Volume 39, Issue 5-6

Congeneric complexes ( S )-{OˆO}MCH 2 SiMe 3 (M=Al, 3 ; Ga, 5 ; In, 6 ) of the triel metals supported by an enantiomerically pure phenolato-alkoxo {OˆO} 2− dianionic tridentate ligand derived from prolinol, along with their chloro derivatives, have been prepared and characterised. The aluminium-alkyl species ( S )-{OˆO}AlMe and 3 form four-coordinate complexes with slightly distorted tetrahedral geometries, whereas the geometry in the Lewis acidic five-coordinate ( S )-{OˆO}GaCl·THF is a distorted trigonal bipyramid. These alkyl complexes do not react cleanly, if at all, with protic sources. The indium(III) compound 6 , which is for instance inert towards i PrOH or BnOH even after hours at 70°C, catalyses at 95°C the controlled, immortal ring-opening polymerisation of racemic lactide (up to 1000 equivalents) in the presence of excess BnOH as a chain transfer agent. It affords atactic, monodisperse polylactides with predictable molecular weights.

Piperazines and fullerene nanocages are versatile compounds. These are discussed in a wide range of academic work, especially in the field of medicine, and considered for various applications by the pharmaceutical industry. In the present research, the potential interaction mechanisms between B-, Si-doped C60 and 1-formylpiperazine (1-fp) were examined within the framework of density functional theory, along with their optimized molecular structures and electronic properties. The calculated binding energies and various other physical and chemical parameters of 1-fp found in this work in comparison with the Si- and B-doped fullerenes suggest that doping of fullerene nanocage leads to a strong interaction mechanism that alters the chemical and electronic properties of the investigated compounds. This finding can be used as a guide for their further applications.

Reactions of Al(OPr i ) 3 with sterically hindered heterocyclic β-diketones,4-acyl-3-methyl-1-phenyl-2-pyrazolone-5-ones have been carried out in 1:1 molar ratio in toluene to yield asymmetric dimeric compounds [RC(O)C:C(O)N(Ph)N:CCH 3 ] 2 Al(μ-OPr i ) 2 Al(OPr i ) 2 where 1 , R=CH 3 ; 2 , R=C 2 H 5 , 3 , R=C 6 H 5 ; 4 , C 6 H 4 Cl. These derivatives have been characterized by elemental analysis, molecular weight measurements and probable structure of these compounds have been proposed on the basis of IR, 1 H, 13 C, 27 Al NMR spectroscopies and FAB mass spectrometry. Based on the spectroscopic evidence an asymmetric structure with tetrahedral and octahedral aluminum centers has been proposed for these derivatives.

A novel coordination polymer, poly[(μ-diacetato)(tetraphthalato)pentabarium(II)], with acetate bridged moiety has been successfully grown by gel diffusion technique. Single crystal X-ray diffraction analysis showed that the compound crystallizes in triclinic space group P 1̅. The grown crystals were further characterized by elemental analysis, FT-IR, UV-visible spectroscopic analysis, and thermogravimetric and powder X-ray diffraction studies. The photoluminescent properties of the complex and the ligand were also investigated.

The compounds MeCl 2 Si[S 2 P(OR) 2 ], MeClSi[S 2 POGO] 2 , and MeSi[S 2 P(OR) 2 ] 3 (where R=Et, n -Pr, i -Pr, i -Bu, and Ph; G=-CH 2 CMe 2 CH 2 -, -CH 2 CEt 2 CH 2 -, and -CMe 2 CMe 2 -) have been prepared by reacting the sodium salt of the appropriate dithiophosphoric acid or the acid itself with MeSiCl 3 in 1:1, 1:2, and 1:3 molar ratios, in benzene, at reflux. These compounds are yellow oily liquids and soluble in common organic solvents. The molecular weight determination corresponds to monomers. The compounds have been characterized by elemental analysis and by 1 H, 13 C, 29 Si, and 31 P NMR spectroscopies. The ligands coordinate in a monodentate mode to the silicon atoms which in turn show a tetrahedral environment. Screening these complexes for their antibacterial activities gave positive results.

Morpholinium trichloroplumbate(II), [ cyclo -O(CH 2 CH 2 ) 2 NH]PbCl 3 ( 1 ), has been synthesized and characterized by elemental analysis, FTIR and 1 H and 13 C NMR spectroscopy, thermogravimetric analysis (TGA), diffuse reflectance spectra, and single-crystal X-ray diffraction analysis. An FTIR spectrum showed a shift of 100 cm -1 in the NH 2 stretching due to the protonated nitrogen of the morpholinium ion. 1 H NMR spectrum of the compound showed significant high-frequency shift of the resonance for the C H 2 protons due to the presence of cationic charge on the adjacent nitrogen and hydrogen bonded interactions. Contrary to 1 H NMR, the 13 C NMR signals showed a lowering of ‘δ’ in the hybrid material. A diffuse reflectance spectrum (DRS) illustrated intense charge transfer in the compound. The observed band gap value for the compound is 3.23 eV based on the DRS data. TG-DT analysis showed the compound to be stable up to 241°C. Single crystal X-ray diffraction analysis of the hybrid material showed the Pb 2+ ion being surrounded by six chloride anions in a distorted octahedral geometry. In addition to the six chloride anions, the oxygen atom of the morpholinium cation is also in short contact with the lead cation. Bond valence sum (BVS) calculation confirmed the formal oxidation state of lead to be +2. Continuous symmetry measure (CSM) calculations indicated the PbCl 6 to be a distorted octahedron with a magnitude of 5.246 clearly far away from the trigonal prismatic geometry.

Magnetite (Fe 3 O 4 ) and lead sulfide (PbS) nanostructures were synthesized via a simple precipitation method in water by using green capping agents. Then, Fe 3 O 4 -PbS nanocomposites were prepared by facile chemical procedure. The effects of concentration, temperature as well as precipitating and capping agents on the morphology and particle size of the magnetic products were investigated. Sugars and carbohydrates were used as green, cost-effective, and safe bio-compatible capping agents. The prepared magnetic products were characterized by X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. Alternating gradient force magnetometer was used to identify the super-paramagnetic property of the samples. The photo-catalytic behaviour of nanocomposites was evaluated using the degradation of azo dyes under ultraviolet light irradiation.

A laboratory experiment was conducted to determine the benefits of some soil organic and inorganic amendments on cadmium (Cd) sorption capacity in non-polluted calcareous soil. The non-polluted soil was separately incubated with organic [municipal solid waste compost (MSWC), rice husk biochars prepared at 300°C (B300) and 600°C (B600)] and inorganic amendments (coal fly ash, CFA), zero valent iron (Fe 0 ), and zero valent manganese (Mn 0 ) at 2% and 5% (W/W) for 90 days at 25°C. After incubation, sorption kinetics and sorption isotherms of Cd were determined using batch experiments. Results show that the adjustments enhanced the sorption capacity of soil for Cd, as indicated by generally higher K F and 1/n values (constants of Freundlich equation) and distribution coefficients (K d ) compared with the control. The increase of Cd sorption in the soils with different amendments followed the sequence Mn 0 >Fe 0 >B600>CFA>MSWC>B300. Among the sorption isotherms and kinetic equations, the linear forms of Freundlich and simple Elovich equations yielded good prediction of Cd sorption, respectively. Generally, all amendments improved and increased Cd sorption rate. Given that Mn 0 treatment had the highest impact on increasing Cd sorption capacity, it can thus be recommended in the immobilization of Cd from polluted soil.

In this study, [2-(Menthoxycarbonyl)ethyl]tris(8-quinolinato)tin, MenOCOCH 2 CH 2 Sn(Ox) 3 (Men=Menthyl, HOx=8-hydroxyquinoline) has been synthesized and characterized by means of elemental analysis, FT-IR, 1 H NMR, and single crystal X-ray diffraction. The tin atom of the monomeric complex is seven-coordinate and possesses [CN 3 O 3 Sn] pentagonal bipyramidal environment formed by C atom as well as N and O atoms of the chelating Ox ligands. The carbonyl of ester is not coordinated to tin.