Orientation of guest benzene molecules in Hofmann-type and related clathrates by molecular mechanics calculation

Molecular mechanics calculations were carried out to interpret the observed orientational angle of the benzene molecule enclathrated in the Hofmann-type M(NH₃)₂Ni(CN)₄·2 C₆H₆ (M = Mn, Ni, Cu, and Cd), Hofmann-en-type Cd(en)Ni(CN)₄·2 C₆H₆ (en = NH₂CH₂CH₂NH₂), and Hofmannmea-type(2) Cd(mea)Ni(CN)₄·2 C₆H₆ (mea = NH₂CH₂CH₂OH) clathrates using the van der Waals potential functions in Molecular Mechanics Version 2. The angle is most influenced by the guest-to-guest contact in the interlayer space between the two-dimensionalcatena-[metal(II) tetra--cyanonickelate(II)] networks for the Hofmann-type series. The discrepancy between the calculated and the observed angles in each crystal structure was at largest 3.5°; the structures of Cd(NH₃)₂Ni(CN)₄·2 C₆H₆ and Cd(en)Ni(CN)₄·2 C₆H₆ have been revised using new data collected by counter-methods.     

Vibrational spectroscopic studies on the en-Td-type benzene clathrates: M(ethylenediamine)M′(CN)4·2C6H6 (M=Mn or Cd,M′=Cd or Hg)

IR spectra of Mn(en)M(CN)₄·2C₆H₆ (M=Cd or Hg), and IR and Raman spectra of Cd(en)M(CN)₄·2C₆H₆ (M=Cd or Hg) clathrates are reported. The spectral features suggest that the first two compounds are similar in structure to the later two Td-type clathrates.     

Synthese von Clathratverbindungen des Typs Cd(mea) m [Pd(CN)4] ·nG

The preparation, identification and some properties of three new clathrate compounds Cd(mea)[Pd(CN)₄] · 2C₆H₆, Cd(mea)₂[Pd(CN)₄] · C₄H₄S and Cd(mea)₂[Pd(CN)₄] · C₄H₄NH (mea = HO-CH₂-CH₂-NH₂) are described.

     

Vibrational spectroscopic studies on the hofmann-Td-type clathrates: M(NH3)2M′(CN)4·2C6H6 (M=Mn or Cd and M′=Cd or Hg0

IR spectra of Mn(NH₃)₂M(CN)₄·2C₆H₆ (M=Cd or Hg), and IR and Raman spectra of Cd(NH₃)₂M(CN)₄·2C₆H₆ (M=Cd or Hg) are reported. The spectral data suggest that the former two compounds are similar in structure to the latter two Td-type clathrates.     

Synthese von Tetracyanoniccolat-clathraten mit Benzol Kurze Mitteilung

Zusammenfassung Durch Ersetzung des Cadmiums im Clathrat Cden[Ni(CN)₄]·2C₆H₆ wurden drei Verbindungen des TypsM(en) _m[Ni(CN)₄]·nC₆H₆ (M ²⁺=Ni, Cu, Zn;m=2–3;n=0.14–0.28) hergestellt und charakterisiert.

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Synthesis of ethylendiamine-(metal II)-tetracyanoniccolate dibenzene clathrate compounds

Replacing cadmium ion in Cden[Ni(CN)₄]·2C₆H₆ clathrate compound three compounds ofM(en) _m[Ni(CN)₄]·nC₆H₆ type (M ²⁺=Ni, Cu, Zn;m=2–3;n=0.14–0.28) were prepared and characterized.

     

The solvent dependence of the sorptive abilities of tetracyanocomplexes

The two different types of tetracyanocomplexes [ZnNi(CN)₄·nH₂O] and [Cd(en)Pd(CN)₄·2C₆H₆] have been examined as sorptive materials in a simple contact with benzene, after their modification with auxiliary solvents and their use in gas chromatographic experiments. All forms of sorption experiments show identical characteristics from the view of the sorption of aromatic compounds as exemplified by benzene. The tetracyanocomplexes exhibit a permanent capability of sorption, even when heated to a temperature of 260°C and show a separation ability towards sorbed materials depending on the solvent used and on the degree of thermal degradation of the tetracyanocomplex. The prducts of the modification and sorption (in static and dynamic) experiments have been characterized by IR spectroscopy, X-ray patterns and by thermal analysis.     

An infrared and Raman spectroscopic study of Td-type 4,4′-bipyridylcadmium(II) tetracyanometallate (II) benzene (1/2) clathrates: Cd(C10H8N2)Cd(CN)4 · 2C6H6 and Cd(C10H8N2)Hg(CN)4 · 2C6H6

Two new benzene clathrates of the form Cd(4,4-bipyridyl)M(CN)₄ · 2C₆H₆, (M=Cd or Hg) have been prepared in powder form. Their spectral data were compared with those of the corresponding host complexes and found to be consistent with the host structure found in Td-type clathrates.     

Vibrational Spectroscopic Studies on the tn-Td-Type Mn(tn)Zn(CN)4_2C6H6 and the Chelated tn-Td-Type Zn(tn)Zn(CN)4_2C6H6 Clathrates

IR spectra of Mn(trimethylenediamine)Zn(CN)₄2C₆H₆ and IR and Raman spectra of Zn(trimethylenediamine)Zn(CN)₄_2C₆H₆ are reported. The spectral data suggest that the host frameworks of these compounds are similar to those of the tn-Td-type Cd(trimethylenediamine)M(CN)₄_2benzene (M = Cd or Hg) and the chelated pn-Td-type Cd(propylenediamine)Cd(CN)₄_1,2-dichloro-ethane clathrates, respectively.     

Vibrational spectroscopic studies of some dimethylpyrazine cadmium (II) tetracyanonickelate benzene clathrates: [Cd(C6H8N2)Ni(CN)4]·C6H6

Two new cadmium dimethylpyrazine (2,3-dimethylpyrazine or 2,5-dimethylpyrazine) tetracyanonickelate benzene clathrates, [Cd(C₆H₈N₂)Ni(CN)₄]·C₆H₆, have been prepared in powder form and characterized by FT-IR spectroscopy, Raman spectroscopy, X-ray diffraction, thermal analyses and elemental analyses. Vibrational assignments are proposed for the bands of the host lattice and guest molecule. It is shown that the spectra are consistent with a proposed crystal structure for these compounds derived from X-ray diffraction measurements. The C, H, N, Cd and Ni analyses were carried out for all the compounds. Thermal behaviors of these compounds are followed using TG and DTA techniques. The FT-IR, Raman spectroscopic, XRD, thermal and elemental analyses results propose that these compounds are similar in structure to the Hofmann-type clathrates. Their structure consists of planar polymeric layers, {M–Ni(CN)₄}_∞, formed from Ni(CN)₄ anions coordinated to the bridging 2,3- or 2,5-dimethylpyrazine molecules bound directly to the cadmium. The cadmium atoms are bound to four N atoms of the CN ions and, the Ni atoms are surrounded by four C atoms of the CN groups in a square-planar layer.     

Hydration reaction of Hofmann's benzene clathrate,diamminenickel(II) tetracyanonickelate(II)-benzene-(1/2), suspended in aqueous media

Hofmann's benzene clathrate Ni(NH₃)₂Ni(CN)₄·2C₆H₆ suspended in ammoniacal, neutral, and acidic aqueous media undergoes the replacement reactions of the guest C₆H₆ and the ligating NH₃ molecules with molecules of water to give Ni(NH₃)₂Ni(CN)₄·?1H₂O, Ni(H₂O)₂Ni(CN)₄·nH₂O(0<n<2), and Ni(H₂O)₂Ni(CN)₄·4～5H₂O, respectively. The integrity of the host metal complex sheet structure is conserved with little change during the replacement reactions.     

The preparation of tetracyanonickelates showing electrical conductivity

The tetracyanonickelates Ni(NH₃)₂Ni(CN)₄·1.9 H₂O (1), Ni(NH₃)_1.65(C₄H₈O₂)_0.2Ni(CN)₄·0.8 C₄H₈O₂·0.35 H₂O (2) and Ni(en)₃Ni(CN)₄·H₂O (3) exhibit, after contact with a solution of iodine (I₂/KI), appreciable weight gains. According to thermal analysis, IR spectra and chemical analysis the new products contain intercalated iodine and iodides with the highest iodine content found in the product formed from (3). The results of high frequency conductance measurements of this product showed the highest value of electrical conductivity (10^–6 S cm^–1). Other compounds show relatively low values of (10^–8–10^–11 S cm^–1).The iodine together with its iodide and polyiodide forms enters host (3) as an intercalated species. The iodide and polyiodide forms are formed during the initial redox reactions between the NH group of the ethylenediamine and the iodine.     

An infrared and Raman spectroscopic study of the Hofmann-type complexes and clathrates: M(piperidine)2Ni(CN)4; M(piperidine)2Ni(CN)4·1.5G (M=Cd, Co, Ni or Cu; G=benzene)

New Hofmann-type complexes and clathrates of the forms M(piperidine)₂Ni(CN)₄ and M(piperidine)₂Ni(CN)₄·1.5G (M=Cd, Co, Ni or Cu; G=benzene) were prepared in powder form and their infrared and Raman spectra are reported. The spectral features suggest that these compounds are similar in structure to the Hofmann-type clathrates except for the copper compounds. The complex and clathrate of Cu have different spectral features in comparison with its analogues due to the Jahn-Teller effect.     

Deuterated benzene and benzene as guest in the copper(II)-en type of tetracyanonickelates

New host-guest complexes of tetracyanonickelates with deuterated benzene and benzene were prepared having the chemical composition Cu(en)₂Ni(CN)₄ 1 C₆D₆ and Cu(en)₂Ni(CN)₄ 2C₆H₆. The spectroscopic behaviour in the range 4000-200 cm^–1, as well as the thermal properties, were investigated and compared with those of similar clathrate compounds.     

Die Kristallstruktur des „supramolekularen”︁ Cadmiumcyanid-Hexamethylentetramin-Addukts [Cd(CN)2 · 2/3 C6H12N4]

The Crystal Structure of the “Supramolecular” Cadmiumcyanide-Hexamethylenetetramine Adduct [Cd(CN)₂ · 2/3 C₆H₁₂N₄] Single crystals of a new compound in the system Cd(CN)₂-hexamethylenetetramine (HMTA) with the composition [Cd(CN)₂ · 2/3 C₆H₁₂N₄] were obtained by crystallization from an aqueous solution containing Cd(CN)₂ and HMTA. The structure consists of a ?supramolecular”? network of ? Cd? CN? Cd- and ? Cd? HMTA? Cd-chains. The structure is compared with that of an already known compound [Cd(CN)₂ · 1/3 C₆H₁₂N₄].     

Tetracyanonickelate compounds as sorptive materials and the substitution of their H2O content by D2O

The compounds NiNi(CN)₄·3,5H₂O and Ni(NH₃)₂Ni(CN)₄·H₂O have been studied to examine the possibility of substituting their H₂O or NH₃ content by D₂O. Contact with D₂O was performed after heating the compounds to several temperatures. Depending on the degree of decomposition of the original compounds different ranges of substitution were possible. In such manner the compounds NiNi(CN)₄·3,5D₂O, NiNi(CN)₄·5D₂O, Ni(NH₃)₂Ni(CN)₄·D₂O, and Ni(D₂O)₂Ni(CN)₄·D₂O were prepared and thermally they were less stable than the original ones. The substitution by D₂O is in agreement with the sorptive properties of the original tetracyanonickelate against different organic compounds using GC, since these could substitute the guest component and sometimes also the ligands during their decomposition.     

Extraction systems of flame atomic absorption determination of trace impurities in high purity nickel salts

Summary Different extraction sytems including long chain quaternary alkylammonium salts and APDC were investigated in order to determine the optimal conditions for extraction separation and preconcentration of traces of Ag, Bi, Cd, Cu, Fe, Mo, Pb, Sb and Zn from high purity NiSO₄·6H₂O, NiCl₂·6H₂O, Ni(OOCCH₃)₂·4H₂O and Ni(NO)₃)₂·6 H₂O. Best results for multielement preconcentration were found with the extraction system HCl-trioctylmethylammonium chloride-0,002 mol/l APDC/MIBK. The proposed method permits the flame atomic absorption determination of 5·10^–6%, Ag, Cd, Cu and Zn, 1·10^–5% Bi, Fe, Pb and 5·10^–5% Mo and Sb with good accuracy and precision.     

Vibrational spectroscopic studies of three dimensional host lattices formed by pyrazine bridges between tetracyanonickelate layers

Three dimensional host lattices have been developed by forming bridges with bidentate pyrazine molecules between adjacent tetracyanonickelate polymeric layers of Ni(II) or Cd(II). The Fourier-transform IR and Raman spectra (4000-200 cm^–1) of the compounds with the general formula M(pyz)Ni(CN)₄, (where M = Ni or Cd) are reported. These host lattices can include benzene molecules but it is found that aniline molecules cannot be included in these structures. They, however, form complexes with the formula M(an)₂Ni(CN)₄, by replacing pyrazine ligands. A monodentate pyrazine complex of Cd(II) with the formula Cd(pyz)₂Ni(CN)₄ has also been prepared.     

Infrared Spectroscopic Study on the Hofmann-dadn-type and the Td-dahxn-type clathrates

Infrared spectra of M(1,10-diaminodecane)Ni(CN)₄ · 1,5 G (M=Co, Ni or Cd; G=o-xylene, m-xylene, p-xylene) and Cd(l,6-diaminohexane)M(CN)₄ · C₆H₆ (M=Cd or Hg) clathrates are reported. The 1,10-diaminodecane and 1,6-diaminohexane molecules in the host permit the inclusion of bulky guest molecules. The spectral data of clathrates were compared with those of the corresponding host. The spectral features suggest that these compounds are similar in structure to other Hofmann-type and Hofmann-T_d type clathrates, respectively.     

Palladium π-adduct of corannulene

The ternary palladium π-adduct of corannulene and benzene, [Pd₆Cl₁₂·(C₂₀H₁₀)₂·(C₆H₆)₂]·C₆H₆ (1), has been prepared by reacting the cubic Pd₆Cl₁₂-cluster with C₂₀H₁₀ in benzene. It was structurally characterized to reveal η¹-binding of Pd₆Cl₁₂ to a hub C-atom of the convex surface of corannulene (Pd?C, 3.085(3) Å) and its η⁶-complexation to benzene (Pd?C_centroid, 3.431(3) Å). The behavior and persistence of 1 in some aromatic solvents has been revealed by UV-vis and ¹H NMR spectroscopy studies.     

An Infrared Spectroscopic Study on the Hofmann T d -Type Clathrates: M(Imidazole) 2 M'(CN) 4 .2C 6 H 6

Infrared spectra of M (Imidazole)2 M' (CN)₄ 2C₆H₆ (M = Mn, Co,Ni, Cd; M' = Zn, Cd) are reported. The spectral data suggest that the clathratesare similar in host structure to of Hofmann T_d-type clathrates.