Study of reactions of some halides, cyclopentadienyl dichlorides, and bis(cyclopentadienyl) chlorides of lanthanides withtrans-stilbene adducts with alkali metals [PhCHCHPh]·−M+ (M=Li, Na)

Reaction of Sml₂(THF)₂ with metallic lithium andtrans-stilbene in 1:2:2 ratio in DME gives the stilbene complex of divalent samarium (PhCHCHPh)Sm(DME)₂. This complex reacts with hydrogen in THF to give SmH₂(THF)₂ and 1,2-diphenylethane. The reaction with (Me₃Si)₂NH gives the amide [(Me₃Si)₂N]₂Sm(DME)₂ and the reaction with triphenylgermane yields Ph₃GeGePh₃. Reaction of CpLuCl₂(THF)₂ with 2 equivalents of [PhCHCHPh]·⁻Na⁺ in DME results in the dimerization of stilbene fragments to give anate-complex {Cp₂Lu[μ-CH (Ph)CH(Ph)CH(Ph)CH(Ph)]}Na(DME)₃. In the reaction of Cp₂GdCl with [PhCHCHPh]·⁻Na⁺, the known complex Cp₃Gd(THF) was isolated as the only lanthanidecontaining product. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1442–1446, August, 2000.     

Synthesis and characterization of adducts of p-azidostyrene derivatives to fullerene C_(60)

Fullerene C60 reacted with p-azidostyrene derivatives in refluxing chlorobenzene,yielding monoadducts 2a and 2d as well as diadduct 2c with aziridine structure at 6/6-ring junctions.Experimental results showed that the addition of the second azide to the monoadduct was regioselective.The diadduct,of Cs symmetry in C60 moiety,was unstable by opening to be 1,6-imido[10]annulene structure.     

Synthesis and characterization of nitrogen-containing Lewis base adducts of bis(O,O′-dialkylmonoselenophosphato)cobalt(II) complexes

The adducts of bis(O,O′-dialkylmonoselenophosphato)cobalt(II) complexes, Co{O(Se)P(OR)₂}₂(L)₄ (where R?=?n-Pr, i-Pr; L?=?C₅H₅N, NC₅H₄Me-2, NC₅H₄Me-3), were synthesized by in situ reactions of CoCl₂?·?6H₂O, Lewis base, and NaO(Se)P(OR)₂. The single crystal structure of Co{O(Se)P(OⁱPr)₂}₂(C₅H₅N)₄ shows distorted octahedral geometry around cobalt(II) and monoselenophosphates are trans. The CoN₄ forms a square plane. These bis(O,O′-dialkylmonoselenophosphato)cobalt(II) adducts were characterized by elemental analyses, spectroscopic techniques (UV-Vis, infrared, ¹H and ³¹P), and magnetic moment measurements.     

Investigation of complexes of zinc(II) and cadmium(II)DI-n-butyldithiocarbamates with 2,2′-bipyridyl

A new mixed-ligand complex, Cd(S₂CN(C₄H₉)_{2 2})₂(2,2′-Bipy), was synthesized. A polycrystal X-ray diffraction analysis was performed (DRON-3M and DRON-UM1 diffractometers, CuK_α radiation, Ni filter) and the crystal structure was determined [Enraf-Nonius CAD-4 automatic diffractometer, MoK_α radiation, 2440 nonzero independent reflections, 153 refined structural parameters, R is 0.11 for I>2σ(I)]. Crystal data for C₂₈H₄₄CdN₄S₄ : a = 28.716(4), b = 6.848(6), c = 17.188(2) Å, space group Pcca, V-3380.2(7) ų, Z = 4, M = 679.42, dcaU.= 1.335 g/cm3. The structure consists of monomeric molecules in which the cadmium atom has a distorted octahedral environment. The polycrystal diffraction analysis revealed that the complex is isostructural with the defined complex Zn(S₂CN(C₄Hg)₂)₂(2,2′-Bipy). A crystal-chemical search on metal dialkyldithiocarbamates in the Cambridge Structural Database was accomplished and isostructural pairs of Zn and Cd metal complexes were found.     

Nitrogen-donor base adducts of bis(O,O′-di-isoamyldithiophosphato)nickel(II)

A series of Ni^II complexes with the O,O-di-isoamylester of dithiophosphoric acid and nitrogen-donor ligands of composition [Ni(i-Am₂dtp)₂(L)]; [dtp = O₂PS₂ ^–; L = 2,2-bipyridine (bpy); 1,10-phenanthroline (phen); 5-nitro-1,10-phenanthroline (nphen); 4,7-diphenyl-1,10-phenanthroline (baphen); 2,9-dimethyl-1,10-phenanthroline (neo), 2-aminomethylpyridine (amp), 2-(2-aminoethyl)pyridine (aep), 2,2-dipiridylamine (dpa), 1,2-diaminopropane (1,2-dap) or trans 1,2-diaminocyclohexane (dch)] have been prepared. The compounds have been characterized by elemental analyses (C,H,N,S), electronic and i.r. spectroscopy, magnetic and conductivity measurements and by cyclic voltammetry. The results show that all complexes behave as non-electrolytes in acetone. Electronic spectra and magnetic moments suggest a distorted cis-octahedral geometry around the Ni^II atom [_eff/_B <3.10, 3.40 >], except for [Ni(i-Am₂dtp)₂(aep)], where the measured temperature dependence of the magnetic susceptibility proved the tetrahedrally coordinated nickel [4.06 _eff/_B (298 K) – 3.20 _eff/_B (80 K)]. In the [Ni(i-Am₂dtp)₂(neo)] complex, the nickel atom is penta-coordinated. The X-ray crystal and molecular structure of [Ni(i-Am₂dtp)₂(1,2-dap)] has been determined.     

Dispersity and kinetic characteristics of dissociation of mono- and hemiaquo adducts of copper N,N′-ethylenebis(acetylacetoniminate) under nonisothermal conditions

Using optical microscopy and thermogravimetry, we have established that determination of the kinetic characteristics of dissociation for the monoaquo adduct of copper N,N-ethylene-bis(acetylacetoniminate) with particle size 0.5–2 mm is hindered by self-dispersal processes. Using a piezoquartz microbalance, we have obtained the kinetic parameters for thermolysis for a phase whose crystal sizes are substantially smaller than the minimal size after self-dispersal of a block of a large crystal (0.5–2 m). For thermolysis of the hemiaquo adduct not accompanied by self-dispersal, the kinetic characteristics of the process for phases of dispersity 0.5–2 mm and 0.5–2 m are comparable.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 28, No. 3, pp. 226–231, May–June, 1992.     

Composite Langmuir–Blodgett (LB) films of polyaniline and cadmium stearate

Composite monolayers of cadmium stearate and polyaniline processed with camphor sulphonic acid have been obtained at the air–water interface and subsequently transferred onto substrates as uniform Langmuir–Blodgett multilayers. Pressure–area (Π-A) isotherm studies indicated that polyaniline molecules are not squeezed out of the cadmium stearate matrix during compression or in the compressed state. Monolayer stability is seen to decrease when the polymer content is increased beyond 60% (in weight) which is probably associated with the formation of microaggregates that also affected the monolayer surface potential at large areas per molecule. With increasing amount of polyaniline in the mixture, a transition from Y-type to Z-type deposition has been observed. Transferred multilayer LB films were characterized by UV-vis, FTIR, XRD, surface potential, and dc electrical conductivity measurements. UV-vis results indicated that though the polyaniline was in the doped state in the spreading solution, the transferred films were in the emeraldine base state. FTIR studies revealed that the transferred films mainly contained cadmium stearate salt in addition to polyaniline. XRD results indicated that the stacking order is dependent on the polyaniline content in the composite films, the order was found to decrease upon increasing the polymer amount. The uniformity of transferred films was confirmed by surface potential studies. A possible packing arrangement in these composite Langmuir and Langmuir–Blodgett films has been proposed.     

Syntheses,crystal structures and fluorescent properties of two 4,4′-dipyridylsulfide based zinc(II) and cadmium(II) helical complexes

Two allomeric helical coordination polymers, {[Zn(4,4′-dps)₂(HSSA)(H₂O)₂] · 3(H₂O)} _n (1) and {[Cd(4,4′-dps)₂(HSSA)(H₂O)₂] · 3(H₂O)} _n (2) (4,4′-dps = 4,4′-dipyridylsulfide, H₃SSA = 5-sulfosalicylic acid), have been synthesized by similar experimental methods and characterized by elemental analysis, single-crystal X-ray diffraction, and fluorescence spectra. Both crystallize in monoclinic system, space group P₂1/n, with a = 11.7947(13) Å, b = 13.7475(15) Å, c = 20.183(2) Å, and Z = 4 for 1 and a = 11.940(7) Å, b = 14.068(8) Å, c = 20.323(12) Å, and Z = 4 for 2. In both complexes, the metal (Zn^II for 1 and Cd^II for 2) are six-coordinate with a N₃O₃ donor set in a distorted octahedron. Half of the 4,4′-dps are μ ₂-bridging, linking adjacent metal centers and forming P₂1/n dimensional helical structures along the b-axis. Fluorescence measurements show that 1 and 2 have medium fluorescent emission at 402 and 405 nm, respectively.     

Synthesis,characterisation and electrochemical study of 4,4′-bis(salicylideneimino) diphenylethane and its complexes with cobalt(II), copper(II) and cadmium(II)

We have prepared and characterised a new series of metal complexes obtained from 4,4-bis(salicylideneimino)diphenylethane (saldipH₂) and cobalt(II), copper(II) and cadmium(II) chlorides. In every case, the coordinating atoms are N and O. However, each compound has its own structure:[Co(saldip)]·2 H₂O is monomeric and a mononuclear species, [Cu₂(saldip)₂(H₂O)] is a binuclear complex and finally the cadmium complex is formulated as:[(CdCl₂)₂(saldipH₂)]·CdCl₂. An electrochemical study (cyclic voltammetry) indicates that the reduction, as well as the oxidation, of copper in [Cu₂(saldip)₂(H₂O)] proceeds in two steps. For the reduction of the two other complexes, two steps are indicated out: the first is attributed to the reduction of the metal and the second to the reduction of the coordinated ligands.     

Extent of M2 δ to ligand π-conjugation in neutral and mixed valence states of bis(4-isonicotinate)-bis(2,4,6-triisopropylbenzoate) dimetal complexes (MM), where M = Mo or W, and their adducts with tris(pentafluorophenyl)boron

The reaction between W(2)(T(i)PB)(4), where T(i)PB = 2,4,6-triisopropylbenzoate, and 2 equiv of 4-isonicotinic acid (nicH) yields the compound W(2)(T(i)PB)(2)(nic)(2), 2, and T(i)PBH. Compound 2 is related to the previously reported molybdenum analog, Mo(2)(T(i)PB)(2)(nic)(2), 1. Compounds 1 and 2 react with 2 equiv of B(C(6)F(5))(3) in THF to form the adducts M(2)(T(i)PB)(2)(nic-B(C(6)F(5))(3))(2), 1B (M = Mo) and 2B (M = W), which have been crystallographically characterized as solvates M(2)(T(i)PB)(2)(nic-B(C(6)F(5))(3))(2)·2THF n-hexane. Compounds 1 and 2 are intensely colored due to M(2) δ to π* MLCT transitions, and upon complexation with B(C(5)F(5))(3) to give 1B and 2B, these bands shift to lower energy and gain in intensity. Each compound shows two one-electron ligand-based reductions with a ΔE(1/2) = 120 (1), 300 (1B), 440 (2), and 650 mV (2B). The larger ΔE(1/2) values for the tungsten compounds reflect the greater orbital mixing of the metal 5d-based M(2) δ and the nic π* LUMO. Reduction of solutions of 1B and 2B with (C(5)Me(5))(2)Co leads to the anions 1B(-) and 2B(-), which have been characterized spectroscopically by electron paramagnetic resonance (EPR) and UV-vis-NIR absorption. The EPR spectra of 1B(-) and 2B(-) are consistent with ligand-based (i.e., organic) radicals. The electronic spectra contain low-energy narrow charge resonance (IVCT) bands at 3800 (1B(-)) and 4500 cm(-1) (2B(-)), consistent with fully delocalized mixed valence radical anions. The results are compared with electronic structure calculations and with the spectral features of the metal-centered delocalized mixed valence radical cations [(Bu(t)CO(2))(3)M(2)](2)-μ(2)-(O(2)C-CO(2))(+), to which they are remarkably similar, as well as with other organic-based mixed valence systems.     

Syntheses, structures and magnetic properties of a family of one-dimensional M(Ⅱ)-lanthanide(Ⅲ) (M =Ni(Ⅱ) and Zn(Ⅱ)) coordination polymers

A series of 1D nickel(Ⅱ)/zinc(Ⅱ)-lanthanide(Ⅲ) coordination polymers, [M(μ-L)2Ln(NO3)3]n· solvents (HL =bis(2-pyridylcarbonyl)amine; M = Ni, Ln = Gd (1 · NiGd), Tb (2· NiTb), Dy (3· NiDy), Ho (4· NiHo), Y (5· NiY);M = Zn, Ln =Gd (6· ZnGd), Tb (7· ZnTb), Dy (8· ZnDy), Ho (9· ZnHo); solvents = H2O or H2O-ethanol), was synthesized and characterized. All of the complexes are isostructural at 293 K and crystallize in the orthorhombic space group Fddd. Magnetic measurements were performed on 1-9, where weak ferromagnetic interaction is found in 1 · NiGd, ferromagnetic interaction in 2·NiTb and 3·NiDy, and antiferromagnetic interaction in 4· NiHo. A remarkable dc magnetic field dependence of ac susceptibilities was found in this series of complexes.     

Syntheses, structures and magnetic properties of a family of one-dimensional M(Ⅱ)-lanthanide(Ⅲ) (M = Ni(Ⅱ) and Zn(Ⅱ)) coordination polymers

A series of 1D nickel(II)/zinc(II)-lanthanide(III) coordination polymers, [M(μ-L)2Ln(NO3)3]n·solvents (HL = bis(2-pyridylcarbonyl)amine; M = Ni, Ln = Gd (1·NiGd), Tb (2·NiTb), Dy (3·NiDy), Ho (4·NiHo), Y (5·NiY); M = Zn, Ln = Gd (6·ZnGd), Tb (7·ZnTb), Dy (8·ZnDy), Ho (9·ZnHo); solvents = H2O or H2O-ethanol), was synthesized and characterized. All of the complexes are isostructural at 293 K and crystallize in the orthorhombic space group Fddd. Magnetic measurements were performed on 1―9, where weak ferromagnetic interaction is found in 1·NiGd, ferromagnetic interaction in 2·NiTb and 3·NiDy, and antiferromagnetic interaction in 4·NiHo. A remarkable dc magnetic field dependence of ac susceptibilities was found in this series of complexes.     

Synthesis, Crystal Structure, and Properties of Inorganic-organic Hybrid M(Ⅱ)-Nb(Ⅴ)(M = Co, Cu)Oxyfluorides

T Two isostructural inorganic-organic hybrid M(Ⅱ)-Nb(Ⅴ)oxyfluorides, namely,M(H<,2>O)<,2>(pyz)NbOF<,5>(M = Co 1, Cu 2; pyz = pyrazine)have been hydrothermally synthesized and structurally characterized. Both compounds possess two-dimensional layer structure constructed by neutral M(H<,2>0)<,2>NbOF<,5> chains inter-connected via bridging pyrazine ligands. The structure is further extended into three-dimensional supramolecular architecture through inter-layer H-bonding interactions between the coordinated water molecules and fluorine ions. The luminescent properties and thermal stability of both compounds have been investigated.     

An MCl inf4 p2− moiety (M = copper,zinc, cadmium and mercury) stabilized by bis(ethylenediamine)copper(II) cation

Summary New ionic bimetallic complexes of the type [Cu(en)₂]-[MCl₄], where M = Cu^II, Zn^II, Cd^II and Hg^II, were prepared by reacting bis(ethylenediamine)copper(II) dichloride (1 mol) with copper, zinc, cadmium and mercury dichlorides (1 mol) in absolute alcohol. Elemental analyses, conductivity and magnetic susceptibility measurements, and spectroscopic data (such as i.r., u.v.-vis. and e.p.r.) confirm that the compounds are 22 electrolytes in MeOH and that the copper(II) ion is paramagnetic, maintaining its square-planar geometry, while metal ions in the anionic moiety of the complexes achieve their usual tetrahedral environment. An augmented magnetic moment has been observed in the [Cu(en)₂] [CuCl₄] complex, which is attributed to the ferromagnetic effect and TIP.Author to whom all correspondence should be directed.     

Synthesis, crystal structure, and luminescence properties of the tetranuclear complex of cadmium(II) acetate with 4,4′-(1,4-phenylenediisopropylidene)bis-aniline

The complex compound [CdL_1.25(CH₃CO₂)₂(H₂O)], where L = NH₂-C₆H₄-C(CH₃)₂-C₆H₄-C(CH₃)₂-C₆H₄-NH₂ was synthesized and its crystal structure was determined. The crystals are triclinic, space group P $ \bar 1 $ , a = 10.160(1) ?,b = 17.442(1) ?, c = 20.232(1) ?, ?? = 67.93(1)°, ?? = 87.22(1)°, ?? = 77.65(1)°, V = 3340.2(4) ?³, ??_calc = 1.392 g/cm³, Z = 4. The structure contains two crystallographically non-equivalent Cd²⁺ ions, each coordinating two nitrogen atoms of two ligands L, four oxygen atoms of two bidentate acetate groups, and one water molecule. The coordination polyhedron of Cd²⁺ ions is anirregular sevenvertex polyhedron. The interaction of cadmium with ligands L gives rise to centrosymmetric tetranuclear complexes [Cd₄L₅].     

Structure of the catena-bis(trimethylamine)cadmium(II)-tetra-μ-cyanonickelate(II) complex and contact self-stabilization of molecules

The [Cd(N(CH₃)₃)₂Ni(CN)₄] complex crystallizes in a tetragonal system, space group 14/mmm with two formula units per unit cell (XRD, Rigaku AFC-6A diffractometer, λ MoK_α, ω/2θ scan mode, θ_max = 38?, 635 observed unique reflections, 53 parameters, R = 0.027). The structure consists of parallel polymer layers made up of coordinated metal atoms and bridging cyanides. The octahedral environment of Cd(II) involves six nitrogen atoms of the four cyanide groups in the layer plane (2.323(4) Å) and the two trimethylamine ligands in the transposition (2.42(1) Å). The square-planar environment of Ni(II) consists of four carbon atoms of the cyanide ligands (1.857(3) Å). The layers are packed according to van der Waals type; the “hollows” near the nickel atoms are filled by the “hills” of the trimethylamino groups from the neighboring layer (the interlayer distance is 7 Å). The spatial complementarity of the layers leads to close packing of the complex and explains the lack of a clathrate-forming ability in the latter. The trimethylamine ligands here play the same role as guest molecules in Hofmann clathrates, stabilizing the planar polymer structure of the complex. This phenomenon is called contact self-stabilization.

     

Interactions of M(z)-X complexes (M = Cu, Ag, and Au; X = He, Ne, and Ar; and z = ±1)

The coupled cluster singles and doubles method with perturbative treatment of triple excitations is applied to calculate the potentials of M(z)-X complexes (M = Cu, Ag, and Au; X = He, Ne, and Ar; and z = ±1). The bond functions and the basis set superposition errors are considered to obtain accurate interaction energies. The potential energy curves of all complexes are obtained. The vibrational energy levels and the spectroscopic parameters for these complexes are determined. The analytical potential energy functions are also fitted based on the potential energies.     

Synthesis,crystal structures,magnetic and luminescent properties of nickel(II) and cadmium(II) coordination polymers bearing 5-(2′-carboxylphenyl) nicotate ligands

Two coordination polymers, namely [M(cpna)(phen)(H₂O)] _n (M = Ni, 1; Cd, 2, H₂cpna = 5-(2′-carboxylphenyl) nicotic acid, phen = 1,10-phenanthroline), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, magnetic and luminescence measurements. Single-crystal X-ray diffraction studies show that the two complexes are isostructural polymers. They have 1D step-like chain structures, which are further extended into 3D metal–organic supramolecular frameworks by π–π stacking interactions. Magnetic studies for complex 1 show antiferromagnetic coupling between the adjacent Ni(II) centers, with g = 2.10 and J = −4.30 cm⁻¹. Complex 2 displays strong green fluorescent emission at room temperature.