Vibrational spectroscopic and thermal studies of some 3-phenylpropylamine complexes

Four new Hofmann–3-phenylpropylamine (3PPA) type complexes with chemical formulae M(3PPA)₂Ni(CN)₄ (M = Ni, Co, Cd, and Pd) have been prepared and their vibrational spectra are reported in the region of 4000–60 cm⁻¹. The vibrational bands arising from 3PPA ligand molecule, the polymeric sheet and metal–ligand bands of the compounds are assigned. The thermal behaviour of these complexes is also provided using the DTA and TGA along with the magnetic susceptibility data. The results indicate that the monodentate 3PPA ligand molecule bonds to the metal atom of |M–Ni(CN)₄|_∞ polymeric layers and hence the compounds are similar in structure to Hofmann-type complexes.     

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.     

Comparing of the host–guest interaction in the Hofmann-1,10-diaminodecane and Hofmann-1,12-diaminododecane-type clathrates

M(1,12-diaminododecane)Ni(CN)4.G (M = Co, Ni or Cd; G = chlorobenzene; 1,2-; 1,3- or 1,4- dichlorobenzene) clathrates were prepared in powder form for the first time and their infrared spectra were reported and then compared with M(1,10-diaminodecane)Ni(CN)₄.1,5G (M = Co, Ni or Cd; G = chlorobenzene; 1,2-; 1,3- or 1,4-dichlorobenzene) clathrates. The spectral results suggest that the characteristic ν(CN) and δ(NiCN) frequencies are found to be similar to those known for the Hofmann type compounds, in that prepared compounds are similar in structure to this type compounds and their structures consist of polymeric layers [M–Ni(CN)₄]_∞ with the 1,12-diaminododecane molecule bound to the metal atom (M). Also, the results suggest that the ligand molecule with 10 to 12 of chain length have no effect on vibrational bands of the guest molecules in the similar Hofmann-diam-type clathrates. The normal mode frequencies and corresponding vibrational assignments of chlorobenzene and 1,2-; 1,3- or 1,4-dichlorobenzene in the ground state were calculated by DFT/B3LYP level of theory using the 6-311G(d, p) basis set in Gauss-view. In addition, these theoretical results were compared to the experimental results for the vibrational modes of host molecules.     

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.     

Synthesis,characterization, and biological and anticancer studies of mixed ligand complexes with Schiff base and 2,2′‐bipyridine

New mixed ligand complexes of transition metals were synthesized from a Schiff base (L¹) obtained by the condensation reaction of oxamide and furfural as primary ligand and 2,2′‐bipyridine (L²) as secondary ligand. The ligands and their metal complexes were studied using various spectroscopic methods. Also thermal analyses were conducted. The mixed ligand complexes were found to have formulae [M(L¹)(L²)]Cl_m ⋅n H₂O (M = Cr(III) and Fe(III): m  = 3, n  = 0; M = Cu(II) and Cd(II): m  = 2, n  = 1; M = Mn(II), Co(II), Ni(II) and Zn(II): m  = 2, n  = 0). The resultant data revealed that the metal complexes have octahedral structure. Also, the mixed ligand complexes are electrolytic. The biological and anticancer activities of the new compounds were tested against breast cancer (MCF‐7) and colon cancer (HCT‐116) cell lines. The results showed high activity for the synthesized compounds.     

Determination of the calibration constant of the isomer shift of 57Fe Mössbauer spectra

Results are presented from quantum-chemical calculations for the iron complexes Fe(CN)₅NO^2–, Fe(CN)₆ ^3–,Fe(CN)₆ ^4–, FeCl₄ ^–, and FeCl₆ ^3– in comparison with Mössbauer-spectroscopic data. The parameters of the Mössbauer spectra were calculated according to specially developed programs. The calibration constant of the isomer shift was determined to be –0.13 mm/sec.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 4, pp. 506–508, July–August 1987.     

Polymer complexes: XLIX—Supramolecular modeling of bonding in novel rare earth polymeric rhodanine drug complexes

Novel supramolecular rare earth polymeric hydrazone complexes of 5-sulphadiazineazo-3-phenyl-2-thiaxo-4-thiazolidinone (HL) of the composition [(Ln)₂(HL)₃(NO₃)₆]_n (where Ln = La(1), Y(2), Pr(3), Nd(4), Sm(5), Gd(6) and Ho(7)) have been prepared and characterized on the basis of their chemical analyses, magnetic measurements, conductance, visible and IR spectral data. Composition, conductance and IR spectral data of complexes show that all these act as a tetradentate ligand. Electronic spectra indicate weak covalent character in the metal–ligand bond. The spectra of Nd³⁺ and Ho³⁺ show characteristic f–f transitions and the metal–ligand covalency in % has been evaluated. The spectral properties of the above polymeric complexes are also discussed.     

Synthesis,crystal structure,and properties of [Cu(LH)]2[M(mnt)2] [M = Ni or Cu; H2L = 3,3′-(1,3-propanediyldinitrilo)-bis(2-butanone oxime); mnt2− = maleonitriledithiolate] complexes containing bridging cyano groups

Interesting complexes containing a mnt^2– bridge, based on the reaction of [M(mnt)₂]^2– [M = Ni or Cu] with [Cu(LH)]⁺, have been prepared and characterized by e.s.m.s., i.r and u.v–vis. spectroscopic techniques and by electrochemistry. The complexes show weak antiferromagnetic interactions between magnetic centers. The X-ray analysis of the molecular structure of [Cu(LH)]₂[Ni(mnt)₂] has been completed. It structurally features the CN group of mnt^2– which can act as a bridging ligand between two transition metals.     

Reaction of hydride complexes of nickel with carbon monoxide

Conclusions When the hydride complexes of nickel (Ph₃P)₃Ni(H)Br and [(Ph₃P)₃Ni(H)(CH₃CN)]⁺BF₄ ^– are reacted with CO, the Ni-H bond is cleaved and carbonyl complexes of Ni(0) are formed.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1919–1920, August, 1981.     

Marked variations of proton release energy of the G–M (M = Li, Na) in the water circumstance

The variations of N1–H proton release energy of G–M (M = Li, Na) cation have been investigated employing density functional theory using B3LYP/6-31++G^**//B3LYP/6-31+G^* method. There are three modes (NO mode, N mode and O mode) when the hydrated-M⁺ bonds to guanine. The bonding energy of the hydrated M⁺ to the guanine reduces following the increase in the number of water molecules. The proton release energies of the G–M⁺ complexes are calculated at the condition of the different numbers of water molecules and the different modes of water molecules bonded on the G–M⁺. The results show that the difference of proton release energy on three modes is very small, and the proton release energies of the Na⁺ complexes are slightly larger than those of the Li⁺ complexes. The effect on the N1–H proton release is very small when the water molecules bond on the M⁺ cation, but the effect is very large when the water molecule bonds on the N1–H proton and the proton releases as the hydrated proton. The IR vibrational frequencies of the hydrated G–M⁺ complexes are calculated using analytic second derivative methods at the B3LYP/6-31+G^* level. The vibrational frequency analyses show that the changes of the vibrational frequency are consistent with the changes of geometry and the changes of the N1–H proton release energy. The N1–H proton release (N1–H proton release energy: 45–60 kcal/mol) of the guanine occurs easily under the biological environment.     

Applications of several spectral techniques to characterize coordination compounds derived from 2,6-diacetylpyridine derivative

The coordination compounds of Cr^III, Mn^II and Co^II metal ions derived from quinquedentate 2,6-diacetylpyridine derivative have been synthesized and characterized by using the various physicochemical studies like stoichiometric, molar conductivity and magnetic, and spectral techniques like IR, NMR, mass, UV and EPR. The general stoichiometries of the complexes are found to be [Cr(H₂L)X] and [M(HL)X], where M = Mn(II) and Co(II); H₂L = dideprotonated ligand, HL = monodeprotonated ligand and X = NO₃⁻, Cl⁻ and OAc⁻. The studies reveal that the complexes possess monomeric compositions with six coordinated octahedral geometry (Cr^III and Mn^II complexes) and six coordinated tetragonal geometry (Co^II complexes).     

Vibrational Spectroscopic Study of [1,2-bis(4-pyridyl)ethane]metal(II) Tetracyanonickelate(II). 2 m-Xylene Clathrates

Four new Hofmann-type clathrates of the form M(bpa)₂Ni(CN)_4· 2m-xylene (M = Mn , Fe , Co and Ni; bpa = 1,2-bis(4-pyridyl)ethane) have been synthesized and characterized by vibrational spectroscopy. The M(bpa)₂Ni(CN)₄ (M = Fe and Co) host structure is similar to the classical Hofmann-type host framework composed of layers of a two dimensional catena-metal tetra--cyanonickelate(II) network, but in M(bpa)₂Ni(CN)₄ (M = Mn and Ni), the Ni(CN)₄ moiety behaves as a bidentate –[NC-Ni(CN)₂-CN–]– unit in the host framework.     

A new generation of cyanide ion-selective membranes for flow injection application: Part III. A simple approach to the determination of toxic metal-cyanide complexes without preliminary separation

A new flow injection approach to total weak acid-dissociable (WAD) metal–cyanide complexes is proposed, which eliminates the need of a separation step (such as gas diffusion or pervaporation) prior to the detection. The cornerstone of the new methodology is based on the highly selective flow-injection potentiometric detection (FIPD) system that makes use of thin-layer electroplated silver chalcogenide ion-selective membranes of non-trivial composition and surface morphology: Ag_2 + δSe_1 − xTe_x and Ag_2 + δSe. An inherent feature of the FIP-detectors is their specific response to the sum of simple CN⁻ + Zn(CN)₄²⁻ + Cd(CN)₄²⁻. For total WAD cyanide determination, ligand exchange (LE) and a newly developed electrochemical pre-treatment procedure for release of the bound cyanide were used. The LE pre-treatment ensures complete recovery only when the sample does not contain Hg(CN)₄²⁻. This limitation is overcome by implementing electrochemical pre-treatment which liberates completely the bound WAD cyanide through cathodic reduction of the complexed metal ions. A complete recovery of toxic WAD cyanide is achieved in the concentration range from 156 μg L⁻¹ up to 13 mg L⁻¹. A three-step protocol for individual and group WAD cyanide speciation is proposed for the first time. The speciation protocol comprises three successive measurements: (i) of non-treated, (ii) LE-exchange pre-treated; (iii) electrochemically pre-treated sample. In the presence of all WAD complexes this procedure provides complete recovery of the total bound cyanide along with its quantitative differentiation into the following groups: (1) Hg(CN)₄²⁻; (2) CN⁻ + Cd(CN)₄²⁻ + Zn(CN)₄²⁻; (3) Cu(CN)₄³⁻ + Ni(CN)₄²⁻ + Ag(CN)₂⁻. The presence of a 100-fold excess in total of the following ions: CO₃²⁻, SCN⁻, NH₄⁺, SO₄²⁻ and Cl⁻ does not interferes. Thus the proposed approach offers a step ahead to meeting the ever increasing demand for cyanide-species-specific methods. The equipment simplicity makes the procedure a good candidate for implementing in portable devices for in-field cyanide monitoring.     

Chelate structures of 5-(H/Br)-2-hydroxybenzaldehyde-4-allyl-thiosemicarbazones (H2L): Synthesis and structural characterizations of [Ni(L)(PPh3)] and [Ru(HL)2(PPh3)2]

The reactions of 5-R-2-hydroxybenzaldehyde-4-allyl-thiosemicarbazone {R: H (L¹); Br (L²)} with [M^II(PPh₃)nCl₂] (M = Ni, n = 2 and M = Ru, n = 3) in a 1:1 molar ratio have given stable solid complexes corresponding to the general formula [Ni(L)(PPh₃)] and [Ru(HL)₂(PPh₃)₂]. While the 1:1 nickel complexes are formed from an ONS donor set of the thiosemicarbazone and the P atom of triphenylphosphine in a square planar structure, the 1:2 ruthenium complexes consist of a couple from each of N, S and P donor atoms in a distorted octahedral geometry. These mixed-ligand complexes have been characterized by elemental analysis, IR, UV–Vis, APCI-MS, ¹H and ³¹P NMR spectroscopies. The structures of [Ni(L²)(PPh₃)] (II) and [Ru(L¹H)₂(PPh₃)₂] (III) were determined by single crystal X-ray diffraction.     

Vibrational Spectroscopic Studies on the Hofmann Type Clathrates: M(1,6-diaminohexane)Ni(CN) 4 .G (M = Co, Ni or Cd; G = chlorobenzene, 1,2-, 1,3- or 1,4-dichlorobenzene)

New Hofmann-diaminohexane(dahxn)-type clathrates of the form M(1,6-dahxn)Ni(CN)₄.G (M = Co, Ni or Cd; G = chlorobenzene, 1,2-, 1,3 or 1,4-dichlorobenzene) were prepared inpowder form and their infrared spectra are reported. The spectral data suggest that these compounds are similar in structure to those of the Hofmann-diam-type clathrates. Their structure consists of planar polymeric layers, {M–Ni(CN)₄}, formedfrom Ni(CN)₄ anions coordinated to the bridging 1,6-diaminohexane molecules bound directly to the metal (M). The M 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.     

Syntheses, spectral and thermal analyses of heteronuclear aqua(2-methylpyrazine)metal(II) complexes with tetracyanonickelate ion and crystal structure of supramolecular [Cd(H2O)(2mpz)Ni(μ-CN)4]n complex

Polymeric tetracyanonickelate complexes of the type [M(H₂O)(2mpz)Ni(μ-CN)₄] _n (2mpz = 2-methylpyrazine, M = Mn(II) (1) or Cd(II) (2)) have been prepared and characterized by FT-IR, Raman spectroscopy, thermal, and elemental analyses. The crystal structure of supramolecular [Cd(H₂O)(2mpz)Ni(CN)₄] _n complex has been determined by X-ray single crystal diffraction. It crystallizes in the orthorhombic system, space group Pnma. The structure consists of corrugated and cyanide-bridged polymeric two-dimensional networks. In the Hofmann-type complexes, the coordination environment of the M(II) ions can be described as distorted octahedral geometry, whereas around the Ni(II) center has square planar geometry. The spectral features suggest that the 2mpz is coordinated to metal ions of the adjacent layers of [M-Ni(CN)₄] _n as monodentate ligand. The thermal decomposition of these complexes takes place in three stages: (i) dehydration, (ii) decomposition of the 2-methylpyrazine ligands, and (iii) release of the CN groups and burning of organic residue.     

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.     

C-N stretching force constants in cyano complexes

Summary The study of CN bonding in cyano complexes from vibrational spectra can be carried out using a simplified model, the Cotton-Kraihanzel Force Field, giving results in good accord with those obtained by means of more rigorous and complex entangled calculations. Application of the model is also made to mixed cyano complexes for which rigorous force constants are not known, and a good predictive ability is found, particularly for [Pt(CN)₅X]^2– compounds.     

Studies of thermal decomposition of palladium(II) complexes with olefin ligands

Thermal decomposition kinetics of ML₂ (M = Ni(II) and Co(II); L = 5-(2-(1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)hydrazono)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione) complexes were investigated by thermogravimetric analysis (TGA). The first decomposition process of the NiL₂ and CoL₂ complexes occurs in the temperature range of 320–350 °C. Kinetics parameters corresponding to this step, such as activation energy, E_α, and apparent pre-exponential factor, ln A_aap, were calculated from the thermogravimetric data at the heating rates of 5, 10, 15 and 20 K min⁻¹ by differential (Friedman's equation) and integral (Flynn–Wall–Ozawa's equation) methods. The results show that the activation energy evidently depends on the extent of conversion. As far as their activation energy is concerned, NiL₂ complex shows a higher thermal stability than the CoL₂ complex.     

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.