Zdeněk Smékal

Synthesis and characterization of binuclear μ-oxalato nickel(II), copper(II) and zinc(II) complexes with 3,3′-diamino-N-methyl-dipropylamine or trans-1,2-diaminocyclohexane

Abstract New binuclear complexes of the type [(Ni(Medpt)NO3)2ox] (1) (Medpt=3,3′-diamino-N-methyl-dipropylamine, H2ox=oxalic acid), [(Ni(dach)2)2ox]NO3·2H2O (2) (dach=trans-1,2-diaminocyclohexane), [(Cu(Medpt))2ox]X2·yH2O (X=NO3, y=2 2/3 (3); X=ClO4, y=0 (4)) and [(Zn(dach)2)2ox](ClO4)2·2H2O (5) have been prepared and characterized by IR and UV–Vis spectroscopies. Spectroscopic data are consistent with oxalate-bridged structures between six-coordinated (N3O3 or N4O2) Ni(II) (compounds 1 or 2), five-coordinated (N3O2) Cu(II) (compounds 3 and 4) or six-coordinated (N4O2) Zn(II) (compound 5). The crystal structure of [(Cu(Medpt))2ox](NO3)2·2 2/3 H2O (3) has been determined by single-crystal X-ray analysis. The structure of (3) consists of centrosymmetric binuclear cations [(Medpt)Cu(ox)Cu(Medpt)]2+, nitrate anions and water molecules of crystallization. The copper atom is five-coordinated by two oxalate–oxygen and three Medpt–nitrogen atoms, in a hybrid arrangement between trigonal–bipyramidal and square–pyramidal. The temperature dependence of magnetic susceptibility (1.8–300 K) was measured for compounds 1–4. Magnetochemical measurements show that Ni(II) complexes are antiferromagnetically coupled, J=−29.4 (1) and −32.7 cm−1 (2) (H=−JS1S2) while the Cu(II) complexes present a very weak coupling, J=−2.6 (3) and +1.9 cm−1 (4), being antiferro- and ferromagnetic in nature.

Oxalato complexes of copper(II) with chelating diamines. Crystal structure of [Cu(dmen)ox(H2O)]2[Cu(dmen)2](ClO4)2

Abstract Four new oxalato complexes of copper(II) of composition [Cu(dmen)ox(H2O)]2 [Cu(dmen)2](ClO4)2 (1) (dmen=N,N-dimethylethylenediamine, H2ox=oxalic acid), [(Cu(dmen)H2O)2ox](ClO4)2·H2O (2), [Cu(tmen)(H2O)(ox)Cu(aep)(H2O)](ClO4)2 (3) (tmen=N,N,N′,N′-tetramethylethylenediamine, aep=2-(2-aminoethyl)pyridine) and [(Cu(dben)NO3)2ox] (4) (dben=N,N′-dibenzylethylenediamine) have been prepared and characterised by IR and UV–Vis spectroscopies and magnetic measurements. The crystal structure of [Cu(dmen)ox(H2O)]2[Cu(dmen)2](ClO4)2 (1) has been determined by single-crystal X-ray analysis. The structure of 1 contains a neutral [Cu(dmen)ox(H2O)] complex, a cationic [Cu(dmen)2]2+ complex and perchlorate anions. The copper(II) atom of the neutral [Cu(dmen)ox(H2O)] unit possesses a distorted square-pyramidal environment with two oxygen atoms of oxalate and two nitrogen atoms of dmen in the basal plane and an oxygen atom of a water molecule in the apical position. The copper(II) atom of the cationic [Cu(dmen)2] unit shows a square-planar environment with four donor nitrogen atoms of two molecules of dmen. The temperature dependence of magnetic susceptibility for compounds 2–4 was measured. Magnetochemical measurements show that copper(II) ions in compounds 2–4 are antiferromagnetically coupled through the oxalate bridge, J=−157, −175 and −167 cm−1 (H=−2JS1S2, S1=S2=1/2) for 2, 3 and 4, respectively.

Binuclear iron(III)-iron(III) complexes with the tetradentate Schiff base N,N′-bis(salicylidene)ethylenediamine and dicarboxylic acids or dithiooxamide as bridging ligands

SummaryComplexes of the type [(Fe(salen))2L]·xH2O (L = glutarate, adipate, pimelate or suberate dianion, x = 0 or L = dithio oxamidate dianion, x = 2) have been prepared and studied by elemental analyses, i.r. and electronic spectra, and magnetic measurements. A dimeric structure with an octahedral arrangement of FeIII (S = 5/2) is proposed. Some of the complexes have been characterized by temperature-dependent magnetic susceptibilities, but an antiferromagnetic exchange interaction was found only for [(Fe(salen))2dta]·2H2O (H2dta = dithio-oxamide).

Synthesis and characterization of (μ-oxalato)nickel(II) complexes

Abstract Three new nickel(II) dinuclear oxalato-bridged compounds Ni(TAA)(ClO 4 )·0.5ox ( 1 ), Ni 2 (APO-sal 2 )ox·2H 2 O ( 2 ) and Niphen 2 oxNiacac 2 ·4H 2 O ( 3 ) have been characterized [TAA  N(CH 2 CH 2 NH 2 ) 3 ox = oxalate, phen = 1,10-phenanthroline, acac = acetylacetonate and APO-sal 2 is the Schiff base formed by the condensation of salicylaldehyde and 1,3-diamino-2-propanol]. The crystal structure of 1 has been determined by a single-crystal X-ray analysis. The nickel atom is coordinated by two oxygen atoms of an oxalato ligand and four nitrogen atoms beloning to TAA in an octahedral arrangement. The intermetallic distance of Ni(1)Ni(2) is 5.412(1) A. Magnetic measurements (77–300 K) show that three compounds are antiferromagnetically coupled, J = −14.4, −11.25 and − 19.3 cm −1 for 1, 2 and 3 , respectively.

Synthesis and characterization of (μ-oxalato) copper(II) and nickel(II) complexes

Four new binuclear complexes of the type [(u(L)x)2ox](ClO4)2 (L = 1,3-diaminopropane (1,3-pn), x = 1.5 (1); L = 1,3-diaminopropane, x = 1 (2)l; L = N-(2-aminoethyl)-1,3-propanediamine (ept), x = 1 (3)) or [(Ni(L)2)2ox](ClO4)2 (L = 1,2-diaminopropane (1,2-pn) (4)) have been prepared and studied by elemental analysis, IR and electronic spectroscopies. Spectroscopic data are consistent with oxalate-bridged structures between five-coordinate (N3O2) Cu(II) (compounds 1 and 3), four coordinate (N2O2) Cu(II) (2) and six-coordinate (N4O2) Ni(II) (4). Magnetochemical measurements (72–300 K) show (2) and (4) are antiferromagnetic (J = −254 and −33 cm−1 respectively (H = −JS1S2)).

Mononuclear and binuclear complexes of iron(III) with the tetradentate Schiff base derived from salicylaldehyde and 1,2 diaminopropane

Abstract The complexes of type [Fe(salpn)L]ClO4 [L = bpy (2,2′-bipyridyl) or phen (o-phenanthroline), H2salpn = N,N′-bis(salicylidene)propylenediamine] and type [(Fe (salpn))2L] (L = terephthalate or fumarate dianion) have been prepared and studied by elemental analyses, IR and electronic spectroscopies and magnetochemical measurements. An octahedral arrangement of iron(III) (S = 5/2) is proposed. The complexes with dicarboxylic acids are probably binuclear and magnetically diluted at room temperature. The compounds with bpy or phen are probably mononuclear. Regarding their anomalous μeff values (5.52 or 4.25 B.M.), the temperature dependence of magnetic susceptibility was measured, but antiferromagnetic exchange interaction or spin equilibrium were not found.

A novel trinuclear nickel(II) complex with a Schiff base derived from m-phenylenediamine and diacetyl monoxime

SummaryA tetradentate Schiff base derived from diacetyl monoxime and m-phenylenediamine (H2mphdao2) reacts in MeOH with NiI2 to form the trinuclear complex Ni3(mphdao2)2I2, which was characterized by elemental and thermal analyses, and i.r. and u.v.-vis. spectroscopies. The magnetic properties have been investigated in the 4.2–300 K range.

The Polynuclear Complexes of Iron(II,III) and Copper(II) with Cyanide as Bridging Ligand

Abstract Five novel complexes of the type [CuL2][Fe(CN)5NO]. xH2O (L = ethylenediamine (en), x = 0; L = o-phenanthroline (phen) or 2,2′-bipyridine (bpy), x = 2), [CuL2]3[Fe(CN)6]2. xH2O (L = bpy, x = 6; L = phen, x = 9) have been prepared and studied by elemental analyses, thermal analyses, IR and UV-vis. spectra and magnetic measurements. The structures are proposed with cyanide bridges between Fe(II) and Cu(II) (nitroprusside complexes) or between Fe(III) and Cu(II) (hexacyanoferrate(III) complexes). The temperature dependence of the magnetic susceptibility of the complex [Cu(bpy)2]3[Fe(CN)6]2. 6H2O was measured in the range 94.4–293.5 K but no exchange interaction was found. The product of the thermal decomposition of the complex [Cu(bpy)2]3[Fe(CN)6]2. 6H2O is a mixture of CuO and CuFe2O4, as determined by X-ray powder diffraction.

MONO- AND BINUCLEAR COMPLEXES OF IRON(III) WITH 1,2-BIS(2-HYDROXYBENZAMIDO)ETHANE

Summary. Complexes of the type [(Fe(L))2O]ċH2O (H2L=1,2-bis(2-hydroxybenzamido)ethane), [(Fe(L))2ter]ċ5H2O H2ter=terephthalic acid), [Fe(L)bpy]BPh4 (bpy=2,2′-bipyridyl), and [Fe(L)phen]ClO4ċH2O (phen=o-phenanthroline) were prepared and studied by elemental analysis, magnetochemical measurements, and spectroscopic methods. [(Fe(L))2O]ċH2O and [(Fe(L))2ter]ċ 5H2O are probably binuclear, and the weak antiferromagnetic exchange interaction, (μeff per one atom of iron(III) was found to be 3.59 BM/77 K−4.91 BM/290 K (J=−7 cm−1, H=−2JS1S2, S1=S2=5/2) for the μ-oxo complex and 4.21 BM/82 K−5.35 BM/297 K (J=−5 cm−1) for the μ-terephthalato complex. The iron(III) complexes with bpy or phen are probably mononuclear; their anomalous μeff values (3.51 BM/80 K−3.68 BM/297 K for (Fe(L)bpy]BPh4 and 4.93 BM/259 K for [Fe(L)phen]ClO4ċH2O, respectively) agree neither with high spin (5.7–6.1 BM) nor with low spin (2.1–2.5 BM) configurations.Zusammenfassung. Komplexe des Typs [(Fe(L))2O]ċH2O (H2L=1,2-Bis(2-hydroxybenzamido)ethan), [(Fe(L))2ter]ċ5H2O (H2ter=Terephthalsäure), [Fe(L)bpy]BPh4 (bpy=2,2′-Bipyridyl) und [Fe(L)phen]ClO4ċH2O (phen=o-Phenanthrolin) wurden hergestellt und mittels Elementaranalyse, magnetochemischer Messungen und spektroskopischer Methoden untersucht. [(Fe(L))2O]ċH2O und [(Fe(L))2ter]ċ5H2O sind wahrscheinlich binuklear, und die schwache antiferromagnetische Austauschwechselwirkung (μeff pro Eisen(III)-Atom) wurde für den μ-oxo-Komplex zu 3.59 BM/77 K−4.91 BM/290 K (J=−7 cm−1, H=−2JS1S2, S1=S2=5/2) und für den μ-terephthalato-Komplex zu 4.21 BM/82 K−5.35 BM/297 K (J=−5 cm−1) ermittelt. Die Eisen(III)-Komplexe mit bpy bzw. phen sind wahrscheinlich mononuklear; ihre anomalen μeff-Werte (3.41 BM/80 K−3.68 BM/297 K für [Fe(L)bpy]BPh4 und 4.93 BM/259 K für [Fe(L)phen]ClO4ċH2O sind weder mit high-spin- (5.7–6.1 BM) noch mit low-spin-Zuständen (2.1–2.5 BM) in Einklang zu bringen.