Rhodium(I) and rhodium(III) arene complexes with N-carbazolyltriphenylphosphinegold(I) and other polycyclic arene ligands

The new heteronuclear arene complexes [(COD)Rh(μ-cbz)AuPPh₃]ClO₄, [{(COD)Rh}₂(μ-cbz)AuPPh₃](ClO₄)₂, [(C₅Me₅)Rh(μ-cbz)AuPPh₃](ClO₄)₂ and [{C₅Me₅) Rh}₂(μ-cbz)AuPPh₃](ClO₄)₄ (COD = 1,5-cyclooctadiene, cbz = carbazolyl), and the mononuclear arene complexes [(COD)Rh(arene)]ClO₄ (arene = tetralin, biphenyl, fluorene, indene, 9,10-dihydroanthracene or carbazole) have been prepared by reaction of the acetone solvated complexes [(COD)Rh(Me₂CO)_x]ClO₄ or [(C₅Me₅)Rh(Me₂CO)₃](ClO₄)₂ with (cbz)AuPPh₃ or the appropriate polycyclic arene ligand.     

Synthesis and Characterization of Bridged Bimetallic Complexes. I. Copper(II) Complexes with Conjugated Diimine Ligands

A series of binucleating Uganda with fully conjugated π-systems have been synthesized. Homobinuclear copper(II) complexes of the form [(Cu(dien)ClO₄)₂L]-(ClO₄)₂, where dien is diethylenetriamine and L is binucleating ligand, were prepared. Mononuclear complexes, with structure similar to that of the preceeding compounds, [Cu(dien)L′(ClO₄)](ClO₄) were synthesized as reference compounds. The infrared spectra, elctronic spectra and magnetic properties were studied. The inductive effect, steric effect and the effect of the length of the conjugated π-system on the magnetic exchange interaction between the two copper ions are discussed. The electrochemical properties of these complexes were investigated by cyclic voltammetry. The copper ions showed the cooperative phenomena and a quasi-reversible sequential transfer of two electrons at the same potential.     

Synthesis and characterization of cobalt(II), nickel(II) and copper(II) perchlorate complexes with bis [(diphenylphosphinyl)methyl] phenylphosphine oxide,bis [(disphenylphosphinyl)methyl]ethyl phosphinate,and bis [(diphenylphosphinyl)methyl] phosphinic acid

The synthesis and characterization of cobalt(II), nickel(II) and copper(II) perchlorate complexes containing bis [(diphenylphosphinyl)methyl] [phenylphosphine oxide (RPPH), bis [(diphenylphosphinyl)methyl] ethyl phosphinate (RPOEt), and bis [(diphenylphosphinyl)methyl] phosphinic acid (RPOH) have been studied. The substituent at the central phosphorus atom of the ligand is responsible for the types of complexes formed. The new complexes [M(RPPh)₂(ClO₄)₂.nH₂O, [M(RPPh)₃](ClO₄)₂.4H₂O, [M(RPOEt)₂](ClO₄)₂.2H₂O, and [M(RPOH)₃] (ClO₄)₂.nH₂O are characterized as high spin and most of them have an octahedral or distorted octahedral geometry [M = Co(II), Ni(II), or Cu(II); n = 2?5]. The coordination of two P = O groups from one ligand to the metal has been proposed for most of the complexes formed. The coordination of all three P = O groups has been assumed for complexes [M(RPPh)₂](ClO₄)₂.nH₂O and [M(RPOEt)₂](ClO₄)₂.2H₂O.     

Heterodinuclear Ruthenium(II) Complexes of the Bridging Ligand 1,6,7,12‐Tetraazaperylene with Iron(II), Cobalt(II), Nickel(II), as well as Palladium(II) and Platinum(II)

The first heterodinuclear ruthenium(II) complexes of the 1,6,7,12‐tetraazaperylene (tape) bridging ligand with iron(II), cobalt(II), and nickel(II) were synthesized and characterized. The metal coordination sphere in this complexes is filled by the tetradentate N,N′‐dimethyl‐2,11‐diaza[3.3](2,6)‐pyridinophane (L‐N₄Me₂) ligand, yielding complexes of the general formula [(L‐N₄Me₂)Ru(µ‐tape)M(L‐N₄Me₂)](ClO₄)₂(PF₆)₂ with M = Fe {[ 2 ](ClO₄)₂(PF₆)₂}, Co {[ 3 ](ClO₄)₂(PF₆)₂}, and Ni {[ 4 ](ClO₄)₂(PF₆)₂}. Furthermore, the heterodinuclear tape ruthenium(II) complexes with palladium(II)‐ and platinum(II)‐dichloride [(bpy)₂Ru(μ‐tape)PdCl₂](PF₆)₂ {[ 5 ](PF₆)₂} and [(dmbpy)₂Ru(μ‐tape)PtCl₂](PF₆)₂ {[ 6 ](PF₆)₂}, respectively were also prepared. The molecular structures of the complex cations [ 2 ]⁴⁺ and [ 4 ]⁴⁺ were discussed on the basis of the X‐ray structures of [ 2 ](ClO₄)₄ · MeCN and [ 4 ](ClO₄)₄ · MeCN. The electrochemical behavior and the UV/Vis absorption spectra of the heterodinuclear tape ruthenium(II) complexes were explored and compared with the data of the analogous mono‐ and homodinuclear ruthenium(II) complexes of the tape bridging ligand.     

Synthetic and structural studies of metal complexes derived from tris(3,5-bimethyl-pyrazolylmethyl)amine and pyridine derivatives

A series of metal complexes with a tripodal ligand, TMPzA, have been synthesized and characterized, and their single crystal structures have been determined by X-ray diffraction techniques. It has been found that when pyridyl derivatives as auxiliary ligands are added to the reaction mixture, the tripodal ligand TMPzA loses a pendant arm and coordinates with the metal centers to form the complexes: [Cu(DMPzA)(2,2′-bipy)]·(ClO₄)₂ (1), [(DMPzA)Cu(μ-4,4′-bipy)Cu(DMPzA)]·(ClO₄)₄ (2), [(TMPzA)Cu(μ-H₂DPC)Cu(DMPzA)]·(ClO₄)₂ (3), [(DMPzA)Co(μ-H₂DPC)Co(TMPzA)]·(ClO₄)₂ (4) [TMPzA = tris(3,5-bimethyl-pyrazolymethyl)amine; bipy = bipyridine; H₂DPC = pyridyl-2,6-bicarboxylate; DMPzA = bis(3,5-bimethyl-pyrazolmethyl)amine]. In order to investigate the effect of the pyridyl ring on the cleavage of the pendant arm in the tripodal ligand, a fifth complex, [(TMPzA)Co(μ-HZPC)Co(TMPzA)·(H₂O)₂]·(ClO₄)₃ (5), has been prepared by using pyrazole-carboxylate (HZPC) instead of pyridyl derivatives, and its crystal structure has been determined. It has been found that the pendant arm in TMPzA ligand has not been removed in complex 5. The results show that the complexes with TMPzA have a strong ability to recognize pyridine compounds in methanol solvent, and they have potential application for molecular devices in the future. The cleavage mechanism has been studied by DFT calculations and ESI-MS spectra.     

Indolylgold(I) derivatives and indole as π-arene ligands in cationic rhodium(I) complexes

The reaction of LAuIn (L = P(C₆H₅)₃, P(2-MeC₆H₄)₃ or P(4-MeC₆H₄)₃; In = indolyl group) with the solvated complexes [(diolefin)Rh(Me₂CO)_x]ClO₄ gives the novel heterometallic complexes [(diolefin)Rh(μ-In)AuL]ClO₄. The mononuclear arene derivatives [(diolefin)Rh(η⁶-HIn)]ClO₄ react with methanolic KOH to give the binuclear complexes [(diolefin)Rh(μ-OMe)]₂, while [(COD)Rh(η⁶-HIn)]ClO₄ reacts with KOH in water/acetone to give the hydroxo-bridged complex [(COD)Rh(μ-OH)]₂.     

Activation of CH bonds in acetylene and terminal alkynes by rhodium(I) species. Crystal structure of cis-(ethynyl)hydride [(NP3)Rh(H)(CCH)]BPh4·1.5C4H8O (NP3 = N(CH2CH2PPh2)3)

The 16-electron fragment (NP₃)Rh⁺ inserts in a highly stereospecific manner across CH bonds from acetylene and 1-alkynes to give the octahedral cis-(alkynyl)hydrides [(NP₃)Rh(H)(CCR)]BPh₄ (R = H, Ph, COOEt). The structure of the cis-(ethynyl)hydride [(NP₃)Rh(H)(CCH)]BPh₄ · 1.5 THF has been established by X-ray diffraction. The trigonal bipyramidal rhodium(I) complex [(NP₃)RhH], reacts with terminal alkynes to give H₂ and the neutral σ-acetylides [(NP₃)Rh(CCR)] (R = Ph, COOEt). These undergo metathesis between terminal alkynes and the σ-acetylide ligand through a mechanism involving consecutive breaking and making of CH bonds.     

Spectral and electrochemical investigation of 1,8-diaminonaphthalene upon encapsulation of p-sulfonatocalix[4]arene

The ligand salt, Me₆[14]diene·2HClO₄ (L·2HClO₄) was prepared by condensation of acetone and ethylene diamine in the presence of perchloric acid. On reduction of this diene ligand salt, L·2HClO₄ with sodium borohydride, the two isomeric ligands, ‘tet-a’ and ‘tet-b’ were produced. The ligands, on reaction with ZnX₂ (X=Cl, ClO₄, NO₃ or CH₃COO) and ZnSO₄ produced the corresponding complexes. These complexes have been characterized on the basis of elemental analyses; IR, UV–Vis and ¹H-NMR spectroscopies; magnetic and conductance data. Based on these data, all of the complexes of the diene ligand L, as well as the perchlorate complexes of all of the ligands attained a square-pyramidal arrangement, whereas the complexes of ‘tet-a’ and ‘tet-b’, with X=NO₃, Cl or CH₃COO and with ZnSO₄ salt, were octahedral. Moreover, all complexes were monometallic except the nitrato complex, [(ZnL)₂(µ-NO₃)](ClO₄)₃ which is bimetallic. The structure of [(ZnL)₂(µ-NO₃)](ClO₄)₃ has been confirmed by X-ray crystallography. In this complex the zinc centres lie within a N₄O donor set, with the four nitrogen donors from L and one of the oxygen atom stemming from the bridging NO₃. The complexes show different electrolytic behavior in different solvents. The antibacterial activities of the ligands and complexes towards different phytopathogenic bacteria have been investigated.     

Effect of Ligand Fields on the Reactivity of O2‐Activating Iron(II)‐Benzilate Complexes of Neutral N5 Donor Ligands

Three new iron(II)‐benzilate complexes [(N4Py)Fe^II(benzilate)]ClO₄ ( 1 ), [(N4Py^Me2)Fe^II(benzilate)]ClO₄ ( 2 ) and [(N4Py^Me4)Fe^II(benzilate)]ClO₄ ( 3 ) of neutral pentadentate nitrogen donor ligands have been isolated and characterized to study their dioxygen reactivity. Single‐crystal X‐ray structures reveal a mononuclear six‐coordinate iron(II) center in each case, where benzilate binds to the iron center in monodentate mode via one carboxylate oxygen. Introduction of methyl groups in the 6‐positions of the pyridine rings makes the N4Py^Me2 and N4Py^Me4 ligand fields weaker compared to that of the parent N4Py ligand. All the complexes ( 1 – 3 ) react with dioxygen to decarboxylate the coordinated benzilate to benzophenone quantitatively. The decarboxylation is faster for the complex of the more sterically hindered ligand and follows the order 3 > 2 > 1 . The complexes display oxygen atom transfer reactivity to thioanisole and also exhibit hydrogen atom transfer reactions with substrates containing weak C?H bonds. Based on interception studies with external substrates, labelling experiments and Hammett analysis, a nucleophilic iron(II)‐hydroperoxo species is proposed to form upon two‐electron reductive activation of dioxygen by each iron(II)‐benzilate complex. The nucleophilic oxidants are converted to the corresponding electrophilic iron(IV)‐oxo oxidant upon treatment with a protic acid. The high‐spin iron(II)‐benzilate complex with the weakest ligand field results in the formation of a more reactive iron‐oxygen oxidant.     

Synthesis, structure, spectroscopic properties, electrochemistry, and DFT correlative studies of N-[(2-pyridyl)methyliden]-6-coumarin complexes of Cu(I) and Ag(I)

6-Aminocoumarin reacts with pyridine-2-carboxaldehyde and has synthesized N-[(2-pyridyl)methyliden]-6-coumarin (L). The ligand, L, reacts with [Cu(MeCN)₄]ClO₄/AgNO₃ to synthesize Cu(I) and Ag(I) complexes of formulae, [Cu(L)₂]ClO₄ and [Ag(L)₂]NO₃, respectively. While similar reaction in the presence of PPh₃ has isolated [Cu(L)(PPh₃)₂]ClO₄ and [Ag(L)(PPh₃)₂]NO₃. All these compounds are characterized by FTIR, UV-Vis and ¹H NMR spectroscopic data. In case of [Cu(L)(PPh₃)₂]ClO₄ and [Ag(L)(PPh₃)₂]NO₃, the structures have been confirmed by X-ray crystallography. The structure of the complexes are distorted tetrahedral in which L coordinates in a N,N′ bidentate fashion and other two coordination sites are occupied by PPh₃. The ligand and the complexes are fluorescent and the fluorescence quantum yields of [Cu(L)(PPh₃)₂]ClO₄ and [Ag(L)(PPh₃)₂]NO₃ are higher than [Cu(L)₂]ClO₄ and [Ag(L)₂]NO₃. Cu(I) complexes show Cu(II)/Cu(I) quasireversible redox couple while Ag(I) complexes exhibit deposition of Ag(0) on the electrode surface during cyclic voltammetric experiments. gaussian 03 computations of representative complexes have been used to determine the composition and energy of molecular levels. An attempt has been made to explain solution spectra and redox properties of the complexes.     

Syntheses,crystal structures and properties of copper(II) complexes of 1,3-bis[(4-methyl-5-imidazol-1-yl)ethylideneamino]propan-2-ol and 1,3-bis[(4-methyl-5-imidazol-1-yl)ethylideneamino] propane

The syntheses of two polydentate ligands comprising imidazole donors, 1,3-bis[(4-methyl-5-imidazol-1-yl) ethylideneamino]propan-2-ol (BIPO), 1,3-bis[(4-methyl-5-imidazol-1-yl)ethylideneamino]propane (BIP), and their copper(II) complexes [Cu(BIPO)(ClO₄)(H₂O)] (NO₃) · H₂O (1) and [Cu(BIP)(ClO₄)](ClO₄) · 2H₂O (2) are reported. Single-crystal structural analyses show that (1) adopts an elongated octahedral geometry with the axial positions occupied by a perchlorate oxygen atom and an aqua ligand, while (2) adopts a distorted square-pyramidal geometry with the axial positions occupied by a perchlorate oxygen atom. Electronic spectra in aqueous solution indicate that both (1) and (2) adopt square-pyramidal geometry. Cyclic voltammetry in aqueous solution gives reduction waves at –0.07 and –0.08 V versus s.c.e. for (1) and (2), respectively. The low reduction potential and general reversibility of the redox reaction of (1) and (2) indicate that BIPO and BIP are flexible enough to stabilize both Cu^II and Cu^I forms of the complexes.     

Synthesis and characterization of mononuclear copper(II) and cadmium(II) complexes with di-(2-picolyl)sulfur

The reaction of Cu(ClO₄)₂·6H₂O and Cd(ClO₄)₂ with di-(2-picolyl)sulfur (dps) leads to the formation of mononuclear complexes [Cu(dps)(H₂O)(ClO₄)](ClO₄) (1) and [Cd(dps)₂](ClO₄)₂ (2). The crystal structure of 1 exhibits a distorted square pyramidal geometry, coordinated by one sulfur and two nitrogen atoms from the dps ligand, one water molecule and one perchlorate oxygen atom. For 2, the environment around cadmium atom is in a distorted octahedron with four nitrogen and two sulfur atoms from the dps ligand. Cyclic voltammetric data show that complexes undergo two waves of a one-electron transfer corresponding to M(II)/M(III) and M(II)/M(I) processes. Spectral and electrochemical behaviors of the complexes are also discussed.     

Preparation, crystal structures and oxidation activity of two novel nickel(II) complexes of tripodal ligand containing coordinated solvent molecules

Two novel Ni^II complexes, [Ni(TMPzA)(CH₃CN)(H₂O)]· (ClO₄)₂ (1) and [Ni(TMPzA)(CH₃OH) (NCS)]· (ClO₄) (2), where TMPzA = tris[(3,5-dimethyl-1-pyrazolemethyl)amine], have been synthesized and characterized. Their crystal structures were determined by X-ray diffraction analysis. Both complexes were isolated from the reactions of TMPzA ligand with metal salts, and thiocyanate as the second ligand in CH₃CN solution for (1) and in CH₃OH solution for (2), respectively. The title complexes are mononuclear structures, and which further assembled into a dimer by the intermolecular hydrogen bond in the unit cell, respectively. The solvent molecules participate in coordination. The spectra properties of the two complexes in solution have been further studied and discussed. The oxidation of styrene catalyzed by the title complexes has been studied, and the new complexes show some catalytic activity under the reaction conditions.     

Synthesis,spectroscopic and the biological activity studies of thiosemicarbazones containing ferrocene and their copper(II) complexes

Two Schiff bases, 1-acetylferrocene thiosemicarbazone (HL¹) and 1,1′-diacetyl-ferrocene dithiosemicarbazone (H₂L²) and their copper(II) complexes were prepared and characterized by elemental analysis, magnetic susceptibility, conductivity, and spectral (IR, UV–Vis, ESR) measurements The IR spectra showed that HL¹ acts as neutral or monobasic bidentate ligand, coordinating to copper(II) through either thiono- or thiolo-sulphur and azomethine-N atoms, whereas H₂L² is a neutral or dibasic mononucleating or binucleating quadridentate ligand coordinating through the same atoms. Other spectral measurements indicate that complexes [(L¹)₂Cu], [(L²)Cu] and [(HL¹)₂Cu]X₂, X?=?Cl, Br or ClO₄ have square-planar geometry around copper(II) while [(HL¹)CuX₂] and [(H₂L²)Cu₂X₄], X?=?Cl or Br, have distorted tetrahedral geometry. The biological activity studies of the complexes and the free ligands towards two gram positive and two gram negative bacteria and one fungal species have been studied and the potential is related to the nature and structure of the tested compounds.     

Synthesis and spectroscopic characterization of a new macrocyclic Schiff base formed by the reaction of 1,5- bis (2-formylphenyl)pentane and 2,6-diaminopyridine,and a study of its metal complexes

A new dialdehyde 1,5-bis(2-formylphenyl)pentane was synthesized from 1,5-dibromopentane with salicylaldehyde and K₂CO₃; macrocyclic ligand was synthesized by reaction of 2,6-diaminopyridine and 1,5-bis(2-formylphenyl)pentane. Cu(II), Ni(II), Pb(II), Zn(II), Cd(II) and La(III) complexes were synthesized by reaction of the ligand and Cu(ClO₄)₂ · 6H₂O, Ni(ClO₄)₂ · 6H₂O, Pb(ClO₄)₂ · 6H₂O, Zn(ClO₄)₂ · 6H₂O, Cd(ClO₄)₂ · 6H₂O and La(ClO₄)₃ · 6H₂O, respectively. The ligand and its metal complexes have been characterized by elemental analysis, IR, ¹H and ¹³C NMR, UV–Vis spectra, magnetic susceptibility, conductivity measurements and mass spectra. All complexes are diamagnetic and Cu(II) complex is binuclear.     

Syntheses,crystal structures,and properties of Ni(II) and Co(III) complexes derived from tripod polypyridine ligands containing N7 or N6 donor set atoms

New complexes [Ni^II(pbpaen)](ClO₄)₂ (1) and [Co^III(pbpaen)](ClO₄)₃ (2) (pbpaen = N′-(pyridin-2-ylmethyl)-N,N-bis {2-[(pyridin-2-ylmethyl)amino]ethyl}ethane-1,2-diamine) have been synthesized and characterized by IR and UV–Vis spectroscopies. An X-ray structure of the nickel(II) complex shows that [Ni(pbpaen)](ClO₄)₂ (1) crystallizes in the monoclinic space group P2_1/c. The cation [Ni(pbpaen)]²⁺ is pseudo-octahedral with one of the three pyridyl nitrogen atom uncoordinated. The crystal lattice of this complex is stabilized by intra and intermolecular hydrogen bonding systems, giving one-dimensional sheets like arrays. All attempts to obtain nickel or cobalt complexes with protonated forms of the ligand resulted in isolation of only [Co^III(bpaen)](ClO₄)₃ (3) compound in which the tripod pbpaen ligand has lost one of the three pyridylmethyl groups, procuring then bpaen ligand {bpaen = N,N-bis{2-[(pyridin-2-ylmethyl)amino]ethyl}ethane-1,2-diamine}. The X-ray crystal structure reveals that the compound 3 crystallizes in the orthorhombic space group Pna2 with the Co³⁺ ion having a distorted-octahedral environment. These two ligands with strong-field N donor stabilise the +3 oxidation state of the Co center.     

Tuning the Electronic Properties in Ruthenium–Quinone Complexes through Metal Coordination and Substitution at the Bridge

A rare example of a mononuclear complex [(bpy)₂Ru(L¹_?H)](ClO₄), 1 (ClO₄) and dinuclear complexes [(bpy)₂Ru(μ‐L¹_?2H)Ru(bpy)₂](ClO₄)₂, 2 (ClO₄)₂, [(bpy)₂Ru(μ‐L²_?2H)Ru(bpy)₂](ClO₄)₂, 3 (ClO₄)₂, and [(bpy)₂Ru(μ‐L³_?2H)Ru(bpy)₂](ClO₄)₂, 4 (ClO₄)₂ (bpy=2,2′‐bipyridine, L¹=2,5‐di‐(isopropyl‐amino)‐1,4‐benzoquinone, L²=2,5‐di‐(benzyl‐amino)‐1,4‐benzoquinone, and L³=2,5‐di‐[2,4,6‐(trimethyl)‐anilino]‐1,4‐benzoquinone) with the symmetrically substituted p‐quinone ligands, L, are reported. Bond‐length analysis within the potentially bridging ligands in both the mono‐ and dinuclear complexes shows a localization of bonds, and binding to the metal centers through a phenolate‐type “O^?” and an immine/imminium‐type neutral “N” donor. For the mononuclear complex 1 (ClO₄), this facilitates strong intermolecular hydrogen bonding and leads to the imminium‐type character of the noncoordinated nitrogen atom. The dinuclear complexes display two oxidation and several reduction steps in acetonitrile solutions. In contrast, the mononuclear complex 1 ⁺ exhibits just one oxidation and several reduction steps. The redox processes of 1 ¹⁺ are strongly dependent on the solvent. The one‐electron oxidized forms 2 ³⁺, 3 ³⁺, and 4 ³⁺ of the dinuclear complexes exhibit strong absorptions in the NIR region. Weak NIR absorption bands are observed for the one‐electron reduced forms of all complexes. A combination of structural data, electrochemistry, UV/Vis/NIR/EPR spectroelectrochemistry, and DFT calculations is used to elucidate the electronic structures of the complexes. Our DFT results indicate that the electronic natures of the various redox states of the complexes in vacuum differ greatly from those in a solvent continuum. We show here the tuning possibilities that arise upon substituting [O] for the isoelectronic [NR] groups in such quinone ligands.     

Synthesis,spectral, thermal and crystallographic investigations on oxovanadium(IV) and manganese(III) complexes derived from heterocyclic β-diketone and 2-amino ethanol

Novel mononuclear oxovanadium(IV) and manganese(III) complexes [VO(L¹)₂·H₂O] (1); [VO(L²)₂·H₂O] (2); [VO(L³)₂·H₂O] (3); [Mn(L¹)₂]ClO₄·H₂O (4); [Mn(L²)₂] ClO₄·H₂O (5); [Mn(L³)₂]ClO₄·H₂O (6) were prepared by condensation of 1 mol of VOSO₄·5H₂O or Mn(OAc)₃· 2H₂O with 2 mol of ligand HL¹, HL² or HL³ (where HL¹ = 4-[(2-hydroxy-ethylamino)-methylene]-5-methyl-2- phenyl-2,4-dihydro-pyrazol-3-one; HL²=4-[(2-hydroxy-ethylamino)-methylene]-5-methyl-2-p-tolyl-2,4-dihydro-pyrazol-3-one; HL³=4-{4-[(2-hydroxy-ethyl-amino)-methyl]-3-methyl-5-oxo-4,5-dihydropyrazol-1-yl} benzene sulfonic acid). The resulting complexes were characterized by elemental analyses, molar conductance, magnetic and decomposition temperature measurements, electron spin resonance, FAB mass, IR and electronic spectral studies. From TGA, DTA and DSC, the thermal behaviour and degradation kinetic were studied. Electronic spectra and magnetic susceptibility measurements indicate distorted octahedral stereochemistry of oxovanadium(IV) complexes and regular octahedral stereochemistry of manganese(III) complexes. Hamiltonian and bonding parameters found from ESR spectra indicate the metal ligand bonding is partial covalent. The X-ray single crystal determination of one of the representative ligand was carried out which suggests existence of amine-one tautomeric form in the solid state. The ¹H-NMR spectra support the existence of imine-ol form in solution state. The LC-MS studies sustain the¹H-NMR result. The electronic structure of the same representative ligand was optimized using 6-311G basis set at HF level ab initio studies to predict the coordinating atoms of the ligand.     

系列过渡金属与三角架多咪唑配合物的合成、结构及表征

以三氨乙基胺和N－甲基咪唑醛为原料合成了三角架多咪唑配体((min)₃tren)，并合成了五个过渡金属配合物：[Zn(min)₃tren](ClO₄)₂1， [Cu(min)₃tren](ClO₄)₂2, [Ni(min)₃tren](ClO₄)₂3, [Co(min)₃tren](ClO₄)₂4, and [Mn(min)₃tren](ClO₄)₂CH₃CN 5，通过元素分析，摩尔电导率，红外和电子光谱确定了化合物的组成。对配合物4和5进行了晶体结构测定。结果表明，在这两个化合物中金属原子均处于扭曲的八面体配位环境，分别与三个亚胺氮原子和三个咪唑氮原子配位。配合物4和5的电化学研究表明在乙腈溶液中，有[Co-O₂]^n-和[Mn-O₂]^n-存在，认为4和5是很好的超氧化物清除剂。     

Synthesis,characterization, and bioactivities of copper complexes with N-substituted Di(picolyl)amines

Three new Cu(II) complexes with ethyl bis(2-pyridylmethyl)amino-2-propionate (Etdpa), or bis(2-pyridylmethyl)amino-2-propionate (Adpa), were synthesized and characterized by physico-chemical and spectroscopic methods. The X-ray crystal structure of [(Adpa)CuCl] shows that the copper(II) atom is coordinated by three N atoms, one oxygen atom from the ligand (Adpa) and one chloride anion, forming a trigonal bipyramidal geometry. The spectrophotometric and fluorescence titration data indicate that the interaction of square pyramidal [(Etdpa)CuCl₂] with ct-DNA is weak, but the trigonal bipyramidal complexes [(Adpa)Cu(H₂O)](ClO₄) and [(Adpa)CuCl] interact with ct-DNA with the mode of intercalation. The inhibition activities of the three new copper(II) complexes on the four cancer cells (Mcf-7, Eca-109, A549, and Hela) are in the order: [(Adpa)Cu(H₂O)](ClO₄) > [(Adpa)CuCl] > [(Etdpa)CuCl₂], which correlates with their DNA-binding properties. The results show that the substituents introduced on the secondary amino nitrogen atom of dpa have great contribution to the antitumor activities of these copper(II) complexes. It is also found that the coordination of copper(II) ions with AdpaH can decrease the toxicity of AdpaH. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.