scholarly journals Comparison of some properties of 2,3 – and 3,4 – dimethoxybenzoates of Cu(II), Co(II) and Nd(III)

2018 ◽  
Vol 33 (2) ◽  
pp. 07
Author(s):  
W. Ferenc ◽  
K. Czapla ◽  
J. Sarzynski ◽  
A. Zwolinska

The physicochemical properties of 2,4-, and 3,4-dimethoxybenzoates of Cu(II), Co(II) and Nd(III) were studied and compared to observe the -OCH3 substituent positions in benzene ring on the character of complexes. The analysed compounds are crystalline hydrated or anhydrous salts with colours depending on the kind of central ions: blue for Cu(II), pink for Co(II) and violet for Nd(III) complexes. The carboxylate groups bind as monodentate, bidentate bridging or chelating and even tridentate ligands. Their thermal stabilities were studied in air at 293-1173K. When heated the hydrated complexes release the water molecules and form anhydrous compounds which are then decomposed to the oxides of respective metals. Their magnetic moment values were determined in the range of 76-303K. The results reveal the compounds of Nd(III) and Co(II) to be the high-spin and that of Cu(II) forms dimer. The various positions of -OCH3 groups in benzene ring influence some of physicochemical properties of analysed compounds.

2006 ◽  
Vol 60 (3) ◽  
Author(s):  
W. Ferenc ◽  
B. Cristóvão ◽  
B. Mazurek ◽  
J. Sarzyński

AbstractSome physicochemical properties of 2-chloro-4-nitrobenzoates of Co(II), Ni(II), and Cu(II) were studied. The complexes were obtained as mono-and dihydrates with a metal ion—ligand mole ratio of 1: 2. All complexes are polycrystalline compounds. Their colours depend on the kind of central ion: pink for Co(II) complex, green for Ni(II), and blue for Cu(II) complexes. Their thermal decomposition was studied only in the range of 293 K–523 K because it was found that on heating in air above 523 K 2-chloro-4-nitrobenzoates decompose explosively. Hydrated complexes lose crystallization water molecules in one step. During dehydration process no transformation of the nitro group to nitrito one took place. Their solubilities in water at 293 K are of the orders of 10−3-10−2 mol dm−3. The magnetic moment values of 2-chloro-4-nitrobenzoates determined in the range of 76 K–303 K change from 3.48µB to 3.82µB for Co(II) complex, from 2.24µB to 2.83µB for Ni(II) 2-chloro-4-nitrobenzoate, and from 0.31µB to 1.41µB for Cu(II) complex. 2-Chloro-4-nitrobenzoates of Co(II) and Ni(II) follow the Curie—Weiss law, but the complex of Cu(II) forms dimer.


2013 ◽  
Vol 69 (12) ◽  
pp. o1782-o1783 ◽  
Author(s):  
Kai-Long Zhong

In the preparation of the title hydrated salt, C14H13N2+·C10H5O8−·H2O, a proton has been transfered to the 2,9-dimethyl-1,10-phenanthrolinium cation, forming a 2,4,5-tricarboxybenzoate anion. In the anion, the mean planes of the protonated carboxylate groups form dihedral angles of 11.0 (5), 4.4 (5) and 80.3 (4)° with the benzene ring to which they are attached. The mean plane of the deprotonated carboxylate group forms a dihedral angle of 10.6 (5)° with the benzene ring. In the crystal, the anions are involved in carboxylic acid O—H...Ocarboxylhydrogen bonds, generating a two-dimensional network parallel to (001) containingR44(28) andR44(32) motifs. The 2,9-dimethyl-1,10-phenanthrolinium cations and water molecules reside between the anion layers and are connected to the anionsviaN—H...Owaterand Owater—H...Ocarboxylhydrogen bonds. An intramolecular O—H...O hydrogen bond is also observed in the anion.


2007 ◽  
Vol 63 (11) ◽  
pp. o4315-o4315
Author(s):  
Krzysztof Ejsmont ◽  
Jacek Zaleski

In the crystal structure of the title compound, 4C4H12N+·C10H2O8 4−·8H2O, there is a centre of symmetry at the centre of the benzene ring; the asymmetric unit comprises one half-anion, two cations and four water molecules. The pyromellitate tetraanion is nonplanar; it and the cations exhibit normal geometry. The two unique carboxylate groups are twisted out of the plane of the benzene ring by about 40 and 50°. The network formed by the ions and water molecules is based on eight O—H...O and six N—H...O strong hydrogen bonds.


Author(s):  
Muhammad Danish ◽  
Muhammad Nawaz Tahir ◽  
Sana Iftikhar ◽  
Muhammad Asam Raza ◽  
Muhammad Ashfaq

The molecule of the title compound, [Co(C8H6NO4)2(H2O)4], is centrosymmetric. It is a cobalt(II) complex, bearing two (2-nitrophenyl)acetate and four aqua ligands. The coordination around the CoIIatom is distorted octahedral, defined by four O atoms of water molecules in the equatorial plane and by two carboxylate O atoms at axial positions. The dihedral angles between the benzene ring and the acetate and nitro groups are 61.90 (10) and 19.21 (11)°, respectively. The water molecules form O—H...O hydrogen bonds with the nitro and carboxylate groups, leading to a layered structural arrangement parallel to (001).


2012 ◽  
Vol 68 (8) ◽  
pp. o283-o287 ◽  
Author(s):  
Vasily S. Minkov ◽  
Elena V. Boldyreva

N,N-Dimethylglycine, C4H9NO2, and its hemihydrate, C4H9NO2·0.5H2O, are discussed in order to follow the effect of the methylation of the glycine amino group (and thus its ability to form several hydrogen bonds) on crystal structure, in particular on the possibility of the formation of hydrogen-bonded `head-to-tail' chains, which are typical for the crystal structures of amino acids and essential for considering amino acid crystals as mimics of peptide chains. Both compounds crystallize in centrosymmetric space groups (PbcaandC2/c, respectively) and have twoN,N-dimethylglycine zwitterions in the asymmetric unit. In the anhydrous compound, there are no head-to-tail chains but the zwitterions formR44(20) ring motifs, which are not bonded to each other by any hydrogen bonds. In contrast, in the crystal structure ofN,N-dimethylglycinium hemihydrate, the zwitterions are linked to each other by N—H...O hydrogen bonds into infiniteC22(10) head-to-tail chains, while the water molecules outside the chains provide additional hydrogen bonds to the carboxylate groups.


2006 ◽  
Vol 62 (4) ◽  
pp. m690-m692
Author(s):  
Ki-Young Choi ◽  
Kyu-Chul Lee ◽  
Han-Hyoung Lee ◽  
Jaejung Ko ◽  
Won-Sik Han

In the title compound, [Cu3(C10H13N2O2)2Cl(ClO4)3(H2O)3]·2H2O, the Cu atoms exhibit octahedral, square-pyramidal and square-planar coordination environments, and they are linked by carboxylate groups to form a trinuclear structure. The five water molecules participate in intra- and intermolecular hydrogen bonding.


2017 ◽  
Vol 73 (11) ◽  
pp. 1599-1602 ◽  
Author(s):  
Matimon Sangsawang ◽  
Kittipong Chainok ◽  
Nanthawat Wannarit

The title compound, [CdNa2(C8H4O4)2(C3H7NO)(H2O)2]nor [CdNa2(1,3-bdc)2(DMF)(H2O)2]n, is a new CdII–NaIheterobimetallic coordination polymer. The asymmetric unit consists of one CdIIatom, two NaIatoms, two 1,3-bdc ligands, two coordinated water molecules and one coordinated DMF molecule. The CdIIatom exhibits a seven-coordinate geometry, while the NaIatoms can be considered to be pentacoordinate. The metal ions and their symmetry-related equivalents are connectedviachelating–bridging carboxylate groups of the 1,3-bdc ligands to generate a three-dimensional framework. In the crystal, there are classical O—H...O hydrogen bonds involving the coordinated water molecules and the 1,3-bdc carboxylate groups and π–π stacking between the benzene rings of the 1,3-bdc ligands present within the frameworks.


2019 ◽  
Vol 4 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Janusz Szklarzewicz ◽  
Anna Jurowska ◽  
Maciej Hodorowicz ◽  
Ryszard Gryboś

The synthesis and physicochemical properties of three new complexes of vanadium at +5, +4 and +3 oxidation state are described and discussed. The octahedral surrounding of vanadium for V(III) complexes of [V(L1)(HL1)] general formula is filled with two ONO tridentate ligand L, for V(IV) one ONO ligand L, oxido ligand and 1,10-phenanthroline (phen) as a co-ligand are presented in complexes of [VO(L2)(phen)]. For V(V) the complexes of [VO2(L1)(solv)] type were formed. As ligands, the H2L Schiff bases were formed in reaction between 5-hydroxysalcylaldehyde and phenylacetic hydrazide (H2L1) and 3,5-dichlorosalicyaldehyde and 4-hydroxybenzhydrazide (L2). The magnetic moment measurements, in 8 year period, show, that V(III) complexes slowly oxidise to V(IV) with preservation of the nonoxido character of the complexes, while V(IV) complexes were found to be stable. The TG and SDTA measurements indicate, that thermal stability depends mainly on the oxidation state of vanadium. The less thermally stable are the V(V) complexes, while V(IV) and V(III) are stable up to ca. 200oC. In solution, at pH 2 (similar to that in human digestion system), again the V(IV) are the most stable, only at pH 7.0 V(III) complexes had higher stability. The most stable, thus best for pharmaceutical use, are V(IV) complexes.


2018 ◽  
Vol 16 (2) ◽  
pp. 124 ◽  
Author(s):  
Asep Bayu Dani Nandiyanto ◽  
Heli Siti Halimatul Munawaroh ◽  
Tedi Kurniawan ◽  
Ahmad Mudzakir

The purpose of this study was to investigate influences of temperature on the conversion of ammonium tungstate pentahydrate (ATP) powder to tungsten trioxide (WO3) particles with controllable sizes, crystallinities, and physicochemical properties. In this study, we used a simple thermal decomposition method. In the experimental procedure, we explored the effect of temperature on the physicochemical properties of ATP by testing various heating temperatures (from 100 to 900 °C). The heated ATP samples were then characterized by a physical observation (i.e. color) and various analysis methods (i.e. a thermal gravimetric and differential thermal analysis, infrared spectroscopy, an X-ray diffraction, and a scanning electron microscope). Experimental results showed that increases in temperature had an impact to the decreases in particle size, the change in material crystallinity, and the change in physical properties (e.g. change of color from white, orange, to yellowish green). The relationships between the reaction temperatures and the physicochemical properties of the ATP were also investigated in detail along with the theoretical consideration and the proposal of the WO3 particle formation mechanism. In simplification, the phenomena can be described into three zones of temperatures. (1) Below 250 °C (release of water molecules and some ammonium ions).; (2) At 250-400 °C (release of water molecules and ammonium ions, restructurization of tungsten and oxygen elements, and formation of amorphous tungsten trioxide). (3) At higher than 400 °C (crystallization of tungsten trioxide). Since ATP possessed reactivity on temperature, its physicochemical properties changing could be observed easily, and the experimental procedure could be done easily. The present study will benefit not only for “chemistry and material science” but also potentially to be used as a model material for explaining the thermal behavior of material to undergraduate students (suitable used for a class and laboratory experiment and demonstration).


IUCrData ◽  
2020 ◽  
Vol 5 (10) ◽  
Author(s):  
Erika Samolová ◽  
Jan Fábry

The crystal structure of the title complex, [Pb3(C4H7O2)6(H2O)2] n , was redetermined on basis of modern CCD-based single-crystal X-ray data at 120 K. The current study basically confirms the previous report [Fallon et al. (1997). Polyhedron, 16, 19–23] at 190 K, but with higher accuracy and precision. In particular, positional disorder of one of the 2-methylpropanoate anions over two sets of sites was resolved, showing a refined ratio of the disorder components of 0.535 (9):0.465 (9). The three independent cations in the structure have coordination numbers of [7 + 1], [6 + 1], and [5 + 3], with O atoms belonging either to carboxylate groups or water molecules. This arrangement leads to the formation of sheets parallel to (\overline{1}01), whereby the hydrophobic 2-methylpropanyl groups of the anions are oriented above and below the hydrophilic sheets to form a layered structure. Within a sheet, hydrogen bonds of the type Owater—H...O are formed, whereas the hydrophobic groups between adjacent layers interact through van der Waals forces.


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