proposed.The crystal structures of the hydrogen-dibenzoato (1), hydrogen-ortho-plithalato (2) and 4-ethoxy-hydrogen-salicylate (3) were determined by single crystal X-ray diffraction. The compounds can be described as having ionic lattices with some donor-acceptor inter­actions between the stibonium centers and the carboxylate oxygen atoms. The anions are characterized by strong hydrogen bonds O...H...O. Thus, the (CH3)4Sb-tetrahedron in 1 is distorted by two benzoate oxygon atoms (at 304(2) and 340(2) pin). The cation in 2 is largely undistorted and the anion has a hydrogenphthalate hydrogen bond of d(O...H...O) = 232 pm. The cation-anion contact in 3 is as short as d(Sb-O) = 289 pm rendering the Sb atom pentacoordinate.

Sign in / Sign up

Export Citation Format

Share Document