Thermal Analysis,Quantum Chemical Calculations,and Structural Characterization by Single Crystal Synchrotron Radiation of a Monoclinic Polymorph of Citraconic acid

Abstract  

The crystal structure of a monoclinic polymorph of methyl maleic acid (citraconic acid, polymorph II) was determined using single crystal synchrotron data from a small fragment extracted from the reagent bottle. The material crystallizes in space group P2₁/c with unit cell parameters a = 8.109(2), b = 7.090(2), c = 10.709(3) ?, β = 114.148(16)°, V = 561.8(3) ?³, Z = 4, d _c = 1.538 g cm⁻³. In this polymorph, the carboxylic group with the α-methyl group participates in cyclic hydrogen bonds with graph set symbol R₂² (8) R_{2}^{2} (8) , while the other carboxylic group participates in a hydrogen bonding pattern represented by the C(4) graph set symbol. In contrast, in a previously reported polymorph (polymorph I) obtained by slow evaporation from ethyl acetate, both carboxylic groups participate in cyclic hydrogen bonding motifs. Thermal analysis suggests that the transformation of polymorph II into polymorph I is monotropic.     

Alkyl Derivatives of Boehmite Having the Second Stage Structure

Abstract

The reaction of aluminum alkoxide in straight-chain primary alcohols at elevated temperatures yielded the alkyl derivatives of boehmite [AlO(OH)_1-x (OR) _x ], a class of intercalation compound where the guest moieties are covalently bonded to the host boehmite layers. The addition of small amounts of water to the reaction system yielded another phase having a larger basal spacing. XRD, IR, and elemental analysis showed that the products had the boehmite layer structure with the alkyl moieties incorporated between the boehmite layers. IR spectra of the products also exhibited bands due to hydrogen bonding between the boehmite layers. These results suggest that the products are the alkyl derivatives of boehmite having the second stage structure. Because water in the reaction medium facilitated the hydrolysis of intermediate aluminum alkoxides, the product with the second stage structure had smaller alkyl/Al ratio and therefore had smaller basal spacing than that expected from the corresponding first stage product.     

Di-hydroxy malonic acid as a building block of hydrogen-bonded 3-dimensional architectures

An examination of the crystal structures of di-hydroxy malonic acid 1 (P2₁/na = 5.384(2), b = 6.268(2), c = 14.354(8) Å, = 103.57(3)°) and N-ethylbenzylammonium di-hydroxy hydrogenmalonate 2 (P2₁2₁2₁ a = 13.373(2), b = 15.342(4), c = 18.741(4) Å,) has highlighted the influence of directional O–H···O interactions in the assembly of hydroxy-substituted dicarboxylic acids. The complementarity of carboxylic and hydroxy groups in 1 creates a very dense 3-D structure (D _c = 1.919 g cm^–3) through four O–H···O hydrogen bonds. In 2, the anions form infinite, spiraling chains created by head-to-tail O–H···O hydrogen bonds. Neighbouring chains are crosslinked into a complex 3-D anionic network with channels parallel to a and b. The cations are positioned within these channels and held in place via two N–H···O interactions.     

Preparation of New Inorganic—Organic Layered Compounds,Hydroxy Double Salts,and Preferential Intercalation of Organic Carboxylic Acids into Them

Abstract

New inorganic—organic layered compounds were prepared by ion-exchange reactions of zinc-nitrate and copper-nitrate HDSs with organic carboxylic acids whose interlayer spacings increased depending on the sizes of carboxylic acids. The amounts of ion-exchanged 2-naphthoic acid and 2,6-naphthalene dicarboxylic acid were larger than those of 1-naphthoic acid and 2, 7-naphthalene dicarboxylic acid, respectively, indicating the molecule recognition ability of the HDSs.     

Syntheses,Crystal Structures and Fluorescence Properties of Zn(II) Complexes with Pyrazolone Derivatives

Abstract   N-(1,3-Diphenyl-4-benzal-5-pyrazolone)-salicylidene hydrazone(H₂L ¹ ) and its zinc complex Zn(HL ¹ )₂ · 2CH₃OH (1) have been synthesized and characterized by elemental analyses, IR spectra, thermal analyses and single-crystal X-ray diffraction studies. The X-ray diffraction analyses of the complex Zn(HL ¹ )₂ · 2CH₃OH (1) and the known compound Zn₄(L ² )₄ (2) (H₂L ²  = N-(1,3-diphenyl-4-phenylethylene-5-pyrazolone)-salicylidene hydrazone) show that different acyl groups in position 4 of pyrazolones may lead to the different coordination mode of the ligands and distinctive structures of the same central metal Zn(II) complexes, of which 1 is a mononuclear complex while 2 is a tetranuclear complex. Meanwhile, two Zn(II) complexes have different thermal stabilities and fluorescence properties. Graphical Abstract        

Synthesis and Structure of a CdI<Subscript>2</Subscript> Coordination Polymer with 1,1′-(1,4-Butanediyl)bis-1<Emphasis Type="Italic">H</Emphasis>-benzotriazole(bbbt)

Abstract  

In this article, solution reaction of cadmium iodide with organic multifunctional ligand 1,1′-(1,4-butanediyl)bis-1H-benzotriazole(bbbt) generated a 1D polymer [CdI₂ (bbbt) (CH₃OH)]_n 1, and the crystal structure has been determined (C₁₇ H₂₀ Cd I₂ N₆ O), Mr = 690.59 a = 10.032(2), b = 13.503(3), c = 16.706(3) ?, space group C2/c, Z = 4, and V = 2223.1(8) ?³. In 1 the tetrahedral coordination of Cd(II) and the conformation of bbbt ligand make it a wave-shaped structure.     

Synthesis and structure of μ-oxo-bis [(acetylacetonato)(thioacetylacetonato)] dioxodimolybdenum(V) and υ-oxo-[tris(acetylacetonato)(thioacetylacetonato)]dioxodimolybdenum(V)

In the reaction of Mo₂O₃ (acac)₄ and Mo₂O₃ (OAc)₄ with thioacetylacetone two new complexes of molybdenum(V), Mo₂O₃ (acac)₂(Sacac)₂ (complexI) and Mo₂O₃(acac)₃(Sacac) (complexII), respectively, have been prepared. Their crystal structures have been determined from single crystal diffractometer data and refined to the finalR values of 0.068 and 0.044, respectively. Both complexes crystallize in the tetragonal space groupI4₁/a with cell dimensions, (I):a=21.646(3),c=11.627(2) Å,D _calc=1.630 g cm^–3,Z=8 and (II):a=21.240(3),c=11.688(2) Å,D _clac=1.644 g cm^3–,Z=8 and have essentially the same structure. In the structure of (II) half of thioacetylacetone of (I) is statistically replaced by acetylacetone causing thus an occupational disorder in this region of the structure. Both complex molecules are dinuclear and have crystallographically imposed ¯1 symmetry with the bridging oxygen atom in the center of symmetry. Molybdenum atoms exhibit distorted octahedral coordinations. Sulfur atom of the Sacac ligand in (I) shows a considerably largertrans influence than the oxo-oxygen atom.     

Synthesis of ZnSn(OH)6 regular octahedrons by a simple hydrothermal process

ZnSn(OH)₆ regular octahedrons were successfully synthesized through a simple hydrothermal method using an aqueous solution containing ZnO flower‐like structures, SnCl₄·5H₂O, and NaOH. Phase structure, morphology and microstructure of the samples were investigated by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). Parameters in preparation process such as the ratios of Sn⁴⁺/OH^‐, the molar ratio of Zn/Sn and reaction time were discussed. Results show that the obtained samples are comprised of ZnSn(OH)₆ regular octahedrons with about 2 μm in side length and ZnSn(OH)₆ urchins‐like structures. ZnSn(OH)₆ urchins‐like structures preferentially grow on the edges and corners of regular octahedrons. Morphology of the products is susceptible to the ratios of Sn⁴⁺/OH^‐. A relatively low concentration of OH^‐ is favored to obtain ZnSn(OH)₆ regular octahedrons with urchins‐like structures on the surface, while a high concentration of OH^‐ results in a handful of regular octahedrons without urchins‐like structures on the surface. When the molar ratio of Zn/Sn changes to 1:2 or 2:1, the edges and corners of regular octahedrons become coarse and urchins‐like structures disappear from the surface. More urchins‐like structures form on the surface of regular octahedrons and the edges and corners of regular octahedrons become coarsened with the increase of reaction time. Moreover, the possible mechanism for ZnSn(OH)₆ regular octahedrons is discussed. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Adsorption of Carboxylic Acids by Diethylenetriamine Intercalation Compound of α-Zr(HPO4)2 · H2O

Abstract

Two kinds of diethylenetriamine (2E3A) intercalation compounds of α-zirconium phosphate with different interlayer distances could be obtained by regulating the reaction time and temperature. Phase I (d = 10.2 Å) slowly transforms to Phase II(d = 15. 8 Å) with transformation enthalpy of 30 kJ-mol^?1 in 2E3A aqueous solution. The conformation of 2E3A in Phase I and Phase II were confirmed to be bent and all trans (straight) forms by³¹P MAS NMR and XRD measurements. Two phases have different adsorption behavior for gaseous carboxylic acids. Phase II can adsorb considerable amount of carboxylic acids whereas Phase I adsorb a little.     

Synthesis and crystal structure of a phthalate-bridged copper(II) complex {[Cu(L)(Phen)(H<Subscript>2</Subscript>O)]⋅H<Subscript>2</Subscript>O}<Subscript><Emphasis Type="Italic">n</Emphasis></Subscript>

A phthalate-bridged copper(II) complex {[Cu(phth)(Phen)(H₂O)] H₂O}_n (H₂phth: phthalic acid, Phen: 1,10-phenanthroline) has been synthesized by the reaction of CuCl₂ and phthalic acid in the presence of 1,10-phenanthroline in aqueous solution. The crystal structure of the complex has been determined by X-ray diffraction analysis to be orthorhombic, with the centrosymmetric space group Pbcm, where a = 11.6652(3) Å, b = 11.1709(3) Å, c = 14.0532(4) Å, V = 1831.28(9) ų, Z = 4. The L^2– (the acid radical of H₂phth) ion is coordinated to the Cu²⁺ ion as a monodentate ligand. Each L^2– ion bridges two adjacent Cu²⁺ ions with its two oxygen atoms from two carboxylic groups to form a one-dimensional zigzag chain. The coordination water and uncoordinated carboxylic oxygen atoms from neighboring chains are linked through hydrogen bonds to form a two-dimensional structure. There is a weak interaction between the coordination water molecule and the Cu²⁺ ion in the neighboring chain.     

Structures and Characterization of [Zn(n-chlorosalicylato)2(N-methylnicotinamide)2(H2O)2] (n?=?4 or 5) Ligand Isomers

Abstract  

Two ligand isomers [Zn{4-ClC₆H₃-2-(OH)COO}₂(Menia)₂(H₂O)₂] (I) and [Zn{5-ClC₆H₃-2-(OH)COO}₂(Menia)₂(H₂O)₂] (II) (Menia = N-methylnicotinamide) were prepared and characterized by elemental analysis, IR spectroscopy and thermal analysis. The X-ray crystal structures of complexes (I) and (II) were determined. Compound (I) crystallizes in the triclinic space group P[`1] P\bar{1} with a = 8.105(1) ?, b = 10.036(2) ?, c = 10.545(2) ?, α = 109.088(9)°, β = 91.416(8)°, γ = 102.757(9)°, V = 786.2(2) ?<sup>3</sup>, Z = 1. Compound (II) crystallizes in the triclinic space group P[`1] P\bar{1} . Its cell parameters are: a = 8.133(1) ?, b = 10.119(2) ?, c = 10.428(1) ?, α = 66.44(1)°, β = 74.32(1)°, γ = 80.16(1)°, V = 755.5(2) ?³, Z = 1. The molecular structure of both isomers is monomeric. Each Zn(II) atom is hexacoordinated by three pairs of unidentate ligands in trans-positions (ZnO₄N₂). The 5-Clsal complex is somewhat less distorted than 4-Clsal complex (Cl-sal = chlorosalicylate). The structural data are compared with those found in similar [Zn(RCOO)₂(NL)₂(H₂O)₂].     

New Regioselective Intercalation Reactions

Abstract

The ordered layered double hydroxide, [LiA1₂(OH)₆]CI. 2H₂O exhibits shape-selective ion-exchange intercalation of dicarboxylate anions. Specific isomeric preferences can be controlled by varying the reaction temperatures. The intercalated guests can be quantitatively recovered from the host lattice with concomitant regeneration of the host offering a novel approach in separation science. To illustrate the potential of this new material in separation science, we describe the isolation of pure 1,4-benzenedicarboxylate and 2, 6-naphthalenedicarboxylate from mixtures of their isomers. The neutral organic acids are both monomers in the synthesis of a range of important polyesters.     

Synthesis,Crystal Structure and DNA-Binding Study of a New Zinc(II) Complex Based on 2,6-Bis(imino)pyridyl Ligand

A new zinc complex [Zn(L1)Cl₂]₂?CH₃OH?2H₂O (complex 1), where L1 stands for 2,6-Bis{[(4-ethylphenyl)imino]ethyl}pyridine (L1) has been synthesized and characterized. The crystal structure of L1 and complex 1 have been determined by single-crystal X-ray diffraction. Both compounds crystallize in the monoclinic P2₁/c space group. For the ligand L1, the crystal parameters are a?=?16.7487(7) Å, b?=?5.8177(3) Å, c?=?21.8427(10) Å, β?=?104.1350(10)° and Z?=?4. For complex 1, the crystal parameters are a?=?8.0216(14) Å, b?=?13.433(2) Å, c?=?24.640(4) Å, β?=?90.223(3)° and Z?=?2. In the crystal structure of complex 1, L1 acts as a tridentate ligand and coordinated with Zn1 with three nitrogen atoms. Together with two chlorine atoms, Zn1 atom is five-coordinated in a trigonal bipyramidal geometry. Hydrogen bonds play great role in the crystal structure of complex 1 and form a two-dimensional network. Furthermore, the DNA-binding property of complex 1 with fish sperm DNA (FS-DNA) has been investigated by electronic absorption titration. The result suggests that complex 1 might interact with FS-DNA via groove binding mode.

Graphical abstract

The single crystals of 2,6-Bis{[(4-ethylphenyl)imino]ethyl}pyridine (L1) and it’s Zinc(II) complex [Zn(L1)Cl₂]?CH₃OH?H₂O (1) were determined. In the crystal structure of complex 1, Zn1 atom is five-coordinated in a trigonal bipyramidal geometry. A two-dimensional network is formed by hydrogen bonds. DNA-binding study indicated that complex 1 interact with FS-DNA via groove binding mode.

     

Structure of “bis(methoxymagnesium)diselenide”: A reagent for the introduction of selenium into organic molecules

The reaction of magnesium and selenium in dry methanol has been reported to yield a reagent tentatively identified as bis(methoxymagnesium) diselenide. The dark red-brown solution obtained from this reaction yielded red crystals that crystallized in the monoclinic space group C2/c, a=17.391(4) ?, b=15.823(3) ?, c=21.626(4) ?, β=110.71(3)°, V=5566.5(19) ?³, Z=4, R=0.0350, wR₂=0.0850 for 4930 reflections. X-ray crystallographic analysis of this reagent showed it to be dodecamethanol-tetramethoxy-di(μ₄-hydroxy)tetra(μ₃-methoxy)hexamagnesium hexaselenide, Mg₆(μ₄-OH)₂(μ₃-OCH₃)₄(OCH₃)₄(CH₃OH)₁₂]Se₆·2CH₃OH (1), not the bis(methoxymagnesium) diselenide as previously described. The structure of 1 is composed of six magnesium ions and six bridging oxygen-containing ligands in a face-sharing cubic arrangement.     

Metal Ion Interactions with Pyridinecarboxylates in Tripodal tris(2-Aminoethyl)amine Ligand System: Crystal Structures of [Ni(tren)(pic)]2(ClO4)2·CH3OH and [Co(tren)(dipic)]ClO4·CH3OH

Abstract  

Two new complexes [Ni(tren)(pic)]₂(ClO₄)₂·CH₃OH (1) and [Co(tren)(dipic)]ClO₄·CH₃OH (2), (tren is tris(2-aminoethyl)amine, pic is the anion of picolinic acid, dipic is the dianion of 2,6-pyridinedicarboxylic acid) have been synthesized and structurally characterized. X-ray analysis indicates that the two complexes are mononuclear with tren acting as a quadridentate ligand. In complex 1, the nickel(II) ion is further coordinated with picolinate in μ₂-N, O bidentate chelating mode. In complex 2, the cobalt(III) ion is coordinated with the pyridine nitrogen and one carboxylic oxygen of 2,6-pyridinedicarboxylate in μ₂-N, O chelating form. The metal atoms in both cases have distorted octahedral geometry. Crystal data: [Ni(tren)(pic)]₂(ClO₄)₂·CH₃OH (1), Mr = 869.03, monoclinic, C2/c, a = 26.354(5) ?, b = 10.407(2) ?, c = 25.839(5) ?, β = 96.24(3)°, Z = 8, V = 7045(2) ?³, R ₁ = 0.0418, wR ₂ = 0.1063 [I > 2σ(I)]; [Co(tren)(dipic)]ClO₄·CH₃OH (2), Mr = 501.77, Triclinic, P-1, a = 8.3667(2) ?, b = 10.4434(2) ?, c = 11.9431(16) ?, α = 73.9590(10)°, β = 88.0240(10)°, γ = 75.5890°, Z = 2, V = 969.97(4) ?³, R ₁ = 0.0408, wR ₂ = 0.1063 [I > 2σ(I)].     

Synthesis,Crystal Structure and Characterizations of New 3,4,7,8-Tetrachloro-1,10-Phenanthroline Zn(II) Complex

Abstract  

A novel 3,4,7,8-tetrachloro-1,10-phenanthroline (Cl₄phen) Zn(II) complex has been synthesized. The complex, [Zn(Cl₄phen)₂(H₂O)₂](NO₃)₂·CH₃CH₂OH (1), has been identified and characterized by single crystal X-ray diffraction, elemental analysis, FT-IR, thermogravimetric analysis and photoluminescence studies. Single crystal X-ray diffraction analysis reveals that complex (1) belongs to the monoclinic system, space group P2(1)/c, a = 10.061(2) Å, b = 18.924(4) Å, c = 18.189(4) Å, β = 100.94(3)°, and Z = 4. Complex (1) consists of cationic species [Zn(Cl₄phen)₂(H₂O)₂]²⁺, NO₃ ⁻ and CH₃CH₂OH. The zinc atom displays a distorted cis-N₄O₂ octahedral geometry. Via extended Zn–O–H···O–N–O···H–O–Zn bridge, every mononuclear unit is linked with other ones to form one-dimensional (1D) infinite chain of hydrogen bond system. Three-dimensional (3D) polymeric network arrangement was built via weak C–H···O and π-stacking interactions between Cl₄phen moieties. A solvent-dependency effect of complex (1) was observed in spectroscopic properties.     

Reactivity of polyiodide toward 1, 3-bis(4-pyridyl)propane (bpp): synthesis and structure of an organic-inorganic hybrid compound [(CuI2)2(N,N′-dimethyl-bpp)] n

The solution-phase reaction of a metal iodide with 1, 3-bis(4-pyridyl)propane (bpp) yields a new organic-inorganic hybrid framework, [(CuI2)2(N,N-dimethyl-bpp)] _n (1), which is made up of organic cations [dimethyl-bpp]²⁺ and an infinite [Cu₂I₄] _n ²⁻ anion chain; The cluster 1 obtained via the reaction between polyiodide complexes and organic N-donor ligand suggests that this simple synthetic approach is likely to be applicable to the construction of polymeric clusters.Supplementary material CCDC-253123 contains the crystallographic data for this paper. These data can be obtained free of charge at www.ccdc.cam.ac.uk/conts/retrieving.html [or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; Fax: +44-1223-336-033; E-mail: deposit@ccdc.cam.ac.uk].     

Synthesis,extended Hückel molecular orbital calculations,and X-ray diffraction structure of the pentamethylcyclopentadienylruthenium complex Cp*Ru(NO)(2,3-quinoxalinediolate)

The reaction between Cp^*Ru(NO)Cl₂ and the heterocyclic compound 2,3-quinoxalinediol in the presence of methanolic KOH leads to the formation of the new piano-stool compound Cp^*Ru(NO)(2,3-quinoxalinediolate) (1). Product isolation and characterization by solution spectroscopic methods (¹H and¹³C NMR and IR) are described. The solid-state structure of Cp^*Ru(NO)(2,3-quinoxalinediolate) confirms the replacement of each chloride ligand in Cp^*Ru(NO)Cl₂ by an oxygen group of the 2,3-quinoxalinediol ligand. Cp^*Ru(NO)(2,3-quinoxalinediolate) crystallizes in the orthorhombic space group Pbca, a=14.846(1) Å,b=12.718(1) Å,c=18.255(2) Å,V=3446.7(5) ų,Z=8,d _calc=1.643 g·cm^–3;R=0.0364,R _w=0.0393 for 1245 observed reflections withI>3(I). The observed Ru–N–O bond angle of 156.3(7)° in the X-ray structure of1 confirms the nonlinear nature of the nitrosyl linkage. This bend in the nitrosyl moiety away from the quinoxalinediolate ligand presumably results from solid-state packing forces and does not derive from electronic interactions, on the basis of extended Hückel molecular orbital calculations. The MO properties of1 are compared with other Cp^*Ru(NO)-substituted complexes previously synthesized in these laboratories.     

X-ray crystal structure of the 1:1 dimethylpicric acid–acenaphthene complex

The dimethylpicric acid–acenaphthene complex is orthorhombic, space group P2₁2₁2₁; at 24° a = 7.3685(1), b = 15.4159(1), c = 16.1296(3) Å, D _x = 1.491(2) g cm^–3, V = 1832.19(4) ų, Z = 4. The phenolic OH group in the dimethylpicric acid is intramolecularly hydrogen bonded to one of the ortho nitro groups with an OO distance of 2.500(2) Å. This nitro group is twisted out of the plane of the benzene ring by 8.2°; the twist angles of the other nitro groups are 52.6 and 83.5°. The acenaphthene molecule deviates slightly from planarity as a consequence of the torsion angle at CH ₂-CH ₂ being 1.8 rather then 0°. The molecules pack in stacks of alternating picric acid and acenaphthene molecules. Each stack is surrounded by a close-packed arrangement of six other stacks. The acenaphthene molecules are 2.7° away from being parallel to the benzene ring in the picric acid. The distances from the benzene ring to the acenaphthene carbon atoms range from 3.26 to 3.49 Å on one side of the ring and from 3.30 to 3.54 Å on the other.     

Synthesis and crystal structure of the coordination compound of pyridoxine with manganese sulfate

The reaction of pyridoxine with manganese sulfate in an aqueous solution gave the coordination compound MnSO₄ · 2C₈H₁₁O₃N · 2H₂O (I). The structure of I was determined from single-crystal X-ray diffraction data. In the centrosymmetric complex (sp. gr. P[`1]P\bar 1, Z = 1), the Mn atom is coordinated by two pyridoxine molecules and two water molecules, thus adopting an octahedral coordination. The sulfate anion is also at a center of symmetry and, consequently, is disordered. The pyridoxine molecules are coordinated to the metal atom through the oxygen atoms of the deprotonated hydroxyl group and the CH₂OH group that retains the hydrogen atom. The nitrogen atom is protonated in such a way that the heterocycle assumes a pyridinium character. The crystal structure also contains six water molecules of crystallization. A thermogravimetric study showed that the decomposition of I occurs in several successive steps, such as dehydration, the combustion of organic ligands, and the formation of an inorganic residue.