Raman-spektroskopische Untersuchungen an Metall-dicyanamiden

Raman Spectroscopic Investigations of Metal Dicyanamides The Raman spectra of 3d metal dicyanamides M{N(CN)₂}₂ (M ? Mn, Fe, Co, Ni, Cu, Zn) and some pyridine complexes [M{N(CN)₂}₂py₂] are investigated. Characteristic variations of these frequencies depending on different parameters are discussed.     

Darstellung und spektroskopische Charakterisierung von Kupfer(II)- und Nickel(II)-tricyanmethanid-Komplexen mit Imidazol-Derivaten – Kristallstruktur von [Cu{C(CN)3}2(2-meiz)2]

Synthesis and Spectroscopic Characterization of Copper(II) and Nickel(II) Tricyanomethanide Complexes with Imidazoles – Crystal Structure of [Cu{C(CN)₃}₂(2-meiz)₂] The copper(II) and nickel(II) tricyanomethanide complexes with imidazoles of the type [Cu{C(CN)₃}₂L₄], [L = 2- or 4-methylimidazole (meiz)] and [M{C(CN)₃}₂L₂] [M = Cu, L = imidazole (iz), 2- or 4-meiz; M = Ni, L = iz, 2- or 4-meiz] were prepared and characterized by electronic, infrared, and – some of them – by ESR spectroscopy. The structure [Cu{C(CN)₃}₂(2-meiz)₂], solved by X-ray crystallographic analysis, shows a two-dimensional network with unsymmetric C(CN)₃-bridges between the Cu^II atoms. Polymeric structures with bridging C(CN)₃-groups were identified by means of spectroscopic methods also for the other [M{C(CN)₃}₂L₂] complexes. On the other hand, for the complexes [M{C(CN)₃}₂L₄] follow molecular structures, in which monodentate C(CN)₃ ligands are present. All compounds under investigation show a tetragonal-bipyramidal geometry with various degree of tetragonal distortion.     

Anionische Nickel-Pseudohalogenid-Komplexe der Typen [Ni{N(CN)2}3]− und [Ni{N(CN)2}2(NCS)2]2−

Anionie Nickel Pseudohalide Complexes of the Types [Ni{N(CN)₂}₃]^? and [Ni{N(CN)₂}₂(NCS)₂]^2? The preparation of a new type of anionic pseudohalide complexes of nickel [Ni{N(CN)₂}₃]^? and of mixed thiocyanate-dicyanamide complexes [Ni{N(CN)₂}₂(NCS)₂]^2? is reported. The structures of the complexes are discussed on the basis of IR- and magnetic measurements. The new compounds are representing polymer octahedral complexes with a bridging function of the dicyanamide ligands.     

Crystal Structures and Melting Behaviors of 2D and 3D Anionic Coordination Polymers Containing Organometallic Ionic Liquid Components

Although coordination polymers generally do not melt, several that do melt have been synthesized recently and have drawn much attention. In this study, two- and three-dimensional coordination polymers that melt were synthesized, [Ru(Cp)(C₆H₅R)][M{C(CN)₃}₂] (R=H, Me, Et; M=K, Rb; Cp=C₅H₅), which are complex salts comprising M[C(CN)₃] and organometallic ionic liquids [Ru(Cp)(C₆H₅R)][C(CN)₃]. They have anionic [M{C(CN)₃}₂]_n⁻ coordination polymer frameworks, whose dimensionalities depend on the size of the organometallic cation inside. Their melting points decreased with increasing cation substituent length and size of the alkali metal ion (T_m=102–239 °C), and these low-melting-point coordination polymers exhibited incongruent melting, forming mixtures of solid M[C(CN)₃] and ionic liquid upon melting. Using the same method, coordination polymers were synthesized with various bridging ligands, [Co(Cp)₂][MX₂] (X=B(CN)₄, C(CN)₃, N(CN)₂; M=K, Na), as well as a paramagnetic coordination polymer, [Fe(Cp)₂][K{C(CN)₃}₂].     

Thermal N(CN)2-bridging reactions of dicyanamide complexes Ni{N(CN)2}2Ln in solid phase

The stoichiometry of thermal decomposition reactions was studied for the following compounds: Ni{N(CN)₂}_2py2 (I) (py-pyridine), Ni{N(CN)₂}₂(2-Mepy)₂ (II), Ni{N(CN)₂}₂(3-Mepy)₂ (III) and Ni{N(CN)₂}₂(4-Mepy)₃ (IV). In complexes I and II the loss of the volatile heterocyclic ligands occurs in one step while in complexes III and IV in two steps. Magnetic and spectral data indicated pseudooctahedral configuration for all complexes. The course of thermal N(CN)₂-bridging reactions of the complexes studied are discussed. Part XXV in the series Heterogeneous reactions of solid Ni(II) complexes.     

X-ray crystallographic and physical investigation of tricyanomethanide and dicyanamide complexes of cobalt(II) with imidazole and its methyl derivatives

Summary Reaction of Co^II with N(CN) _inf2 ^sup– or C(CN) _inf3 ^sup– in the presence of imidazole (iz) or its methyl derivatives (2-meiz and 4-meiz) gave eight compounds of Co^II: ligand stoichiometry 12, including two isomeric pairs ( and ) for the complexes [Co{C(CN)₃}₂(2-meiz)₂] and [Co{C(CN)₃}₂-(4-meiz)₂]. The complexes were studied by electronic and i.r. spectroscopies. For -[Co{C(CN)₃}₂(2-meiz)₂] singlecrystal X-ray analysis was performed; its crystal structure consists of one-dimensional chains, formed by C(CN) _inf3 ^sup– anions bridging between the Co^II atoms. The Co^II atom is nearly octahedrally coordinated by two tertiary nitrogens of 2-meiz and four nitrogens of C(CN) _inf3 ^sup– . The spectra of these compounds and of the complexes with iz, as well as that of -[Co{C(CN)₃}₂(4-meiz)₂], indicate all these compounds to have basically the same bridging polymeric octahedral structure. However, the spectra indicate distorted tetrahedral structures for the remaining compounds.     

The in vitro antifungal activity of some dithiocarbamate organotin(IV) compounds on Candida albicans— a model for biological interaction of organotin complexes

The in vitro antifungal activity of the dithiocarbamate organotin complexes [Sn{S₂CN(CH₂)₄}₂Cl₂] ( 1 ), [Sn{S₂CN(CH₂)₄}₂Ph₂] ( 2 ), [Sn{S₂CN(CH₂)₄}Ph₃] ( 3 ), [Sn{S₂CN(CH₂)₄}₂n‐Bu₂] ( 4 ), [Sn{S₂CN(CH₂)₄}Cy₃] {Cy = cyclohexyl} ( 5 ), [Sn{S₂CN(C₂H₅)₂}₂Cl₂] ( 6 ), [Sn{S₂CN(C₂H₅)₂}₂Ph₂] ( 7 ), [Sn{S₂CN(C₂H₅)₂}Ph₃] ( 8 ), [Sn{S₂CN(C₂H₅)₂}₃Ph] ( 9 ) and [Sn{S₂CN(C₂H₅)₂}Cy₃] ( 10 ) has been screened against Candida albicans (ATCC 18804), Candida tropicalis (ATCC 750) and resistant Candida albicans collected from HIV‐positive Brazilian patients with oral candidiasis. All compounds exhibited antifungal activities and complexes 3 and 8 displayed the best results. We have investigated the effect of compounds 1–10 on the cellular activity of the yeast cultures. Changes in mitochondrial function have not been detected. However, all drugs reduced ergosterol biosynthesis. Preliminary studies on DNA integrity indicated that the compounds do not cause gross damage to yeast DNA. The data suggest that these compounds share some mechanisms of action on cell membranes similar to that of polyene but not with azole drugs, normally used in Candida infections. Copyright © 2008 John Wiley & Sons, Ltd.     

Zur Charakterisierung von 1,1,2,3,3-Pentacyanopropenid als Komplexligand in ein- und zweizähniger Funktion. Darstellung von Komplexen des Typs [MX(PPh3)n] (M = CuI,AgI; X = NCC{C(CN)2}2; n = 2, 3)

Pseudoelement Compounds. XII. [1] On the Characterization of 1,1,2,3,3-Pentacyanopropenide in Unidentate and Bidentate Function. Syntheses of Complexes of the Type [MX(PPh₃)_n] (M = Cu^I, Ag^I; X = NCC{C(CN)₂}₂; n = 2, 3) 1,1,2,3,3-Pentacyanopropenide is characterized as unidentate and bidentate ligand. For that reason compounds of the types [MX(PPh₃)₃] ( 6 ) and [MX(PPh₃)₂]₂ ( 8 ) (M = Cu^I, Ag^I) are synthesized. In the complexes 6 the ionic ligand is coordinated unidentately through an end-on nitrile group of a C(CN)₂ unit and in the dimeric complexes 8 bidentately bridging through the N atoms of a C(CN)₂ moiety too. The compounds are characterized by ¹³C NMR, ³¹P NMR and IR spectroscopy. The crystal structure of [AgX(PPh₃)₃] is presented and the structural parameters of the anion in this complex and in [CuX(PPh₃)₂]₂ [X = NCC{C(CN)₂}₂] are compared.     

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.     

Nickel(II) complexes with dicyanamide and tetramines

Four new pseudohalide complexes of the type [NiL{N(CN)₂}₂] (L = N(CH₂CH₂NH₂)₃, TAA; triethylenetetramine, TTA) and [NiL{N(CN)₂}]ClO₄ have been prepared and characterized by spectroscopic and magnetic methods. The X-ray crystal structures of [Ni(TAA){N(CN)₂}₂] and [Ni(TTA){N(CN)₂}₂] have been determined, and analyses show that in both complexes the Ni ion posseses distorted octahedral geometry. The temperature dependence of the magnetic susceptibility of [Ni(TTA){N(CN)₂}](ClO₄) was measured, but no antiferromagnetic interaction was detected.     

Clathrate and inclusion compounds: Part V. An infrared and Raman study of the decomposition of the Hofmann aniline clathrates M(NH3)2Ni(CN)4.2C6H5NH2 {M = Cd(II) and Ni(II)}

The time-dependent changes which are observed in the infrared and Raman spectra of samples of the two Hofmann aniline clathrates M(NH₃)₂Ni(CN)₄.an₂ {M = Cd(II), Ni(II), an = C₆H₅NH₂} indicate the occurrence of a solid state ligand replacement reaction in which the aniline guest molecule replaces the coordinated ammonia to give Man₂Ni(CN)₄ as the final product. The rate of replacement is greater for the cadmium than for the nickel clathrate, and for both clathrates evacuation of the sample greatly increases the rate of replacement. The Man₂Ni(CN)₄ complexes can themselves act as host lattices forming clathrates containing guest molecules such as aniline.     

Solid-State Properties of Hexaazatriphenylenehexacarbonitrile HAT(CN)6.− Radical Anions in Crystalline Salts Containing Cryptand(M+) and Crystal Violet Cations

Crystalline {Cryptand[2.2.2](Na⁺)}{HAT(CN)₆^.−}⋅0.5C₆H₄Cl₂ ( 1 ), {Cryptand[2.2.2](K⁺)}{HAT(CN)₆^.−} ( 2 ), (CV⁺){HAT(CN)₆^.−} ( 3 ), and (CV⁺){HAT(CN)₆^.−}⋅2C₆H₄Cl₂ ( 4 ) salts (where CV⁺ is the crystal violet cation) containing hexaazatriphenylenehexacarbonitrile radical anions have been obtained. The solid-state molecular structure as well as the optical and magnetic properties of HAT(CN)₆^.− are studied. The formation of HAT(CN)₆^.− in 1 – 4 leads to the appearance of new bands in the visible range, at 694 and 740 nm. The HAT(CN)₆^.− radical anions have spin state S=1/2 and are packed in one-dimensional stacks containing the {HAT(CN)₆^.−}₂ dimers alternated with weaker interacting pairs of HAT(CN)₆^.− in 1 and nearly isolated {HAT(CN)₆^.−}₂ dimers in 2 . The {HAT(CN)₆^.−}₂ dimers are diamagnetic in 1 but they effectively mediate one-dimensional antiferromagnetic coupling of spins within the stacks with moderate exchange interaction of J/k_B = −80 K. The behaviour of salt 2 is described by a singlet–triplet model for the {HAT(CN)₆^.−}₂ dimers with an energy gap of 434(±7) K. Magnetic behaviour of both salts agree well with the data of extended Hückel calculations. Salts 3 and 4 contain isolated stacks of alternated HAT(CN)₆^.− and CV⁺ ions, and in this case, nearly paramagnetic behaviour is observed with Weiss temperatures of −1 and −7 K, respectively. Narrow Lorentzian EPR signals with g = 2.0033–2.0039 were found for the HAT(CN)₆^.− radical anions in 1 and 4 but in solution g-factor shifts to 1.9964. The electronic structure of HAT(CN)₆^.− is analysed based on X-ray diffraction data for 2 , showing a Jahn–Teller distortion of the radical anion that reduces the symmetry from D_3h to C_s and splits the initially degenerated LUMOs.     

An infrared and raman spectroscopic study of metal(II) Di(2-methylpyridine) tetracyanonickelate complexes: Ni(C6H7N)2Ni(CN)4 and Cd(C6H7N)2Ni(CN)4

The results of an infrared and Raman spectroscopic study are reported for two new metal 2-methylpyridine tetracyanonickelate complexes, M(C₆H₇N)₂Ni(CN)₄, M=Ni or Cd. Their structure consists of corrugated polymeric layers of {M-Ni(CN)₄} with 2-methylpyridine molecules bound directly to the metal (M). These complexes can act as host lattices in the formation of inclusion compounds with dioxane guest molecules.     

Metall-Pseudohalogenide. XXXIX. Dicyanamid-Komplexe von Palladium(II) und Platin(II) des Typs M{N(CN)2}2L2

Metal Pseudohalides. XXXIX. Dicyanamide Complexes of Palladium(II) and Platinum(II) of the Type M{N(CN)₂}₂L₂ The synthesis of mixed dicyanamide complexes of the type M{N(CN)₂}₂L₂ (M: Pd, Pt) is reported. Infrared and NMR-spectroscopic investigations are indicating the hitherto undescribed coordination type M? N(CN)₂ of the anionic ligand.     

Synthesis of PbSe nanocrystallites using a single-source method. The X-ray crystal structure of lead (II) diethyldiselenocarbamate

The compounds Pb{Se₂CN(C₂H₅)₂}₂ and Pb{Se₂CN(CH₃)(C₆H₁₃)}₂ were synthesised and characterised. The X-ray crystal structure of Pb{Se₂CN(C₂H₅)₂}₂ is reported. The use of these compounds as single-molecule precursors to produce PbSe by thermolysis in tri-n-octylphosphine oxide was investigated. The optical and morphological properties of the PbSe particulates were analysed; strong quantum confinement effects were observed in the optical spectra of nanodispersed PbSe in organic solvents.     

Magnetic and spectral properties of the coligand isomer pair: Cu{N(CN)2}2(pyrazole)2 and Cu{pyrazole · N(CN)2}2

Summary New coligand isomers of composition Cu{N(CN)₂}₂(pz)₂ and Cu{pz · N(CN)₂}₂ (pz = pyrazole) were prepared and studied by measuring their magnetic susceptibilities up to 4.2K and by aid of their e.s.r., ligand field and i.r. spectra. The susceptibility data have been analysed with various models for the exchange-coupled copper(II) polymers. It is shown that the resultant exchange coupling is ferromagnetic for Cu{N(CN)₂}₂(pz)₂ (J 1.1 - 1.4 cm^–1) but antiferromagnetic for Cu{pz · N(CN)₂}₂ (J –0.4 cm^–1). A polymeric chain structure is proposed for Cu{N(CN)₂}₂(pz)₂ havingpseudo-octahedrally coordinated copper(II) and CN-bridging dicyanamide ligands. Its coligand isomer contains anionic chelate ligands, formed by nucleophilic addition between N(CN)₂ and pz in the copper(II) coordination sphere, and giving with this central atom a square-planar system. Definite, but slight axial interaction takes place between these structure units.     

Metall-Pseudohalogenide. XL. Zur Kenntnis anionischer Dicyanamidkomplexe [M{N(CN)2}4]2− des Palladium(II) und Platin(II)

Metal Pseudohalides. XL. Dicyanamido Metallates [M{N(CN)₂}₄]^2? of Palladium(II) and Platinum(II) The synthesis of homologeous tetrakis-(dicyanamido) metallates(II), [M{N(CN)₂}₄]^2? is reported. The coordination type of the ambivalent dicyanamide ligand is discussed on the basis of the i.r. and n.m.r. spectra of the new complexes.     

Synthesis,structure and magnetic properties of 2-D and 3-D [cation]{M[Au(CN)2]3} (M = Ni, Co) coordination polymers

In order to study the templating effect of the cation and the resulting impact on the magnetic properties, reactions of M(II) salts with [cation][Au(CN)₂] were conducted, yielding a series of coordination polymers of the form [cation]{M[Au(CN)₂]₃} (cation = ⁿBu₄N⁺, PPN⁺ (bis(triphenylphosphoranylidene)ammonium); M = Ni(II) and Co(II)). The structures of ⁿBu₄N{M[Au(CN)₂]₃} and PPN{M[Au(CN)₂]₃} (M = Ni and Co) contain two distinct 3-D anionic frameworks of {M[Au(CN)₂]₃}⁻, hence the framework was sensitive to the cation, but not to the identity of the metal center. In ⁿBu₄N{M[Au(CN)₂]₃}, the metal centers are connected by [Au(CN)₂] units to form six 2-D (4, 4) rectangular grids that are fused through the M centers to yield a complex three-dimensional framework which accommodates the ⁿBu₄N⁺ cations. In PPN{M[Au(CN)₂]₃}, the framework adopts a simpler non-interpenetrated Prussian-blue-type pseudo-cubic array, with the PPN⁺ cations occupying each cavity; no reduction in dimensionality occurs despite the large cation size. In the presence of water, {Co(H₂O)₂[Au(CN)₂]₂} · ⁿBu₄N[Au(CN)₂] was obtained, a 2-D layered polymer that contains neutral sheets of {Co(H₂O)₂[Au(CN)₂]₂} which are separated by ⁿBu₄N[Au(CN)₂] layers; aurophilic interactions of 3.4250(13) Å and hydrogen-bonding connect the layers. The magnetic properties of all compounds were investigated by SQUID magnetometry. The Ni(II) polymers have similar magnetic behaviour, which are dominated by zero-field splitting with very weak antiferromagnetic interactions at low temperature (D ∼ 2–3 cm⁻¹, zJ < 1 cm⁻¹). The magnetic behaviour of all of the Co(II) polymers were found to be very similar, and dominated by single-ion effects (i.e. a large first-order orbital contribution). No significant magnetic coupling is observed in any of these coordination polymers, suggesting that the [Au(CN)₂] bridging unit behaves as a poor mediator of magnetic exchange in these high-dimensionality systems.     

Structural Organization of Nickel(II), Zinc(II), and Copper(II) Complexes with Diisobutyldithiocarbamate: EPR, <Superscript>13</Superscript>C and <Superscript>15</Superscript>N CP/MAS NMR,and X-Ray Diffraction Studies

The structures and spectroscopic properties of nickel(II), zinc(II), and copper(II) complexes with dibutyl- and diisobutyldithiocarbamate were studied by EPR and ¹³C and ¹⁵N CP/MAS NMR spectroscopy and X-ray diffraction analysis. According to the EPR data, copper(II) forms mononuclear [^63/65Cu{S₂CNR₂}₂] and heterobinuclear complexes [^63/65CuZn{S₂CNR₂}₄] under magnetic dilution conditions. The isomeric forms of nickel(II) and zinc(II) diisobutyldithiocarbamates were detected by ¹³C and ¹⁵N NMR spectroscopy. The crystalline zinc(II) diisobutyldithiocarbamate was found to have a unique structural organization with alternating mononuclear [Zn{S₂CN(i-C₄H₉)₂}₂] and binuclear molecular forms [Zn₂{ S₂CN(i-C₄H₉)₂}₄] in the 1 : 1 ratio.     

Infrared and raman spectroscopic investigations of cadmium tetracyanonickelate complexes of aminopyridines

The infrared and Raman spectra of three new complexes of the formula CdL₂Ni(CN)₄ {L = 2-aminopyridine or 2-amino-4-methylpyridine} and Cd(L) (NH₃)-Ni(CN)₄ {L = 2-amino-3-methylpyridine} are reported. It is concluded that the ring nitrogen and not the amino nitrogen is involved in complex formation. Vibrational assignments for all the bands observed are proposed. The complexes are shown to have a structure consisting of two dimensional polymeric layers formed with Ni(CN)₄ ions bridged by CdL₂ {L = 2-aminopy or 2-amino-4-methylpy} or Cd(NH₃)(L) {L = 2-amino-3-methylpy} cations. Several modes of coordinated aminopyridines have upward wavenumber shifts in comparison to those of the free molecules. These are thought to be due to the coupling of the internal modes of aminopyridines with the MN vibrations.