An Infrared Spectroscopic Study on the Hofmann-diam-type 1,12-Diaminododecanemetal(II) Tetracyanonickelate(II)-aromatic Guest Clathrates: M(H2N(CH2)12NH2)Ni(CN)4ċG(M=Co, Ni or Cd; G = Benzene, Naphthalene, Anthracene, Phenanthrene or Biphenyl)

Three Hofmann-diaminododecane-type clathrates of the form M(1,12-diaminododecane) Ni(CN)₄G (M = Co, Ni or Cd; G = benzene, naphthalene, anthracene, phenanthrene or biphenyl) have been prepared in powder form. The 1,12-diaminododecane molecules in the host lattice permit the inclusion of bulky guest molecules. The spectral features suggest that these compounds are similar in structure to the other Hofmann-diam-type clathrates.     

Vibrational Spectroscopic Studies on the Td-Type Clathrates: M(trimethylenediamine)M'(CN)4⋅2C6H6 (M=Mn or Cd, M';=Cd or Hg)

IR spectra of Mn(C3H10N2)M(CN)42C6H6 (M=Cd or Hg),and IR and Raman spectra of Cd(C3H10N2)M(CN)4 2C6H6(M=Cd or Hg) are reported. The spectral data suggest that the former twocompounds are similar in structure to the latter two Td-type clathrates.     

An Infrared Spectroscopic Study on the Hofmann-diam-type 1,9-Diaminononanemetal(II) Tetracyanonickelate(II)-Aromatic Guest Clathrates: M(H2N(CH2)9NH2)Ni(CN)4 ċG(M = Cd or Ni; G = Benzene, Naphthalene, Anthracene or Phenanthrene

IR spectra of M(1,9-Diaminononane)Ni(CN)₄G (M = Cd or Ni; G = benzene, naphthalene, anthracene or phenanthrene) are reported. The spectral data suggest that the host structures in these clathrates are similar to those of Hofmann-, -diaminoalkane type clathrates.     

An Infrared Spectroscopic Study of Pyrazine- and 4,4′-bipyridyl-Td-type Clathrates: Mn (pyrazine) M(CN)4 benzene (M = Cd or Hg) and Mn (4,4′-bipyridyl) M(CN)4. benzene (M = Zn, Cd or Hg)

The infrared spectra of the title compounds have been reported. The spectral data suggest that the host framework of these compounds are similar to those of the en-T_d-type clathrate compounds. There is good evidence for hydrogen bonding from ligand molecules to benzene molecules as a to hydrogen bond.     

Infrared spectroscopic studies of some piperidine metal(II) clathrates: M(C5H11N)2Ni(CN)4·G (M = Co,Ni; G = m-xylene,p-xylene or o-xylene; M = Ni; G = dioxane)

IR spectra of M(C₅H₁₁N)₂Ni(CN)₄·G (M=Co, Ni; G=o-, m- or p-xylene; M=Ni; G=dioxane) are reported. These clathrates are analogues to the previously reported classical Hofmann-type clathrates.     

Vibrational Spectroscopic Investigations of M(Imidazole)2Ni(CN)4·2 Dioxane Clathrates

Four new clathrates of the formula M(Im)2Ni(CN)4·2·Dioxane (where M = Co, Ni, Cu, Cd; Im = Imidazole) have been prepared in powder form and their FT-IR and laser-Raman spectra are reported for the first time. These clathrates are analogues to the previously reported classical Hofmann type clathrates except for the copper clathrate. The Cu clathrate has different spectral features in comparison with its analogues due to the Jahn-Teller effect.     

An Infrared and Raman Spectroscopic Study of pn-Td-Type dl% -Propylenediaminemetal(II) Tetracyanometallate(II) Benzene Clathrates: M(dl-pn)M'(CN)4.nC6H6 (M = Mn, M' = Zn, Cd or Hg; M = Cd, M' = Cd or Hg; 1≤n≤1.5)

IR spectra of Mn(dl-propylenediamine)M(CN)4.nC6H6 (M = Zn, n = 1.25; M = Cd, n = 1.00 or M = Hg, n = 1.18), and IR and Raman spectra of Cd(dl-propylenediamine)M(CN) 4. 1.5C6H6 (M = Cd or Hg) are reported. The spectral data suggest that the former three compounds are similar in structure to the latter two pn-Td-type clathrates.     

Cyclohexylamine) 2 M(CN) 4 ⋅2C 6 H 6 (M = Cd or Hg)

Two new title compounds have been prepared in powder form. Their spectral data are found to be consistent with the structure foundin Hofmann-T_d-type clathrates.     

Vibrational spectroscopic study on some Hofmann-Td type clathrates: Ni(4-phenylpyridine)2M(CN)4·2G (M=Cd or Hg, G=1,4-dioxane)

New Hofmann-T(d) type clathrates in the form of Ni(4-Phpy)(2)M(CN)(4)·2G (where 4-Phpy=4-phenylpyridine, M=Cd or Hg and G=1,4-dioxane) have been prepared in powder form and their FT-IR and Raman spectra have been reported. The results suggest that these compounds are similar in structure to the Hofmann-T(d) type clathrates.     

Infrared Spectroscopic and Gravimetric Studies on the Dicyclopentylaminemetal(II) Tetracyanonickellate(II) Host–Aromatic Guest Systems

The host complexes M(Cyclopentylamine)₂Ni(CN)₄ (M=Co or Cd) havebeen prepared in powder form. The spectral data suggest that the structures of thesecompounds are similar to those of the Hofmann-dma-type hosts. The absorptionand the liberation processes of the aromatic guests (benzene, toluene, 1,2-, 1,3-,1,4-dichlorobenzene, 1,4-dibromobenzene o-, m-, p-xylene, naphthalene)in these hosts have been examined at room temperature by gravimetric and spectroscopicmeasurements. The desorption of the benzene guest against time has been measured. Thehost structures do not change on inclusion and liberation of the guests. The host compoundshave been suggested as sorbents for isomeric separations.     

Electrophilic Substitution Mn(II) → M(II) (M = Co,Ni, Cu,Zn, Cd) in Gelatin-Immobilized Mn2[Fe(CN)6]

Reactions of electrophilic substitution Mn(II) M(II) (M = Co, Ni, Cu, Zn, Cd) are studied in gelatin-immobilized Mn(II) hexacyanoferrate(II) systems brought in contact with aqueous solutions of metal chlorides MCl₂. As the result of this contact, Mn(II) is replaced by Co(II), Ni(II), Cu(II), Zn(II), or Cd(II) to give heteronuclear metal hexacyanoferrates(II) (MHCF) of Mn(II) and two-charged ions. Neither of the systems under study showed a complete substitution of Mn(II) or the formation of the respective mononuclear hexacyanoferrate(II) M₂[Fe(CN)₆]. When any of the above gelatin-immobilized MHCF was brought in contact with an aqueous solution of MnCl₂, no electrophilic substitution M(II) Mn(II) was observed even for a long contact time.     

Why are the Homoleptic Diyl Complexes M(InR)4 with M = Ni and Pt Stable Compounds while only Ni(CO)4 but not Pt(CO)4 can become Isolated? A Theoretical Study of M(EMe)44 and M(CO)4 (M = Ni,Pd, Pt; E = B,Al, Ga,In, Tl)

The equilibrium geometries and first bond dissociation energies of the homoleptic complexes M(EMe)₄ and M(CO)₄ with M = Ni, Pd, Pt and E = B, Al, Ga, In, Tl have been calculated at the gradient corrected DFT level using the BP86 functionals. The electronic structure of the metal‐ligand bonds has been examined with the topologial analysis of the electron density distribution. The nature of the bonding is revealed by partitioning the metal‐ligand interaction energies into contributions by electrostatic attraction, covalent bonding and Pauli repulsion. The calculated data show that the M‐CO and M‐EMe bonding is very similar. However, the M‐EMe bonds of the lighter elements E are much stronger than the M‐CO bonds. The bond energies of the latter are as low or even lower than the M‐TlMe bonds. The main reason why Pd(CO)₄ and Pt(CO)₄ are unstable at room temperature in a condensed phase can be traced back to the already rather weak bond energy of the Ni‐CO bond. The Pd‐L bond energies of the complexes with L = CO and L = EMe are always 10 — 20 kcal/mol lower than the Ni‐L bond energies. The calculated bond energy of Ni(CO)₄ is only D_o = 27 kcal/mol. Thus, the bond energy of Pd(CO)₄ is only D_o = 12 kcal/mol. The first bond dissociation energy of Pt(CO)₄ is low because the relaxation energy of the Pt(CO)₃ fragment is rather high. The low bond energies of the M‐CO bonds are mainly caused by the relatively weak electrostatic attraction and by the comparatively large Pauli repulsion. The σ and π contributions to the covalent M‐CO interactions have about the same strength. The π bonding in the M‐EMe bonds is less than in the M‐CO bonds but it remains an important part of the bond energy. The trends of the electrostatic and covalent contributions to the bond energies and the σ and π bonding in the metal‐ligand bonds are discussed.     

NATURE OF SELENOCYANATE BONDING IN THE COMPLEXES OF MM'(NCSe)4 (M=Co,Ni, Zn,Cd; M′=Zn,Cd, Hg); WITH LEWIS BASES (PART II)

Abstract

Complexes of [MM′(NCSe)₄] (M=Co, Ni, Zn, Cd; M′=Zn, Cd, Hg;) with certain ligands (L), viz., ethylenediamine(en), isonicotinic acid hydrazide(inh), 3-aminopyridine(apy), pyridine(py), pyrazine 2-carboxamide(pza), pyrazine 2–3-dicarboxamide(pzd) and tetrahydrofuran(thf) have been synthesized and characterized. Their molar conductance, magnetic moments, infrared and electronic spectral studies indicate that these complexes are of three types: (i) cationic-anionic, viz., [ML₆] [M′(NCSe)₄] (M=Ni, M′=Cd, L=inh; M=Cd, M′=Hg, L=py; and M=Zn, M′=Cd, Hg; L=en;) (ii) monomeric bridged, viz., L₄ M(NCSe)₂ M′(SeCN)₂ (M=Co, Ni; M′=Cd, Hg; L=pzd;) (iii) polymeric bridged, viz., [dbnd](SeCN)₂ L₂ M(NCSe)₂ Hg (M=Co, Ni; M′=Zn, Cd, Hg; L=thf, pza and apy). The nature of bonding in these complexes has been related to the softness difference of M and M′ and the basicity of the ligands.     

Vibrational spectroscopic study on some Hofmann type clathrates: M(2-(1-cyclohexenyl)ethylamine)2Ni(CN)4·2benzene (M=Ni and Cd)

New Hofmann type benzene clathrates in the form of M(CyHEA)2Ni(CN)4·2benzene (where CyHEA=2-(1-cyclohexenyl)ethylamine and M=Ni or Cd) have been prepared in powder form and FT-IR and Raman spectra have been reported. The results suggest that title compounds are similar in structure to Hofmann type clathrates and their structures consist of polymeric layers of |M-Ni(CN)4|∞ with the CyHEA molecule bounded to the metal atoms (M).     

Magnetic properties of isostructural M(H2O)4[Au(CN)4]2-based coordination polymers (M = Mn, Co, Ni, Cu, Zn) by SQUID and μSR studies

A series of isomorphous M(H(2)O)(4)[Au(CN)(4)](2)·4H(2)O (M = Mn, Co, Ni, Zn; Cu is similar) coordination polymers was synthesized from the reaction of M(II) with KAu(CN)(4); they consist of octahedrally coordinated metal centres with four equatorial water molecules and trans-axial N-cyano ligands from [Au(CN)(4)](-) moieties, generating a linear 1-D chain of M(H(2)O)(4)[Au(CN)(4)]-units. An additional interstitial [Au(CN)(4)](-) unit forms AuN and hydrogen bonds with adjacent chains. The Cu(II) system readily loses water to yield Cu[Au(CN)(4)](2)(H(2)O)(4), which was not structurally characterized. The magnetic properties of these polymers were investigated by a combination of SQUID magnetometry and zero-field muon spin relaxation (ZF-μSR). Only weak antiferromagnetic interactions along the chains are mediated by the [Au(CN)(4)]-units, but the ZF-μSR data indicates that interchain interactions yield a phase transition to a magnetically ordered state for Cu[Au(CN)(4)](2)(H(2)O)(4) below 0.6 K, while for M(H(2)O)(4)[Au(CN)(4)](2)·4H(2)O (M = Co), depopulation of zero-field split Kramer's doublets to an effective "S = 1/2" ground state yields a transition to a spin-frozen magnetic state below 0.26 K. On the other hand, only a simple slowing-down of spins above 0.02 K is observed for the more weakly zero-field split M(H(2)O)(4)[Au(CN)(4)](2)·4H(2)O (M = Mn, Ni) complexes.     

Electrophilic Substitution Co(II)→M(II) (M = Mn,Ni, Cu,Zn, Cd) in Co2[Fe(CN)6] Gelatin-Immobilized Matrices

Electrophilic substitutions Co(II) M(II) (M = Mn, Ni, Cu, Zn, Cd) in cobalt(II) hexacyanoferrate(II) gelatin-immobilized matrices in contact with aqueous solutions of corresponding chlorides MCl₂ were studied. As a result of this contact, Co(II) was shown to be replaced to some extent by Ni(II), Cu(II), Zn(II), or Cd(II) and to give heteronuclear cobalt(II) hexacyanoferrates(II) and two-charge ions. A complete substitution of Co(II) or the formation the respective mononuclear hexacyanoferrate(II) M₂[Fe(CN)₂] was observed in neither of the studied systems Co(II) M(II). No Co(II) Mn(II) substitution was observed, even though the immobilized matrix was in contact with a solution for a long time.     

MF2 vibrations and librations of water molecules in the series MF2·4H2O (M = Fe,Co, Ni or Zn)

The infrared absorption spectra of the series MF₂·4H₂O (M = Fe, Co, Ni or Zn) and of the respective deuterates were recorded at 296 and ∼ 100 K in the 1200-400 cm⁻¹ wavenumber region. Using the known ZnF₂·4H₂O structure as a model, the number of i.r. active librations and MF₂ vibrations was predicted with the aid of a group theoretical treatment. The librations were distinguished from the MF₂ and MO vibrations and assigned, using isotopic ratios and correlations between the unit cell volumes, the uncoupled OH and OD stretch vibrations of HDO and the twisting libration. The six librations are assigned to two types of water molecules with low symmetry and with different hydrogen bond strengths, and are compatible with an orthorhombic Pca2₁ structure. The v₁ and v₃ intramolecular MF₂ vibrations are assigned, using ZnF₂·4H₂O crystal data and matrix-isolated v₁ and v₃ (v_1.3) values as guide. Shifts of v_1.3 and v₁/v₃ relative to the matrix-isolated values suggest smaller MF bond lengths. The shifts in the values of v_1.3 and v₁/v₃ upon deuteration and lowering of the temperature indicate smaller MF bond lengths and FMF angles.     

Synthesis, Spectroscopic, Thermal, and Structural Characterization of Complex Ferrocyanides KLnFe(II)(CN)6 ⋅ 3.5H2O (Ln = Gd-Ho)

Four new mixed metal cyanides of lanthanides (Ln = Gd-Ho) and iron with the general formula KLnFe(CN)₆ 3.5H₂O have been synthesized and characterized by chemical, infrared and thermal techniques. X-ray diffraction (XRD) analysis have shown that all the complexes have orthorhombic unit cells with space group Cmcm. Cyanide bridges link to nine coordinated LnN₆(H₂O)₃ groups to the octahedral FeC₆ groups. Cavities within the structure are occupied by uncoordinated zeolitic water molecules and potassium ions. The potassium cations form a pseudo-hexagonal 2D sublattice. Thermal decomposition involves two consecutive steps: dehydration and inorganic residue evolution to ternary oxides.     

金属串配合物[MM′M″(dpa)4(Cl)2](M=Co,Ni;M′,M″=Co,Rh)电子输运的理论研究

采用密度泛函理论DFT/BP86方法研究金属串配合物[MM'M″(dpa)₄(Cl)₂] [MM'M″=CoCoCo(1), CoCoRh(2), CoRhRh(3), NiCoRh(4)] 的结构和电子输运性质. 结果表明, 配合物1, 2和4的最稳定自旋态均存在1个(MM'M″)⁶⁺的离域$\sigma_{3}^{3}$键($\sigma^{2}\sigma_{nb}^{1}\sigma^{*0}$); 但配合物3具有1个(MM'M″)⁶⁺的离域$\sigma_{3}^{4}$键($\sigma^{2}\sigma_{nb}^{2}\sigma^{*0}$)和2个$\pi_{3}^{5}$键($\pi^{4}\pi_{nb}^{4}\pi^{*2}$), 故Rh—Rh键和Co—Rh键较强; Rh的引入使M—M键增强, Ni的引入则使M—M键减弱, 键强次序为Rh—Rh>Co—Rh>Co—Co>Ni—Co. 配合物14的传输通道均含有π和σ型轨道. 正偏压下, 配合物2和3的电流大于配合物1和4的. 负偏压下, 配合物4中出现负微分电阻效应. 配合物3中形成传输通道的σ_nbα/β和π^*α/β轨道能级分裂明显, (MM'M″)⁶⁺对β自旋的π^*轨道的贡献(88%)比α自旋(74%)的大, 使β自旋的电子更易传输, 具有较好的自旋过滤效应(70%80%).     

氧心羧桥异三核过渡金属簇合物[Fe2MO(CH3COO)6Py3].Py(1,M=Mn;2,M=Co;3,M=Ni)和[Fe2MO(CCl3COO)6(THF)3](4,M=Mn;5,M=Co;6,M=Ni)电子光谱的研究

The UV/VIS spectra for pyridine solution of complexes [Fe_2MO(CH_3COO)_6Py_2]·Py and THF solution of complexes Fe_2MO(CCl_3COO)_6(THF)_3 were studied. The d-d transitions were assigned and the ligand field parameters(B,D_q,β) were calculated for the related metal ions according to ligand field theory (Tanabe-Sugano diagram) in terms of O_h symmetry and reasonably good fits were obtained for the calculated and observed frequencies. The calculated results show that (1) the larger the ionic potential for M~(2+) ion, the larger the values of B, D_q for Fe~(3+) ion (2) the ligand field parameters of metal ions vary in parallel with the electronagativity of R in RCOO~-.