Crystal structures of seven-coordinate (NH4)2[MnII(edta)(H2O)]·3H2O, (NH4)2[MnII(cydta)(H2O)]·4H2O and K2[MNII(hdtpa)]·3.5H2O complexes

The title compounds, (NH₄)₂[Mn^II(edta)(H₂O)]·3H₂O (H₄edta = ethylenediamine-N,N,N′,N′-tetraacetic acid), (NH₄)₂[Mn^II(cydta)(H₂O)]·4H₂O (H₄cydta = trans-1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acid) and K₂[Mn^II(Hdtpa)]·3.5H₂O (H₅dtpa = diethylenetriamine-N,N,N′,N″,N″-pentaacetic acid), were prepared; their compositions and structures were determined by elemental analysis and single-crystal X-ray diffraction technique. In these three complexes, the Mn²⁺ ions are all seven-coordinated and have a pseudomonocapped trigonal prismatic configuration. All the three complexes crystallize in triclinic system in P-1 space group. Crystal data: (NH₄)₂[Mn^II(edta)(H₂O)]·3H₂O complex, a = 8.774(3) ?, b = 9.007(3) ?, c = 13.483(4) ?, α = 80.095(4)°, β = 80.708(4)°, γ = 68.770(4)°, V = 972.6(5) ?³, Z = 2, D _c = 1.541 g/cm³, μ = 0.745 mm⁻¹, R = 0.033 and wR = 0.099 for 3406 observed reflections with I ≥ 2σ(I); (NH₄)₂[Mn^II(cydta)(H₂O)]·4H₂O complex, a = 8.9720(18) ?, b = 9.4380(19) ?, c = 14.931(3) ?, α = 76.99(3)°, β = 83.27(3)°, γ = 75.62(3)°, V = 1190.8(4)?³, Z = 2, D _c = 1.426 g/cm³, μ = 0.625 mm⁻¹, R = 0.061 and wR = 0.197 for 3240 observed reflections with I ≥ 2σ(I); K₂[Mn^II(Hdtpa)]·3.5H₂O complex, a = 8.672(3) ?, b = 9.059(3) ?, c = 15.074(6) ?, α = 95.813(6)°, β = 96.665(6)°, γ = 99.212(6)°, V = 1152.4(7) ?³, Z = 2, D _c = 1.687 g/cm³, μ = 1.006 mm⁻¹, R = 0.037 and wR = 0.090 for 4654 observed reflections with I ≥ 2σ(I). Original Russian Text Copyright ? 2008 by X. F. Wang, J. Gao, J. Wang, Zh. H. Zhang, Y. F. Wang, L. J. Chen, W. Sun, and X. D. Zhang The text was submitted by the authors in English. Zhurnal Strukturnoi Khimii, Vol. 49, No. 4, pp. 753–759, July–August, 2008.     

A novel hydrogen-bonded cyclic dibromide in an organic diammonium salt

The organic diammonium salt N,N′-dibenzyl-N,N,N′,N′-tetramethylethylenediammonium dibromide dihydrate, (dbtmen)Br₂.2H₂O (1), was prepared by the reaction of N,N,N′,N′-tetramethyl-ethylenediamine (tmen) with benzyl bromide.1 crystallizes in the triclinic space group with the following unit cell dimensions for C₂₀H₃₄Br₂N₂O₂ (M = 494.31):a = 8.6672(6) ?,b = 11.7046(8) ?,c = 11.7731(8) ?, α = 76.988(8)°, β = 88.978(8)°, γ= 76.198(8)γ,V= 1129.26(13) ?³, Z=2. Three components, namely the (dbtmen)²⁺ dication, two bromide anions and two crystal water molecules constitute the structural arrangement of1. H₂O molecules are linked to bromide anions via O-H...Br hydrogen bonding interactions resulting in the formation of a four-membered O₂Br₂ cyclic dibromide. The O₂Br₂ units and the dications are arranged as alternating layers extending in the crystallographicbc plane. The arrangement of anions and cations may be viewed as a typical lamellar structure. The crystal water molecules can be removed by heating 1 at 140°C and the anhydrous dibromide thus formed can be fully rehydrated as evidenced by IR spectra and X-ray powder patterns. Dedicated to Prof S Chandrasekaran on the occasion of his 60th birthday     

Simultaneous separation and determination of Cu(II), Fe(III), and Pb(II) by reversed-phase ion-pair chromatography withN,N,N′, N′-ethylene-diaminetetrakis(methylenephosphonic Acid)

Summary A reversed-phase ion-pair chromatographic (RPIPC) method withN,N,N′, N′-ethylenediaminetetrakis(methylenephosphonic acid) (EDTMP) as coordinating agent has been developed for simultaneous separation and detection of Cu(II), Fe(III), and Pb(II) ions. Response is linearly dependent on amount of sample over the range 9.52–50.8 μg mL⁻¹ for Cu(II), 8.31–41.8 μg mL⁻¹ for Fe(III), and 37.3–51.8 μg mL⁻¹ for Pb(II). The method has been applied successfully to an artificial mixed-ore sample.     

Alkylation of salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides with alkyl halides and dimethyl sulfate

Salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides, RCH(OH)CH₂N(O)=NO⁻ M⁺ (R=Me, Prⁱ, or Bu^t; and M=Li, Na, K, Ag, NH₄, or Me₄N), were prepared. Their alkylation with alkyl halides R′X (X=Cl, Br, or I) and dimethyl sulfate was studied. Generally, alkylation afforded mixtures ofN-(β-hydroxyalkyl)-N′-alkoxydiazeneN-oxides RCH(OH)CH₂N(O)=NOR′ andO-alkyl-N-(β-hydroxyalkyl)-N-nitrosohydroxylamines RCH(OH)CH₂N(NO)OR′. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1996–2001, October, 1998.     

Binary and Ternary Complexes of Copper(II) Involving N,N,N′,N′-Tetramethylethylenediamine (Me4en) and Various Biologically Relevant Ligands

Binary and ternary complexes of copper(II) involving N,N,N′,N′-tetramethylethylene-diamine (Me₄en) and various biologically relevant ligands containing different functional groups are investigated. The ligands (L) used are dicarboxylic acids, amino acids, peptides and DNA unit constituents. The ternary complexes of amino acids, dicarboxylic acids or peptides are formed by simultaneous reactions. The results showed the formation of Cu(Me₄en)(L) complexes with amino acids and dicarboxylic acids. The effect of chelate ring size of the dicarboxylic acid complexes on their stability constants was examined. Peptides form both Cu(Me₄en)(L) complexes and the corresponding deprotonated amide species Cu(Me₄en)(LH₋₁). The ternary complexes of copper(II) with (Me₄en) and DNA are formed in a stepwise process, whereby binding of copper(II) to (Me₄en) is followed by ligation of the DNA components. DNA constituents form both 1:1 and 1:2 complexes with Cu(Me₄en)²⁺. The concentration distribution of the complexes in solution was evaluated. [Cu(Me₄en)(CBDCA)] and [Cu(Me₄en)(malonate)] are isolated and characterized by elemental analysis and infrared measurements.     

Sensitive determination of nitric oxide in some rat tissues using polymer monolith microextraction coupled to high-performance liquid chromatography with fluorescence detection

A simple, sensitive, selective, and low-cost method is proposed for rapidly determining nitric oxide (NO) in some rat tissues. Polymer monolith microextraction (PMME) using a poly(methacrylic acid–ethylene glycol dimethacrylate) (MAA-EGDMA) monolithic column was combined with derivatization of NO using 1,3,5,7-tetramethyl-8-(3′,4′-diaminophenyl)-difluoroboradiaza-s-indacene (TMDABODIPY), and this was used to analyze the derivatives of NO by high-performance liquid chromatography (HPLC) with fluorescence detection at λ _ex/λ _em = 498/507 nm. The baseline separation of TMDABODIPY and its NO derivative is performed under simple conditions in which a C₁₈ column is used and eluted with 50 mmol L⁻¹ ethanolamine and methanol. The conditions for the extraction of NO derivatives were optimized. The limit of detection of NO was 2 × 10⁻¹² mol L⁻¹ (S/N = 3). The linearity range of the method was 9 × 10⁻¹¹−4.5 × 10⁻⁸ mol L⁻¹. The interday and intraday relative standard deviations were less than 5%. The proposed method was successfully applied to the determination of NO levels in some rat tissue samples including heart, kidney, and liver with recoveries varying from 87.1 to 95.2%.     

Vinamidinium salts of N-substituted aminoacetic acids

Formylation of N-phthaloylglycine with the POCl3-DMF system afforded N,N,N′, N′-tetramethyl-2-(N-phthaloyl)vinamidinium perchlorate (2). X-ray diffraction study showed that molecule 2 is planar and contains two equivalent nitrogen atoms in the three-carbon vinamidinium fragment. Salt 2 undergoes transamination with primary aromatic amines to give the corresponding bis-azomethines. The reactions with hydrazines produce substituted 4-aminopyrazoles. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 832–835, May, 2006.     

Synthesis of 2-(2-hydroxyaroylmethylene)hexahydropyrimidines from 2-trichloromethylchromones and trimethylenediamine

The reactions of 2-trichloromethylchromones with trimethylenediamine in ethanol at room temperature afford 2-(2-hydroxyaroylmethylene)hexahydropyrimidines. Under analogous conditions, 2-methylchromone gives a mixture ofN,N′-trimethylenebis[3-amino-1-(2′-hydroxyphenyl)-2-buten-1-one] andN,N′-trimethylenebis(imine) of 2-hydroxyacetophenone. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2140–2143, November, 1999.     

Fluorimetric determination of traces of europium(III) using a new chelator and acetate or phosphate in dimethylsulfoxide as enhancers

A new Schiff-base ligand [N, N′, N″-Tri- (2,4-dihydroxyacetophenone) – triaminotriethylamine (TDATA)] with a tripodal structure was synthesized. Its fluorescence intensity with the europium(III) complex was increased about 178-fold in the presence of sodium acetate (NaAc) and about 126-fold in the presence of sodium phosphate (Na₃PO₄) solution. After adding the organic solvent dimethylsulfoxide (DMSO) to the above system, which leads to Eu³⁺ the fluorescence was further enhanced about 12-fold. Spectrofluorimetric determination of trace amounts of Eu³⁺ based on the phenomenon was performed. The excitation and emission wavelength is 365 nm and 615 nm, respectively. Under optimum conditions, the fluorescence intensities vary linearly with the concentration of Eu³⁺ in the range of 4.9 × 10⁻¹²–3.2 × 10⁻⁶ mol · L⁻¹ with a detection limit of 4.5 × 10⁻¹² mol · L⁻¹ (for the TDATA-NaAc-DMSO system) or 6.2 × 10⁻¹¹–8.6 × 10⁻⁶ mol · L⁻¹ with a detection limit of 6.0 × 10⁻¹¹ mol · L⁻¹ (for the TDATA-Na₃PO₄-DMSO system). Interferences of some rare earth metals and other inorganic ions are described. The method is a selective, sensitive, rapid and simple analytical procedure for the determination of europium(III) in a high purity yttrium oxide and synthetic sample. The mechanism for the fluorescence enhancement is also discussed.     

ESR study of low-temperature radiolysis and photolysis of substitutedN′-furfurylidenebenzhydrazides

Low-temperature (77 K) γ- and UV irradiation of substitutedN′-furfurylidenebenzhydrazides produces paramagnetic particles in radiation-chemical yields of (0.05–0.5)/100 eV and quantum yields of 4·10⁻⁵–10⁻³, respectively. ESR study showed that hydrazyl radicals and HC·O and N·O₂ are the main products of radiolysis and photolysis, and the latter decay upon heating of the sample to 190 K, whereas the hydrazyl radicals survive up to 423 K. Further heating results in thermodestruction of the hydrazides, and the ESR spectrum exhibits only a singlet with splitting at 1 mT, which is characteristic of polyconjugated compounds. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2078–2082, November, 1999.