Magdi F. Iskander

Coordination compounds of hydrazine derivatices with transition metals—XIX

Abstract The reaction of differently substituted aroyl hydrazones (R·CHN·NH·CO·R′) with nickel(II) and copper(II) salts were investigated. Magnetic and spectral data showed that in the case of nickel(II) chloride, octahedral complexes were formed with the ligands reacting in the keto form whereas in the case of nickel(II) and copper(II) acetate square planar complexes were obtained with the ligands coordinating through the enol form. With copper(II) chloride, reduction took place and mono (aroyl hydrazone) copper(I) monochloride compounds were isolated.Abstract The reaction of differently substituted aroyl hydrazones (R·CHN·NH·CO·R′) with nickel(II) and copper(II) salts were investigated. Magnetic and spectral data showed that in the case of nickel(II) chloride, octahedral complexes were formed with the ligands reacting in the keto form whereas in the case of nickel(II) and copper(II) acetate square planar complexes were obtained with the ligands coordinating through the enol form. With copper(II) chloride, reduction took place and mono (aroyl hydrazone) copper(I) monochloride compounds were isolated.

Coordination compounds of hydrazine derivatives with transition metals. X. Cobalt(II) aroylhydrazone complexes

Abstract The reactions of some aroylhydrazones (HL) with cobalt(II) salts were investigated and chelates of the types [Co(HL) 2 X 2 ] and [Co(L) 2 ] were isolated. Analytical data, infrared studies, magnetic moments and solution spectra as well as some conductivity measurements were used to characterise these chelates. The [Co(HL) 2 X 2 ] chelates were found to possess octahedral configuration in solid state but dissociate in DMF solutions. Attempts were made to identify the dissociation products. A dimeric pentacoordinate structure was tentatively assigned for the neutral [Co ( L ) 2 ] chelates.

Coordination compounds of hydrazine derivatives with transition metals. VIII. Copper(II) complexes with salicylaldehyde and acetylacetone aroyl-hydrazones.

Abstract Copper(II) chelates of salicylaldehyde aroylhydrazones [H 2 Sal-R] and acetylacetone aroylhydrazones [H 2 Acac-R] have been prepared. Elemental analyses, infrared and electronic spectra as well as the magnetic susceptibility measurements are used for their characterisation. A distorted square pyramidal structure is tentatively assigned for chelates of the type [Cu(H SalR)CI · X] (X = H 2 O or pyridine), whereas the anhydrous chelates [Cu(H Sal-R)Cl] possess square planar arrangement with the chloride ion occupying a coordination site. In both types the hydrazone molecule acts as a monobasic tridentate ligand. The neutral chelates [Cu(Sal-R)] and [Cu(Acac-R)] on the other hand, possess subnormal magnetic moments and may achieve square planar structure through molecular association. In these chelates, the hydrazone molecule acts as a dibasic tridentate ligand. Their interaction with pyridine afforded the monomeric monopyridinate adducts.

Coordination compounds of hydrazine derivatives with transition metals—XII Nickel(II) and copper(II) chelates of bis(n-salicylidene)dicarboxylic acid dihydrazides

Abstract A series of nickel(II) and copper(II) chelates with polydentate ligands derived from the condensation of salicylaldehyde with some dicarboxylic acid dihydrazides have been prepared. Elemental analyses, IR and visible spectra have been used to characterize the metal chelates prepared. The complexes prepared are of the general formulae: M(H3Lig)X·nH2O, M2(H2Lig)X2·nH2O, M(H2Lig)·nH2O M2(Lig)·nH2O and M(H3Lig)2. In these chelates, the ligands show different degrees of deprotonation. The different modes of chelation of the ligands and the stereochemistry of the metal (II) chelates are discussed.

Synthesis, reactivity and magnetochemical studies on copper(II) complexes derived from N-salicylidenearoylhydrazines. X-ray structure of [mononitratoOO( -1) (N-salicylidenatobenzoylhydrazine) - ONO( -1)]copper(II) monohydrate

Abstract A series of new mononuclear and binuclear copper(II) complexes derived from N-salicylidenearoylhydrazines (H2L) of the types K2[{Cu(L)(OH)}2]·nH2O, [Cu(HL)Cl·H2O]·nH2O, [{Cu(HL)Cl}2], [Cu(HL)NO2]·H2O, [{Cu(HL)}2]·2NO3, [{Cu(HL)H2O}2]·2NO3·nH2O and [Cu(HL)NCS]·H2O have been prepared and characterized. The X-ray crystal and molecular structure of [Cu(HSBzh)NO3]·H2O, where HSBzh refers to the mononegative N-salicylidenebenzoylhydrazine anion, has been determined. The complex is monomeric with the copper(II) adopting a (4+1) distorted square pyramidal coordination, with the ONO aroylhydrazone tridentate anion and an oxygen atom of the unsymmetric bidentate nitrate ion occupying the basal plane. The fifth coordination site is occupied by the other oxygen of the nitrate ion. The magnetic susceptibilities of both mononuclear and binuclear complexes were measured within the temperature range 4.2–298 K. All binuclear copper(II) complexes show strong antiferromagnetic interactions, and the singlet–triplet separation (−2J) recorded for μ-dihydroxy bridged complexes K2[{Cu(L)OH}2}]·nH2O are within the range 172–276 cm−1, while (−2J) for binuclear complexes [{Cu(HL)Cl}2], [{Cu(HL)}2]·2NO3 and [{Cu(HL)H2O}2]·2NO3·nH2O are respectively within the range 400–460, ca. 340 and ca. 390 cm−1. There are no appreciable exchange interactions between copper(II) ions in the monomeric complexes [Cu(HL)Cl·H2O]·nH2O, [Cu(HL)NO2]·H2O and [Cu(HL)NCS]·H2O. The IR spectra of the prepared complexes are also discussed.

Synthesis, magnetochemical studies and X-ray molecular structures of some mononuclear copper(II)–1H-pyrazole adducts and mono(μ-pyrazolate) bridged dicopper(II) complexes derived from N-salicylidenearoylhydrazines

Abstract 1H-Pyrazole complexes, [Cu(HL)HPz Cl] nH2O and [Cu(L)HPz] nH2O were prepared and characterized, where HL and L, respectively, refer to the mononegative and dinegative N-salicylidenearoylhydrazine anions. The X-ray crystal and molecular structure of [monochloro(N-salicylidenebenzoylhydrazinato)ONO(−1)monopyrazole] copper(II) monohydrate, [Cu(HSBzh)HPz Cl] H2O, and [(N-salicylidenebenzoylhydrazinato)ONO(−2)monopyrazole] copper(II) hemihydrate, [Cu(SBzh)HPz] 1/2H2O, were determined. The Cu(II) in [Cu(HSBzh)HPz Cl] H2O is in a distorted square pyramidal environment and is bound in the equatorial plane with the mononegative tridentate aroylhydrazone anion and pyrazole nitrogen, the axial fifth coordination site is occupied by a chloride ion. On the other hand, the complex [Cu(SBzh)HPz] 1/2H2O consists of two monomeric crystallographically independent but chemically similar molecules. In each molecule, the Cu(II) is in a distorted square planar geometry and is coordinated to the dinegative tridentate aroylhydrazone via the phenoxy oxygen, azomethine nitrogen and enolimide oxygen, and the fourth coordination site is occupied by the pyrazole nitrogen. The mono(μ-pyrazolate) dicopper(II) complexes, K[Cu2(L)2Pz] nH2O, were also prepared and the X-ray molecular structure of K2[Cu4(SBzh)4(Pz)2] 2H2O 1/2CH3OH was determined. In this complex, two copper(II) atoms are bridged by only one pyrazolate anion forming a dicopper mono(μ-pyrazolate) unit. Each two units are connected together by a five coordinate K+ cation forming a tetranuclear assembly. These tetranuclear assemblies are connected together by another K+ cation forming a supramolecular structure. Variable temperature magnetic studies on these pyrazolate complexes indicated antiferromagnetic behaviour with −2J values varying from 25 to 36 cm−1.

Coordination compounds of hydrazine derivatives with transition metals—VI: The reaction of aroylhydrazines with nickel(II), cobalt(II) and copper(II) salts

Abstract The reaction of aroylhydrazines with nickel(II), cobalt(II) and copper(II) ions were investigated. Both bis and tris nickel(II) and cobalt(II) chelates were isolated; magnetic and spectral measurements revealed their octahedral structure. With copper(II) nitrate and sulphate, aroylhydrazines gave only bis complexes. However, with copper(II) chloride, both mono and bis chelates were obtained at low temperature while at high temperature, oxidation-reduction reactions occurred with the formation of complexes with mixed oxidation states of copper. In all the metal chelates prepared in this work, the aroylhydrazine molecule acted as a neutral bidentate ligand, coordinating via the carbonyl oxygen and the amino-nitrogen.

Synthesis, characterization and magnetochemical studies of some imidazole and imidazolate copper(II) ternary complexes derived from N-salicylidenearoylhydrazines. X-ray crystal and molecular structures of [(N-salicylidene-p-chlorobenzoylhydrazine)ONO(−2)imidazole]copper(II) monohydrate and dimeric [(N-salicylidene-p-methylbenzoylhydrazine)ONO(−2)imidazole]copper(II) hemihydrate

Abstract The reactions of imidazole (Him) with N-salicylidenearoylhydrazine copper(II) complexes have been studied and a number of ternary copper(II) complexes, [Cu(L)Him]·nH2O, [Cu(HL)X·Him]·nH2O and [{Cu(L)}2Im]·nH2O, have been prepared and characterized (HL and L refer, respectively, to mono- and dinegative N-salicylidenearoylhydrazine anions and X is a mononegative monodentate ligand). The X-ray crystal and molecular structure of [(N-salicylidene-p-chlorobenzoylhydrazine)imidazole]copper(II) monohydrate, [Cu(Sp-ClBzh)Him]·H2O, and [(N-salicylidene-p-methylbenzoylhydrazine)imidazole]copper(II) hemihydrate, [Cu(Sp-CH3Bzh)Him]·1/2H2O, were measured. The p-chloro complex [Cu(Sp-ClBzh)Him]·H2O is monomeric with the Cu(II) in a distorted square planar environment and is coordinated to the tridentate hydrazone via phenoxy oxygen, azomethine nitrogen and enolimide oxygen, the fourth coordination site is occupied by the imidazole nitrogen. The p-methyl complex [Cu(Sp-CH3Bzh)Him]·1/2H2O was found to be a centrosymmetric dimer, the monomeric unit being bridged through the phenoxy oxygen. The Cu(II) is in a square pyramidal environment and is bounded in the equatorial plane with the enolimide oxygen, azomethine nitrogen and phenoxy oxygen of the hydrazone ligand while the fourth site is occupied by the symmetry related phenoxy oxygen of the other unit; the axial fifth coordination site is occupied by the imidazole nitrogen. The magnetic susceptibility measurements at different temperatures (5–298 K) have been recorded and are discussed. The binuclear imidazolate complexes show antiferromagnetic exchange coupling interactions, the measured −J values are within the range 17.0–20.0 cm−1, while the imidazole complexes do not show any appreciable exchange interactions.

ORGANOTIN(IV) COMPLEX WITH TRIDENTATE LIGANDS. II: SYNTHESIS AND CHARACTERIZATION OF MONO- AND DIMETHYLTIN(IV) COMPLEXES WITH N-(2-PYRIDINYLMETHYLENE) BENZOYLHYDRAZINE. THE CRYSTAL AND MOLECULAR STRUCTURE OF MONOMETHYLDICHLORO N-(2-PYRIDINYLMETHYLENE)BENZOYLHYDRAZINATE NNO(-1)TIN(IV)

Abstract Two organotin(IV) complexes with N-(2-pyridinylmethylene)benzoylhydrazine (HPyBzh), of the general formulae SnMeCl2(PyBzh) and SnMe2Cl(PyBzh), were prepared and characterized by mass, IR, UV-vis and NMR spectral techniques. The X-ray crystal and molecular structure of SnMeCl2(PyBzh) has been determined. The PyBzh− anion in this complex acts as a monobasic NNO-tridentate ligand, the tin(IV) lying in an elongated distorted octahedral environment where the pyridyl nitrogen, azomethine nitrogen and hydrazide oxygen, together with the methyl carbon, are in the equatorial plane, whereas the two chlorides are the apical ligands. The structures of these complexes in different solvents have also been discussed.

Organotin(IV) complexes with tridentate ligands—III. Synthesis and characterization of some organotin(IV) complexes with N-(2-pyridinylmethylene)hydrazinecarbothioamide: the X-ray crystal structure of dimethylmonochloro[N-(2-pyridinylmethylene)hydrazinecarbothioamidato) NS(—1)]Tin(IV) hemihydrate

Abstract Three organotin(IV) complexes with 2-formylpyridine thiosemicarbazone (HFPT) of formulae [Sn(CH 3 )(FPT)Cl 2 ] and [SnR 2 (FPT)Cl] (R = CH 3 and C 2 H 5 ) were prepared and characterized by elemental analysis as well as IR and mass spectral techniques. The X-ray crystal structure of [Sn(CH 3 ) 2 (FPT)Cl]·0.5H 2 O has been determined. In this complex, the FPT − anion acts as a mononegative NS bidentate ligand, while the pyridine nitrogen remains uncoordinated. The tin(IV) is in a strongly distorted trigonal bipyramidal configuration where the thiol sulphur and the two methyl carbons occupy the equatorial plane while the chloride and the azomethine nitrogen occupy the apical positions. The 1 H and 13 C NMR spectra as well as the electronic absorption spectra of these complexes are discussed.