Studies on the interactions of polymer-anchored copper(II) complexes with tRNA

The binding interactions between tRNA and polyethyleneimine-anchored copper(II) complexes with 1,10-phenanthroline and 2,2′-bipyridine ligands and varying degrees of coordination have been studied using physico-chemical techniques. In both sets of polyethyleneimine-anchored complexes, the complexes with higher degree of coordination bind more strongly to tRNA than those with lower degree of coordination. Binding to tRNA appears to be mainly electrostatic in nature.     

Geometric isomerism of copper(II) with monochlorobenzhydrazide chelate complexes

Summary Chelate complexes having a 12 Cu^II ion:(singly deprotonated ligand ratio, formed from Cu^II including 2-, 3- and 4-chlorobenzhydrazides, (ClC₆H₄C(O)NHNH₂) have been studied in the pH > 10 region. With the 2-chloro substituted derivative the cis-isomer is formed, whereas with the 3- and 4-chloro substituted derivatives trans-isomers are formed. The complexing schemes are described.     

The reaction of (SO2)2 and (CO2)2 with Ba

The reactions of (CO₂)₂ and (SO₂)₂ with Ba have been investigated using a crossed beam arrangement and the laser-induced fluorescence technique. Internal energy in the BaO product was probed in order to study differences between monomeric and dimeric reactions. The reaction cross section for the dimers of CO₂ was found to be between four and eightfold larger than that of the monomers. This can be explained by the change in the reaction mechanism due to the positive electron affinity of the dimers versus the negative electron affinity of the monomers. The product BaO from the dimeric reactions is much colder rotationally than in the monomeric case. This phenomenon can be explained based on the kinematics.     

SO2 oxidation in aqueous solutions of Cu(II)

Kinetic studies of SO₂ oxidation by Cu(II) complexes in aqueous solutions containing halide ions X(X=Cl^–, Br^– and I^–) indicate that the highest activity is observed for mixed chloro-iodo complexes of Cu(II). A reaction mechanism is suggested where the principal role is assigned to CuX ₄ ^2– aq complexes and HSO₃ radicals.

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SO₂ Cu(II) , X(X=Cl^– Br^–, I^–). , - Cu(II). CuX^2–aq HSO₃.

     

Studies on the intermolecular interactions of metal chelate complexesIX: On the interaction of copper(II) dithiocarbamate with some lewis acids

The intermediate products of the reaction between copper(II) dithiocarbamate complex and some Lewis acids (HgI₂, HgBr₂, GeCl₄, AsBr₃, CoCl₂, C(NO₂)₄) as well as some organometallic compounds (SnEt₄ and PbEt₄) were studied using EPR spectroscopy. In non-polar and non-coordinating solvents HgI₂, HgBr₂ and GeCl₄ formed adducts with Cu(dtc)₂, whereas in polar and coordinating solvents the mixed-ligand complexes of the type Cu(dtc)⁺…A^?(A = HgX₃) were obtained with a complex counterion in the second coordination sphere of copper(II). With C(NO₂)₄ the intermediate reaction product in non-polar solvents was assumed to be Cu(dtc)·NO₂ which dissociates to Cu(dtc)⁺…NO₂^? in polar solvents. Similar EPR spectra were obtained with SnEt₄ and PbEt₄. The reaction of Cu(dtc)₂ with CoCl₂, AsBr₃ and SbCl₃ yielded the mixed-ligand complexes of the type Cu(dtc)X_n (n = 1 or 2) exhibiting well resolved superhyperfine splitting from one or two halogen nuclei. The influence of the medium on the above interaction is also discussed.     

Studies on the intermolecular interactions of metal chelate complexesVIII: On the interactions of dithiocarbamato-copper(II) and -copper(I) complexes with haloalkanes

The interaction of Cu(II)(dtc)₂ and Cu(I)(dtc) complexes with haloalkanes were studied by the EPR method. It was found that the Cu(II)(dtc)₂ complex reacted with haloalkanes only in the presence of weak Lewis bases which formed adducts with it. The intermediate reaction product is the mixed-ligand complex Cu(II)(dtc)X_n (X = Cl, Br, n = 1 or 2); the final products being CuX₂B_n (B = Lewis bases, n = 1 or 2) and unstable resin-like residue. Cu(I)(dtc) reacted with haloalkanes without any promoters giving the mixed-ligand complex Cu(II)(dtc)X_n as product. Free radicals were detected in the reaction of Cu(I)(dtc) using the method of “radical scavenger” and were not found in the reaction of Cu(II)(dtc)₂. The reported results confirmed one of the two reaction mechanisms proposed in the previous studies. The role of the solvent on the EPR parameters of the mixed-ligand Cu(II)(dtc)X complex is also discussed.     

Vibrational study of hydrogen bonding and structural disorder in Na2H(SO4)2, K3H(SO4)2 and (NH4)3H(SO4)2 crystals

Infrared and Raman spectra on Na₃H(SO₄)₂, K₃ H(SO₄)₂ and (NH₄)₃ H(SO₄)₂ crystals have been investigated at 300 and 100 K in the 4000 to 30 cm⁻¹ region. An assignment of bands in terms of OH group frequencies and more or less distorted tetrahedra of ammonium and sulphate ions is given. The crystallographic and spectroscopic symmetry and/or dissymetry of OHO hydrogen bonds linking sulphate ions into dimers is discussed using OH group frequencies and the splitting of the v₁ (SO₄) Raman bands as criteria. In the particular case of (NH₄)₃H(SO₄)₁ compound containing several solid phases it can be shown that the room temperature phase (II) is strongly disordered, principally because of an orientational disorder of ammonium ions, and that a progressive ordering takes place with temperature lowering.     

The synthesis and vibrational spectra of the antimony(V)fluoride-fluorosulfates SbF3(SO3F)2, SbF4(SO3F) and Sb2F9(SO3F)

The synthesis of the title compounds by a variety of routes is described. These routes involve the oxidation of antimony(III)fluoride by bis(fluorosulfuryl)peroxide and the use of non-statistical ligand redistribution reactions. Complex formation with ClO₂SO₃F leads to ClO₂[SbF_n(SO₃F)_6-n], with n=3 or 4. Polarized Raman data and low temperature infrared data are reported. All antimony(V)fluoride-fluorosulfates are found to have fluorosulfate bridges with SbF₃(SO₃F)₂ and SbF₄(SO₃F) being polymers. Ionic formulations for the ClO⁺₂ complexes are again based on vibrational spectra.     

Exchange interactions in bis(diethyldithiocarbamato)copper(II), Cu(detc)2

The exchange coupling constant J in bis(diethyldithiocarbamato)copper(II) has been derived through analysis of the EPR g values and linewidth as a function of orientation, frequency and temperature. The single line in the ac* plane is due to the averaging of the fine-structure splitting by interdimer exchange for which a lower limit of 0.02 cm^?1 has been obtained. Analysis of the spectra in the bc plane gives an estimate of 0.008 cm^?1 for the intersite exchange.     

Investigation of phase equilibria in the systems K2SO4Sc2(SO4)3, Rb2SO4Sc2(SO4)3 and Cs2SO4Sc2(SO4)3

Phase diagrams of the systems K₂SO₄Sc₂(SO₄)₃, Rb₂SO ₄Sc₂(SO₄)₃ and Cs₂SO₄ Sc₂(SO₄)₃ have been investigated by X-ray diffraction phase analysis and differential thermal analysis techniques. A salient feature of all the systems is the formation of M₃Sc(SO₄)₃, which melt incongruently, and MSc(SO₄)₂, which on heating decompose in the solid state.     

Palladium(II) and platinum(II) complexes in MN2x2 chromophores

Some Pd(II) and Pt(II) halide complexes with 2-bromo- and 2-chloro-1,3,4-thiadiazoles have been prepared and characterized by electronic, NMR, Raman and IR spectroscopy, and by thermogravimetric analysis and conductivity measurements. All of the complexes appear to have square-planar stereochemistry with MN₂x₂ (X = Cl or Br) chromophores. Two of them are present in the cis configuration while for all the others unambiguous trans configurations are observed.     

Influence of chelate ring interactions on copper(II) chelate stability studied by connectivity index functions

Linear models for estimation of the first (K1), second (K2), and overall stability constant (beta2) based on the valence connectivity index of the third order ((3)chi(v)) were developed and checked on four sets of copper(II) chelates (with diamines, N-alkylated glycines, and naturally occurring amino acids, including their mixed complexes). Univariate models were valid when log K1 and log K2 values were linearly correlated, i.e., when there was no interaction between chelate rings. The univariate models proved applicable for estimation of all three stability constants of complexes with diamines and N-alkylated glycines, but for complexes with amino acids additional terms were needed (bivariate models). Models reproduced stability constants with an error usually less than 0.3 log K units.     

原位产生的SO42-配位的二维无机钴配合物K2[Co3(OH)2(SO4)3(H2O)2]的水热合成及晶体结构

相同的水热反应条件下4-氨基-二(2-吡啶基)-1，2，4-三氮唑(abpt)、KSCN与钴盐(CoCl₂·6H₂O)反应合成了2种新的钴配合物:零维的单核配合物[CoSCN(abpt)] (1α)和二维的无机层状配合物K₂[Co₃(OH)₂(SO₄)₃(H₂O)₂] (1β)，并通过元素分析和红外光谱对其进行了表征。配合物1α的晶体属于单斜晶系，P2₁/c空间群。配合物1β晶体属于正交晶系，Cmc2₁空间群。在配合物1α中，abpt和SCN^-配体都参与配位与Co(Ⅱ)离子形成了2个不同的单核单元，这些单核单元又通过S原子和N原子之间的氢键作用连成了三维超分子结构;在配合物1β中，abpt配体没有参与配位，而SCN^-配体则被氧化成了SO₄^2-离子并与Co(Ⅱ)离子配位形成了二维配位层状结构，相邻层之间进一步通过氢键作用形成了沿c轴方向有孔道的三维超分子网络，这些孔道里面填充着反离子K+。     

Calculation of the rate of SO2 oxidation to SO3

Approximate equation to calculate the effectiveness factor of catalyst for SO₂ oxidation to SO₃ has been derived. Calculated data agree well with those predicted by a quasi-homogeneous model.

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A new and unusual isomerism in [Fe(CO)2 {P(OR)3}2 (SO2)] complexes (R = aryl)

[Fe(CO)₂ {P(OR)₃}₂ (SO₂)] complexes (R = aryl) exist in solution as equilibrium mixtures of two isomers; both have been shown by X-ray diffraction studies (where R = Ph or o-MeC₆H₄) to have planar coordination about SO₂ and trigonal bipyramidal coordination about Fe, but in one isomer (R = Ph) the equatorial plane is occupied by SO₂ and two CO ligands whilst in the other one (R = o-MeC₆H₄) it is occupied by the SO₂ and two P ligands.     

Fe2(SO4)3/γ-Al2O3固体超强酸的Mössbauer谱研究

采用浸渍法制备了一系列Fe2(SO4)3/ γ-Al2O3型固体超强酸样品,用Moessbauer谱和XRD研究了不同温度处理对样品中铁组分的存在状态及稳定性的影响。结果表明,随Fe2(SO4)3含量的变化,铁组分可以在γ-Al2O3表面以单层分散和无定形形式存在;当温度≥600℃时,无定形状态的Fe2(SO4)3又生成晶态的Fe2(SO4)3,而形成的晶态Fe2(SO4)3即使在700℃时也不分解。     

Arenetitatnium(II) complexes of formula Ar-TiCl2-Al2Cl6

The synthesis and properties of Ar-TiCl₂-Al₂Cl₆(Ar=benzene or a methylbenzene) complexes have been studied, and the results indicate an increase in stability of the arenetitanium π-bond in the order: benzene < toluene < xylenes < mesitylene < durene < hexamethylbenzene.An exchange reaction of the aromatic ligands was observed. On the basis of conductivity measurements it was ascertained that the complexes are partialy ionize in solution.     

Bond function parameter transferability in SO2, SF2 and SO2F2

Ab initio MO studies of the use of gaussian bond functions in the molecules SO₂,SF₂ are presented. It is shown that optimization of bond function exponent and position parameters in the small molecules is a good approximation to the optimum parameter set for SO₂F₂,     

Ferromagnetic exchange coupling in phosphonato-bridged dinuclear copper(II) compound with monoethyl (pyridyn-2-ylmethyl)phosphonate ligand (2-mpmpe): Cu2(2-mpmpe)2(H2O)2(NO3)2

The interaction of diethyl (pyridyn-2-ylmethyl)phosphonate (2-pmpe) with Cu(NO₃)₂ · 6H₂O leads to a partial hydrolysis of the starting ligand and formation of the compound of the formula Cu₂(2-mpmpe)₂(H₂O)₂(NO₃)₂, where 2-mpmpe = monoethyl (pyridyn-2-ylmethyl)phosphonate. The crystal and molecular structure of a copper(II) compound was determined by single X-ray diffraction method. Its structure consists of five-coordinated in distorted square planar geometry (CuNO₄ chromophore) copper(II) ions doubly bridged by OPO from phosphonate. The Cu?Cu distance is 4.69 Å. The crystal packing is determined by the interdinuclear hydrogen bond system, which leads to a three-dimensional (3D) H-bonds network. The compound was characterized by infrared, ligand field, EPR spectroscopy, and magnetic studies. The magnetic properties of the title compound investigated over the 1.8–300 K, revealed the occurrence of a weak ferromagnetic coupling through phosphonate bridge (J = 1.86 cm⁻¹) and interdimer superexchange coupling through H-bond network (zJ′ = −0.17 cm⁻¹). Spectroscopic and magnetic properties are presented in the light of crystal structure.