Preparation of non-valence compounds of zinc(II) with 1,2- and 1,4-benzenedicarboxylic acids via self-assembly

Nanostructured non-valence compounds based on coordination compounds of zinc(II) with phthalic and terephthalic acids have been prepared. The purity and composition of prepared compounds have been elucidated from X-ray diffraction analysis, IR spectroscopy, elemental analysis, and thermogravimetry studies; thermal decomposition of the non-valence compounds has been studied as well. The prepared self-assembled compounds are co-precipitated with one water molecule and 1.5 acetic acid molecules per unit of the dicarboxylic acid: [Zn₄(OH)₆·o-C₆H₄(COO)₂]·H₂O·1.5CH₃COOH and [Zn₄(OH)₆·p-C₆H₄(COO)₂]·H₂O· 1.5CH₃COOH.     

Crystal and molecular structures of tetraaqua(di-<Emphasis Type="Italic">para</Emphasis>-oxybenzoato)iron(II) tetrahydrate

The new complex [(p-HOC₆H₄CO₂)₂Fe(H₂O)₄] · 4H₂O is synthesized and studied by X-ray diffraction analysis. The Fe(II) cation is coordinated by two para-hydroxybenzoate anions through the mono-dentate mode. Four oxygen atoms of the water molecules complete the coordination polyhedron of the central atom to an octahedron. Four molecules of water of crystallization “cross-link” the monomers to form a polymeric structure.     

The role of distonic ions in the formation of CH3NH 3 + and (CH3)2NH 2 + from the molecular ions of octopamine and synephrine

It is shown by mass-analyzed ion kinetic energy spectrometry that the metastably decomposing molecular ions of octopamine (p-HOC₆H₄CH(OH)CH₂NH₂) and synephrine (p-HOC₆H₄CH(OH)CH₂NHCH₃) yield only protonated methylamine and dimethylamine, respectively, as product ions. From deuterium labeling and variation of the internal energy of the molecular ions, experimental support has been obtained that these product ions are generated via the occurrence of a distonic ion-neutral complex. In the case of octopamine, this complex would consist of a nitrogen-protonated aminomethyl radical and p-hydroxylbenzaldehyde in which the former species abstracts the aldehydic or phenolic hydrogen atom from the latter to give protonated dimethylamine.     

Chemistry of 2-mercaptophenol (H2mp) . Part iii. One dimensional arrays of binuclear anions of Mo (VI) linked by bis (2-hydroxyphenyl) disulfide via hydrogen bondings

The reaction of (Bu₄N) ₄ [Mo₈O₂₆] with a suitable amount of 2-mercaptophenol (H₂mp) in MeOH in the presence of equimolar Et₃N gave the complex (Bu₄N) ₂ [{MoO₂ (2-SC₆H₄O) }₂ (μ-O) ] (2 2′-HOC₆H₄SSC₆H₄OH) 2H₂O (1) with a one-dimensional chain network formed via hydrogen bondings (average OH OMo distance 2655 Å) of the hydroxyl groups in the spacer 2 2′-HOC₆H₄SSC₆H₄OH with the terminal oxo groups of the dimolybdenum anions 2 2′-HOC₆H₄SSC₆H₄OH was obtained by oxidation of H₂mp in the presence of molybdenum when the reaction was run in air The characteristic cis-MoO₂² absorptions appear at 913 and 864 cm^{−1 1} H NMR and ¹ H–¹ H COSY spectra characterized the phenyl protons of the mercaptophenol groups in the anion and in 22′-HOC₆H₄SSC₆H₄OH in the ranges of 6700–6270 and 7368–6799 ppmrespectivelywith ³J and ⁴J coupling constants of 8 and 1 Hz respectively.     

Hydration reaction of Hofmann's benzene clathrate,diamminenickel(II) tetracyanonickelate(II)-benzene-(1/2), suspended in aqueous media

Hofmann's benzene clathrate Ni(NH₃)₂Ni(CN)₄·2C₆H₆ suspended in ammoniacal, neutral, and acidic aqueous media undergoes the replacement reactions of the guest C₆H₆ and the ligating NH₃ molecules with molecules of water to give Ni(NH₃)₂Ni(CN)₄·?1H₂O, Ni(H₂O)₂Ni(CN)₄·nH₂O(0<n<2), and Ni(H₂O)₂Ni(CN)₄·4～5H₂O, respectively. The integrity of the host metal complex sheet structure is conserved with little change during the replacement reactions.     

Preparation and study of chiral boron containing amine-cyano(pyrrolyl-1)borane complexes. Preparation of (−)-(S)-α-phenylethylamine-(−)-cyano(pyrrolyl-1)borane and (+)-(R)-α-phenylethylamine-(+)-cyano(pyrrolyl-1)borane

Several amine-cyano(pyrrolyl)borane complexes [A · BH(NC₄H₄)CN] containing a chiral boron atom were prepared from the reactions of sodium cyanohydrodipyrrolylborate-tridioxane¹ [NaBH(NC₄H₄)₂CN · 3C₄H₈O₂] with amine hydrochlorides as well as by base exchange from the appropriate 4-cyanopyridine complex [4-CNC₅H₄N · BH(NC₄H₄)CN]. Amines with an sp² N atom give stable complexes of a wide range of basicity (pK_a = 0.8?9.7), in contrast to the anines with sp³ hybridized N where only the stronger bases (pK_a ? 7.3) are capable of giving stable complexes (mainly secondary and tertiary amines). These compounds undergo hydrolysis in neutral and alkaline media, while in strong acids they give stable boronium ions by protonation at the α-C atom of the pyrrolyl group. The compounds (?)-(S)-α-phenylethylamine-(?)-cyanopyrrolylborane and (+)-(R)-α-phenylethylamine-(+)-cyanopyrrolylborane have been prepared in pure form; in solution they undergo slow epimerization. Treatment of the appropriate complexes with KH has given the chiral boron-containing borates KBH(NC₄H₄)(CN)X (X = imidazolyl-, pyrazolyl-). Dicyanohydropyrrolylborane was obtained from 4-cyanopyridine-cyanopyrrolylborane and NaCN.     

Berberine formate–succinic acid (1/1)

The title compound [systematic name: 9,10‐di­methoxy‐2,3‐methyl­ene­dioxy‐5,6‐di­hydro­dibenzo­[a,g]­quinolizinium form­ate–succinic acid (1/1)], C₂₀H₁₈NO₄⁺·CHO₂⁻·C₄H₆O₄, con­tains centrosymmetric pairs of almost planar berberine cations, and hydrogen‐bonded (C₄H₆O₄⋯HCOO⁻)₂ rings of succinic acid with formate anions, bonded by O—H⋯O hydrogen bonds with O⋯O distances of 2.4886 (15) and 2.5652 (16) Å. Pairs of cations and mol­ecules of succinic acid are connected by non‐conventional weak C—H⋯O hydrogen bonds, with C⋯O distances of 3.082 (2) and 3.178 (2) Å.     

The dimeric unit [La(H2O)4(m-PO3C6H4COOH)(m-PO2(OH)C6H4COOH)(m-PO(OH)2C6H4COOH)]2 as building block of layered hybrid material

A new hybrid organic–inorganic material with the structural formula unit [La(H₂O)₄(m-PO₃C₆H₄COOH)(m-PO₂(OH)C₆H₄COOH)(m-PO(OH)₂C₆H₄COOH)]₂ (or [La(H₂O)₄C₂₁H₁₈O₁₅P₃]₂) has been synthesized under hydrothermal condition from La(NO₃)₃·6H₂O and 3-phosphonobenzoic acid (m-PO(OH)₂–C₆H₄–COOH) which is a rigid organic precursor possessing two types of functional groups: phosphonic acid and carboxylic acid. The two units of the produced hybrid are linked together by hydrogen bonds leading to a layered framework composing of by a repetition of inorganic and organic slices. The organic layers consist of dimeric units made of two meta-phosphono-benzoic acid linked together by hydrogen bonds involving their COOH groups. Two kinds of dimeric units are observed: PO₃C₆H₄COOH?HOOCC₆H₄PO(OH)₂, present 2 times in the structure, and PO₂(OH)C6H4COOH?HOOCC₆H₄PO₂(OH). The material crystallises in a monoclinic cell (C2/c (15) space group) with the following parameters: a = 42.515(4) Å, b = 7.4378(6) Å, c = 20.307(2) Å, β = 118.031(6)°, V = 5668.2(9) Å³, Z = 4, density = 1.908 g/cm³.     

Standard Molar Enthalpies of Formation of Ce(TCA)_3·3H_2O(s) and Ce(TCA)(C_9H_6NO)_2(s)

IntroductionBothrareearthions1and 8 hydroxyquinolineareofantibacterialfunction ,2 andtheircomplexeshavemorepowerfuldisinfection .Theirbinarycomplexeswerereport edasearlyasin 196 3.Atthesametime ,theresearchontheirternarycomplexeshavebecomeveryactiveinrecentyears,andtheyarewidelyappliedinmanyfields .3 6Dong6 reportedthesynthesisandcharacterizationofthecomplexesofrareearthtrichloroaceticacidsaltswith 8 hy droxyquinoline.Itsapplicationinleathermouldyproofshowedthatthecomplexeshavepowerfuldisinfe…     

Synthesis and characterization of mixed-ligand complexes of nickel(II) with 5,5′-thiodisalicylic acid and amines

The 5,5′-thiodisalicylato complexes of nickel(II) with water, ammonia, methylamine and pyridine were synthesized and their structure established to be [Ni(TDSA)L₂·nH₂O], where TDSA = 5,5′-thiodisalicylic acid, [C₆H₃(OH)(COOH)SC₆H₃(OH)(COOH)]. LH₂O, NH₃ CH₃NH₂ or pyridine, and n=3 for H₂O, 2 for NH₃ and CH₃NH₃, and 1 for pyridine complexes, from elemental analysis, IR and electronic spectroscopy, and magnetic susceptibility measurement. The thermal behaviour of the complexes has been studied by TG and DTA. TG shows three main steps of decomposition, viz. dehydration, axial base liberation, and decarboxylation leading to the formation of NiO at the final stage.     

2‐Aminopyridinium–succinate–succinic acid (2/1/1)

In the title compound, 2C₅H₇N₂⁺·C₄H₄O₄^2?·C₄H₆O₄, cyclic eight‐membered hydrogen‐bonded rings exist involving 2‐amino­pyridinium and succinate ions. The succinic acid and succinate moieties lie on inversion centres. Succinic acid mol­ecules and succinate ions are linked into zigzag chains by O—H?O hydrogen bonds, with O?O distances of 2.6005 (16) Å.     

Preparation of photoluminescent compounds of Eu(III), Sm(III), and Dy(III) containing anions of tetrafluoroterephthalic acid

The Ln₂(H₂O)₄(L)₃·2H₂O and Ln₂(phen)₂(L)₃·2H₂O complexes [Ln = Eu(III), Sm(III), or Dy(III); H₂L = C₆F₄(COOH)₂, phen = 1,10-phenanthroline] have been prepared. Structures of the prepared compounds have been confirmed by X-ray diffraction and IR spectroscopy studies. The complexes of Eu(III) have exhibited red photoluminescence stronger than that of the complexes of Sm(III) and Dy(III).     

Analytical applications of the reaction of thorium with benzenephosphonic acid

Benzenephosphonic acid quantitatively precipitates thorium as Th(C₆H₅PO₃)₂·3H₂O at pH values as low as 0.5. The compound may be dried at 140° to 180° C and weighed, as a gravimetric means of determining thorium. On ignition, Th (C₂H₅PO₃)₂ 3 H₂O undergoes decomposition at 240° to 300° C to form Th(C₆H₅PO₃)₂·2H₂O, at 450° to 650° C to form Th(HPO₄)₂·2H₂O and finally at 800° to 1000° C to form Th(HPO₄)₂. The latter compound is stable to 1200° C.Potentiometrically (pK₁' = 0.91, pK₂' = 6.41) and spectrophotometrically (pK₁' = 0.96, pK₂' = 6.51) determined pK' values are reported. Absorption spectra of C₆H₅PO₃H₂, C₆H₅PO₃H^- and C₆H₅PO₃^-2 are reported. The solubility of Th (C₆H₅PO₃)₂·3H₂O was studied as a function of pH and the average value of the solubility product (K_sp = 4s³) was found to be 3.24·10^-31.     

Synthesis and photoluminescence of Eu(III) complex compounds containing anions of perfluoro-3-methylbenzoic acid

Photoluminescent Eu(III) compounds with anions of the acid 3-CF₃C₆F₄COOH (LH) of composition Eu(L)₃·2H₂O and Eu(phen)(L)₃ were synthesized. The photoluminescence intensity of the complex Eu(phen)(L)₃ is higher than that of a similar Eu(III) complex containing anions of the acid 4-CF₃C₆F₄COOH as ligands.     

Structures of poly(p-hydroxybenzoic acid) (PHBA) at ambient temperature

The molecular structure of poly (p-hydroxybenzoic acid) (C₆H₄COO)_x at ambient temperature was determined by x-ray powder diffraction analysis. The diffraction pattern is explained as a mixture of two orthorhombic phases having the same space group Pbc2₁ with four C₆H₄COO chemical repeats in the unit cell and the following cell parameters: a = 7.42 Å, b = 5.70 Å, and c = 12.45 Å for phase I (ρ_calc = 1.51 g cm^?3); and a = 3.83 Å, b = 11.16 Å, and c = 12.56 Å for phase II (ρ_calc = 1.48 g cm^?3). The chain conformation is the same in both phases, involving two benzoyl rings staggered by ca. 120° along the chain. Disorder has been considered in the packing of phase I by giving equal occupancy to the two molecules oriented up or down along the c chain axis. ©1995 John Wiley & Sons, Inc.     

Mechanism of the reaction of N-p-tosylsulphilimine and related compounds with thiophenolate ion

The reaction of alkyl aryl N-p-tosylsulphilimines with thiophenolate ion was found to afford quantitatively the sulphide that arises by an S_N2 like reaction on the carbon atom adjacent to the tri-valent sulphur atom. This reaction was also found to proceed smoothly with such compounds as sulphoxides and sulphones and sulphoxmanes. The kinetic study on the reaction between aryl methyl N-p-tosylsulphilimine with thiophenolate ion in DMF reveals that the reaction is of second order, namely, first order with respect to each thiophenolate ion and the sulphilimine. The enthalpy and entropy of activation for the reaction are ΔH^≠ = ?17· kcal/mol and ΔS^≠ = ?5·7 eu respectively. The effect of substituents in the reaction, p-XC₆H₄⁺(^?SO₂C₆H₄Y-p)CH₃ + p-ZC₆H₄SK is nicely correl with Hammett σ values giving ?_x = + 2·4, ?_y = + 1·2 and ?_z = ?1·8 respectively. Meanwhile, a marked steric retardation by a bulky alkyl group in alkyl phenyl N-p-tosylsulphilimine is observed. Furthermore, from the stereochemical study of the reaction using an optically active sec-octyl phenyl N-p-tosylsulphilimine with thiophenolate ion it is concluded that the reaction proceeds via a typical S_N2 process on α-carbon atom attached to the tri-valent sulphur atom.     

Threefold interweaving of (4,4) nets built from R(58) rings in the hydrogen‐bonded adduct 1,4‐diaza­bicyclo[2.2.2]octane–5‐hydroxy­isophthalic acid (1/1)

The 1:1 adduct of 1,4‐di­aza­bi­cyclo­[2.2.2]­octane and 5‐hydroxy­isophthalic acid is a salt, [H(C₆H₁₂N₂)]⁺·­[HOC₆H₃(COOH)COO]^? or C₆H₁₃N₂⁺·C₈H₅O₅^?. The ions are linked by three types of hydrogen bond, i.e. N—H?O, O—H?O and O—H?N, into continuous two‐dimensional (4,4) nets built from a single type of R(58) ring. Six independent sheets of this type make up the structure and these are interwoven in sets of three.     

Complexes derived from the copper(II) perchlorate/maleamic acid/2,2′-bipyridine and copper(II) perchlorate/maleic acid/2,2′-bipyridine reaction systems: Synthetic,reactivity, structural and spectroscopic studies

A systematic investigation of the reactions of Cu(ClO₄)₂ · 6H₂O with maleamic acid (H₂L) in the presence of 2,2′-bipyridine (bpy) has been carried out. The chemical and structural identity of the products depends on the solvent, the absence or presence of external hydroxides in the reaction mixture and the molar ratio of the reactants. Various reaction schemes have led to the isolation of the complexes [Cu₂(HL)₂(bpy)₂(H₂O)₂](ClO₄)₂ (1), [Cu₂(HL)₂(bpy)₂(H₂O)₂](ClO₄)₂ · 2H₂O (1 · 2H₂O), [Cu(L′′)(bpy)]_n · 2nH₂O (2 · 2nH₂O), [Cu₂(L′′)(bpy)₂(H₂O)₂]_n(ClO₄)_2n · 0.5nH₂O (3 · 0.5nH₂O), [Cu₂(L′′)₂(bpy)₂] · 2MeOH (5 · 2MeOH), [Cu₂(L′)₂(bpy)₂(ClO₄)₂] (6) and [Cu(ClO₄)₂(bpy)(MeCN)₂] (7b), where L′′^2? and L′^? are the maleate(?2) and monomethyl maleate(?1) ligands, respectively. The HL^? ion has been transformed to L′′^2? and L′^? in the known compounds 2 · 2nH₂O and 6, respectively, via metal ion-assisted processes involving hydrolysis (2 · 2nH₂O) and methanolysis (6) of the primary amide group. The reaction that leads to 6 takes place through the formation of the mononuclear complex [Cu(ClO₄)₂(bpy)(MeOH)₂] (7a), whose structure was assigned on the basis of its spectral similarity with the structurally characterized complex 7b. The structures of the cations in 1 and 1 · 2H₂O consists of two Cu^II atoms bridged by the carboxylate groups of the two HL^? ligands, each exhibiting the less common η² coordination mode; a chelating bpy molecule and a H₂O ligand complete square pyramidal coordination at each metal centre. The structure of the dinuclear repeating unit in the 1D coordination polymer 3 · 0.5nH₂O consists of two Cu^II atoms bridged by two syn,syn η¹:η¹:μ₂ carboxylate groups belonging to two L′′^2? ions; each ligand bridged two neighboring [Cu^II,II₂] units thus promoting the formation of a helical chain. The structure of the dinuclear molecule of complex 5 · 2MeOH consists of two Cu^II atoms bridged by two η² carboxylate groups from two L′′^2? ligands; the second carboxylate group of each maleate(?2) ligand is monodentately coordinated to Cu^II, creating a remarkable seven-membered chelating ring. The L′^? ion behaves as a carboxylate-type ligand in 6, with the carboxylate group being in the familiar syn,syn η¹:η¹:μ₂ coordination mode; a chelating bpy molecule and a coordinated ClO₄^? complete five-coordination at each Cu^II centre. The crystal structures of the complexes are stabilized by various H-bonding patterns. Characteristic IR bands of the complexes are discussed in terms of the known structures and the coordination modes of the ligands.     

Reactions of 2-(1-carboxyl-2-hydroxyphenyl)thiazolidine with chromium(III) salts leading to newer synthesis of chromium(III) complexes

Reactions of 2-(L-carboxyl-2-hydroxyphenyl)thiazolidine with different chromium(III) salts [CrCl₃?·?6H₂O, K₃[Cr(SCN)₆], NH₄[Cr(NH₃)₂(SCN)₄]?·?H₂O, [Cr(urea)₆]Cl₃?·?3H₂O and [Cr(CH₃COO)₂H₂O]₂] under varied reaction conditions afforded many new mixed-ligand chromium(III) complexes. The ligand is a tridentate dibasic NSO donor except for complexes 1 and 4 where two moles of the ligand are present for each molecule of complex, one functioning as a dibasic tridentate (NSO) and the other as a monobasic bidentate (NS) (phenolic OH and carboxylic COOH groups remaining uncoordinated). The complexes have been characterized by elemental analyses, magnetic susceptibilities, molar conductances, molecular weights and spectroscopic (IR, Uv-vis) data. The ligand field parameters and NSH Hamiltonian parameters suggest tetragonal geometries of the complexes.     

Synthesis, characterization and thermal analysis of 1:1 and 2:3 lanthanide(III) citrates

The synthesis and characterization of lanthanide(III) citrates with stoichiometries 1:1 and 2:3; [LnL·xH₂O] and [Ln₂(LH)₃·2H₂O], Ln=La, Ce, Pr, Nd, Sm and Eu are reported. L stands for (C₆O₇H₅)^3? and LH for (C₆O₇H₆)^2?. Infrared absorption spectra of both series evidence coordination of carboxylate groups through symmetric bridges or chelation. X-ray powder patterns show the amorphous character of [LnL·xH₂O]. The compounds [Ln₂LH₃·2H₂O] are crystalline and isomorphous. Emission spectra of Eu compounds suggest C _2v symmetry for the coordination polyhedron of [LnL·xH₂O] and C _4v for [Ln₂(LH)₃·2H₂O]. Thermal analyses (TG-DTG-DTA) were carried out for both series. The thermal analysis patterns of the two series are quite different and both fit in a 4-step model of thermal decomposition, with lanthanide oxides as final products.