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.     

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.     

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.     

Coordination behaviour of nicotinamide: an infrared spectroscopic study

A series of Hofmann-type complexes containing two nicotinamide(nia) molecules attached to transition metal (II) (M) tetracyanonickelate frame with the formula: M(nia)₂Ni(CN)₄ (where M=Mn, Co, Ni, Cu or Cd) have been synthesised for the first time. Metal (II) halide complexes of nicotinamide complexes of the type [M(nia)₂X₂ (M=Cd, Ni, Cu, Hg; X=Cl, Br) and Ni(nia)₄Br₂ nia=nicotinamide] have also synthesised. The FTIR spectra are reported in the 4000-400 cm⁻¹ region. Vibrational assignments are given for all the observed bands. The analysis of the vibrational spectra indicates that there are some structure-spectra correlations. A pronounced change was observed in the N-H stretching frequencies of the NH₂ group. It is proposed that the amide NH₂ group influence by the intramolecular hydrogen bond in the complexes. The coordination effect on the nicotinamide modes is analysed.     

An infrared spectroscopic study of dianiline-metal(ii) tetracyanometalate complexes

The results of an IR spectroscopie study are presented for six new dianiline metal tetracyanometalate complexes, M(an)₂M'(CN)₄ (M = Mn, Fe, Co or Cu and M'= Ni; M = Ni or Cd and M' = Pt; an = aniline). Their structure consists of polymeric layers of (M-M'(CN)₄)∞ with the aniline molecules bound directly to metal (M). For these series of isomorphous complexes there is a correlation between the shifts of some aniline bands on coordination and the strength of metal-nitrogen bonding measured by the v(M-N) value. Low temperature (83 K) data are also reported and it is noted that whilst the aniline ring and CH mode frequencies are virtually insensitive to temperature, the NH₂ wagging, NH₂ rocking and the metal-ligand stretching v(M-N) frequencies increase with decreasing temperature, whilst the v(NH₂) modes decrease with decreasing temperature. The vibrational frequencies of the M'(CN)₄ group are also temperature dependent and increase in value upon cooling the sample to 83 K. The changes are thought to be due to a slight contraction in the cavity size with decreasing temperature. The relationship between these complexes and Hofmann-type aniline clathrates, M(NH₃)₂M'(CN)₄ · 2 an, is indicated.     

Ionic coordination complexes based on [Re6S8(CN)4L2]n– (L = OH–, NH3; n = 2, 3) cluster anions,and Ni(II) and Cd(II) ammine cations

Two new complexes containing M(II) ammine cations (M = Ni, Cd) and octahedral rhenium(III) thiocyanoammine and thiocyanohydroxoammine cluster anions, [Ni(NH₃)₆][Re₆S₈(CN)₄(NH₃)₂]?2H₂O (1) and [Cd(NH₃)₆][{Cd(NH₃)₅}{Re₆S₈(CN)₄(OH)(NH₃)}]₂?5H₂O (2), have been synthesized by hydrothermal reactions starting from Cs_1.83K_2.17[Re₆S₈(CN)₄(OH)₂]?2H₂O. The compounds were structurally characterized by single-crystal X-ray diffraction analysis, elemental analysis, energy dispersive spectroscopy, and IR spectroscopy. Both compounds adopt monoclinic crystal structures composed from discrete ionic species which are held together by multiple hydrogen bonds between CN^–, OH^–, and NH₃ ligands and lattice water. 2 consists of {Cd(NH₃)₅}²⁺ attached to the OH group of the [Re₆S₈(CN)₄(OH)(NH₃)]^3– cluster anion via the Re–OH–Cd linkage.     

Preface

Abstract

The FT-IR and Raman spectra of eight new complexes of formula ML₂Ni(CN)₄ (where M = Mn, Fe, Co, Ni, Cu or Cd and L = 2-chloropyridine; M = Ni or Cd and L = 2-bromopyridine) are reported. The spectroscopic results indicate that the complexes have structures consisting of corrugated polymeric layers of [M-Ni(CN)₄]∞ with 2-substituted pyridine molecules bound directly to the metal (M). For a given ligand (2-Clpy or 2-Brpy) the effects of metal-ligand bond formation on the ligand modes are examined. Metal-ligand bond strengths of the halo-derivatives of pyridine (L = 2-Clpy or 2-Brpy), inferred by the effects on frequency shifts of certain ligand modes, have also been compared.     

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.     

Complexes of rhodium carbonylchloride and phosphorus(iii) cyanides in mediated electrochemical reduction of 2-carbomethoxy-2-methyl-1,1-dichlorocyclopropane

Electrochemical reduction of the complexes Rh(CO)ClL₂ [L = (EtO)₂PCN (1), Ph₂PCN (2)] and Rh₂(CO)₄L [L = P(CN)₃ (3), (4)] and their catalytic properties in electrochemical reduction of 2-carbomethoxy-2-methyl-1,1-dichloro-cyclopropane were studied. The catalytic electroreduction of a substrate at the reduction potentials of the central ion was developed for complexes2–4. This process is accelerated substantially for complexes2 and3 in the presence of anthracene.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1970–1972, October, 1995.     

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.     

Cyano-bridged complexes based on re tetrahedral cluster anions, Ni2+ cations, and polydentate amines

Interaction of the tetrahedral chalcocyanide cluster anionic complexes of Re, K₄[Re₄Q₄(CN)₁₂] (Q=S, Se, Te), with Ni²⁺ cationic complexes with polydentate amines, such as ethylenediamine (En), diethylenetriamine (Dien), or triethylenetetraamine (Trien) was used to synthesize six novel complexes: [Ni(NH₃)₄(En)][{Ni(NH₃)(En)₂}Re₄Te₄(CN)₁₂] · 2H₂O, [{Ni(En)₂}₂Re₄Se₄(CN)₁₂] · 3.5H₂O, [Ni(NH₃)₃(Dien)]₂[Re₄Se₄(CN)₁₂] · 5.5H₂O, [{Ni(NH₃)₂(Dien)}₂Re₄Te₄(CN)₁₂] · 2.5H₂O. [Ni(NH₃)₂(Trien)][{Ni(NH₃)(Trien)}Re₄Se₄(CN)₁₂] · 2.5H₂O, [{Ni(Trien)}₂Re₄S₄(CN)₁₂] · 3H₂O. The complexes were studied by single-crystal X-ray diffraction analysis.     

Synthesis and crystal structure of the octahedral cyano-bridged cluster complex β-[{Ni(NH3)5}2{Re6Te8(CN)6}]·4H2O

The rhenium cyano-bridged cluster complex with a composition of β-[{Ni(NH₃)₅}₂{Re₆Te₈(CN)₆}]−4H₂O is obtained and structurally characterized. The compound pound crystallizes in the P $ P\bar 1 $ P\bar 1 triclinic space group with the unit cell parameters: a = 9.997(2) ?, b = 10.423(2) ?, c = 11.714(2) ?, α = 100.92(3)°, β = 111.87(3)°, γ = 98.05(3)°, V = 1082.1(4) ?³, Z = 1, d _calc = 4.072 g/cm³. The rhenium atoms of the {Re₆Te₈} cluster core are coordinated by CN ligands to form the [Re₆Te₈(CN)₆]⁴⁻ cluster; two nitrogen atoms of CN ligands trans-positioned with respect to each other are coordinated to Ni atoms in the {Ni(NH₃)₅}²⁺ fragments to form the molecular complexes of [{Ni(NH₃)₅}₂}Re₆Te₈(CN)₆}]. The crystal structure is the H-bonded packing of these molecular complexes and crystallization water molecules.     

Synthesis,crystal structure and catalytic performance of bis (imino)pyridyl nickel complexes

Two new Ni(II) complexes of 2,6-bis[1-(2,6-diethylphenylimino)ethyl]pyridine (L¹), 2,6-bis[1-(4-methylphenylimino)ethyl]pyridine (L² ) have been synthesized and structurally characterized. Complex Ni(L¹)Cl₂?·?CH₃CN (1), exhibits a distorted trigonal bipyramidal geometry, whereas complex Ni(L¹)(CH₃CN)Cl₂ (2), is six-coordinate with a geometry that can best be described as distorted octahedral. The catalytic activities of complexes 1, 2, Ni{2,6-bis[1-(2,6-diisopropyl-phenylimino)ethyl]pyridine} Cl₂?·?CH₃CN (3), and Ni{2,6-bis[1-(2,6-dimethylphenylimino) ethyl]pyridine}Cl₂?·?CH₃CN (4), for ethylene polymerization were studied under activation with MAO.     

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.     

Solvent Effect on the Assembly of Two Cadmium(II) Coordination Polymers Derived from 3,3′‐(Diazenediyl)dibenzoic Acid: Syntheses,Structures, Stabilities,and Photocatalytic Properties

Abstract. Two cadmium(II) coordination polymers, {CdL₂[(CH₃)₂NH₂]₂ · 2DMF}_n ( 1 ) and {[Cd₃L₄[(CH₃)₂NH₂]₂] · EtOH · 2DMF}_n ( 2 ) were synthesized from the solvothermal reactions of Cd(OAc)₂ · 2H₂O with 3,3′‐(diazenediyl)dibenzoic acid (H₂L) in different solvents. Both complexes were characterized by elemental analysis, IR spectroscopy, powder X‐ray diffraction, TG analysis, and single‐crystal X‐ray diffraction. In compound 1 , central cadmium(II) atoms were linked with the surrounding L ligands to generate an infinite 1D chain with repeated rings. Compound 2 displayed a 3D threefold interpenetrating framework based on cage‐like [Cd₃L₆]₈ species and exhibited a 4¹²6³ topological structure. The results demonstrated that the different solvents had significant effect on the construction of different coordination compounds from the same components. In addition, they exhibited excellent stability and good photocatalytic activity towards the degradation of methylene blue in aqueous solution under UV irradiation.     

Tris(dimethylamino)phosphine Selenide Complexes of Cadmium(II): Synthesis and Multinuclear (31P, 77Se,and 113Cd) NMR Characterization in Solution

The complexes CdL₄(ClO₄)₂ (1), CdL₂(NO₃)₂ (2), and CdL₂Cl₂ (3) (L = (Me₂N)₃P(Se)) have been prepared and characterized by elemental analysis, conductivity measurements, IR, and multinuclear (³¹P, ⁷⁷Se, and ¹¹³Cd) NMR spectroscopy. ³¹P and ⁷⁷Se NMR data were informative of changes associated with complex formation. The structure of the prepared complexes was further confirmed in solution by their ¹¹³Cd NMR spectra, which show a quintuplet for the perchlorate complex and a triplet for each of the nitrate and chloride complexes due, respectively, to coupling with four and two equivalent phosphorus atoms, consistent with a four coordinate tetrahedral geometry for the cadmium center. The NMR data are discussed and compared with those reported for related complexes.     

Hydrothermal Synthesis,Crystal Structures,and Catalytic Properties of Three Coordination Polymers Containing ­Flexible Bis(benzimidazole) and Dicarboxylate Ligands

Three metal‐organic coordination polymers, namely {[Cd(L1)(1,2‐chdc)] · 2H₂O}_n ( 1 ), {[Ni(L2)(1,2‐chdc)] · H₂O}_n ( 2 ), and [Cd(L2)(npht)]_n ( 3 ) [L1 = 1,2‐bis(2‐methylbenzimidazol‐1‐ylmethyl)benzene, L2 = 1,2‐bis(5,6‐dimethylbenzimidazol‐1‐ylmethyl)benzene, 1,2‐H₂chdc = 1,2‐cyclohexanedicarboxylic acid, H₂npht = 3‐nitrophthalic acid] were synthesized under hydrothermal conditions and structurally characterized by single‐crystal X‐ray diffraction methods, IR spectroscopy, TGA, and elemental analysis. In compound 1 , two 1,2‐chdc^2– ligands connect two neighboring Cd atoms to form a dinuclear [Cd₂(1,2‐chdc)₂] subunit, which is further linked by L1 ligands to construct a 1D ladder‐like chain. Compound 2 exhibits a 2D (4,4) coordination network with {4⁴.6²} topology, whilst compound 3 shows a 1D helical chain structure. The fluorescence, UV/Vis diffuse reflection spectra, and catalytic properties of complexes 1 – 3 for the degradation of the congo red azo dye in a Fenton‐like process are investigated.     

Coordination modes of N-2-(4-amino-1-methyl-5-nitroso-6-oxo-1,6-dihydropyrimidinyl) potassium L-alaninate toward Ag(I), Cd(II) and Pd(II). Crystal structure of {Ag((η4-μ3-L)]·3H2O}n,first example of a silver 3D-polymer with a pyrimidine-derivative ligand

The acid-base behaviour of the N-2-(4-amino-1-methyl-5-nitroso-6-oxo-1,6-dihydropyrimidinyl) potassium L-alaninate (KL) and its reactivity with Ag(I), Cd(II) and Pd(II) metal ions have been studied. Three solid species with formulae AgL·3H₂O, CdL₂·6H₂O and PdClL·H₂O have been obtained and characterized by IR, ¹H and ¹³C NMR spectroscopic methods and thermal, conductivity and magnetic measurements. The structure of {Ag((η⁴-μ₃-L)]·3H₂O}_n has been established by single-crystal X-ray diffraction and consists in a 3D-polymer. Within the polymer each Ag(I) ion is tetrahedrally coordinated to three differents L anions, while each ligand is coordinated in a rather unusual η⁴-μ₃ coordination mode. Spectroscopic data show a similar coordination mode for the Cd(II) complex, while for the Pd(II) one a different coordination mode is proposed.     

Crystal structure of the Hofmann-dma type clathrate

Seven new Hofmann-dma type clathrates Cd(dma)₂Ni(CN)₄-xG (x = 1, G = aniline, 2,3-xylidine, 2,4-xylidine, 2,5-xylidine, 2,6-xylidine, 3,5-xylidine and x = 2, G = 2,4,6-trim ethylaniline) were prepared by replacing the amine in a Hofmann type clathrate Cd(NH₃)₂Ni(CN)₄-2G by dimethylamine (dma). The structure of the Hofmann-dma type clathrate is formed with stacked host two-dimensional metal complexes of Cd(dma)₂ Ni(CN)₄ and guest molecules accommodated in the space between the stacked host complexes. This basic structure scheme is the same as that of the Hofmann type clathrate. However, the guest species accommodated in the Hofmann-dma type clathrate are more various than those of the Hofmann type clathrate, and their crystal structures are classified into four types depending on the geometry of the guest species. In order to clarify the structure of the Hofmann-dma type clathrate, single crystal X-ray diffraction experiments were canied out on the seven new clathrates, and the crystal structures of the o-, m- and p- toluidine clathrates were refined. The X-ray structure analyses showed that the host two-dimensional metal complex of the Hofmann-dma tvpe clathrate has stmctural flexibility to form a puckered structure, which results from the angular distortion of the bond between Cd and N of the cyanide bridge in the host two-dimensional complex. This stmctural flexibility of the host complex leads to the diversity of crystal structures and guest species in Hofmann-dma type clathrates. Translated fromZhurnal Strukturnmoi Khimii, Vol. 40, No. 5, pp. 898–926, September–October, 1999.     

Solid-state vibrational spectroscopy: Part VI. An infrared and raman spectroscopic study of transition metal(II)4-methylpyridine complexes

Infrared (4000–200 cm^?1) and Raman (3500–300 cm^?1 ) spectra are reported for metal(II) halide and thiocyanate 4-methylpyridine complexes of the following stoichiometries: (MX₂(4-Mepy)₂) {M = Mn, Co, Cu or Zn, X = Cl or Br; M = Mn, Ni or Zn, X = NCS}; (MX₂(4-Mepy)₄) {M = Mn, Fe, Co or Ni, X = Cl or Br; M = Mn, Fe, Co, W or Cu, X = NCS}. For a given series of isomorphous complexes there is a correlation between the sum of the differences between the liquid and ligand values of the ν₁, ν₂, ν₃, ν₄, ν₅, ν₆, ν₇, ν₈, ν₉, ν₁₀, ν₁₂, ν₁₃ and ν₁₄ modes of 4-methylpyridine and the strength of the metal-nitrogen bond. Comparison of the shift values of pyridine and 4-methylpyridine complexes supports the suggestion that, unlike the situation in the pyridine complexes, back-donation from the metal to the ligand is unimportant in the 4-methylpyridine complexes.