The sorption of 2,2′-biquinoline onto natural and ion-exchanged montmorillonite (Fe-, Co- or Cu-montmorillonite) and saponite from Anatolia have been investigated using FT-IR and FT-Raman Spectrometry. The intercalation of 2,2′-biquinoline within natural and ion-exchanged montmorillonite and saponite has been shown by X-ray diffraction to increase the interlayer spacing. The difference of basal spacing of air-dried clays and biquinoline treated ones shows monolayer arrangement. Raman spectroscopy was particularly useful for investigation of clay-organic interaction. Vibrational spectroscopy indicates that intercalated 2,2′-biquinoline molecules are coordinated to exchangeable cations (directly and indirectly through water bridges) and/or Lewis acid sites or as bidentate ligand.

This paper reviews the results obtained from vibrational studies (infrared and Raman) of host-guest compounds. These techniques can give information such as: confirmation of inclusion compound formation; host-guest interactions; the state of aggregation and configuration of the guest molecules; the translational and rotational motions of the guest; the spectra of hosts and guests in unusual configurations.

Four new clathrates of the formula M(Imidazole)2Ni(CN)4·2C6H12 (M is Mn, Co, Ni and Cd) have been prepared and their infrared and the Raman spectrum of Cd clathrate are reported. The spectral results suggest that these compounds belong to the Hofmann-type clathrates.

Infrared and Raman spectra over the temperature range room temperature to 74K have been recorded for a range of inclusion compounds of thiourea containing monosubstituted cyclohexanes C6H11X (X =Cl,Br,I,CN,NCO) as guests. The liquid phase of all the cyclohexanes consists of an equilibrium mixture of axial and equatorial conformers, with the equatorial conformer being the more abundant. At room temperature the chloro, bromo and cyano substituted guests exist predominantly as the axial conformer, whereas the iodo and isocyanato substituted guests exist as a mixture of both conformers, but with the axial conformer being the more abundant. The iodocyclohexane inclusion compound was the only one to display a temperature dependent change in the intensity ratio of the conformer bands. This could be due to a change in the conformer ratio or to a structural phase change.

The adsorption of 2-aminopydine (2AP) on natural and ion-exchanged bentonites (Mn-, Fe-, Co- or Ni-bentonite) have been investigated using IR and Raman Spectroscopy. The intercalation of 2AP within natural and ion-exchanged bentonites has been shown by X-ray diffraction to increase the interlayer spacing. Vibrational spectroscopy indicates that intercalated 2AP molecules are coordinated to Lewis acid sites or exchangeable cations (directly or indirectly through water bridges). It is concluded that ring nitrogen, not the amino nitrogen is involved in coordination. Moreover amino group hydrogens are found to be involved in hydrogen bonding interaction with water molecules (NH⋯OH2).

The adsorption of 2-aminopyridine by Anatolian sepiolite was investigated by Fourier-transform infrared and Fourier-transform Raman spectroscopy. The spectroscopic results indicate that 2-aminopyridine molecules adsorbed on sepiolite are coordinated to Lewis acidic centers or surface hydroxyls by H-bonding interaction through the pyridine ring nitrogen lone pairs. No physical sorbed species has been detected. Monocationic surface species has also not been detected under the conditions applied. It must be noted that the adsoiption of aminopyridine affected the hydroxyl group vibrations of sepiolite.

The synthesis and the results of an infrared and Raman spectroscopic study are reported for metal(II) halide 3,5-lutidine (3,5-dimethylpyridine) complexes, M(3,5L)(2)X-2, M = Cd or Zn, X = Cl, Br or I; M = Co, Cu or Hg, X = Cl or Br; M = Mn, Fe or Ni, X = Cl, 3,5L = 3.5-lutidine. Vibrational assignments are given for all the observed bands. Some structure-spectra correlations were found. For a given series of isomorphous complexes the sum of the difference of the values of the vibrational modes of 3,5-lutidine between the free ligand as liquid and the complexed ligand was found to increase in the order of the second ionization potentials of the metals. The frequency shifts were also found to depend on the halogen.

FTIR spectroscopy has been employed in order to investigate α-tocopherol (α-T) and α-tocopheryl acetate (α-TA) induced effects on the molecular organization of dimyristoyl-l-α-phosphatidylcholine (DMPC) bilayers, at various temperatures and concentrations. It was concluded that α-T interacts much more strongly than α-TA, indicating that α-T has a more polar location in the membrane than α-TA. The observed changes in the carbonyl and phosphate group vibrational modes of DMPC on addition of α-T or α-TA are discussed

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.

Fourier transform infrared (4000-200 cm(-1)) and Raman (3500-50 cm(-1)) spectra are reported for metal(II) halide 3,5-lutidine (3,5-dimethylpyridine) complexes of the following stoichiometries: M(3,5L)(4)X(2) M=Co or Ni, X=Cl or Br; M=Mn or Cu, X=Br; M=Cd, X=I; M(3,5L)(3)X(2) M=Fe, X=Cl; M=Cu, X=Br; Hg(3,5L)X(2) X=Cl or Br. Vibrational assignments are given for all the observed bands. Some structure-spectra correlations are found. For a given series of isomorphous complexes the sum of the difference between the liquid and ligand values of the vibrational modes of 3,5-lutidine is found to increase in the order of the second ionization potentials of the metals. The frequency shifts are also found to depend on the halogen.

The adsorption of 4,4′-bipyridyl by natural attapulgite from Anatolia (Turkey) has been studied using vibrational spectroscopy. Investigations of Fourier-transform infrared and Fourier-transform Raman spectra of adsorbed 4,4′-bipyridyl indicate the presence of physical and chemical sorbed surface species. No anionic surface species has been observed. It is proposed that chemisorbed 4,4′-bipyridyl molecules are coordinated to either Lewis acidic centers or surface hydroxyls as monodentate ligands.

Infrared and Raman (4000-200 cm−1) spectra are reported for 1,4-diaminobenzene complexes of nickel (II) and cadmium (II) chloride, MCl2PPD, where MNi or Cd and PPD=1,4-diaminobenzene (p-phenylenediamine). Vibrational spectroscopic investigation indicated that complexes have polymeric structures containing bidentate bridging molecules of 1,4-diaminobenzene.

The adsorption of pyrazine by two different Anatolian sepiolites and by natural and ion-exchanged (Fe, Co, Cu and Sn) bentonites was investigated by vibrational spectroscopy, The spectroscopic results indicate that the pyrazine molecules adsorbed on sepiolite and bentonites are coordinated to either surface hydroxyls by H-bonding interaction (in the case of sepiolite) or to exchangeable cations (in the case of bentonites) through both nitrogen lone pairs as bidentate ligands, X-ray diffraction patterns of the days were also recorded and the basal spacings of pyrazine-treated natural and ion-exchanged bentonites were found to be around 14.7 Angstrom. The results suggest that pyrazine molecules intercalate the interlayers of bentonite with a monolayer arrangement.

The FT-IR and Raman spectra of eight new Hofmann-type complexes of 3- and 4-methylpyridine, ML(2)Ni(CN)(4) (M = Mn, Fe, Co or Zn; L = 3- or 4-methylpyridine) are reported. The structure consists of corrugated polymeric layers of [M-Ni(CN)(4)](infinity) with methylpyridine molecules bound directly to the metal (M). For a given ligand (3-Mepy or 4-Mepy) the effects of metal-ligand bond formation on the ligand modes are examined and the metal sensitivity sequence of the ligand frequencies is found to be Mn < Fe < Co < Zn. The metal-ligand bond strengths of the methyl derivatives of pyridine in which the substituents are in different positions have also been compared and are found to increase in the order 3-Mepy < 4-Mepy for a given transition metal. The effective magnetic moments of the complexes are given.

The techniques of infrared (IR) and Raman spectroscopy are compared with particular emphasis on their use in water analysis. IR spectroscopy can be used for quantitative analysis provided that the analyte can be extracted into a non-aqueous solvent. Resonance Raman spectroscopy can be used for in-situ qualitative analysis. Examples of the use of both techniques are given.

The perturbations induced by melittin and cholesterol on the molecular organization of dimyristoyl-l-α-phosphatidylcholine (DMPC) bilayers, depending on the temperature and concentrations of both melittin and cholesterol, were studied using FT-IR spectrometry. Analysis of the amide I and amide II bands of melittin indicates that melittin exists as a monomer at all temperatures in the DMPC-melittin system (lipid:protein molar ratio R = 14:1) and in DMPC-cholesterol-melittin dispersions (R = 14 and 25) for low cholesterol concentrations (10 mol%). However in the DMPC-cholesterol-melittin systems with high cholesterol (20 mol%) and high melittin (R = 14) concentrations, melittin is found to be in a tetrameric form at T > Tm. The melittin-induced effects in DMPC bilayers containing a low melittin concentration (R = 25) are found to decrease on addition of cholesterol (10 or 20 mol%). Cholesterol, however, has the opposite effect in DMPC-cholesterol-melittin systems containing high cholesterol (20 mol%) and high melittin concentrations (R = 14), i.e., and increased lipid-protein interaction. Cholesterol- and melittin-induced effects on the spectral features of the phospholipid are discussed.

The adsorption of benzidine by sepiolite obtained from Eskisehir (Turkey) has been studied by Fourier-transform infrared spectroscopy. A deep green colouration results on reaction of benzidine and sepiolite. In the IR spectrum of benzidine treated sepiolite ν(C-N+) vibrational modes of the uni- and di-positive radical cations are observed in addition to vibrational modes of coordinated benzidine. Spectroscopic results indicate that the principle adsorption mechanism for benzidine is coordination to surface hydroxyls from nitrogen lone pairs and to a relatively small extent, formation of radical cations. No physical sorbed species have been detected. It must be noted that the adsorption of benzidine affected the hydroxyl group vibrations of sepiolite.

The FT-IR and laser-Raman spectra of five new complexes of the formula ML2Ni(CN), (where M = Mn, Fe, Ni, Zn or Cd; L = 3-chloropyridine) are reported. The complexes are shown to have a structure consisting of two-dimensional polymeric layers formed with Ni(CN)4 ions bridged by ML2 cations. For a given series of isomorphous complexes, the effects of metal ligand bond formation on the ligand vibrational modes are examined and the metal-sensitivity sequence of the ligand frequencies is found to be Mn almost-equal-to Cd < Fe < Zn < Ni.