J. Eric D. Davies

Solid-state vibrational spectroscopy: Part 11. An infrared and raman vibrational spectroscopic study of metal(II) halide aniline complexes

Abstract Infrared (4000−200 cm −1 ) and Raman (3500−50 cm −1 ) spectra are reported for metal(II) halide aniline complexes of the following stoichiometries: (MX 2 an 2 ) (M  Co, Ni or Hg, X  Cl; M  Mn, X  Cl or Br; M  Zn or Cd, X  Cl, Br or I); (MX 2 an 3 ) (M  Mn, X  Cl or Br; M  Ni, X  Cl); (CdCl 2 an) and an assignment is proposed for all the observed bands. Low-temperature (83 K) IR spectra are also reported and it is noted that whilst the aniline ring and CH mode values are virtually insensitive to temperature, the NH 2 rocking and metal-ligand stretching mode values increase with decreasing temperature, whilst the NH 2 stretching mode values decrease with decreasing temperature.

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.

Volatile characteristics of peralkaline rhyolites from Kenya: an ion microprobe, infrared spectroscopic and hydrogen isotope study

Peralkaline rhyolites of the Greater Olkaria Volcanic Complex, Kenya Rift Valley, were derived from separated, though closely related, magma chambers. Ion microprobe analyses of glass inclusions in quartz phenocrysts show pre-eruptive water contents of up to 3.4 wt% contrasting with previous estimates that the magmas were anhydrous. The values approach predicted solubility levels corresponding to water saturation at low crustal pressures (1 kbar). The glass matrices of the rhyolites have low water contents, ranging from 0.07 to 0.46 wt%, suggesting significant degassing during, or prior to, eruption. Infrared measurements of the matrix glasses show variation in the relative proportions of the two hydrous species dissolved in the glasses. The amount of molecular water, determined semi-quantitatively, apparently increases with increased fluorine content and peralkalinity. This suggests a competition between hydroxyl groups and fluoride ions for similar sites within the melt structure. The mechanism of degassing has been investigated using hydrogen isotopes. The range of δD values in most rocks can be produced by varied degrees of open-system degassing of rhyolite melt initially in equilibrium with water of a fixed, or limited, δD value. There is evidence to suggest that closed-system degassing may also have been a significant component in some rhyolites. The exact mechanisms of degassing remain uncertain. Particular problems include the relative contribution of open-and closed-system degassing during eruption and the initial vapour compositions and solubility relationships.

Adsorption of 2,2′-bipyridyl onto sepiolite, attapulgite and smectite group clay minerals from anatolia: The FT-IR and FT-Raman spectra of surface and intercalated species

The adsorption of 2,2′-bipyridyl by natural sepiolite, attapulgite, hectorite, saponite and natural and ion exchanged (Mn, Fe, Co, Ni, Cu, Zn or Sn) bentonites has been investigated by FT-IR and FT-Raman spectroscopy. Spectroscopic results indicate that most of the adsorbed molecules are coordinated to either exchangeable cations (in the case of smectite group clays) or Lewis acidic centres (in the case of sepiolite and attapulgite) as bidentate ligands. The formation of monoanionic surface species has also been detected, to a relatively small extent. No physisorbed surface species has been observed. XRD patterns and UV-visible spectra of the samples are also recorded for additional information.

Vibrational Spectroscopic Studies of 4,4′-Bipyridyl Metal(II) Tetracyanonickelate Complexes and their Clathrates

The infrared spectra of M(4,4′-bipyridyl)Ni(CN)4 complexes (M=Ni or Cd) and their dioxane, benzene, toluene, aniline andN,N-dimethylaniline clathrates are reported. Additional information regarding the structure of the host lattice is obtained from the Raman spectra of the M=Cd complex. It is shown that the structure of the host lattice consists of infinite polymeric layers of {M-Ni(CN)4}∞ analogous to those of Hofmann type clathrates that have tetragonal symmetry. Bidentate 4,4′-bipyridyl molecules form bridges between the metal atoms {M} in the adjacent {M-Ni(CN)4}∞ layers. It is found that the 4,4′-bipyridyl molecules are centrosymmetric in this structure.

Solid-state vibrational spectroscopy. Part V. An infrared and Raman spectroscopic study of metal(II) halide pyridine complexes

Infrared (200–4 000 cm–1) and Raman (300–3 500 cm–1) spectra are reported for metal(II) halide pyridine complexes of the following stoicheiometries: [MX2(py)2](M = Mn, Fe, Co, Ni, Cu, Zn, Cd, or Hg); [MX2(py)4](M = Fe, Co, or Ni); [MX2(py)2](M = Co, Cu, Cd, or Hg); and [Hg3X6(py)2](X = Cl or Br). Structure–spectra correlations have been found for the dipyridine complexes whose structures are either monomeric tetrahedral {M = Zn or Co; X = Cl or Br; [HgBr2(py)2] and [Cdl2(py)2]}, polymeric octahedral (M = Mn, Ni, or Cd; X = Cl or Br; M = Fe or Co; X = Cl), or distorted polymeric octahedral {M = Cu, X = Cl or Br; and [HgCl2(py)2]}. For a given series of isomorphous complexes there is a correlation between the sum of the difference between the liquid and ligand values of ν2, ν3, ν4, ν5, ν6, ν7, ν8, ν9, ν10, ν17, ν27, and (ν9+ν10) and the strength of the metal–nitrogen bond as measuredbythe ν(M–N) value.

The Adsorption of Herbicides and Pesticides on Clay Minerals and Soils. Part 2. Atrazine

The adsorption of atrazine and two model compounds,2-chloropyrimidine and 3-chloropyridine on clay minerals(bentonite, montmorillonite and kaolinite), organic matter (humic acid) and soil (with and without organic matter) has beenstudied using FT-infrared spectroscopy (IR), thermogravimetric analysis (TGA), high pressureliquid chromatography (HPLC) and X-ray diffraction (XRD).3-Chloropyridine, 2-chloropyrimidine and atrazine were adsorbedthrough hydrogen bonding on bentonite, montmorillonite, humic acid and soil. In addition tohydrogen bonding, protonation of 3-chloropyridine and atrazine was also observed.In the adsorption of 2-chloropyrimidine on bentonite and montmorillonitean ion exchange mechanism also occurred. No adsorption of 3-chloropyridine or 2-chloropyrimidine wasobserved on the kaolinite clay mineral.Both the clay minerals and organic matter of soil contribute tothe adsorption of organic compounds on soil but the clay minerals bentonite and montmorilloniteplay a major role in their adsorption on soil.

Clathrate and inclusion compounds: Part V1. 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)}

Abstract The time-dependent changes which are observed in the infrared and Raman spectra of samples of the two Hofmann aniline clathrates M(NH 3 ) 2 Ni(CN) 4 .an 2 {M = Cd(II), Ni(II), an = C 6 H 5 NH 2 } indicate the occurrence of a solid state ligand replacement reaction in which the aniline guest molecule replaces the coordinated ammonia to give Man 2 Ni(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 Man 2 Ni(CN) 4 complexes can themselves act as host lattices forming clathrates containing guest molecules such as aniline.

Vibrational spectroscopic investigations of M(Imidazole)2Ni(CN)4·2C6H12 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.

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.