Spectrophotometric study of pseudopurpurin-Pd(II) dimer complex. Spectrophotometric determination of traces of Pd(II)

We have studied spectrophotometrically the Pseudopurpurin-Pd(II) complex in an ethanolic-water medium ¦Ethanolamine ¦_optimum = 4 × 10⁻¹M; λ = 670 nm; 20% H₂O; stable for at least 4 hr; ¦Reagent¦_optimum = 5 × 10⁻⁵M; stoichiometry 2:2; log K = 17.7. A new method for the spectrophotometric determination of Pd traces is proposed for concentrations between 0.30 and 2.40 ppm. The relative error and the interferences of the method have been investigated.     

Sensitive spectrofluorimetric determination of ruthenium at nanotrace levels using 2-(α-pyridyl) thioquinaldinamide [PTQA]

A new spectrofluorimetric method for the determination of ruthenium with nonfluorescent 2-(α-pyridyl) thioquinaldinamide (PTQA) is described. The oxidative reaction of Ru(III) upon PTQA gives oxidised fluorescent product (λ_ex(max)=347 nm; λ_em(max)=486 nm). The sensitivity of the fluorescence reaction between ruthenium and PTQA is greatly increased in the presence of Fe (III). The reaction is carried out in the acidity range 0.01–0.075 M H₂SO₄. The influence of reaction variables is discussed. The range of linearity is 1–400 μg l⁻¹ Ru(III). The standard deviation and relative standard deviation of the developed method are ±1.210 μg l⁻¹ Ru (III) and 2.4%, respectively (for 11 replicate determinations of 50 μg l⁻¹ Ru (III)). The effect of interferences from other metal ions, anions and complexing agents was studied; the masking action is discussed. The developed method has been successfully tested over synthetic mixtures of various base metals and platinum group metals, synthetic mixtures corresponding to osmiridium, certified reference materials in spiked conditions and rock samples.     

Colorimetric determination of palladium (II) by means of promazine hydrochloride

In acetate buffer medium palladium(II) ions form with promazine hydrochloride (PM) two complexes: an orange one of a formula [Pd(C₁₇H₂₀N₂S)]²⁺ (λ_max = 460 nm, ε = 4.5 × 10³, at 20 °C and pH = 2) and a violet one of a formula [Pd(C₁₇H₂₀N₂S)₂]²⁺ (λ_max = 540 nm, ε = 8.8 × 10³ at 20 °C and pH = 2).The values for instability constants determined by Bjerrum's method amount to pK₁ = 3.95; pK₂ = 3.07; pβ₁ = 3.95; pβ₂ = 7.02, respectively.A colorimetric method of the determination of palladium(II) has been elaborated. The method consists in a measurement of the absorbance of the violet complex of palladium(II) with promazine hydrochloride at λ = 540 nm. The method permits the determination of 2–17 μg Pd/ml with an error of ±2%. The time of the determination is 20 min. Iron(III), Ce(IV), Pt(IV), V(V), Cr(VI), and HNO₃ interfere with the determination.     

[As(V)As(III)O6]: An uncommon anion group in the crystal structure of K2Cu3(As2O6)2

The crystal structure of K₂Cu₃(As₂O₆)₂ was determined from single-crystal X-ray data by a direct method strategy and Fourier summations [a = 10.359(4) Å, B = 5.388(2)Å, C = 11.234(4) Å, β = 110.48(2)°; space group C2/m; Z = 2; R_w = 0.025 for 1199 reflections up to sin /λ = 0.81 Å⁻¹]. In detail, the structure consists of As(V)O₄ tetrahedra and As(III)O₃ pyramids linked by a common O corner atom to [As(V)As(III)O₆]⁴⁻ groups with symmetry m. The bridging bonds As(V)---O [1.749(3) Å] and As(III)---O [1.838(2) Å] are definitely longer than the other As(V)---O bonds [mean 1.669 Å] and As(III)---O bonds [1.764(2) Å, 2×]. The angle As(V)---O---As(III) is 123.0(1)°. The Cu atoms are [4 + 2]- and [4 + 1]-, and the K atom is [9]-coordinated to oxygen atoms. The As₂O₆ groups and the Cu coordination polyhedra are linked to sheets parallel to (001). These sheets are connected by the K atoms. Single crystals of K₂Cu₃(As₂O₆)₂ suitable for X-ray work were synthesized under hydrothermal conditions.     

Molecular inclusion in calixarenes. XVIII. Crystal and molecular structure of thep-tert-butylcalix[7]arene 1 : 3 pyridine complex/clathrate

The structure of thep-tert-butylcalix[7]arene 1:3 pyridine complex/clathrate (C₇₇H₉₈O₇ · 3 C₅H₅N) has been determined by X-ray crystallography. The crystal data are as follows: monoclinic, space groupP2₁/c,a = 37.790(4),b = 9.423(2),c = 29.075(4)Å; = 112.74(2)°;V = 8285(3)ų;Z = 4;D _calc = 1.10 g·cm^–3. The hostp-tert-butylcalix[7]arene links one pyridine molecule through a hydrogen bond between one of the seven hydroxy groups and the nitrogen of the pyridine. Two other guest molecules have been found in the crystal lattice, so the title compound may be defined as a complex/clathrate hybrid. The unambiguous conformation of the macrocycle is described by an alternative method, which avoids the use of dihedral angles (and the ambiguities in their values).Part XVII. Ref. [2].     

Investigation of Protonation of the Tetraazamacrocyclic Complex of Gold(III) [Au(C14H22N4)]+ in Water. Synthesis and Crystal and Molecular Structures of [Au(C14H23N4)](ClO4)2

The equilibrium of protonation of tetraazamacrocyclic complex of gold(III) [AuL]⁺ (L = 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,6,11,13-tetraenato(2-)) in a water solution has been investigated. A monoprotonated tetraazamacrocyclic metallocomplex with two inequivalent (iminate and imine) six-membered chelate cycles and charge 1- was obtained and isolated for the first time. The compound [AuHL](ClO₄)₂ was characterized by chemical analysis, IR and UV-VIS spectroscopy, powder and single crystal X-ray diffraction. The proton was shown to be attached to the β-carbon of one of the two six-membered chelate rings of the macrocycle. Crystal data for [AuHL](ClO₄)₂ are: a = 7.693(1) Å, b = 17.366(2) Å, c =15.172(2) Å; β = 96.82(1)°, V = 2012.6(4) ų, Z = 4, d _calc = 2.123 g/cm³, space group P2₁/c. The structure is built from practically planar [Au(C₁₄H₂₃N₄)]²⁺ cations and perchlorate anions [ClO₄]⁻.Original Russian Text Copyright © 2004 by V. A. Afanasieva, I. V. Mironov, L. A. Glinskaya, R. F. Klevtsova, and L. A. Sheludyakova__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1059–1066, November–December, 2004.     

Fluorinated 1,3-diketones, 2-trifluoroacetyl phenols and their derivatives: versatile reactants in phosphorus chemistry

The role of fluorinated β-diketones, their tautomers (keto–enols) and their derivatives as reagents towards λ³P compounds is reviewed, including 2-trifluoroacetyl phenols, possessing formally a keto–enol system, and their derivatives. In an ‘insertion’ reaction phosphine and the keto–enol tautomers of 1,1,1,5,5,5-hexafluoro- and 1,1,1-trifluoropentan-2,4-dione furnished primary (S) or (R) α-hydroxy phosphines, whose enol functions probably isomerized the corresponding keto compounds. Further addition and isomerisation furnished 1,3α,5,7β-tetrakis(trifluoromethyl)-2-phospha-6-oxa-9-oxabicyclo[3.3.1]-nonan-3β,7α-diol and 1,7-trifluoromethyl-3,5-methyl-2,4,8-trioxa-6-phophaadamantane, exclusively one diastereomer in each case. The main mechanistic feature of these reactions is a consecutive diastereoselective hemiketal cyclization. 1,1,1,5,5,5-Hexafluoro- and 1,1,1-trifluoropentan-2,4-dione, as well as 2-trifluoroacetyl phenol and its imino derivatives reacted diastereospecifically with phosphonous acid dichlorides, RPCl₂ to give in a concerted mechanism thermally stable tricyclic λ⁵σ⁵P phosphoranes containing two five-membered rings and one six-membered ring. Surprisingly, the two CF₃ groups bonded to an sp³-hybridized carbon were in a cisoid arrangement having closest non-bonding FF distances of 301.4 or 273.5 pm. These findings reflect the ‘through space’ F---F coupling constants of the tricyclic phosphoranes (J_FF=4.0–7.0 Hz), in solution. 4,4,4-Trifluoro-3-hydroxy-1-phenyl-butan-1-one and methyl or phenyl phosphonous acid dichlorides gave similar tricyclic phosphoranes decomposing at ambient temperature to furnish 1,2λ⁵σ⁴-oxaphospholanes and (E)-1,1,1-trifluoro-4-phenyl-but-2-en-4-one. Dialkylphosphites and 1,1,1,5,5,5-hexafluoropentan-2,4-dione reacted to give either the (Z)-enol phosphonates or the respective γ-ketophosphonates from which in two cases four diastereomeric 2-oxo-2,5-dialkoxy-3,5-bis(trifluoromethyl)-3-hydroxy-1,2λ⁵σ⁴-oxa-phospholanes were obtained. 2-Trifluoroacetyl cyclohexanone, 4,4,4-trifluoro-3-trimethylsiloxy-1-phenylbutan-1-one, 1-benzoyl-2-trifluormethyloxirane, 1-benzoyl-2-trifluoro-methylaziridine, 2-trifluoroacetyl-1-trimethylsiloxybenzene and (trifluoroacetyl-1-phenyl) diethyl phosphate reacted with tris(trimethylsilyl) phosphite to give functionalized α-trimethylsiloxy phosphonates, which could easily be transferred into the respective phosphonic acids. In the case of an oxirane and an aziridine ketone no ring cleavage was observed. For 1,1′-(2-hydroxy-5-methyl-m-phenylene)-bis-ethanone and 1,1′-(2-trimethylsiloxy-5-methyl-m-phenylene)-bis-ethanone benzoxaphospholanes were obtained. Trialkyl phosphites and 1,1,1,5,5,5-hexafluoropentan-2,4-dione furnished cyclic phosphoranes containing the 3-hydroxy-3,5-bis(trifluoromethyl)-1,2λ⁵σ⁵-oxaphospholene structural element, stable at ambient temperature only in the case of one cyclic phosphite precursor. (E)-1,1,1-Trifluoro-4-phenyl-but-2-en-4-one and trimethylphosphite reacted to form 1,2λ⁵σ⁵-oxaphosphol-4-ene as the sole product. Results similar to the reaction of 1,1′-(2-hydroxy-5-methyl-m-phenylene)-bis-ethanone with diethyltrimethylsilylphosphite were obtained for trimethylphosphite and 2-trifluoroacetyl phenol where a deoxygenated phosphorane was found, easily hydrolyzed to give the respective phosphonic acid. With dialkylisocyanato phosphites and the keto components, 1,1,1,5,5,5-hexafluoro- and 1,1,1-trifluoropentan-2,4-dione, 4,4,4-trifluoro-1-phenyl-1,3-butandione, 2-trifluoroacetyl cyclohexanone, 2-trifluoroacetyl phenol and 1,1′-(2-hydroxy-5-methyl-m-phenylene)-bis-ethanone reacted in a ‘double’ cycloaddition to form bicyclic phosphoranes containing the 4,8-dioxa-2-aza-1λ⁵σ⁵-phosphabicyclo[3.3.0]-oct-6-en-3-one ring system; for the imino derivatives of 2-trifluoroacetyl phenol a corresponding 8-oxa-2,4-diaza- system was generated. For (E)-1,1,1,5,5,5-hexafluoro-4-trimethylsiloxy-3-penten-2-one however, a cyclic spiroimino phosphorane was obtained which underwent a [2+2] cyclodimerization to form a diazadiphosphetidine. Dimethylpropynyl phosphonite and 1,1,1,5,5,5-hexafluoropentan-2,4-dione yielded diastereoselectively a bisphosphorane, namely 1,4-bis(trifluoromethyl)-3,6-dioxa-2,2,7,7-tetramethoxy-2,7-di(1-propynyl)-2,7-diphosphabicyclo[2.2.1] heptane. When trimethylsilanyl–phosphenimidous acid bis-trimethylsilanyl–amide, Me₃SiN=PN(SiMe₃)₂, was allowed to react with 1,1,1,5,5,5-hexafluoro- and 1,1,1-trifluoropentan-2,4-dione, (E)-1,1,1,5,5,5-hexafluoro-4-trimethylsiloxy-3-penten-2-one, 2-trifluoroacetyl cyclopentanone, 2-trifluoroacetyl phenol and its imino derivatives, 2-imino-1,2λ⁵σ⁴-oxaphospholenes were found containing two diastereomers in each case, which added hexafluoroacetone across the P=N bond to give 1,3,2λ⁵σ⁵-oxazaphosphetanes.     

Substitutions of organopalladium(II) species with benzimidazole derivatives

The [Pd(cod)(cotl)]ClO₄ complex (cod = cycloocta-1,5-diene; cotl = cyclooctenyl, C₁₈H₁₃ ^–) undergoes substitutions with new Schiff base ligands containing benzimidazole L [L = 2-(2-N-n-propylidenephenyl)benzimidazole (L¹); 2-(2-N-i-propylidenephenyl)benzimidazole (L²); 2-(2-N-n-butylidenephenyl)benzimidazole (L³); 2-(2-N-i-butylidenephenyl)benzimidazole (L⁴)]. Facile displacement of cod by L occurs to produce complexes of the type [Pd(cotl)L]ClO₄· nMe₂CO (n= 0; L = L¹, L² or L³; n= 2, L = L⁴). Dihalobridge complexes of the type [Pd(cotl)X]₂(X = Cl or Br) undergo halogen-bridge cleavage with L¹–L⁴ to give mononuclear complexes of the type Pd(cotl)LX · nH₂O (n= 2, X = Cl, L = L¹; n= 0, X = Br, L = L¹; n= 0, X = Cl, L = L²; n= 0, X = Cl or Br, L = L³; n= 0, X = Cl, L = L⁴; n= 2, X = Br, L = L⁴) and a binuclear complex [Pd(cotl)Br]₂L². The complexes were characterised by physical properties, i.r., ¹H- and ¹³C-n.m.r. spectral techniques and by mass spectra. Probable structures have been proposed.     

[RhCl(CO)(PPh3)]2. A precursor for the synthesis of cationic rhodium complexes with nitrogen donor ligands

Summary The use of [RhCl(CO)(PPh₃)]₂ as a precursor for the synthesis of complexes of the types [Rh(CO)L₂(PPh₃)]A (A = [ClO₄]^– or [BPh₄]^–; L = pyridine type ligand) and [Rh(CO)(L-L)(PPh₃)]A (A = [ClO₄]^– or [BPh₄]^–; L-L = bidentate nitrogen donor) and the preparation of several complexes of the types [Rh(CO)L(PPh₃){P(p-RC₆H₄)₃}]BPh₄ and [Rh(CO)(phen)(PPh₃){P(p-RC₆H₄)₃}]A (A = [ClO₄]^– or [BPh₄]^–; R = H or Me) is described.Author to whom all correspondence should be directed.     

Electrochemical synthesis and magnetic studies of neutral transition metal imidazolates and pyrazolates

Summary The single-step electrochemical synthesis of neutral transition metal complexes of imidazole, pyrazole and their derivatives has been achieved at ambient temperature. The metal was oxidized in an Me₂CO solution of the diazole to yield complexes of the general formula: [M(Iz)₂] (where M = Co, Ni, Cu, Zn; Iz = imidazolate); [M(MeIz)₂] (where M = Co, Ni, Cu, Zn; MeIz = 4-methylimidazolate); [M(PrⁱIz)₂] (where M = Co, Ni, Cu, Zn; PrⁱIz = 2-isopropylimidazolate); [M(pyIz)_n] (where M = Co^III, Cu^II, Zn^II; pyIz = 2-(2-pyridyl)imidazolate); [M(Pz)_n] (where M = Co^III, Ni^II, Cu^II, Zn^II; Pz = pyrazolate); [M(ClPz)_n] and [M(IPz)_n] (where M = Co^III, Ni^II, Cu^II, Zn^II; ClPz = 4-chloropyrazolate; IPz = 4-iodopyrazolate); [M(Me₂Pz)_n] (where M = Co^II, Cu^I, Zn^II; Me₂Pz = 3,5-dimethylpyrazolate) and [M(BrMe₂Pz)_n] (where M = Co^II, Ni^II, Cu^I, Zn^II; BrMe₂Pz = 3,5-dimethyl-4-bromopyrazolate). Vibrational spectra verified the presence of the anionic diazole and electronic spectra confirmed the stereochemistry about the metal centre. Variable temperature (360-90 K) magnetic measurements of the cobalt and copper chelates revealed strong antiferromagnetic interaction between the metal ions in the lattice. Data for the copper complexes were fitted to a Heisenberg (S= ) model for an infinite one-dimensional linear chain, yielding best fit values of J=–62––65cm^–1 andg = 2.02–2.18. Data for the cobalt complexes were fitted to an Ising (S= ) model with J=–4.62––11.7cm^–1 andg = 2.06–2.49.     

Three new copper(II)–nickel(II) heterodinuclear complexes with the <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N′</Emphasis>-bis(2-pyridyl-ethyl)oxamide dianion. Syntheses,spectra, and magnetic properties

Three new Cu(II)–Ni(II) heterodinuclear complexes: [Cu(PMoxd)Ni(phen)₂](ClO₄)₂ (1), [Cu(PMoxd)Ni(NO₂-phen)₂](ClO₄)₂ (2), [Cu(PEoxd)Ni(Me₂-bpy)₂](ClO₄)₂ (3), [where Cu(PMoxd)=N,N′-bis(pyridyl-methyl)oxamidatocopper(II), Cu(PExod)=N,N′-bis(2-pyridyl-ethyl)oxamidatocopper(II), phen=1,10-phenanthroline and NO₂-phen=5-nitro-1,10-phenanthroline and bpy=2,2′-bipyridine] were prepared and characterized by i.r. and electronic spectra, and by magnetic properties. The magnetic analysis was carried out by means of the theoretical expression of the magnetic susceptibility deduced from the spin Hamiltonian H=−2JS₁S₂, leading to J=−70.83 cm⁻¹ (1); −56.23 cm⁻¹ (2); −57.30 cm⁻¹ (3), indicating a weak antiferromagnetic spin–exchange interaction between Cu(II) and Ni(II) ions within three complexes.     

Chloroaqua Complexes [M3S4(H2O)9?xClx](4?x)+ (M = Mo, W; x = 4, 6, 7) and Their Supramolecular Compounds with Cucur[8]uril

Compounds of trigonal cluster chloroaqua complexes with cucurbit[8]uril were synthesized by slowly evaporating HCl solutions of chalcogenides heterometallic cubane cluster complexes of molybdenum and tungsten with cucurbit[8]uril in air; the complexes were characterized by X-ray diffraction analysis: (H₃O)₈[Mo₃S₄(H₂O)_2.5Cl_6.5]₂Cl(PdCl₄)·(C₄₈H₄₈N₃₂O₁₆)· 29H₂O (a = 13.3183(17) Å, b = 13.7104(18) Å, c = 18.225(3) Å; α = 80.263(3)°, β = 77. 958(3)°, γ = 87.149(4)°, V = 3207.4(7) ų, space group P , Z = 1, ρ(calc) = 1.900 g/cm³), (H₃O)₄ [Mo₃S₄(H₂O)₃Cl₆]₂·(C₄₈H₄₈N₃₂O₁₆)₃·68H₂O (a = 21.413(6) Å, c = 49.832(10) Å; γ = 120°, V = 19788(8) ų, space group R , Z = 3, ρ(calc) = 1.695 g/cm³), (H₃O)₆ [Mo₃S₄(H₂O)₃Cl₆]₂Cl₂·(C₄₈H₄₈N₃₂O₁₆)·12H₂O (a = 15.881(2) Å, b = 17.191(2) Å, c = 23.276(4) Å; β = 98.865(15)°, V = 6278.7(15) ų, space group P2₁/c, Z = 2, ρ(calc) = 1.638 g/cm³), [W₃S₄(H₂O)₅Cl₄]₂·(C₄₈H₄₈N₃₂O₁₆)₃·35H₂O (a = 21.038(3) Å; α = 61.20(1)°, V = 6762.0(14) ų, space group R , Z = 1, ρ(calc) = 1.582 g/cm³). The [Mo₃S₄(H₂O)₃Cl₆]²⁻ anion complex was isolated as three geometrical isomers.Original Russian Text Copyright © 2004 by E. V. Chubarova, D. G. Samsonenko, H. G. Platas, F. M. Dolgushin, A. V. Gerasimenko, M. N. Sokolov, Z. A. Starikova, M. Yu. Antipin, and V. P. Fedin__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 6, pp. 1049–1058, November–December, 2004.     

The crystal and molecular structure of potassium aquapentachloroiridate(III) and the H, C, N NMR coordination shifts in iridium(III) chloride complexes with 2,2′-bipyridine or 1,10-phenanthroline

The crystal and molecular structure of potassium aquapentachloroiridate(III) (K₂[Ir(H₂O)Cl₅]) was reported. The [Ir(H₂O)Cl₅]²⁻ anions are nearly octahedral, the axial Ir–Cl bond (2.322(2) Å) being shorter than the equatorial ones (2.346(2)–2.360(2) Å); the Ir–O bond length is 2.090(4) Å. Ir(III) chloride complexes with 2,2′-bipyridine (LL = bpy) or 1,10-phenanthroline (LL = phen), of the general formulae K[Ir(LL)Cl₄] and cis-[Ir(LL)₂Cl₂]Cl, were studied by far-IR and ¹H–¹³C, ¹H–¹⁵N HMBC/HMQC/HSQC–NMR. High-frequency ¹H NMR coordination shifts (Δ^1H_coord = δ^1H_complex − δ^1H_ligand; max. ca. +1 ppm) were noted for [Ir(LL)Cl₄]⁻ anions, while for cis-[Ir(LL)₂Cl₂]⁺ cations they had variable sign and magnitude (max. ca. ±1 ppm); they were dependent on the proton position, being mostly expressed for the nitrogen-adjacent hydrogens (H(6) for bpy, H(2) for phen). ¹³C NMR signals were high-frequency shifted (by max. ca. 8 ppm), whereas all ¹⁵N nuclei were shifted to the lower frequency (by ca. 105–120 ppm). The experimental ¹H, ¹³C, ¹⁵N NMR chemical shifts were reproduced by semi-empirical quantum-chemical calculations (B3LYP/LanL2DZ+6-31G^**//B3LYP/LanL2DZ+6-31G*).     

基于2,5-噻吩二甲酸的钙(Ⅱ)和钡(Ⅱ)配位聚合物的合成、晶体结构及性质

在溶剂热条件下,合成了2个碱土金属配位聚合物[Ca (tdc)(DMF)₂]_n(1)和[Ba (tdc)]_n(2)(H₂tdc=2,5-噻吩二甲酸),分别用元素分析、红外光谱、X射线单晶衍射、粉末衍射、热重分析和荧光光谱对它们进行了表征。结构分析表明,配合物1具有4,4连接的二维层状结构,拓扑符号为(4⁴·6²),而配合物2呈现三维网络结构。固体荧光测试表明配合物1比配合物2具有更显著的荧光性能。     

Vibrational spectroscopy and solid-state MAS NMR studies of mercury(II) acetate complexes [Hg(X)OAc]: Crystal structure of [Hg(CN)OAc]

The syntheses of [Hg(X)OAc] (OAc=acetate; X=CN, Cl, Br, I, SCN) are reported, and the crystal structure of the cyano complex has been determined. The asymmetric unit contains two [Hg(CN)OAc] molecules which show almost linear C–Hg–O bonding (Hg–C=2.019(13), 2.016(11) Å; Hg–O=2.067(9), 2.058(8) Å; C–Hg–O=176.0(4), 172.3(5)°), with only one of the two acetate oxygen atoms bound directly to the mercury atom. Secondary HgO and HgN contacts in the range 2.6–2.8 Å are about 0.2 Å shorter than the secondary HgO contacts in the corresponding X=Ph complex. The ν(HgX) and ν(HgO) modes have been assigned in the IR and Raman spectra of [Hg(X)OAc] (X=CN, Cl, Br, I, SCN); these spectra show that the complexes have structures with essentially linear O–Hg–X bonding, similar to that of the cyanide. Solid-state ¹⁹⁹Hg MAS NMR spectra have been recorded for HgX₂ (X=CN, Cl) and [Hg(X)OAc] (X=Me, Ph, CN, Cl, SCN), and spinning sideband analysis has been used to determine the ¹⁹⁹Hg shielding anisotropy and asymmetry parameters Δσ and η. A semi-empirical method for the calculation of the local paramagnetic contribution to the shielding is given, and a linear relationship between Δσ and the isotropic shielding σ_iso which is predicted by this model for linear HgXY species is found to be obeyed reasonably well by the experimental data for HgX₂ and [Hg(X)OAc]. The same method is used to analyse the effects of secondary bonding on the ¹⁹⁹Hg shielding parameters. The ¹³C MAS NMR spectrum of [Hg(SCN)OAc] shows ²J(¹⁹⁹Hg¹³C) and ³J(¹⁹⁹Hg¹³C) coupling to the acetate carbon atoms, with magnitudes similar to those found previously for Hg(OAc)₂. The CN carbon signals in Hg(CN)₂ and [Hg(CN)OAc] are split into 2:1 doublets due to residual dipolar coupling to the quadrupolar ¹⁴N nucleus.     

金属离子导向自组装的磺酰化对氨基苯甲酸配合物的合成与表征

用普通溶液法合成了4个配合物:[Cu(Ts-p-aba)2(phen)(H2O)]n(1)、[Zn(Ts-p-aba)2(phen)(H2O)]·H2O(2)、[Pb(Ts-p-aba)2(phen)]2(3)和{[Pb(Ts-p-aba)(phen)(NO3)](DMF)}n(4)(Ts-p-aba=N-对甲苯磺酰对氨基苯甲酸,phen=菲咯啉,DMF=N,N-二甲基甲酰胺)。X-射线单晶衍射结果表明:配合物1和2均为三斜晶系,P1空间群。配合物1的中心铜离子处于变形的八面体配位环境,并通过配体N-对甲苯磺酰对氨基苯甲酸扩展为一维直线链结构;配合物2是个单核分子,锌离子的配位多面体为四角锥体。配合物3和4均为单斜晶系,P21/c空间群。配合物3由配体N-对甲苯磺酰对氨基苯甲酸桥联成二聚体,铅离子处于变形的八面体配位环境;配合物4是具有一维链状结构的配位聚合物,铅离子处于变形的一面心八面体配位环境。另外,对4个配合物的热稳定性、电化学性能和荧光性质也进行了研究。     

Spectrofluorometric determination of hesperidin by manual and flow-injection methods

A reliable and highly sensitive method for the determination of hesperidin is described. It involves the formation of a highly fluorescent complex between hesperidin and aluminium (III) in a micellar medium. There is a linear relationship between fluorescence intensity (λ_em = 496 nm, λ_ex = 391 nm) and hesperidin concentration over the range 5 × 10^–7– 2 × 10^–5 mol L^–1. The detection limit is 79 μg L^–1. The method can easily be adapted to a flow system using a three-channel manifold, the peak height being proportional to the hesperidin concentration over the range 1 × 10^–6– 1 × 10^–4 mol L^–1. Manual and flow-injection procedures have been successfully applied to the determination of hesperidin in orange peel and orange juice. Received: 21 October 1998 / Revised: 16 December 1998 / Accepted: 25 December 1998     

Mixed-Ligand Complexes of Ni(i-Bu2PS2)2 with 4-Aminopyridine. Structure of [Ni(4-NH2Py)(i-Bu2PS2)2]

Mixed-ligand complexes [Ni(4-NH₂Py) (i-Bu₂PS₂)₂] (I) and Ni(4-NH₂Py)₂(i-Bu₂PS₂)₂ (II) have been synthesized. Single crystals were grown and X-ray diffraction data (CAD-4 diffractometer, Mo_{K α} radiation, 1477 F _hkl , R = 0.0320) were used to determine the structure of I. The crystals are orthorhombic: a = 10.675(1) Å; b = 21.681(2) Å; c = 26.302(4) Å, V = 6087.5(12) ų, Z = 8, ρ(calc) = 1.247 g/cm³, space group Pbca. Complex I possesses a mononuclear molecular structure. The coordination polyhedron of the Ni atom is a tetragonal pyramid NS₄ whose base is formed by four S atoms of two cyclic bidentate ligands i-Bu₂PS ₂ ⁻ and the axial position is occupied by the N atom of the 4-NH₂Py cycle. According to electron spectroscopy data, complex II has an octahedral N₂S₄ environment of the Ni atom.Original Russian Text Copyright © 2004 by T. E. Kokina, L. A. Glinskaya, E. A. Novoselova, R. F. Klevtsova, and S. V. Larionov__________Translated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 5, pp. 899–904, September–October, 2004.     

Synthesis and characterization of a complex salt and heterobimetallic coordination polymers of 1-benzoyl-1-cyanoethylene-2,2-dithiolate

The complex salt (NBu₄ⁿ)₂ [Cu(bcd)₂] and heterobimetallic coordination polymers MM′(bcd)₂ [M=2Ag^I, Cd^II, Hg^II or Pb^II; M′=Ni^II or Cu^II; bcd²⁻=1-benzoyl-1-cyanoethylene-2,2-dithiolate] have been synthesized from the reaction of Na₂[M′(bcd)₂] generated in situ with NBu₄ⁿBr or metal salts MX₂ [X=MeCO₂⁻, NO₃⁻, Cl⁻ or SO₄²⁻]. The complexes were characterized by elemental analyses, molar conductance, magnetic susceptibility, i.r., n.m.r., electronic and e.s.r. spectra and solid-state conductivity measurements. The MCu(bcd)₂ polymers are diamagnetic, suggesting strongly antiferromagnetically coupled Cu^II ions. The conductivities of the pressed pellets of the compounds are very small and they do not show semiconducting behaviour in the considered temperature range.*Presented at the 10th Symposium on Modern Trends in Inorganic Chemistry (MTIC-X), December 15–17, 2003, Indian Institute of Technology, Mumbai, India.     

新型荧光试剂1,5-二(4,6-二氯三嗪)-氨基萘与酪氨酸相互作用

合成了一种新型三嗪荧光探针1,5-二(4,6-二氯三嗪)-氨基萘并利用元素分析、IR和核磁共振谱进行了表征。在pH=12.0的柠檬酸钠-NaOH缓冲溶液中,与酪氨酸在35℃下反应30 min后,λex/λem=400 nm/465 nm处,1,5-二(4,6-二氯三嗪)-氨基萘与酪氨酸反应使体系的荧光强度增强,且增强的荧光强度与酪氨酸的浓度成正比,依此建立了一种测定酪氨酸的新方法。测定的线性范围是1.1×10-7~1.1×10-5mol/L,检出限为6.8×10-8mol/L。该方法成功用于测定人尿和血清样品中的酪氨酸。