Preparation of bis-(γ-trifluoropropyl)dichloro

Summary It was shown that (CF₃CH₂CH₂)₂SiCl₂, along with Cl₃SiCH₂CH₂CF₃ and CH₃Si(Cl)₂CH₂CH₂CF₃ may easily be prepared without danger by the addition of H₂SiCl₂ and HSiCl₃ or CH₂SiHCl₂ in the presence of platinohydrochloric acid.     

(1)H and (13)C NMR studies of asymmetrically substituted bis- and tris-Tröger's bases

The (1)H and (13)C NMR spectra of two stereoisomeric bis-Tr?ger's bases and four stereoisomeric tris-Tr?ger's bases asymmetrically substituted on the external aromatic rings were recorded and the corresponding signals assigned. The relative configuration of the stereogenic units has been unequivocally determined on the basis of homoallylic couplings and NOE experiments.     

Synthesis and Crystal Structure of catena-Poly[bis-(benzimidazole)cobalt(II) μ-Phthalato]

1 INTRODUCTION Chemists have recognized that intermolecular inter- actions are the basis of functional properties for most molecular assembles, and detailed understan- ding of non-covalent chemistry is therefore funda- mental to interpreting and predicting the relation- ship between structure and function. Among intermo- lecular interactions, the π-π stacking between aro- matic rings is correlated with the electron transfer process in some biological systems[1], and the nature of π-π s…     

Synthesis and Crystal Structure of catena-Poly[bis-(benzimidazole)cobalt(Ⅱ) μ- Phthalato]

The title polymeric complex [Co(C8H4O4)(C7H6N2)2]n has been prepared and its crystal structure was determined by X-ray diffraction method. The crystal belongs to monoclinic,space group C2/c with a = 7.7865(12), b = 20.4215(18), c = 13.4880(14) (A),β = 103.298(2)°, V = 2087.3(4) (A)3, Mr = 459.32, Z = 4, Dc= 1.462 g/cm3,μ = 0.859 mm-1, F(000) = 940, R = 0.0636 and wR = 0.1639 for 1278 observed reflections (I ＞ 2σ(Ⅰ)). The complex assumes a distorted tetrahedral coordination geometry, formed by two phthalate anions and two benzimidazoles (bzim). The phthalate anions bridge the neighboring Co(Ⅱ) atoms to form the polymeric chains. The centroid distance of 3.471(3) (A) between the parallel bzim rings of adjacent polymeric chains suggests the existence of π-π stacking.     

The structure of organic derivatives of hexacoordinated germanium. (O→Ge) chelated bis-(2-oxo-1-hexahydroazepinylmethyl)difluorogermane and bis-(2-oxo-1-hexahydroazepinylmethyl)fluorogermane tetrafluoroborate

Two fluoro derivatives of hexacoordinated germanium containing chelated 2-oxo-1-hexahydroazepinylmethyl ligands were investigated by X-ray diffraction analysis. The coordination polyhedron of the Ge atom in difluoride1 is a somewhat distorted octahedron with the following bond lengths (Å): Ge-F 1.799(2), GeO 2.185(3), and Ge-C 1.945(4). Tetrafluoroborate 2 has an ionic structure; the valence environment of the Ge atom is a distorted trigonal bipyramid open in the direction of the BF ₄ ^– anion. The bond lengths in 2 are: Ge-F 1.792(8), GeO 2.001(4), and Ge-C 1.937(9) Å; the Ge...F(anion) distances are 3.43(1) and 3.68(1) Å. Analysis of the geometry of1,2, and related structures containing hexa-coordinated germanium shows that the parameters of their hypervalent moieties are related to each other by dependences similar to those observed in compounds of pentacoordinated Si and Ge.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1427–1431, August, 1994.This work was carried out with the financial support of the Russian Foundation for Basic Research (project No 93-03-4855).     

Catalytic and antimicrobial studies of binuclear ruthenium(III) complexes containing bis-β-diketones

A series of new binuclear Ru(III) complexes of the type {[RuX₃(EPh₃)]₂(bis- β-dk)} [X = Cl/Br; E = P/As bis- β-dk = bis(β-diketone)] have been prepared by reacting [RuCl₃(PPh₃)₃], [RuCl₃(AsPh₃)₃], [RuBr₃(PPh₃)₃], [RuBr₃(AsPh₃)₃] with bis(β-diketones) in a 2:1 molar ratio in benzene. These complexes have been characterized by physico-chemical and spectroscopic methods. The redox property of the complexes were studied by cyclic voltammetric technique. The complexes were found to be effective catalysts for the aryl–aryl coupling and oxidation of benzyl alcohol, cyclohexanol, propan-1-ol and 2-methylpropanol to benzaldehyde, cyclohexanone, propionaldehyde and 2-methylpropionaldehyde, respectively, using molecular oxygen as primary oxidant. All the complexes have been screened for their antibacterial and antifungal activities.     

Temperature-dependent vibrational spectra of zinc(II) bis-(N,N′-diethyldithiocarbamate) in solid state and solution

The IR spectra of zinc(II) bis-(N,N′-diethyldithiocarbamate) in the solid state (at 20, 80 and 120°C) as well as in solution (20°C) have been recorded and discussed as to the changes in the zinc coordination sphere that may occur upon heating and dissolution. The decreased number of bands in the high-temperature and in the solution specta as compared with the room temperature solid state spectra has been explained by removal of the intermolecular contacts upon dissolution or thermal averaging in the high temperature solid state.     

Salt effects on reactivity for the formation and dissociation of bis-(ethane-1,2-diamine)cobalt(III)-μ-pyrazinecarboxylato-pentacyanoferrate(II)

Dependences of rate constants on added salt concentrations have been established for approach to equilibrium for reaction of pyrazinecarboxylato-bis-1,2-diaminoethane-cobalt(III) with the pentacyanoferrate(II) complex [Fe(CN)₅L]^3– with L = MeCN. Added salt effects on dissociation of the binuclear bis-1,2-diaminoethanecobalt(III)(-pyrazine-carboxylato)pentacyanoferrate(II), [(en)₂Co(-pzCO₂)Fe(CN)₅]^–, produced in this reaction are compared with those on dissociation of other pentacyanoferrate(II) complexes. The activation volume for dissociation of this binuclear complex has been derived from the observed salt effects via the dependence of rate constants on surface tension and the thence-derived surface area of activation.     

Fe(HSO4)3·SiO2 as an efficient,heterogeneous and recyclable catalyst for the synthesis of bis-(β-enaminones) and bis-(β-enamino esters)

Fe(HSO₄)₃·SiO₂ is used to catalyze the condensation of β-diketones and β-keto esters with aromatic and aliphatic diamines in solvent-free conditions at room temperature. This afforded the corresponding bis-(β-enaminones) and bis-(β-enamino esters) in very good to excellent yields. Short reaction times, easy work-up procedure, and reusability of the catalyst are the merits of this study.     

Tin,palladium and platinum derivatives of 1,1′-bis(diphenylphosphine)ferrocene. Crystal and molecular structures of 1,1′- bis-(diphenylphosphine)ferrocenedichloropalladium(II) and of 1,1′-bis(diphenylphosphine)ferrocenedichloroplatinum(II)

Summary Ten derivatives of 1,1-bis(diphenylphosphine)ferrocene (BDPF) are described in this paper. The first three, [BDPF·SnCl₄] (1), [BDPF·MeSnCl₃] (2) and [BDPF·PhSnCl₃] (3), present the two phosphorus atoms of the ligand directly bonded to a Sn centre. Two others, [BDPF-PdCl₂ (4) and [BDPF·PtCl₂] (5), similarly have the ligand BDPF acting as a bidentate species towards a transition metal. The crystal and molecular structures of (4) and (5) are presented here. Two other BDPF complexes were obtained with Pd and Pt, with the transition metals in the zerovalent state, namely [Pd(BDPF)₂] (6) and [Pt(BDPF)₂] (7). Finally, three trimetallic complexes are also described; [BDPF·Pd(-Cl)₂SnCl₂] (8), [BDPF· Pt(-Cl)₂SnCl₂] (9) and [BDPF·PdClSnCl₃] (10).     

The infrared spectra of ethylenediamine complexes—II. Tris-, bis- and mono(ethylenediamine) complexes of metal(II) halides

The i.r. spectra of the complexes M(en)₃X₂ (M = Mn, Fe, Co, Ni, Cu, Zn), trans-Cu(en)₂X₂, Ni(en)₂X₂ and M(en)X₂ (M = Ni, Cu, Zn; X = Cl, Br, I) have been studied. Assignments are proposed for the tris(ethylenediamine) complexes on the basis of ¹⁵N-, N₂D₄- and C₂D₄-labelling of en and the effects of metal ion substitution in relation to our earlier study of [M(en)₃]SO₄ complexes. Assignments for the bis(ethylenediamine) complexes are based on our observations of halogen-sensitivity and earlier studies on metal isotope labelling and ligand deuteration of the halide complexes and a normal coordinate analysis of the [Cu(en)₂]²⁺ species. The spectra of the halide complexes have been extended below 200 cm⁻¹ for the first time. Finally, the spectra of the mono(ethylenediamine) complexes are discussed in relation to their known or probable structures.     

Nickel(II) and copper(II) complexes with chiral bis-α-thiooxime,the derivative of natural terpenoid (+)-3-carene: Synthesis and structures

Chiral bis-α-thiooxime (H₂L¹), the derivative of the natural monoterpenoid (+)-3-carene, was synthesized and used to prepare paramagnetic complexes of the composition M(H₂L¹)Cl₂ (M=Ni, Cu). The crystal structures of [Ni(H₂L¹)Cl₂] (I) and [Cu(H₂L¹)Cl₂] (II) were determined by X-ray diffraction analysis. Crystals I and II consist of mononuclear acentric molecules. The Ni²⁺ ion in a molecule of complex I coordinates two N atoms and two S atoms of a tetradentate chelating ligand (the H₂L¹ molecule) and two Cl atoms. The NiCl₂N₂S₂ coordination core forms octahedron compressed along the apical N atoms. In a molecule of complex II, the Cu²⁺ ion coordinates two S atoms and the N atom of a tridentate chelating H₂L¹ ligand and two Cl atoms. The CuCl₂NS₂ coordination core forms a trigonal bipyramid.     

Synthesis and properties of Cu(II) and Pd(ii) complexes with chiral bis-α-sulfanyl oxymes,the derivatives of natural monoterpene, α-pinene

Coordination compounds Cu₂(H₂L¹)Cl₄ (I), Pd₂(H₂L¹)Cl₄ (II), Cu₂(H₂L²)Cl₄ (III), and Pd₂(H₂L²) Cl₄ (IV) with chiral bis-α-sulfanyloximes, the derivatives of the monoterpenoid (−)-α-pinene, were obtained. The complexes I and III are paramagnetic (μ_eff = 2.45 and 2.67 μ_B, respectively), II and IV are diamagnetic. According to IR spectroscopy, in the compounds I–IV the nearest environment of Cu and Pd atoms includes N, S, and Cl atoms. The values of μ_eff and parameters of ESR spectra of the solid phase and solutions of I and III show a binuclear structure of the Cu(II) complexes. Parameters of the ¹H and ¹³C NMR spectra of compounds II and IV indicate the formation of binuclear Pd(II) complexes of C ₂ symmetry and the closure of fivemembered chelate rings PdNSC₂. The PdCl₂ fragments are in transoid position. H₂L¹ and H₂L² are tetradentate bridging chelating ligands.     

Synthesis of C2-symmetrical bis-β-amino alcohols from (R)-cysteine and their application in enantioselective catalysis

Six new sulfur-containing C₂-symmetrical bis-β-primary and sec-amino-tert-alcohols have been synthesized from (R)-cysteine and applied successfully in the enantiocontrolled catalytic addition of diethylzinc to benzaldehyde. The resulting 1-phenyl-1-propanol could be obtained in good enantiomeric excess of up to 94%. Using the same chiral auxiliaries in the enantioselective borane reduction of acetophenone afforded 1-phenyl-1-ethanol in enantiomeric excesses of up to 82%.     

Synthesis and structure of bis-μ-[(methylenedicyclopentanone-2,2′-dioximato)triphenylantimony]

The reaction of pentaphenylantimony with methylenedicyclopentanone-2,2 dioxime affords bis--[(methylenedicyclopentanone-2,2-dioximato)triphenylntimony] having, according to the X-ray diffraction data, a centrosymmetric structure with two Ph₃Sb moieties linked by dioxime bridges. The antimony atom has a distorted trigonal bipyramidal coordination. The Sb-C bond lengths vary in an interval of 2.111(1)–2.137(3) , and the Sb-O distances are equal to 2.064(1) and 2.0663(9) . The molecule contains short intramolecular contacts SbN of 2.876(1) and 2.910(1) .Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 172–176.Original Russian Text Copyright © 2005 by Sharutin, Molokova, Sharutina, Alyabeva, Kukharev, Akimova, Pushilin.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

Synthesis,characterization and redox properties of mono- and bis-β-diketonate ruthenium complexes

Complexes of the type [RuIII(L)Cl2(PPh3)2] and [RuII(L)2(PPh3)2] (HL=benzoylacetone or acetylacetone) have been synthesized by the reaction of [RuCl2(PPh3)3] with HL under various experimental conditions. The [RuIII(L)Cl2(PPh3)2] complexes are one-electron paramagnetic species and, in solution, they show intense LMCT transitions in the visible region together with weak ligand-field transitions at lower energies. The [RuII(L)2(PPh3)2] complexes are diamagnetic and their solutions show sharp 1H n.m.r. signals and also show intense MLCT transitions in the visible region. In MeCN solution, the [RuIII(L)Cl2(PPh3)2] complexes show a reversible RuIII-RuII reduction near –0.3V and an irreversible RuIII- RuIV oxidation near 1.2 V versus s.c.e. A reversible RuII-RuIII oxidation is displayed by the [RuII(L)2(PPh3)2] complexes in MeCN solution near 0.3 V versus s.c.e. followed by another reversible RuIII-RuIV oxidation near 1.1 V versus s.c.e. The [RuII(L)2(PPh3)2] complexes have been oxidized to the corresponding [RuIII(L)2(PPh3)2]+ analogues and isolated as ClO4– salts in the solid state. The oxidized complexes are one-electron paramagnetic. They are 1:1 electrolytes in solution and show intense LMCT transitions in the visible region along with weak ligand-field transitions at lower energies.     

Crystal and molecular structure of dicopper bis-(3-amino-5-methylisoxazole)tetraacetate [Cu2(μ-OCOCH3)2L2]

It was established by X-ray diffraction analysis that in the dimer complex of 3-amino-5-methylisoxazole (L) [ Cu₂(μ-OCOCH₃)₄L₂ ] the coordination bond is localized at the endocyclic pyridine type N atom. Arguments are given against other possible types of coordination in aminoisoxazole complexes conjectured from IR spectroscopy data in a number of publications. The dimer structure of the complex agrees with antiferromagnetic data (2J = -280 cm^-1 ). Translated fromZhurnal Strukturnoi Khimii, Vol. 41, No. 3, pp. 572-580, May–June, 2000.     

Polymorphs and aurophilic interactions in colorless crystals of Au2(μ-1,2 bis-(diphenylarsino)ethane)X2, (X = Cl, Br, I)

Solutions containing the components Au(+), dpae (dpae is 1,2 bis-(diphenylarsino)ethane), and X(-) (X is Cl, Br, or I) can produce two different types of crystals with the composition Au(2)(μ-dpae)X(2): colorless blocks and colorless needles. Crystallographic studies of these crystals show that they are polymorphs with different structural motifs. In the α-polymorphs, which are isostructural, individual molecules of Au(2)(μ-dpae)X(2) form discrete dimers through two identical Au···Au contacts. In the β-polymorphs, which each have unique crystallographic parameters, the Au(2)(μ-dpae)X(2) molecules assemble into polymeric chains through aurophilic interactions. The Au···Au contacts in the α-polymorph (3.1163(2), 3.1064(3), and 3.0842(2) ? for Cl, Br, I, respectively) are somewhat shorter than those in the β-polymorph (3.1668(3), 3.1042(8), and 3.1046(2) for Cl, Br, I respectively). The systematic study we now report shows an increase in the strength of this aurophilic interaction for the α-form in the series X = Cl < Br < I, which is in good agreement with theoretical studies by Pyykk? and his co-workers.     

Mössbauer spectra of bis-[π-(3)-1,2-dicarbollyl] cobaltate(III), tetrachlorogallate,and ferricinium molybdate

The Mössbauer spectra of the new salt-like complexes of the ferricinium ions [Fe^IIICp₂]⁺{Co^III[π-(3)-1,2-B₉C₂H₁₁]₂}^? (I) with π-sandwich aromatic anions and of the [FeCp₂]⁺[GaCl₄]^?(II) and [FeCp₂] ₂ ⁺ [MoO₄]^2? (III) compounds are compared. It is shown that the Mössbauer spectra of these compounds are broadened asymmetric lines whose broadening and asymmetry increase with decreasing temperature. The peculiarities of the spectra are associated with paramagnetic relaxation effects, in particular, with the Blume effect. In I–III, the sign of the electric field gradients on the iron nuclei is negative, while ferrocene exhibits a positive electric field gradient. It is noted that the nature of the anion affects the frequency of spin fluctuations, but has no effect on the electronic state of iron atoms, as well as on the symmetry of its local surrounding in FeCp ₂ ⁺ . Analysis of the probability of the Mössbauer effect suggests that in compound I the anion-cation interaction is stronger than that in compounds II and III.