Synthesis and magnetic properties of chloroanilato-bridged manganese(II) binuclear complexes

Five chloroanilato-bridged manganese(II) binuclear complexes, [Mn₂(CA)L₄](ClO₄)₂, where L = 4,4′-dimethyl-2,2′-bipyridine (Me₂-bpy), 5-methyl-1,10-phenanthroline (Me-phen), 5-chloro-1,10-phenanthroline (Cl-phen), 5-nitro-1,10-phenanthroline (NO₂-phen) and 2,9-dimethyl-1,10-phenanthroline (Me₂-phen), and CA represents the dianion of chloroanilic acid, have been synthesized and characterized by elemental analyses, molar conductivity and room temperature magnetic moment measurements, and by spectroscopy. It is proposed that these complexes have CA-bridged structures and consist of two manganese(II) ions in a distorted-octahedral environment. The complexes [Mn₂(CA)(Me₂-bpy)₄](ClO₄)₂ (1) and [Mn₂(CA)(Me-phen)₄](ClO₄)₂ (2) were characterized by variable temperature magnetic susceptibility measurements (4–300 K) and the observed data were successfully simulated by an equation based on the spin Hamiltonian operator, Ĥ = −2JŜ ₁ Ŝ ₂, giving the exchange integral J = −1.98 cm⁻¹ for (1) and J = −2.41 cm⁻¹ for (2). This result indicates that there is a weak antiferromagnetic spin-exchange interaction between the two Mn^II ions within each molecule. This revised version was published online in June 2006 with corrections to the Cover Date.     

Synthesis and Single-crystal Structures of Two Copper(II) Complexes and One Iron(II) Complex Prepared by in situ Ligand Substitution at Room Temperature

Two hexa-coordinate copper(II) complexes formulated as [Cu(phen)(4-dmampy)₂(ClO₄)₂] and [Cu(bpy)(3-ampy)₂(ClO₄)₂] · 0.5CH₃OH · 0.5H₂O (phen = 1,10–phenanthroline bpy = 2,2′-bipyridine, 3-ampy = 3-aminopyridine, 4-dmampy = 4-dimethylaminopyridine), and one low-spin ferrous complex formulated as [Fe(dmbpy)₃](ClO₄)₂ · H₂O (dmbpy = 4,4′-dimethyl-2,2′-bipyridine), were synthesized by in situ ligand substitution at room temperature, and characterized by X-ray single-crystal diffraction. This is the first structural report where either 4-dmampy and phen molecules, or 3-ampy and bpy molecules, are located simultaneously around one metal center.     

Synthesis,structure and magnetic studies of copper(II)-nickel(II) complexes withN,N′-bis(2-aminopropyl)oxamidocopper(II)

Three novel heterobinuclear complexes have been prepared and identified as [Cu(oxap)Ni(L)₂](ClO₄)₂·ξH₂O, where oxap denotes theN,N′-bis(2-aminopropyl)oxamido dianion and L denotes 2,2′-bipyridine (bipy), 1,10-phenanthroline (phen) or 5-nitro-1,10-phenanthroline (NO₂-phen). The crystal structure of [Cu(oxap)Ni(phen)₂]-(ClO₄)₂·2H₂O has been determined. Crystal data: triclinic, space group , a=12.079 (6), b=12.409 (4), c=17.261 (8) ?, α=70.91 (2), β=86.72 (4), γ=89.19 (3)^o. At room temperature, Z=2. The Cu^II is in a square planar environment and the Ni^II is in an octahedral environment. The Cu−Ni distance is 5.292 ?. The temperature dependences of the magnetic susceptibilities of [Cu(oxap)Ni(phen)₂]-(ClO₄)₂·2H₂O and [Cu(oxap)Ni(bipy)₂](ClO₄)₂ have been studied in the 4.2–300 K range, giving the exchange integral J=−92.4 cm⁻¹ for bipy and J=−94.3 cm⁻¹ for phen. These results are commensurate with antiferromagnetic interactions between the adjacent metal ions.     

Mixed ligand complex formation of FeIII with boric acid and typical N-donor multidentate ligands

Equilibrium study of the mixed ligand complex formation of Fe^III with boric acid in the absence and in the presence of 2,2′-bipyridine, 1,10-phenanthroline, diethylenetriamine and triethylenetetramine (L) in different molar ratios provides evidence of formation of Fe(OH)²⁺, Fe(OH) ₂ ⁺ , Fe(L)³⁺, Fe(H₂BO₄),Fe(OH)(H₂BO₄), Fe(OH)₂(H₂BO₄)^2-, Fe(L)(H₂BO₄) and Fe₂(L)₂(BO₄)⁺ complexes. Fe(L) ₂ ³⁺ , Fe(L)₂(H₂BO₄) and Fe₂(L)₄(BO₄)⁺ complexes are also indicated with 2,2′-bipyridine and 1,10-phenanthroline. Complex formation equilibria and stability constants of the complexes at 25 ± 0.l°C in aqueous solution at a fixed ionic strength,I = 0.1 mol dm^-3 (NaNO₃) have been determined by potentiometric method.     

Ruthenium(II) complexes containing 2,9-dimethyl-1,10-phenanthroline and 4,4′-dimethyl-2,2′-bipyridine as ancillary ligands: synthesis,characterization and DNA-binding

Two new Ruthenium (II) polypyridyl complexes [Ru(dmp)₂(ipbp)](ClO₄)₂ (1) (dmp = 2,9-dimethyl-1,10-phenanthroline, ipbp = 3-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)-4H-1-banzopyran-2-one) and [Ru(dmb)₂(ipbp)](ClO₄)₂ (2) (dmb = 4,4′-dimethyl-2,2′-bipyridine) have been synthesized and characterized by elemental analysis, FAB-MS, ES-MS and ¹H NMR and cyclic voltammetric methods. The DNA-binding behaviors of these complexes were investigated by spectroscopic titration, viscosity measurements, and thermal denaturation. Absorption titration and thermal denaturation studies reveal that these complexes are moderately strong binders of calf thymus DNA (CT-DNA). Viscosity measurements show that the complexes 1 and 2 interact with CT-DNA by intercalative mode. The DNA-binding affinity of the complex 2 is larger than that of complex 1.     

Syntheses and Characterization of a New One-Dimensional Polymer Containing (µ-Thiocyanate)(bpy)Lead(II) Molecule and New Mixed-Anion Lead (II) Complexes: Crystal Structures of [Pb(bpy)(SCN)2] n (byp = 2,2'-Bipyridine) and [Pb(phen)2(NO3)0.7(ClO4)0.3](ClO4) (phen = 1,10-Phenanthroline)

Complexes [Pb(bpy)(SCN)₂] _n (bpy = 2,2′-bipyridine), [Pb (phen)₂(NO₃)_0.7(ClO₄)_0.3](ClO₄), Pb(phen)₂(SCN)-(NO₃), and Pb(phen)₂(SCN)(ClO₄) (phen = 1,10-phenanthroline)], have been synthesized using a direct reaction between Pb(NO₃)₂ and ligands. The complexes have been isolated and characterized by IR-spectra and CHN-elemental analysis. The structures of [Pb(bpy)(SCN)₂] _n and [Pb(phen)₂(NO₃)_0.7(ClO₄)_0.3](ClO₄) have been confirmed by X-ray crystallography. The single crystal X-ray crystallography of a new one-dimensional complex of Pb(II) with 2,2′-bipyridine, [Pb(bpy)(SCN)₂] _n , shows the complex to be polymeric as a result of thiocyanate ligand bridging. The Pb atom being in a unsymmetrical eight-coordinate, N₄S₄, environment and the arrangement of the 2,2′-bipyridine, thiocyanate anion suggest a gap in coordination geometry around the Pb(II) ion, occupied possibly by a stereoactive lone pair of electrons on lead (II) and the coordination around atoms is hemi-directed. There is a π-π interaction between the aromatic rings of the interchains in [Pb(bpy)(SCN)₂] _n , this stacking causes the complex to be more stable. An attempt to isolate single crystals of Pb(phen)₂(NO₃)(ClO₄) from water led to the isolation of [Pb(phen)₂(NO₃)_0.7(ClO₄)_0.3](ClO₄). The single crystal X-ray study shows the complex to be monomeric. The Pb atom lies in an unsymmetrical six-coordinate, N₄O₂, environment and the arrangement of the 1,10-phenanthrolines, suggest a gap in coordination geometry around the Pb(II) ion, occupied possibly by a stereoactive lone pair of electrons on lead (II) and the coordination around atoms is hemi-directed.     

Studies on the synthesis and magnetic property of binuclear oxovanadium(IV) complexes bridged by chloranilato group

Six novel oxovanadium(IV) binuclear complexes have been synthesized and characterized, namely, [(VO)₂(CA)L₂]SO₄ [L denotes 5-methyl-1,10-phenanthroline (Me-phen); 2,9-dimethyl-1,10-phenanthroline (Me₂-phen); 5-chloro-1,10-phenanthroline (Cl-phen); diaminoethane (en); 1,3-diaminopropane (pn) and 1,2-diaminopropane (ap) respectively.], where CA represents the dianion of chloranilic acid. Based on elemental analyses, molar conductivity and room temperature magnetic moment measurements, IR and electronic spectral studies, it is proposed that there complexes have CA-bridged structures and consist of two vanadium(IV) ions in a square-pyramidal environment. The complexes [(VO)₂(CA)(Me-phen)₂]SO₄ (1) and [(VO)₂(CA)(Me₂-phen)₂]SO₄ (2) were characterized by variable temperature magnetic susceptibility measurements (4～300 K) and the observed data were fitted to the modified Bleaney-Bowers equation by the least-squares method, giving the exchange integral J=-15.8 cm^?1 for 1 and J=-10.6 cm^?l for 2. This result indicates that there is a weak antiferromagnetic spin-exchange interaction between the two VO²⁺ ions within each molecule.     

Syntheses and characterization of three hybrid materials based on polymeric copper complexes and saturated Keggin polyoxoanions

Three novel heteropolytungstates, [Cu(phen)₂]₄[α-SiW₁₂O₄₀] (1), [Cu₄(4,4′-bpy)₃(2,2′-bpy)₄][α-SiW₁₂O₄₀] · H₂O (2) and [Cu(4,4′-bpy)(4,4′-Hbpy)_0.5]₂[PW₁₂O₄₀] (3) (phen = 1,10-phenanthroline, 4,4′-bpy = 4,4′-bipyridine, 2,2′-bpy = 2,2′-bipyridine), have been synthesized and characterized by elemental analyses, IR, TG analyses and single-crystal X-ray diffraction. Compound (1) exhibits interesting chiral layer constructed from interperpendicular helical chains running along a crystallographic 2₁ axis in the c and a directions. Furthermore, the chiral layers are connected by the [α-SiW₁₂O₄₀]⁴⁻ anions via hydrogen bonding interactions to form a 3D superamolecular structure. The [Cu₄(4,4′-bpy)₃(2,2′-bpy)₄]⁴⁺ coordinated complexes in compound (2) are packed together via the aromatic π–π stacking interactions and exhibit an interesting 3D sandglasslike “host” network with 1D channels, in which [α-SiW₁₂O₄₀]⁴⁻ anions “guests” reside. Compound (3) has a unique 2D superamolecular network, which is composed of cationic Cu^I coordination polymer chains and discrete [PW₁₂O₄₀]³⁻ polyoxoanions as linkers. It is noteworthy that the monprotonated 4,4′-bpy ligands of (3) act as arms and connect the adjacent 2D network, generating a 3D interpenetrating superamolecular structure.     

Synthesis and crystal structures of ruthenium(II) complexes with polypyridyl: [Ru(bpy)2(AFO)](ClO4)2 · H2O and [Ru(dmp)2 (AFO)](ClO4)2 · 1/2DMF · 1/2MeCN

Two ruthenium(II) complexes with polypyridyl ligands, [Ru(bpy)₂(AFO)](ClO₄)₂ · H₂O (1) and [Ru(dmp)₂ (AFO)](ClO₄)₂ · 1/2DMF · 1/2MeCN (2) (bpy = 2,2′-bipyridine; dmp = 2,9-dimethyl-1,10-phenanthroline; AFO = 4,5-diazafluoren-9-one; DMF = N,N-dimethylformamide), were synthesized and characterized by elemental analyses, i.r. and u.v.-vis. spectra. The structures of the two complexes were determined by single crystal X-ray diffraction techniques. To relieve ligand interaction, the coordination sphere is distorted so as to form specific angles (δ) between the polypyridyl ligand planes and coordination planes (N-Ru-N). This revised version was published online in June 2006 with corrections to the Cover Date.     

Allyl rhodium(III) complexes containing heterocyclic nitrogen ligands

Summary A series of hexacoordinated Rh^III complexes of general formula trans-[RhCl₂(allyl)(N-N)] (allyl = C₃H₅ or C₄H₇; N- = 1,10-phenanthroline, 2,9-dimethyl-1,10-phenanthroline, 4,7-diphenyl-1,10-phenanthroline, 2,2-bipyridine or 4,4-dimethyl-2,2-bipyridine) have been synthesized and characterized by spectroscopic methods. The complexes have an octahedral geometry with the Cl ligands coordinated in the trans positions. The catalytic activity of [RhCl₂(C₄H₇)(phen)] with respect to hydrogenation of alkenes has been investigated.     

Synthesis and magnetism of 6-nitrobenzimidazolate and imidazolate-bridged copper(II) complexes

Summary Four new trinuclear copper(II) complexes, [Cu(phen)-(NBzIm)] (ClO₄) (1), [Cu(bpy)(NBzIm)](ClO₄) (2), [Cu-(Me₂-bpy)(NBzIm)](Ac)·1/2H₂O (3) and [Cu(Me₂-bpy)-(Im)](ClO₄)·1/2H₂O (4) (phen = 1, 10-phenanthroline, bpy = 2,2-bipyridine, NBzIm = 6-nitrobenzimidazolate ion, Im=imidazolate ion) have been prepared and characterized by variable temperature magnetic susceptibility measurements. A weak antiferromagnetic spin exchange interaction operates between copper(II) ions, exchange integrals evaluated as J =-23.82 cm^-1 for (1); and J=-21.91 cm^-1 for (2).     

Supramolecular frameworks composed of copper(II), zinc(II), and ferrous(II) complexes having 3-bromo or 3,8-dibromo-1,10-phenanthroline ligand with different molar ratios of metal and ligand

Abstract  

Three copper(II), one zinc(II), and one ferrous(II) complexes having 3-bromo or 3,8-dibromo-1,10-phenanthroline ligand with different metal/ligand molar ratios, formulated as [Cu(3-bromo-phen)(ClO₄)(C₃H₇NO)₂(H₂O)](ClO₄) (1), [Cu(3,8-dibromo-phen)(ClO₄)(C₃H₇NO)₂(H₂O)](ClO₄) (2), [Cu(3,8-dibromo-phen)(ClO₄)(H₂O)₃](ClO₄)(H₂O)₃ (3), [Zn(3,8-dibromo-phen)₂(H₂O)₂](ClO₄)₂(H₂O)₂ (4), and [Fe(3,8-dibromo-phen)₃](ClO₄)₂(H₂O)(CH₄O)(C₃H₆O)₂ (5) (phen = 1,10-phenanthroline), have been synthesized and characterized in this paper. X-ray single-crystal diffraction studies reveal the different crystallographic symmetry and packing fashions between neighboring phen rings in 1:1 Cu(II) complexes 1–3 due to the alteration of bromo substituent 1,10-phenanthroline ligands and coordinated or free solvent molecules. Additionally, in 1:2 Zn(II) and 1:3 Fe(II) complexes 4 and 5, continuous π–π stacking and alternating π–π and dimeric p–π stacking are found.     

Synthesis and magnetic studies of phthalato-bridged oxovanadium(IV) binuclear complexes

Six new μ-phthalato binuclear oxovanadium(IV) complexes, namely [(VO)₂(PHTH)-(L)₂]SO₄ (L denotes 2,2′-bipyridine (bpy); 1,10-phenanthroline (phen); 4,4′-dimethyl-2,2′-bipyridine (Me₂ bpy); 5-nitro-1,10-phenanthroline (NO₂-phen); 5-chloro-1,10-phenanthroline (Cl-phen) and 5-methyl-1,10-phenanthroline (CH₃-phen), where PHTH is the phthalate dianion), have been synthesized and characterized by elemental analyses, IR, electronic spectra, magnetic moments at room temperature and molar conductivity measurements. The temperature dependence of the magnetic susceptibility of complexes [(VO)₂(PHTH)(phen)₂]SO₄ (1) and [(VO)₂(PHTH)(CH₃-phen)₂]SO₄ (2) was measured in 4—300 K range and the observed data were successfully simulated by the equation based on the spin Hamiltonian operator, ?=?2J?₁·?₂, giving the exchange integrals J=?12.8 cm^?1 for 1 and J=?7.9 cm^?l for 2. This indicates an antiferromagnetic spin-exchange interaction between the metal ions within each molecule.     

1,10-(phenanthroline)-bis{1-alkyl-2-(arylazo)imidazole} ruthenium(II) perchlorate: Synthesis,spectral study,and electrochemistry

The hetero-tris-chelates of the formula [Ru(Phen)(RAaiR′)₂](ClO₄)₂ (Phen = 1,10-phenanthroline, RAaiR′ = 1-alkyl-2-(arylazo)imidazole, p-R-C₆H₄-N=N-C₃H₂-NN-1-R′, where R = H (a), Me (b), Cl (c) and R′ = Me (II), Et (III), CH₂Ph (IV)) have been isolated from the reaction of ctc-[RuCl₂(RAaiR′)₂] with AgNO₃ + Phen or [Ag(Phen)₂](ClO₄) in acetone at 40°C in dark followed by the addition of NaClO₄ (aq). The stereo-chemistry of the complexes have been supported by ¹H NMR data. Considering the arylazoimidazole and phenanthroline moietie there are twenty different carbon atoms in the molecule which gives a total of twenty different peaks in the ¹³C NMR spectrum of complex Ia. Cyclic voltammograms show Ru(III)/Ru(II) couple at 1.3–1.4 V vs SCE along with three successive ligand reductions. The article is published in the original.     

Synthesis and characterization of new metal(II) complexes with formates and some nitrogen donor ligands

New mixed-ligands complexes with empirical formulae: M(2,4′-bpy)₂L₂·H₂O (M(II)Zn, Cd), Zn(2-bpy)₃L₂·4H₂O, Cd(2-bpy)₂L₂·3H₂O, M(phen)L₂·2H₂O (where M(II)=Mn, Ni, Zn, Cd; 2,4′-bpy=2,4′-bipyridine, 2-bpy=2,2′-bipyridine, phen=1,10-phenanthroline, L=HCOO⁻) were prepared in pure solid state. They were characterized by chemical, thermal and X-ray powder diffraction analysis, IR spectroscopy, molar conductance in MeOH, DMF and DMSO. Examinations of OCO⁻ absorption bands suggest versatile coordination behaviour of obtained complexes. The 2,4′-bpy acts as monodentate ligand; 2-bpy and phen as chelating ligands. Thermal studies were performed in static air atmosphere. When the temperature raised the dehydration processes started. The final decomposition products, namely MO (Ni, Zn, Cd) and Mn₃O₄, were identified by X-ray diffraction.     

Standard molar enthalpies of formation of [RE(Gly)<Subscript>4</Subscript>(Im)(H<Subscript>2</Subscript>O)](ClO<Subscript>4</Subscript>)<Subscript>3</Subscript> (<Emphasis Type="Italic">RE</Emphasis>=Eu,Sm)

The two complexes, [RE(Gly)₄(Im)(H₂O)](ClO₄)₃(s)(RE = Eu, Sm), have been synthesized and characterized. The standard molar enthalpies of reaction for the following reactions, RECl₃·6H₂O(s)+4Gly(s)+Im(s)+3NaClO₄(s) = =[RE(Gly)₄(Im)(H₂O)](ClO₄)₃(s)+3NaCl(s)+5H₂O(l), were determined by solution-reaction colorimetry. The standard molar enthalpies of formation of the two complexes at T = 298.15 K were derived as Δ_f H _m^Θ {Eu(Gly)₄(Im)(H₂O)}(ClO₄)₃(s)} = = −(3396.6±2.3) kJ mol⁻¹ and Δ_f H _m^Θ {Sm(Gly)₄(Im)(H₂O)}(ClO₄)₃(s)} = −(3472.7±2.3) kJ mol⁻¹, respectively.     

Heterometallic compounds with the binuclear complex anion [Cr<Subscript>2</Subscript>(OH)(Ac)(Nta)<Subscript>2</Subscript>]<Superscript>2−</Superscript>: Synthesis and structure

Heterometallic compounds BaCr₂(OH)(Ac)(Nta)₂ · 4H₂O (I) and [Fe(L)₃][Cr₂(OH)(Ac)(Nta)₂] · nH₂O (L is Bipy (II) and Phen (III); Bipy is, αα′-bipyridine, Phen is o,o′-phenanthroline, Ac⁻ is acetate ion, Nta is nitrilotriacetate ion; n = 8 (II) and 6.25 (III)) are synthesized. According to the X-ray diffraction data, compounds II and III have ionic structures built of the isolated complex cations [Fe(L)₃]²⁺, binuclear complex anions [Cr₂(OH)(Ac)(Nta)₂]²⁻, and crystallization water molecules. The magnetic properties of compounds II and III in the interval from 2 to 300 K confirm assumptions on the diamagnetic character of [Fe(L)₃]²⁺ and indicate the antiferromagnetic interaction between the chromium atoms in the dimeric fragment [Cr₂(OH)(Ac)(Nta)₂]²⁻.     

Synthesis and magnetic properties of heterobinuclear copper(II)–iron(II) complexes with N,N′-bis(2-aminopropyl)oxamidocopper(II)

Six new -oxamido heterobinuclear complexes, namely [Cu(oxap)Fe(L)2]SO4, where oxap denotes the N,N-bis(2-aminopropyl)oxamido dianion and L represents 1,10-phenanthroline (phen); 5-nitro-1,10-phenanthroline (NO2-phen); 5-chloro-1,10-phenanthroline (Cl-phen); 5-methyl-1,10-phenanthroline (Me-phen); 2,2-bipyridine (bpy); and 4,4-dimethyl-2,2-bipyridine (Me2bpy), have been synthesized and characterized by elemental analyses, i.r. spectra, electronic spectra, magnetic moments (at room temperature) and molar conductivity measurements. The temperature dependent magnetic susceptibilities of [Cu(oxap)Fe(bpy)2]SO4 (1) and [Cu(oxap)Fe(phen)2]SO4 (2) have been studied in the 4.2–300K range, giving the exchange integrals J=–20.9cm–1 for (1) and J=–22.5cm–1 for (2). These results are commensurate with antiferromagnetic interactions between adjacent metal ions within each molecule.     

Synthesis,DNA-binding and photocleavage studies of cobalt(III) complexes [Co(bpy)<Subscript>2</Subscript>(dpta)]<Superscript>3+</Superscript> and [Co(bpy)<Subscript>2</Subscript>(amtp)]<Superscript>3+</Superscript>

Two novel cobalt(III) mixed-polypyridyl complexes [Co(bpy)₂(dpta)]³⁺ and [Co(bpy)₂(amtp)]³⁺ (bpy = 2,2′-bipyridine, dpta = dipyrido-[3,2-a;2′,3′-c]-thien-[3,4-c]azine, amtp = 3-amino-1,2,4-triazino[5,6-f]-1,10-phenanthroline) have been synthesized and characterized. The interaction of Co^III complexes with calf thymus DNA was investigated by spectroscopic and viscosity measurements. Results suggest that the two complexes bind to DNA via an intercalative mode. Moreover, Co^III complexes have been found to promote the photocleavage of plasmid DNA pBR322 under irradiation at 365 nm. The mechanism studies reveal that hydroxyl radical (OH^•) is likely to be the reactive species responsible for the cleavage of plasmid DNA by [Co(bpy)₂(dpta)]³⁺ and superoxide anion radical (O ₂ ^•− ) acts as the key role in the cleavage reaction of plasmid DNA by [Co(bpy)₂(amtp)]³⁺.     

One Novel Cu(II)–Amino Acid Schiff Base Complex Derived from Salicylaldehyde and L-Serine: Identification of Unusual Monodentate 4,4′-Bipyridine

One novel copper(II) complex [Cu(L)(4,4′-bipy)](ClO₄) (1), (where L: tridentate Schiff base derived from salicylaldehyde and L-serine) has been synthesised and characterised by spectroscopic and electrochemical studies. The single-crystal structure of the complex was determined. The crystal structure features the presence of [Cu(L)(4,4′-bipy)]⁺ cations and ClO₄⁻ anions aggregated by hydrogen bonding. Here, 4,4′-bipyridine functions as a monodentate ligand, which appears to be an unusual phenomenon.