Mohyi M. El-essawi

Characterization of Surface Modification, Thermal Stability, and Metal Selectivity Properties of Silica Gel Phases‐Immobilized Dithiocarbamate Derivatives

Abstract Carbon disulphide was used to modify the surface of silica gel phases containing amine moieties for the formation of four phases-immobilized dithiocarbamate derivatives (I–IV). Characterization of the surface modification by the organic modifier was accomplished by several means of instrumental analysis. These include infrared, secondary ion mass spectrometry (SIMS), as well as, thermal desorption analysis for determination of the surface coverage values (1.051–1.501 mmol g−1). The thermal stability and structure characterization of the modified silica gel phases (I–IV), along with their mercury(II) adducts, were studied and evaluated on the basis of electron impact mass spectrometric analysis (EI‐MS). The results of this study proved higher thermal stability characters incorporated into the metal adduct compared to the free silica gel phase. The selectivity properties incorporated into the modified silica gel phases for binding and interaction with a series of bi‐ and trivalent metal ions were studied and evaluated by determination of the distribution coefficient and separation factor. The results of these evaluation processes were found to point out the higher selectivity and preference of these four phases for binding with mercury(II), copper(II), and cadmium(II) compared to other metal ions.

Coordination compounds of hydrazine derivatives with transition metals. Part 26. Coordination properties of α-diketone and α-ketoaldehyde bishydrazones derived from hydrazine-S-methylcarbodithioate

SummaryMetal(II) chelates with α-diketone and α-ketoaldehyde bishydrazones derived from hydrazine-S-methylcarbodithioate with the general formula M[α-dik(hydth)2-2H] (M=ZnII, CdII, NiII, Cu and PdII) were prepared and characterized by i.r., electronic and mass spectra as well as magnetic properties. The NiII, ZnII and CdII chelates are most probably pentacoordinated dimers whereas the CuII chelates are polymeric through Cu-S linkages. The PdII chelates are square planar monomers.

Koordinationschemie von Dinitroresorcin mit Kupfer-, Kobalt-, Nickel-, Eisen- und Zinksalzen

The reactions of the bidentate dinitrosoresorcinol (DNR) with copper, cobalt, nickel, iron and zinc salts were investigated. This ligand was found to react with these metal salts in aqueous media where hydrogen ion was confirmed to be liberated except in case of iron. The solid complexes were prepared in alcoholic media. Chemical analyses, magnetic and spectral data were compatible to determine the structure of these complexes and their mode of chelation.

Coordination compounds of transition metal hydrazine derivatives. Part 25. Monohydrazine-S-methylcarbodithioate schiff bases derived from α-dicarbonyl compounds

SummaryThe monohydrazones derived from the condensation of diacetyl and benzil with hydrazine-S-methylcarbodithioate (Dahydth) and (Benhydth) were prepared and their ligation properties with nickel(II), copper(II), palladium(II), zinc(II) and cadmium(II) were studied. A series of bisligand chelates were isolated and characterized. In the zinc(II), cadmium(II) copper(II) and palladium(II) bisligand chelates, both Dahydth and Benhydth act as mononegative bidentate molecules. The Ni(Dahydth-H)2 chelate possesses an octahedral structure where Dahydth acts as a mononegative tridentate ligand. The1H n.m.r. spectra of the two ligands as well as of the diamagnetic metal(II) chelates are discussed. The fragmentation in a mass spectrometer of all these chelates was also studied.

Nickel(II), Copper(II), Zinc(II) and Cobalt(III) Complexes of N-Salicylidene-4-Amino-5-OXO-3- Thioxo-6-Methyl-2.3.4.5-Tetrahydro-1.2.4-Triazine

Abstract The N-Salicylidene derivative of 4-amino-5-oxo-3-thioxo-6-methyl-2, 3. 4. 5-tetrahydro-1.2.4-triazine (Sal. MeTzn) was prepared and characterized. The reaction of Sal. MeTzn with nickel(II), cobalt (II). copper (II) and zinc(II) salts was studied and the mono-ligand chelates M(Sal.MeTzn-2H), M = Ni. Cu and Zn. and bis-ligand Co(III) chelate Co(Sal. MeTzn-H) (Sal.MeTzn-2H) were isolated. The infrared and electronic spectra as well as the magnetic properties of these chelates were discussed.

Crystal Structure and Mass-, Electronic-, Infrared Spectral Studies on Hexaaqua Ni(II) Bis(O-Tolylazo-Citrazinate) Hexahydrate Complex

Abstract A new crystalline octahedral hexaaqua Ni(II) bis(o-tolylazo-citrazinate)hexahydrate complex was synthesized. The analytical data proved the formation of 1:2 stoichiometry. An X-ray structure investigation has been carried out. The triclinic space group is p and the unit cell parameters are a = 585.5 pm, b = 993 pm, c = 1139.4 pm, α = 101.6°, β = 97.4°, γ = 102.4°. Evaluation of intensity data revealed the structure with an R-value of 0.03 (2316 observed independent reflections). The compound consists of hexaaqua nickel(2+) ions, univalent anions of the carboxylic acid and six additional water molecules per