Ian S. Butler

FT-Raman and high-pressure infrared spectroscopic studies of dicalcium phosphate dihydrate (CaHPO4·2H2O) and anhydrous dicalcium phosphate (CaHPO4)

Abstract The FT-Raman spectra and the pressure dependence of the infrared spectra of the hydrated and anhydrous forms of dicalcium phosphate, CaHPO4 · 2H2O and CaHPO4, have been studied. The hydrated salt exhibits a phase transition at 21 kbar (1.0 kbar=0.1 Gpa) but no high pressure transition was observed for anhydrous dicalcium phosphate. The O–H stretching frequencies of the water molecules in CaHPO4 · 2H2O all showed negative pressure dependences and correlate with the O ⋯ O distances. The PO–H stretch increased with increasing pressure, indicating a strong hydrogen bond. The frequencies associated with the phosphate ion showed a normal pressure dependence.

An Overview of 195Pt Nuclear Magnetic Resonance Spectroscopy

Abstract This brief, non‐exhaustive review describes some basic theoretical aspects of 195Pt nuclear magnetic resonance spectroscopy and also the empirical approach used by the researchers in the field. The different factors which influence the chemical shifts are discussed. The couplings constants between 195Pt and other isotopes, which have a spin of 1/2 (such as, 1H and 13C) bring further important information on the structures of Pt compounds. Recently, 195Pt‐NMR spectroscopy in the liquid state has been used successfully in many research fields, e.g., the determination of enantiomeric composition and absolute configuration, in the area of biosensors and biomarkers, in cluster chemistry, in cancer research and in kinetic studies. While liquid‐state 195Pt‐NMR spectroscopy encompasses a wide range of areas, the parallel solid‐state technique has only been employed over the past few years, mainly in studies of heterogeneous catalysis and is more industrially oriented.

Carbonylmetalloimmunoassay (CMIA) a new type of non-radioisotopic immunoassay: Principles and application to phenobarbital assay

A new non-radioisotopic immunoassay procedure, which we have termed carbonylmetalloimmunoassay (CMIA), is described. The tracers used in this approach are organometallic carbonyl complexes that can be detected at femtomole levels (300-700 fmol) by Fourier transform infrared (FT-IR) spectroscopy. The validity of the technique has been tested in a phenobarbital assay using as the marker a cyclopentadienylmanganese (I) tricarbonyl (cymantrene) moiety, ethyl acetate extraction to separate the free and bound organometallic fractions, and FT-IR spectroscopy to detect the CO stretching modes of the organometallic label. Typical dilution and standard curves obtained with this CMIA procedure are presented. The method was of comparable sensitivity to a [14C] radioimmunoassay (RIA) for the detection of phenobarbital. A comparison of the results for phenobarbital assays by both CMIA and RIA showed that higher titres were obtained using the CMIA method. The standard curves suggest that CMIA is a reliable and reproducible immunoassay procedure for phenobarbital.

An FT-Raman Spectroscopic Investigation of Dentin and Collagen Surfaces Modified by 2-Hydroxyethylmethacrylate

Although 2-hydroxyethylmethacrylate (HEMA) is commonly used for adhesive bonding to dentin, its role in promoting adhesion is not completely understood. Here, we use FT-Raman spectroscopy to elucidate further the nature of the interaction of HEMA with dentin. Ground dentin was exposed to 2.5% (w/w) nitric acid, washed, dried in air, and treated with HEMA. The samples were then sequentially washed with distilled water, with FT-Raman spectra being obtained after different wash times. Hydroxyapatite and bovine type I collagen were similarly treated with HEMA except for the acid exposure. The FT-Raman spectra of these samples were also recorded. The spectra of HEMA-treated, water-washed dentin and collagen revealed the following changes: (1) The band intensities of HEMA absorbed on dentin and collagen decreased with increasing wash times; (2) the v(C=O) and v(CCO) modes of HEMA at 1718 and 607 cm -1, respectively, either disappeared or decreased after extensive washing; (3) the v(C=C) (1640 cm-1) and δ(=CH2) (1403 cm -1) bands exhibited minor variations in band position and relative intensity. These results demonstrate that HEMA interacts with dentin both physically and chemically. The chemical interaction can be interpreted by either hydrogen bonding or the formation of a new bond to the ester group of HEMA.

Characterisation of uranium oxides by micro-Raman spectroscopy

Abstract The micro-Raman spectra of four oxides of uranium are presented and discussed. Attention is drawn to certain features and trends of the spectra which lead to their use in the characterisation of uranium oxide particles. Much lower laser powers than are normally used for Raman measurements have proved possible because of the high collection efficiency of the microscope optics and the multiscanning capability of the spectrometer. Raman spectra can now be obtained for materials earlier thought to be too unstable to survive the long periods of continuous radiation necessary.

Synthesis, spectroscopic characterization, X-ray structure and evaluation of binding parameters of new triorganotin(IV) dithiocarboxylates with DNA

Three new triorganotin(IV) dithiocarboxylates (1-3) with general formula R(3)SnL, where R=C(4)H(9) (1), C(6)H(11) (2), C(6)H(5) (3) and L=4-(4-nitrophenyl)piperazine-1-carbodithioate, have been synthesized and characterized by elemental analysis, Raman, FT-IR, multinuclear NMR ((1)H, (13)C and (119)Sn) and mass spectrometry. The crystal structure of complex 3 confirmed distorted trigonal-bipyramidal geometry around Sn atom. The interaction of compounds 1-3 with DNA was investigated by cyclic voltammetry (CV) and UV-vis spectroscopy. The positive peak potential shift in CV and hypochromic effect in spectroscopy evidenced intercalative mode of interaction. The results indicate that the binding affinity varies in this sequence: 1>3>2.

FT-Raman and high-pressure FT-infrared spectroscopic investigation of monocalcium phosphate monohydrate, Ca(H2PO4)2·H2O

Abstract The FT-infrared spectra of monocalcium monohydrate, Ca(H 2 PO 4 ) 2 ·H 2 O, have been measured as a function of pressure up to 50 kbar. A phase transition occurs at 18 kbar. The Lippincott–Schroeder model for the hydrogen bond has been used to explain the pressure dependence of the vibrational frequencies.

Synthesis, characterization and anticancer studies of mixed ligand dithiocarbamate palladium(II) complexes

Six mixed ligand dithiocarbamate Pd(II) complexes (1-6) of general formula [(DT)Pd(PR(3))Cl], where DT = dimethyldithiocarbamate (1, 5), diethyldithiocarbamate (2, 3), dicyclohexyldithiocarbamate (4), bis(2-methoxyethyl)dithiocarbamate (6); PR(3) = benzyldiphenylphosphine (1), diphenyl-2-methoxyphenylphosphine (2), diphenyl-p-tolylphosphine (3), diphenyl-m-tolylphosphine (4), tricyclohexylphosphine (5), diphenyl-2-pyridylphosphine (6) have been synthesized and characterised using Elemental analysis, FT-IR, Raman and multinuclear magnetic resonance (NMR) spectroscopy. Compounds 1 and 2 were also characterized by single crystal X-ray diffraction technique (XRD). The XRD study reveals that the Pd(II) moiety has a pseudo square-planar geometry, in which two positions are occupied by the dithiocarbamate ligand in a bidentate fashion, while at the remaining two positions organophosphine and chloride are present. The anticancer activity of the synthesized metallodrugs was checked against DU145 human prostate carcinoma (HTB-81) cells, the IC(50) values indicate that the compounds are highly active against these cells. These Pd(II) complexes also show moderate antibacterial activity against gram positive and gram negative bacteria.

Reactions of metal carbonyl complexes I. halodicarbonyl complexes of manganese(i)

Abstract The halopentacarbonylmanganese(I) complexes, Mn(CO)5X (X=Cl, Br, I) react with trialkyl phosphites, L [X=CI, L=P(OMe)3; X=Br, L=P(OMe)3, P(OEt)3, P(OCH2CH2Cl)3, P(OCH2CH=CH2)3], PPh(CH2CH2PPh2)2 (Triphos), and PMe2Ph to produce the halodicarbonyl complexes, Mn(CO)2L3X, Mn(CO)2(Triphos)X, and Mn(CO)2(PMe2Ph)3Br. The Mn(CO)2L3X complexes react with Ph2PCH2CH2PPh2 (Diphos) and Triphos to give the mixed ligand complexes, Mn(CO)2L(Diphos)X and Mn(CO)2L(Triphos)X. The Triphos ligand is only coordinated to the manganese atom through two of its three phosphorus atoms in the Triphos complexes. Some of the Diphos complexes can also be prepared by the reaction of fac-Mn(CO)3(Diphos)Br with L. The halotricarbonyl complexes, mer-trans[P(OPh)3]2Mn(CO)3X (X=Cl, Br), react with a variety of bidentate ligands, A-A [X=Cl, A-A=Diphos; X=Br, A-A=Diphos, Ph2AsCH2CH2AsPh2 (Diarsine), etc.] to form the mixed ligand halodicarbonyl complexes, Mn(CO)2[P(OPh)2] (A-A)X, and small amounts of fac-Mn(CO)3(A-A)X. The structures proposed for the new complexes are discussed on the basis of their IR spectra and molar conductances.

Structural Motifs and Biological Studies of New Antimony(III) Iodide Complexes with Thiones

Eight new antimony(III) iodide complexes of the heterocyclic thioamides, 2-mercapto-1-methylimidazole (MMI), 2-mercaptobenzimidazole (MBZIM), 5-ethoxy-2-mercaptobenzimidazole (EtMBZIM), 2-mercaptothiazolidine (MTZD), 3-methyl-2-mercaptobenzothiazole (NMeMBZT), 2-mercapto-3,4,5,6-tetrahydropyrimidine (tHPMT), 2-mercaptopyridine (PYT), and 2-mercaptopyrimidine (PMT) of formulas {[SbI(3)(MMI)(2)].MeOH} (1), [SbI(3)(MBZIM)(2)] (2), {[SbI(2)(mu(2)-I)(EtMBZIM)(2)](2).H(2)O} (3), [SbI(3)(MTZD)] (4), [(NMeMBZT)SbI(2)(mu(2)-I)(2)(mu(2)-S-NMeMBZT)SbI(2) (NMeMBZT)] (5), {[SbI(3)(tHPMT)(3)].MeOH} (6), [SbI(3)(PYT)] (7), and [SbI(3)(PMT)(2)] (8), have been synthesized and characterized by elemental analysis, FT-IR spectroscopy, FT-Raman spectroscopy, and TG-DTA analysis. The crystal structures of 3, 4, 5, 6, and 7 were also determined by X-ray diffraction. The complexes show interesting structural motifs. Complex 6 is a monomer, with octahedral (Oh) geometry around the metal ion formed by three sulfur and three iodide atoms. Complexes 3 and 5 are dimers, with a square pyramidal (SP) geometry in each monomeric unit, while complexes 4 and 7 are polymers with pseudotrigonal bipyramidal (psi-TBP). Two or three sulfur atoms from thioamide ligands and three iodide atoms are bound to Sb atoms forming building blocks for the dimers and polymers. Strong intramolecular interactions between mu(2)-I and/or mu(2)-S and Sb atoms stabilize both structures. In dimer complex 5, two terminal iodide and one terminal sulfur atom are bonded to the Sb ion, while two mu(2)-I and one mu(2)-S bridging atoms bridge the metal ions forming psi-Oh geometry. Computational studies using multivariant linear regression (MLR) and artificial neural networks (ANN) and considering biological results (50% inhibitory concentration, IC(50)) as dependent variables derived a theoretical equation for IC(50) values of the complexes studied. The calculated IC(50) values are compared satisfactorily with the experimental inhibitory activity of the complexes measured. Complexes 3-7 were used to study their influence upon the catalytic peroxidation of linoleic acid by the enzyme Lipoxygenase (LOX). Compounds 1-8 were also tested for in vitro cytotoxicity, and they showed mostly a moderate cytostatic activity against a variety of tumor cell lines but comparable with those found for the antimony(III) chloride and bromide complexes, reported earlier [Ozturk et al. Inorg. Chem. 2007, 46, 2861-2866; Ozturk et al. Inorg. Chem. 2009, 48, 2233-2245].