Aluminiumorganic compounds of some metaldioximates

Coordinated dioximes with nickel(II), palla‐dium(II) and copper(II) ions proved capable of giving substitution reactions with a series of aluminiumorganic compounds. Studies made on the reaction products have revealed that in the case of both dimethylglyoxime and diphenylglyoxime. The reaction products result from substitution of the O? H…O hydrogen bridges existing in such compounds by O? Al? O bridges. All compounds reported in this paper were separated from the reaction mixture as coloured powders and were characterized by chemical analyses, IR spectroscopy, X‐ray diffraction spectra, proton NMR spectra and magnetic properties. Copyright © 2001 John Wiley & Sons, Ltd.     

Zinc organic compounds of some oximes coordinated with nickel(II), palladium(II) and copper(II) ions

Coordinated oximes with nickel(II), palladium(II) and copper(II) ions proved capable of giving substitution reactions with a series of zinc organic compounds. Studies have revealed that, in the cases of dimethylglyoxime and salicylaldoxime, the reaction products result from substitution of the O? H···O hydrogen bridges existing in such compounds by O? Zn? O bridges. All compounds reported in this paper were separated as colored powders and characterized by elemental analyses, IR spectroscopy, X‐ray diffraction and magnetic measurements. The new zinc organic compounds form amine adducts. Among the amine adducts, only those with pyridine were isolated and characterized. Copyright © 2001 John Wiley & Sons, Ltd.     

Nickel(II) complexes of substituted diphenylcarbazones and their adducts with heterocyclic nitrogen bases

The complexing behaviour of novel 1,5-di(4-chloro-2- methylphenyl)carbazone and 1,5-di(2,4-dichlorophenyl)carbazone towards nickel(II) ions has been investigated by elemental analysis, magnetic susceptibility, u.v. -vis., i.r. and 1H-n.m.r. spectral studies. The ligands act as bidentate N,O donors and form 1:2 complexes with the metal ions. The adducting behaviour of nickel(II) complexes with nitrogen bases has been studied spectrophotometrically in a chloroform monophase. The nickel(II) di(4-chloro-2-methylphenyl)carbazonate forms hexacoordinate adducts with monodentate and bidentate bases with 1:2 and 1:1 chelate:base stoichiometries, respectively, whilst, nickel(II) di(2,4-dichloro-phenyl)carbazonate forms penta- and hexacoordinate adducts of 1:1 chelate:base stoichiometry with monodentate and bidentate bases, respectively. The results are discussed on the basis of steric properties and the basicity of the nitrogen bases.     

In vitro antitumour activities of a novel 2:3 condensation product of salicylaldoxime with di-n-butyltin(IV) oxide

The antitumor activities of three novel condensation products of salicylaldoxime with di-n-butyltin(IV) oxide (compound 1), di-t-butyltin oxide (compound 2) and diphenyltin oxide (compound 3) are presented. Against MCF-7, a human mammary tumor cell line, compounds 1 and 2 are characterized by inhibition doses ID₅₀ in vitro of 67 and 49 ng cm^?3 respectively, whereas cis-platin, an antitumor drug used clinically, has an ID₅₀ of 850 ng cm^?3. Against WiDr, a colon carcinoma, they also score better than cis-platin: 215 and 121 ng cm^?3 versus 624 ng cm^?3. In contrast, the diphenyltin compound, 3, is inactive against both tumor cell lines. The results of a pre-screening performed on compound 1 by the National Cancer Institute (NCI) on a panel of 60 human tumor cell lines show that two of the selectivity parameters calculated by the NCI for that compound are statistically significant, namely D_G150 (51.9>50) and MGD_H (80.1>75). One is almost satisfactory (D_H = 72.4 = ca75). The other two, D_TGI (40.0<50) and D_LC50 (16.7<50) are not. (Abbreviations are explained in the text and in Gielen, M. and Willem, R. Anticancer Res., 1992, in press).     

Vibrational spectra of nucleic acid bases and their Watson–Crick pair complexes

The vibrational spectra of the nucleic acid bases adenine, thymine, guanine, and cytosine are calculated in the frame of density functional theory (DFT). In particular we use the Kohn–Sham scheme with gradient corrections for exchange and correlation to determine normal modes, frequencies, and intensities. The DFT results are found to be in good agreement with the experiment. Our computations provide assignments for IR, Raman, and neutron inelastic scattering spectroscopies; yield characteristic vibrational fingerprints of each compound for its identification in larger systems; and show general vibrational trends of nucleic acids. The Kohn–Sham scheme is further applied to obtain the spectra of the Watson–Crick pairs adenine-thymine and guanine-cytosine. A large number of monomeric vibrations are recognized in dimers; characteristic vibrations of pairs, which are mainly attributed to hydrogen bridges, are quantified according to changes in normal modes and frequency shifts. Binding and zero-point vibrational energies are analyzed to establish the stability of the complexes and discuss the quality of the energetic calculations. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 511–530, 1999     

Organotellurium cations: Organotellurium perchlorates and their complexes with Lewis bases

Solutions of diorganotellurium(IV) diperchlorates R₂Te(ClO₄)₂ (where R = Ph, p-CH₃OC₆H₄, R₂Te = $\text{C}{}_4\text{H}{}_8\text{Te}$) may be prepared by the reaction of R₂TeCl₂ and AgClO₄ or by the reaction of diorganyltelluroxide with excess of 70% HClO₄.IR and conductivity data indicate that Ph₂Te(ClO₄)₂ possesses covalently bonded perchlorate groups in solution. Interaction of the freshly prepared solutions with Lewis bases affords cationic complexes of the types [R₂Te(ClO₄)(L)][ClO₄] and [R₂Te(L)₂][ClO₄]₂ which have been characterised by IR elemental analyses and conductivity measurements.     

Preparation and characterization of heterobimetallic tetraxanthates and their complexes with Lewis bases

Some new heterobimetallic tetraxanthates of the type M[Ag(Etxant)₂]₂ [M = Co(II) or Ni(II), Etxant = ethylxanthate] and their complexes of general formula M[Ag(Etxant)₂]₂.xL [x = 2 when L= dimethylsulphoxide (DMSO), triphenylphosphine (Pph₃), pyridine(py) or 2-aminopyridine (2-ampy); x = 3 when L = 2,2′-bipyridine (bipy)] have been prepared and characterized by elemental analysis, molar conductance, magnetic susceptibility, infrared and electronic spectral studies. Magnetic and electronic spectral studies indicate square planar geometry around Ni(II) and Co(II) in heterobimetallic tetraxanthates and Ni[Ag(Etxant)₂]₂.2PPh₃ and octahedral geometry around the above metal ions in the remaining complexes.     

Preparation and reaction of phosphorus peri-bridged naphthalenes and their adducts with Lewis acids

The reaction of dilithionaphthalene with R₂NPCl₂ (R = ⁱPr and Et) gave diisopropylamino-naphtho[1,8-bc]phosphete 3a and its diethyl analog 3b (phosphorus versions of single-atom peri-bridged naphthalene). The nature of the strained four-membered ring thus formed was examined by treating 3a with four types of electrophiles, BH₃, elemental sulfur, methyltriflate, and a metal fragment W(CO)₅, all of which gave the corresponding electrophile adducts with the strained ring retained. X-ray analysis was performed for 3b and all of the above adducts, showing that the trigonal plane of the amino group was commonly oriented almost perpendicular to the naphthalene plane, which was rationally understood on the basis of the favorable overlap between the lone pair orbital of the sp² nitrogen center and the σ¹ orbital(s) of the two P–C bonds. In addition, when the W(CO)₅ adduct, W(3a)(CO)₅, was treated with Pt(PPh₃)₄ and then with a CO gas, its four-membered ring was expanded to give a tungsten–platinum heterodinuclear complex having a five-membered platina–phospha heterocycle.     

水杨醛肟和乙酰氧肟酸钛氧簇合物的合成及光电性质

通过溶剂热合成方法,以水杨醛肟(H₂Saox)和乙酰氧肟酸(H₂Ahox)为染料敏化功能配体,分别以异丁酸(HiBuac)和苯基膦酸(PhPO₃H₂)为辅助配体,与钛酸四异丙酯(Ti (OⁱPr)₄)反应,合成了六核钛氧簇配合物[Ti₆(μ₃-O)₄(Saox)₂(ⁱBuac)₄(OⁱPr)₈](1)和八核钛氧簇配合物[Ti₈(μ₃-O)₂(Ahox)₂(PhPO₃)₄(OⁱPr)₁₆](2)。配合物1和2均通过红外光谱、元素分析和单晶X射线衍射进行了结构表征。光谱性质表明,配合物1和2在可见光区均有吸收,其带隙分别为2.43和2.61 eV。配合物2是首个基于乙酰氧肟酸的钛氧簇,具有光催化析氢性能且速率可达140.2 μmol·g^-1·h^-1。     

Spectrophotometric study of adducts of nickel-5 nitro-8-quinolinate with heterocylic and other nitrogen bases

Adduct formation constants have been determined by spectrophotometric study of the organic base-adducts of nickel (II) chelate of 5-nitro-8-quinolinol in a monophase-chloroform. Bathochromic and hypsochromic shifts were observed in the optical spectra, in visible range, due to adduct formation. A penta coordinated square-base pyramidal structure is proposed for the low pK pyridine base adducts whereas hexa coordinated octahedral structure is favoured for adducts with bases of higher pK values. The stabilities of the nickel adducts increase in the following order of the base: 2,4-lutidine <2-picoline <2,4,6-collidine <pyridine <4-picoline <neocuproin <1,10-phenanthroline < ethylenediamine < 2,2¹-bipyridyl.     

Some compounds of iron(III) with tertiary and secondary nitrogen bases

Summary The iron(III) compound, FeCl(OH)(MeCO₂) · MeCO₂ H · 0.5 H₂O, combines with tertiary nitrogen bases, pyridine, quinoline and-picoline, to form FeCl(OH)(MeCO₂) · (Base) 0.5 H₂O and with-picoline to give FeCl(OH)(MeCO₂) (-picoline). The secondary nitrogen bases (BH), such as, piperidine, pyrrolidine and diethylamine, on the other hand, react with the elimination of base hydrochloride to form Fe(B)(OH)(MeCO₂) · 0.5 H₂O compounds, containing covalently bonded bases. Pyrrole and indole (BH) combine with the partial elimination of chlorine to give Fe₃Cl₂(B)(OH)₃(MeCO₂)₃ · 3(BH). Phthalimide (BH), however, forms a simple addition compound Fe₂Cl₂(OH)₂(MeCO₂)₂ · (BH). The i.r. spectra, room temperature magnetic susceptibilities, thermal decompositions wherever possible and molar conductance have been studied.     

Lewis acid properties of phosphenium and arsenium cations: Study of their adducts with pyridine

In the growing field of dicoordinated Group 15 cations, the quantitative study of the Lewis acid properties of phosphenium or arsenium cations has not yet been undertaken. Moreover, there are only a few described examples of syntheses of arsenium cations. The aim of this work is to enhance this series and to develop a quantitative comparative study of their complexation with Lewis bases such as pyridine. The observation of the ¹³C NMR C-4 variation in the pyridine ring is a good probe to obtain the apparent equilibrium constant K_c and thus a Lewis acidity scale. Phosphenium cations are more acidic than arsenium cations.     

Interaction of iron carbonyls with Lewis bases

The interaction of iron carbonyls Fe _n (CO) _m (wheren = 1,m = 5;n = 2,m = 9;n = 3,m = 12) with anionic Lewis bases (H^–, F^–, Cl^–, Br^– , I^–, CN^–, SCN^–, N₃ ^–, MeSO₃ ^–, MeCO₂ ^–, CF₃CO₂ ^–, S₂ ^–, CO₃ ^2–, and SO₄ ^2–) passes through two-stage redox-disproportionation. The first stage is the formation of an iron carbonyl-base complex, [Fe _n (CO) _m–1C(O)L]^–, and the second is a single-electron reduction of this complex by another molecule of the initial iron carbonyl, giving rise to Fe(l) and Fe(–l) derivatives.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 248–249, January, 1996.     

Reaction of butylmercury nitrate with Lewis bases

The reaction of butylmercury nitrate with organic bases has been studied in four solvents. BuHgNO₃ is molecular in benzene and acetone but ionic in water; in acetonitrile there is an equilibrium between molecular and ionic species. In benzene solution bases form 1 : 1 adducts, 3-coordinate with pyridine, 4-methylpyridine, bipyridine, Et₃N, Bu₃N, PBu₃, PPh₃ or diphos, 4-coordinate with tetramethyldiaminoethane. Adduct stabilities and enthalpies of formation are reported. In acetone solution bases displace nitrate, in water bases displace coordinated water and in acetonitrile they displace nitrate or coordinated solvent; in all three solvents the end products are BuHg · base⁺ and NO₃^-. Enthalpies are reported for these reactions.Distribution of BuHgNO₃ between benzene and water is concentration dependent. Addition of phosphines increases the proportion of the mercury in the benzene phase; addition of heterocyclic bases increases the proportion in the aqueous phase; addition of tertiary amines first increases the proportion in the benzene phase, then, with higher base concentrations, that in the aqueous phase.     

Complexes of borazine and its analogs with Lewis acids and bases

The author’s review summarizes the results of B3LYP/TZVP quantum chemical calculations of complexes of borazine, substituted borazines, polyborazines, alumazine, and boraphosphabenzene with Lewis acids and bases. The effects of the nature of the heterocycle, substituents, and the donor and acceptor properties of the molecules on the thermodynamic characteristics of complex formation are considered. The reactivity of the complexes of heterocycles in hydrogenation and electrophilic substitution reactions was studied.     

气液色谱法测定一些Lewis碱与Ni(ENAC).H2O的加合常数

配位不饱和的过渡金属配合物作为一种Lewis酸(A)可以进一步和Lewis碱(B)作用,形成配合物AB.许多生化过程和催化过程都与这种类型的配合物有关.曾经用光谱和量热等方法研究过配位键A—B的强弱.本文在Drago等人的工作基础上,利用气液色谱法