Synthesis and spectral studies of novel copper(II) chelates of sulphur-containing oximes

Summary Copper complexes of benzil--monoxime-2-iminoethanethiol (BMETH₂), benzil--monoxime-2-iminobenzenethiol (BMBTH₂), benzil--monoximethiosemicarbazone (BMTH₂) and benzil--monoximesemicarbazone (BMSH₂) were synthesized and characterized by physicochemical and spectroscopic measurements. The molar conductivities show that all of the complexes are nonelectrolytes. The i.r. spectra suggest that the ligands are tetradentate in all cases, whilst the electronic spectra suggest planar geometries for all the complexes. The calculated e.s.r. parameters show an axial dx ² - y ² ground state and suggest coordination through sulphur, in agreement with the i.r. results. In all of these complexes, the =N—;O group acts as a bridging function to give dimeric structures.     

β-diketone complexes of manganese(II), cobalt(II), nickel(II) and palladium(II)

Summary The reactions of manganese(II), cobalt(II) and nickel(II) acetates (1 mole) with antipyrine-4-azo--ethylcyanoacetate (HL¹) and antipyrine-4-azo--acetylacetone (HL²) (1 mole) produce complexes of the M(L)₂ type. K₂PdCl₄ (1 mole) reacts with HL¹ and HL² (1 mole) to yield complexes of the general formula PdLCl, the ligands behaving as monobasic tridentates. The electronic spectral and magnetic data show the complexes to be high-spin octahedral, whereas the palladium(II) complexes are diamagnetic square planar. The complexes were characterized by elemental analyses, conductance measurements and i.r. and electronic spectra as well as magnetic susceptibility measurements and thermal (t.g.a. and d.t.a.) analysis.Nuclear Material Authority.     

4,4′-Bipyridyl complexes of iron: Magnetic,Mössbauer and other spectroscopic studies

Summary 4,4-Bipyridyl (4,4-bipy) complexes of ferrous salts of the Fe(4,4-bipy)_x(anion)_y type (where x or y=1 or 2) and of ferric salts of the Fe(4,4-bipy)_m(anion)_n type (where m=1 or 2 and n=3) have been synthesised. Elemental analyses, i.r. and electronic spectra, magnetic and Mössbauer studies have been performed to characterize the complexes. 4,4-Bipy and some anions are inferred to act as bridging ligands. The magnetic moments, electronic and Mössbauer spectra suggest that the complexes are of high spin type with distorted octahedral structures. The value of the isomer shift and quadrupole splitting are discussed in terms of bonding of the ligand and anions.     

Bonding properties of copper(II)—N chromophores: Preparation,structure, and spectroscopic properties of ethylenediaminecopper(II) complexes. Molecular structure of [Cu(ethylenediamine)(pyridine)2(ClO4)2]

Summary Ethylenediaminecopper(II) perchlorate complexes of the [Cu(ethylenediamine)L₂(ClO₄)₂] type, where L = imidazole, N-methylimidazole, 2-methylimidazole, 4-methylimidazole, and pyridine, have been prepared and characterized by elemental analyses, and electronic, vibrational, and e.p.r. spectroscopic measurements. The molecular structure of [Cu(ethylenediamine)(pyridine)₂(ClO₄)₂] has been determined by three-dimensional X-ray diffraction data. The Cu^II ion is coordinated by one ethylenediamine and two pyridine ligands forming an equatorial plane, and by two perchlorate anions located on the z axis. The pyridine ligands incline at 54.9 ° to the CuN₄ plane suggesting virtually no -interaction in the complex. Similar structures with a CuN₄ coordination plane are proposed for other complexes based on the spectroscopic data. The bonding properties of these complexes are elucidated and discussed with reference to the electronic structures deduced from Gaussian analyses of their LF spectra.     

Thermal and electrical conductivity properties of some CrIII, MnII and UO 2 II amino alcohol complexes

Cr^III, Mn^II and UO₂ ^II amino alcohol complexes were prepared and analyzed. The IR spectra proved that the ligation occurs via oxygen and nitrogen atoms. The nujol mull electronic absorption spectra joined with the room temperature magnetic moment values proved that the complexes are of O_h geometry. The thermal behaviour of the complexes was studied by DTA and TG techniques. The mechanism of the decomposition was suggested. The thermodynamic parameters of the decomposition were evaluated and discussed. The entropy of activation changes, S*, showed that the transition states are more ordered than the reacting complexes. The D.C. electrical conductivity measurements of Cr- and Mn-amino alcohol complexes are of semiconductor behaviour. Empirical equations were deduced for the conduction of the investigated complexes.This revised version was published online in November 2005 with corrections to the Cover Date.     

Iron(III) complexes of some thiosemicarbazones derived from 2-acetylpyridine,its 6-methyl derivative and itsN-oxide

Summary A series of iron(III) complexes of thiosemicarbazones derived from 2-acetylpyridine, 6-methyl-2-acetylpyridine and 2-acetylpyridineN-oxide have been prepared from Fe(ClO₄)₃ and FeCl₃. All of the isolated solids have cations involving two monobasic tridentate ligands, and either perchlorate or tetrachloroferrate(III) anions and are 11 electrolytes. Coordinationvia the pyridine nitrogen (or theN-oxide oxygen), the imine nitrogen and the sulphur atom are confirmed by infrared spectra and x-ray diffraction. The presence of two different iron(III) species is indicated by the electron spin resonance spectra of the tetrachloroferrate(III) solids. E.s.r. along with electronic spectra prove the spin-paired configuration of these cationic iron(III) complexes.NATO Fellow, on leave from Istanbul Medical Faculty, Istanbul University.     

The structure of bis(Dihaloalane-di-μ-halo)(η-arene)titanium(II) complexes containing different halogen atoms

Summary An attempt was made to detect deviations from the random distribution of chlorine and bromine atoms in the series of bis(dihaloalane-di--halo)( ⁶-arene) titanium(II) complexes of overall formula (C₆H₆) · TiAl₂Cl_xBr_8–x (1). The distribution of halogen atoms between bridge and outer positions of (1) was studied by the shift of g-values in the e.s.r. spectra of bis(dihaloalane-di--halo)( ⁵-cyclopentadienyl)titanium(III) complexes obtained by the reaction of (1) with cyclopentadiene, and by the shift of thev ₂ band in the electronic spectra of (1). Both methods indicated the preferred occupation of bridge positions by chlorine atoms based on the assumption that the g-value and thev ₂ band position were linearly dependent on the chlorine content in the bridge positions.     

Molybdenum complexes of biochemical iinterest. New coordination complexes of oxomolybdenum(V) with the tridentate ONO donor schiff bases derived from salicylaldehydes and ethanolamine

Summary New oxomolybdenum(V) complexes MoOCIL (where LH₂ = Schiff base) derived from ethanolamine and salicylaldehyde, 5-chlorosalicylaldehyde, 5-bromosalicylaldehyde, 5-nitrosalicylaldehyde, 3-ethoxysalicylaldehyde and 2-hydroxy-1-naphthaldehyde have been synthesized and characterised by elemental analyses, conductance, molecular weight, i.r. and electronic spectra and magnetic measurements. The Schiff bases behave as dibasic tridentate ONO donor ligands. The complexes are non-electrolytes and dimers. The complexes exhibit subnormal magnetic moments and are involved in antiferromagnetic exchange withS=0 ground state. The complexes exhibit electronic spectral bands atca. 13000 andca. 17000 cm^–1 due to the transitionsd _xy d _xz,yz (²B₂ ²E) andd _xy d _x ²–y² (²B₂ ²B₁), respectively. The (Mo=O) frequency of the complexes is observed in the 900–970 cm^–1 region. On the basis of the magnetic susceptibility, i.r. and molecular weight data a dimetallic structure with alcoholic oxygen atoms as the bridging atoms is suggested.Abbreviations sal salicylaldehyde - 5-chlorosal 5-chlorosalicylaldehyde - 5-bromosal 5-bromosalicylaldehyde - 5-nitrosal 5-nitrosalicylaldehyde - 3-ethoxysal 3-ethoxysalicylaldehyde - hydroxy 2-hydroxyl-1-naphthaldehyde     

Studies on the complexes of 4′-substituted benzo-15-crown-5 ligands with sodium picrate and picric acid

Complexes of nine 4'-substituted benzo-15-crown-5 ligands with sodium picrate were prepared. A good linear relationship of the . values from the UV spectra and Hammett [_p - _m] values was observed. Charge transfer complexes of ten 4'-substituted benzo-l5-crown-5 ligands with picric acid were isolated in crystalline form. The color of the complexes depended on the nature of the substituents. All of the complexes were identified by elemental analyses, UV and IR spectra.     

Electrochemical studies of copper(II) complexes derived from bulky Schiff bases. The crystal structure of bis[N-(1- adamantyl)-salicylaldiminato]copper(II)

Three Schiff base ligands and their corresponding copper(II) complexes have been prepared and characterized. Elemental analyses, mass spectra, i.r., electronic spectra, eff and the X- ray crystal structure for one of the complexes, as well as elemental analyses, mass spectra, i.r., electronic and 1H n.m.r. spectra of the ligands, have been obtained. The X-ray study shows that the geometry around the metal atom is intermediate between square planar and tetrahedral. Electrochemical studies on the complexes reveal a dependence of the CuII/CuI potentials on the extent of distortion of the planar structure observed in solid state.     

H2O soluble ternary complexes of divalent transition metal ions with AN-(2-acetamido)iminodiacetic acid and heterocyclic diimines

Summary H₂O soluble mixed ligand complexes of the type [M-(ADA)B·H₂O] where M = Ni^II or Cu^II; [ADA]^2- = divalent anion of N-(2-acetamido)iminodiacetic acid, B = heterocyclic diimine (2,2'-bipyridyl or 1,10-phenanthroline), were prepared and characterized by elemental and thermal analyses, i.r. and electronic spectra, as well as conductivity measurements. Formation constants for the 111 ternary cobalt(II), nickel(II) and copper(II) complexes formed in solution were determined potentiometrically at 24 °C and = 0.1mol dm^-3(KNO₃).     

Complexes of nickel(II) and palladium(II) with thiobenzamide

Summary The electronic and vibrational spectra of Ni^II and Pd^II complexes with thiobenzamide, L, are discussed. L acts as a sulphur donor ligand. The Pd^II compounds and (NiL₄)(ClO₄)₂ are square planar. PdL₂Cl₂ has acis-structure, while PdL₂X₂ (X=Br or I) istrans; NiL₄Cl₂ istrans-octahedral. The i.r. bands due to(M.S) and(MX) have been assigned. The influence of the anions on the properties of the complexes, both in solution and in the solid state, is discussed.     

X-Ray Emission Spectra and Electronic Structure of Palladium β-Diketonate Complexes

A series of palladium -diketonate complexes have been studied by X-ray spectroscopy. For interpreting the X-ray emission spectra, electronic structure calculations have been performed by the INDO method for the Pd(acac)₂ and Pd(hfac)₂ complexes in the ground state. The results of these calculations indicate that if one HOMO is excited, the electronic structure of the whole complex undergoes considerable rearrangements changing the sequence of HOMOs.     

Modeling of the Electronic Absorption Spectra and Photoionization of Scandium and Titanium Tris(acetylacetonates) by the DV-XαMethod

In order to interpret the electronic absorption spectra of titanium tris(-diketonates) and to establish the correlation between the ionization and excitation energies, the oscillator strengths and energies and the ionization energies for the model complexes M(Mal)₃(Mal is deprotonated malonodialdehyde, M = Sc, Ti) were calculated in the transition state approximation of the DV-Xmethod. The good agreement between the calculated photoelectron spectra and the experimental data and the correlation found between two types of excitation justified the assignment of the experimental absorption bands to the electronic states of Ti(Acac)₃.     

Transition metal chemistry of oxime-containing ligands,VI: magnetic and structural properties of mono (pyridine-2-aldoxime) dithiocyanato iron (II) and mono (6-methylpyridine-2-aldoxime) dithiocyanato iron (II) complexes

The complexes of pyridine-2-aldoxime (HPOX) and 6-methylpyridine-2-aldoxime (HMPX) with iron (II) thiocyanate of the type [Fe(L)(NCS)₂] (L=HPOX and HMPX) have been prepared and characterized. A study of X-ray, magnetic, vibrational spectra (conventional and far-infrared), electronic spectra andMössbauer spectra has indicated that these complexes have polymeric, pseudo octahedral, coordination geometry with linear bridging thiocyanate ligands. The electronic spectra of mono complexes show a larger, low symmetry, ligand field than that present in [Fe(L)₂(NCS)₂] complexes. UnperturbedMössbauer spectra show a large quadrupole splitting, E _Q, and smaller isomer shift values in these iron (II) thiocyanate complexes. The magnetically perturbedMössbauer spectra of these iron(II) thiocyanate complexes at room temperature show that the principal component of the electric field gradient tensor is positive and corresponds to ad _xy (⁵B₂) ground state.With 2 Figures     

Mixed-ligand cobalt(III) complexes derived from bis(dehydroacetato)ethylenediimine

Summary A hydroxocobalt(III) complex (1a), has been obtained by reaction of bis(dehydroacetato)ethylenediimine (H₂dhaen) with cobalt(II) hydroxide or acetate in the presence of air. Addition of a second complexing agent leads to the formation of a series of mixed-ligand complexes (2)-(26) having either the trans- or cis- configuration. In the cis- complexes, the quadridentate ligand dhaen adopts a nonplanar conformation. Configurations are distinguishable from characteristic differences in the electronic and n.m.r. spectra.     

An X-ray photoelectron study of the electronic structure of Cu(II) complexes with dia- and paramagnetic derivatives of 2-imidazoline

The electronic structure of free radicals and Cu(II) complexes with the nitronyl nitroxide radical and aminonitrone is studied by X-ray photoelectron spectroscopy (XPS). N1s XPS spectra of nitrogen atoms of Cu(II) complexes with aminonitrones confirm the diamagnetic nature of the ligands. The binding energies of the main peak and the intense satellite structure in the Cu2p _3/2,1/2 spectra of the complexes under study correspond to the Cu(II) state. The structure of the satellite in the Cu2p _3/2,1/2 spectrum depends on the environment of the metal ion.     

Mixed-ligand and binuclear complexes of oxovanadium(IV)

Summary Mixed ligand complexes of the type [VOLA]ClO₄ where L=5-bromosalicylaldehyde (L) or 5-nitrosalicylaldehyde (L) and A=2, 2-dipyridyl (A) or 1, 10-phenanthroline (A) have been prepared. Treatment of the mononuclear complexes, [VOLA]ClO₄, withp-phenylenediamine (ppd) orm-phenylenediamine (mpd) yielded homobinuclear [VOLA-NC₆H₄N-LAVO](ClO₄)₂, complexes, which were characterised by elemental analyses, spectra, magnetic susceptibility and molar conductance measurements.     

New ruthenium(III) complexes containing tetradentate Schiff bases and their antibacterial activity

Ruthenium(III) complexes, [RuX(EPh₃)(LL)] (X = Cl, Br; E = P, As; LL-acactet, dbm-tet, dbm-o-ph), have been synthesised by reacting [RuCl₃(PPh₃)₃], [RuCl₃(AsPh₃)₃], [RuBr₃(AsPh₃)₃] or [RuBr₃(PPh₃)₂(MeOH)] with tetradentate Schiff bases such as bis(acetylacetone)tetramethylenediimine (H₂acactet), bis(dibenzoylmethane)tetramethylenediimine (H₂dbmtet) and bis(dibenzoylmethane)-o-phenylenediimine (H₂dbm-o-ph). All the complexes have been characterised by elemental analysis, i.r., electronic spectra, e.p.r., magnetic moment and cyclic voltammetric data and an octahedral structure has been tentatively proposed. These new complexes have been tested for their antibacterial activities.     

Cyanato-Kupfer(II)-Komplexe mit organischen Liganden, 3. Mitt.: Darstellung,magnetische Suszeptibilität und Elektronenspektren der Cyanato-Kupfer(II)-Komplexe mit methylsubstituierten Pyridinen

Zusammenfassung Neue Cyanato-Kupfer(II)-Komplexe des Typs Cu(NCO)₂ L ₂ wurden bereitet, wobeiL -, - bzw. -Picolin, 2,4-Lutidin, 2,6-Lutidin oder 2,4,6-Collidin bedeutet; ferner Komplexe des Typs Cu(NCO)₂ L, wobeiL -Picolin oder 2,4-Lutidin ist. Ihre magnetische Suszeptibilität wurde bei verschiedenen Temperaturen gemessen und ihre Diffusions-Reflexionsspektren wurden dargestellt. Auf Grund der ermittelten magnetischen und spektralen Daten wird den Komplexen Cu(NCO)₂ L ₂ tetragonale Struktur verschiedenen Distorsionsgrades zugesprochen; der sterische Effekt der -methylsubstituierten LigandenL wird diskutiert. Die magnetischen und spektralen Eigenschaften der Komplexe Cu(NCO)₂ L hingegen deuten auf eine ungewöhnliche Art der Koordination.

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Cyanato copper(II) complexes with organic ligands, III: Preparation, magnetic susceptibility, and electronic spectra of the cyanato copper(II) complexes with methyl substituted pyridines

New cyanato copper complexes of the type Cu(NCO)₂ L ₂ have been prepared, whereL represents -, - or -picoline, 2.4-lutidine, 2.6-lutidine or 2.4.6-collidine. In a further series of complexes, Cu(NCO)₂ L, L represents -picoline or 2.4-lutidine. Their magnetic susceptibilities were determined at various temperatures and their diffusion-reflection spectra measured. On the basis of these data a tetragonal structure with varying degrees of distortion is assigned to the complexes Cu(NCO)₂ L ₂, and the steric effect of the -methyl-substituted ligandsL is discussed. The magnetic and spectral properties of the complexes Cu(NCO)₂ L indicate, however, a rather unusual kind of coordination.

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Teil der Habilitationsschrift vonJ. Kohout, Slowakische Technische Hochschule, Bratislava 1970.