Synthesis and properties of ms- and β-substituted Pt(II) and Pt(IV) tetraphenylporphyrinates

The interaction of 5,10,15,20-tetraphenylporphyrin, 5,10,15,20-tetra-(4-chlorophenyl)porphyrin, 2-bromo-5,10,15,20-tetraphenylporphyrin, and 2,3,12,13-tetrabromo-5,10,15,20-tetraphenylporphyrin with platinum(II) chloride in boiling phenol has been studied. The corresponding platinum(II) porphyrinates have been synthesized; their subsequent treatment with bromine in chloroform resulted in platinum(IV) porphyrinates. The Pt(II) and Pt(IV)(Br)₂ porphyrinates have been identified by elemental analysis, electron absorption, IR, and ¹H NMR spectroscopy.     

Preparation and characterization of octacyanomolybdates(IV and V) and octacyanotungstates(IV and V) with 2,2′-bipyridylium cation

Reaction of protonated 2,2′-bipyridine (bpy) with octacyanometalates(IV and V), [M(CN)₈]ⁿ⁻ (M = Mo or W, n = 3 or 4), gave the following complexes: {(bpyH)₃[M(CN)₈]·4H₂O}, {(bpyH)₃(H₃O)[M(CN)₈]·H₂O}, {(bpyH₂)₂[W(CN)₈]·3H₂O} and {(bpyH₂)K₂[W(CN)₈]·2H₂SO₄·7H₂O}. These salts were characterized by electron absorption and reflectance spectrometry, IR, Raman and ESR spectrometry, thermo gravimetry and differential thermal analysis, cyclic voltammetry and potentiometry. The solubility of the salts in water and some polar organic solvents has been measured. The intensively coloured salts of molybdenum(IV) and tungsten(IV) have been discussed in terms of the bpyH⁺-[M(CN)₈]⁴⁻ ion pairs, which exhibit an outer-sphere electron transfer between adjacent redox sites.     

Crystal Structures and Characterizations of Bis(pyrrolidinedithiocarbamato) Cu(II) and Zn(II) Complexes

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Trichloro- and triisopropoxy-niobium(V) and tantalum(V) bis -( O,O ′-alkylene dithiophosphates): synthesis and characterization

Trichloro- and triisopropoxy-niobium(V) and tantalum(V) alkylene dithiophosphates, (M = Nb(V) or Ta(V); G =–CHMeCHMe–,–CMe₂CMe₂–,–CH₂CMe₂CH₂–,–CH₂CEt₂CH₂–or–CMe₂CH₂CHMe–and X = Cl or OPrⁱ) have been synthesized by reaction of metal(V) chloride, MCl₅, or triisopropoxymetal(V) dichloride, (PrⁱO)₃MCl₂, with the sodium salts of O,O′-alkylene dithiophosphoric acids, in 1 : 2 molar ratio in THF under anhydrous conditions. These pink-purple or light-yellow compounds are viscous, semi-solid or solid, hydrolyzable and soluble in common organic solvents. These compounds have been characterized by elemental analyses, molecular weight determinations and spectral studies like IR and heteronuclear NMR (¹H, ¹³C and ³¹P), which indicated a bidentate mode of chelation of dithio ligands, leading to a pentagonal bipyramidal geometry around the niobium(V) or tantalum(V) centers.     

α-hydroaxyalkyl(benzyl)furozans and α-hydroxyalkyl(benzyl)furoxans synthesis and reactivity

A general and simple preparative method for the synthesis of -hydroxyalky(benzyl)furazan and -furoxan derivatives is proposed, The method involves reduction of acyl or ethoxycarbonyl substituents in these heterocyclic compounds with NaBH₄ in ethanol. Based on the alcohols thus prepared, a number of previously unknown functional derivatives (-nitroxyalkyl--haloalkyl-, and -azidoalkylfurazans and -furoxans) have been synthesized.Translated fromInvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7. pp, 1782–1788, July, 1996.     

Solvatochromism and piezochromism of pentacyanoferrates(II) and of mixed valence iron(II)—iron(III) and ruthenium(II)—ruthenium(III) species

Pressure effects on the MLCT bands of the pyrazine- and 4-cyanopyridine-pentacyanoferrate(II) anions have been established. The relation of these piezochromic effects to the solvatochromism of each complex is put into the correlation between these parameters developed for other d⁶ ternary complexes. The conformance of piezochromic and solvatochromic efrects on MMCT bands for diiron and diruthenium mixed valence complexes to this correlation is examined.     

Synthesis and Characterization of Chlorobis(cyclopentadienyl) Titanium(IV) and Zirconium(IV) O,O’-Dialkyl and Alkylene Dithiophosphates

Abstract

Reactions of O,O′-dialkyl and alkylene dithiophosphoric acids with bis (cyclopentadienyl) titanium(IV) and zirconium (IV) dichloride in a 1:1 molar ratio in refluxing benzene proceeds with elimination of HCl and formation of the substituted derivatives, Cp₂MCl[S₂P(OR)₂] (where R = Et, Pr-n, Pr-i, Bu-i and Ph), Cp₂MCl[S₂POGO] (where G = ?CH₂CMe₂CH₂?, ?CH₂CEt₂CH₂? and ?CMe₂CMe₂?), (M = Ti and Zr). The complexes are dark red and yellow solids, soluble in common organic solvents and monomeric in nature. These have been characterized on the basis of elemental analyses, molecular weight determinations, IR, and NMR (¹H, ¹³C, and ³¹P).

GRAPHICAL ABSTRACT      

Determinations of combustion and formation enthalpies of C_(60)and C_(70)

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Calcium and strontium,and zinc (phenazine)−· species

Calcium and strontium react with phenazine in tetrahydrofuran (THF) at ca 20 ° C to yield red solutions containing paramagnetic species based on (phenazine)⁻· (ESR characterization). Zinc reacts in THF in the presence of zinc chloride or bromide, or without metal halide in pyridine, to yield green or red ESR-active solutions also based on (phenazine)⁻·, and then, for the reaction in pyridine, a brown paramagnetic solid of composition Zn(phenazine)(pyridine)₂.     

Enzymatic resolution of (±)-cis- and (±)-trans-1-aminoindan-2-ol and (±)-cis- and (±)-trans-2-aminoindan-1-ol

Pseudomonas cepacia lipase (PSL) efficiently catalyses the kinetic resolution of (±)-cis- and (±)-trans-1-aminoindan-2-ol through the O-acylation reaction of the corresponding N-benzyloxycarbonyl derivative using vinyl acetate as the acyl donor. In a similar way, cis-N-Cbz-2-aminoindan-1-ol is resolved when isopropenyl acetate is used as the acylating agent. The enantioselectivity of the reaction was lower for (±)-trans-N-Cbz-2-aminoindan-1-ol due to the different steric requirements for the two conformers of this substrate.     

Synthesis and Structural Studies of Some β-Diketone Phenylhydrazones and their Complexes with Co(II), Ni(II), and Cu(II)

Summary.  New β-diketone phenylhydrazones prepared by condensation of substituted 3-arylidene-2,4-pentanediones with phenylhydrazine, have been characterized by their elemental analyses, IR, ¹H NMR, and mass spectra. Some complexes of these Schiff bases with Co(II), Ni(II), and Cu(II) ions have been synthesized; in addition to the above methods, their structures were studied by magnetic susceptibility and thermogravimetry measurements. Received January 26, 2000. Accepted (revised) April 14, 2000     

Syntheses and Crystal Structures of Cd(Ⅱ) and Ni(Ⅱ) Complexes Containing Flexible Sulfide and Nitrogen Heterocyclic Ligands

Two new coordination polymers [Cd(EBLA)(ip)(H2O)](1) and [Ni(EBSA)(im)2(H2O)]n(2) were synthesized by hydrothermal and solution methods using 2,2'-dithiosalicylicacid(EBSA), 1H-imidazo[4,5-f][1,10]phenanthroline(ip), imidazole(im), Cd(NO3)2·4H2O and Ni(NO3)2·6H2O. The complexes were characterized by elemental analysis and FT-IR. Meanwhile, the crystal structures, fluorescence properties of complex 1 and thermogravimetrie analysis of complex 2 have been studied. In complex 1, 2,2'-dicarboxydiphenylthioether(EBLA) was prepared with 2,2'-dithiosalicylicacid(EBSA) in situ reaction by hydrothermal method. Complex 1 is a dinuclear structure and Cd2+ is five-coordinated in a distorted trigonal bipyramidal geometry. Complex 2 is a one-dimensional infinite linear chain and Ni2+ is six-coordinated to form a distorted octahedral geometry. Hydrogen bonding and π-π interactions are observed in these complexes.     

Simultaneous speciation of arsenic (As(III), MMA, DMA, and As(V)) and selenium (Se(IV), Se(VI), and SeCN−) in petroleum refinery aqueous streams

High-performance liquid chromatography (HPLC) coupled to an ICP-MS with an octapole reaction system (ORS) has been used to carry out quantitative speciation of selenium (Se) and arsenic (As) in the stream waters of a refining process. The argon dimers interfering with the ⁷⁸Se and ⁸⁰Se isotopes were suppressed by pressurizing the octapole chamber with 3.1 mL min⁻¹ H₂ and 0.5 mL min⁻¹ He. Four arsenic species arsenite—As(III), arsenate (As(V)), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA)—and three inorganic Se species—selenite Se(IV), selenate Se(VI), and selenocyanate (SeCN⁻)—were separated in a single run by ion chromatography (IC) using gradient elution with 100 mmol L⁻¹ NH₄NO₃, pH 8.5, adjusted by addition of NH₃, as eluent. Repeatabilities of peak position and of peak area evaluation were better than 1% and about 3%, respectively. Detection limits (as 3σ of the baseline noise) were 81, 56, and 75 ng L⁻¹ for Se(IV), Se(VI), and SeCN⁻, respectively, and 22, 19, 25, and 16 ng L⁻¹ for As(III), As(V), MMA, and DMA, respectively. Calibration curve R ² values ranged between 0.996 and 0.999 for the arsenic and selenium species. Column recovery for ion chromatography was calculated to be 97 ± 6% for combined arsenic species and 98 ± 3% for combined selenium species. Because certified reference materials for As and Se speciation studies are still not commercially available, in order to check accuracy and precision the method was applied to certified reference materials, BCR 714, BCR 1714, and BCR 715 and to two different refinery samples—inlet and outlet wastewater. The method was successfully used to study the quantitative speciation of selenium and arsenic in petroleum refinery wastewaters.     

99mTc labeled ethylene-bis (valine) and ethylene-bis (α-alanine) and their preliminary biobistribution

The preparation of^99mTc-Sn-EBV and^99mTC-Sn-EBA is described. Different parameters affecting the labeling efficiency (ligand concentration, pH, molar ligand: reducing agent ratio) as well as the time-dependent stability of labeled compounds were investigated. Preliminary biodistribution studies in Wistar rats showed accumulation of the above mentioned compounds in kidneys.     

Structures and Spectroscopic Properties of(1)Dipyridine Quinoxaline with Hg(Ⅱ), Cu(Ⅰ) and Ag(Ⅰ)

The interaction of Hg(Ⅱ), Cu(Ⅰ) and Ag(Ⅰ) with dipyridine quinoxaline ligand 2,3-bis(2-pyridyl)quinoxaline(DPQ) were investigated, and three new complexes have been synthesized and characterized. Complex 1 exhibits a 0D dual-core structure, complex 2 is a 0D tetra nuclear case based on a dual-core Cu unit, and complex 3 shows a one-dimensional pipeline structure. Furthermore, the optical properties of complex and DPQ were also investigated, and the results showed that the fluorescence intensity of complexes was weaker than that of ligand DPQ.     

Complexation between decamethyl-3,3′-bis(dipyrrolylmethene) and zinc(II), copper(II), and cobalt(II) acetates

Decamethyl-3,3′-bis(dipyrrolylmethene) dihydrobromide H₂L · 2HBr (H₂L is bis(3,4,7,8,9-pentamethylpyrrol-3-yl)methane), which is the simplest representative of a novel class of oligo(dipyrrolylmethenes) belonging to chromophore chelating nonmacrocyclic ligands, were examined by ¹H NMR, IR, and electronic absorption spectroscopy. Complexation reactions of H₂L · 2HBr with M(AcO)₂ (M = Zn(II), Cu(II), and Co(II)) in DMF at 298.15 K were monitored by electronic absorption spectroscopy and studied by the molar ratio method. The thermodynamic constants K ⁰ of these reactions were estimated. The d metal ions coordinate H₂L to give the binuclear homoleptic complexes [M₂L₂]. The reactions proceed through the intermediate binuclear heteroleptic complex [M₂L(AcO)₂] detected by spectroscopic methods. The thermodynamic stabilities of [M₂L₂] and [M₂L(AcO)₂] increase when moving from Cu(II) to Zn(II) and Co(II). The probability of formation and stability of [M₂L₂] containing 3,3′-bis(dipyrrolylmethene) are substantially higher than those of analogous complexes with the 2,2′-isomer (decamethyl-2,2′-biladienea, c). The low K ⁰ values for the complexation between H₂L and Cu(AcO)₂ are due to slow oxidation of the biladiene ligand into a bilatriene with participation of Cu²⁺ ions.     

Luminescence and energy transfer of Ce~(3+) and Dy~(3+) in BaLaB_9O_(16)

Under the excitation of UV light, the composition dependence of luminescence properties of Ce3+ and Dy3+ in BaLaB9O16 has been studied. The mechanisms of energy transfer from Ce3+ to Dy3+ and of concentration quenching of Dy3+ emission under the excitation of UV light have been presented as well.     

Intensity-tunable micelles and films containing bimetal ions—europium(III) and terbium(III)

In this paper, multicolored micelles were prepared by coordination of lanthanide(III) (europium(III) (Eu(III)) and terbium(III) (Tb(III))) ions with block copolymer in different molar ratios of n _Eu(III)/n _Tb(III). The micelles formed by polymer–Eu(III)/Tb(III) could emit higher quantum yield luminescence than the mixture of polymer–Eu(III) micelles and polymer–Tb(III) micelles. The micelles containing Eu(III) and Tb(III) could emit a yellow-green color, and the intensity varied with the molar ratios of n _Eu(III)/n _Tb(III). In the constant concentrations of Eu(III) and 1,10-phenanthroline (Phen), the intensity of ⁵D₀→⁷F₂ increased with the addition of Tb(III), and the intensity of ⁵D₄→⁷F₅ decreased with the increasing of Eu(III) in the constant concentrations of Tb(III) and Phen. All the multicolored micelles could be spin-coated as intensity-tunable films.     

Planar tetranuclear Dy(III) single-molecule magnet and its Sm(III), Gd(III), and Tb(III) analogues encapsulated by salen-type and β-diketonate ligands

The syntheses, structures, and magnetic properties are reported for four new lanthanide clusters [Sm(4)(μ(3)-OH)(2)L(2)(acac)(6)]·4H(2)O (1), [Gd(4)(μ(3)-OH)(2)L(2)(acac)(6)]·4CH(3)CN (2), and [Ln(4)(μ(3)-OH)(2)L(2)(acac)(6)]·2H(2)L·2CH(3)CN (3, Ln = Tb; 4, Ln = Dy) supported by salen-type (H(2)L = N,N'-bis(salicylidene)-1,2-cyclohexanediamine) and β-diketonate (acac = acetylacetonate) ligands. The four clusters were confirmed to be essentially isomorphous by infrared spectroscopy and single-crystal X-ray diffraction. Their crystal structures reveal that the salen-type ligand provides a suitable tetradentate coordination pocket (N(2)O(2)) to encapsulate lanthanide(III) ions. Moreover, the planar Ln(4) core is bridged by two μ(3)-hydroxide, four phenoxide, and two ketonate oxygen atoms. Magnetic properties of all four compounds have been investigated using dc and ac susceptibility measurements. For 4, the static and dynamic data indicate that the Dy(4) complex exhibits slow relaxation of the magnetization below 5 K associated with single-molecule magnet behavior.     

Synthesis, Characterization and Antimicrobial Activity of Potassium Hydro(benzoyl)(phthalyl)borate and Its Cobalt(II), Nickel(II), and Copper(II) Complexes

A new organoborate ligand, hydro(benzoyl)(phthalyl)borate has been synthesized as its potassium salt (KL) and treatment of KL with one equivalent of MCl2•6H2O gave complexes ML(H2O)x•Cl [x＝2, M＝Co(II), Ni(II); x＝1, M＝Cu(II)]. All compounds were characterized by elemental analysis, FTIR, 1H NMR, ESI MS, UV-Vis techniques, conductivity and magnetic data measurements. Spectroscopic results suggest a square planar geometry in the Cu(II) complex, while the Co(II) and Ni(II) complexes possess an octahedral geometry. Antibacterial activities (in vitro) of the ligand and its metal complexes were studied against two Gram positive (B. subtillis and B. magterium) and two Gram negative bacteria (E. Coli and S. boydi) at a single concentration (75 μg/mL) by using the Disc diffusion method. Antifungal activities (in vitro) were also checked for the compounds by using the same method against Candida albicans 10261, Penicillium sp. and Asperjillius niger., at a single concentration (50 μg/mL). The results showed that all the metal complexes, specially the nickel(II) complex, have higher antibacterial and antifungal activities than the corresponding potassium salt.