Control of oxygen atom chirality and chelate ring conformation by protected/free sugar hydroxyl groups in glucose-pendant dipicolylamine-copper(II) complexes

A pair of copper(II) complexes 1 and 2 exhibit an enantiomeric chiral center at the oxygen atom that coordinates to the metal center. The configurations of the oxygen atom chirality and the chelate ring conformation are simply controlled by protected/free hydroxyl groups of the sugar moiety, yielding mirror image CD spectra. In this system, repulsive and attractive forces are used to regulate chirality on the copper-coordinated oxygen atom both in the solid state and in solution.     

Asymmetric sulfur atom coordination in a copper(II) dipicolylamine (DPA) complex with a thioglycoside ligand

The 2,2'-dipicolylamine (DPA)-tethered thioglycoside ligand, N,N-bis(2-pyridylmethyl)-2-aminoethyl 1-deoxy-1-thio-2,3,4,6-tetra-O-acetyl-beta-d-glucopyranoside (sL1), has been prepared and its copper(II) complex synthesized. Using copper(II) chloride, the copper complex was isolated as a chloride-bound species formulated as [Cu(sL1)Cl(ClO(4))](1). The corresponding O-glycoside complex ([Cu(L1)Cl](ClO(4)), 2) was also prepared using L1 (N,N-bis(2-pyridylmethyl)-2-aminoethyl 2,3,4,6-tetra-O-acetyl-beta-d-glucopyranoside), and both complexes were characterized and compared by means of X-ray crystallography, cyclic voltammetry, electronic absorption and circular dichroism (CD) spectra. Although both complexes exhibited similar copper coordination geometries, the absolute configuration of the O/S chiral center generated by the copper coordination was inverted. The electronic and CD spectra of acetonitrile solutions of 1 and 2 were different likely due to the presence of a copper-sulfur charge-transfer band for 1. Complex also exhibits a large Cotton effect around 700 nm. The corresponding d-d transition of the copper(II) center reveals that the asymmetric copper-sulfur (oxygen) coordination remains even in solution.     

Predetermined chirality at metal centers of various coordination geometries: a chiral cleft ligand for tetrahedral (T-4), square-planar (SP-4), trigonal-bipyramidal (TB-5), square-pyramidal (SPY-5), and octahedral (OC-6) complexes

Two tetradentate bispinene-bipyridine type ligands, each with six stereogenic carbon centers, were synthesized from (-)-alpha-pinene. Their ability to predetermine chiral configurations at metal centers was studied. The two diastereoisomers, L1 and L2, differ in their absolute configuration at the bridgehead position. These ligands form metal complexes with Ag(I), Pd(II), Zn(II), Cu(II), and Cd(II), with coordination numbers four, five, and six and with complete control of chirality at the metal centers. Using L1 rather than L2 leads to complexes of inverted absolute configuration at the metal centers. These diastereomeric coordination species can be obtained either as separate compounds or, in some cases, as solids containing them in a 1:1 ratio. Ligands L1 and L2 thus show that the pinene-bipyridines are versatile molecules for the formation of metal complexes with predetermined chirality. In all cases, absolute configurations were determined in the solid state by X-ray diffraction methods and in solution by CD spectroscopy. The sign of exciton couplets from the pi-pi* transitions always agrees with the expectations for a given local configuration at the metal center. The five-coordinate, inherently chiral species of Zn(II) and Cu(II) described in this article are the first examples of trigonal-bipyramidal metal complexes with predetermined absolute configuration containing topologically linear ligands.     

Fe(II) mononuclear complexes with a new aminopyridyl ligand bearing a pivaloylamido arm. Preparation and spectroscopic characterizations of a Fe(III)-hydroperoxo complex with oxygen and nitrogen donors

Two new mononuclear FeII complexes, [(L52aH)FeII](PF6)2 (1-(PF6)2) and [(L52a)FeII]BPh4 (2-(BPh4)) have been synthesized with the new aminopyridyl ligand bearing a pivaloylamido arm L52aH (2,2-dimethyl-N-[6-({[2-(methyl-pyridin-2-ylmethyl-amino)-ethyl]-pyridin-2-ylmethyl-amino}-methyl)-pyridin-2-yl]-propionamide), or its deprotonated form L52a-. The structures of the ferrous complexes have been determined by X-ray analysis. The mononuclear FeII is in a pseudo-octahedral environment in both complexes, the six positions around the metal center being occupied by five nitrogen atoms and one oxygen atom from the ligand. Whatever the protonation state of the amide function, the structures are very similar, the FeII being 6-fold coordinated by the two amines, three pyridines, and the oxygen atom from the ligand. These two complexes exhibit an acid/base equilibrium in solution that has been studied by UV-vis spectroscopy and cyclic voltammetry in acetonitrile. The reactivity of 1-(PF6)2 with H2O2 in methanol affords the formation of a new low-spin FeIII(OOH) intermediate in which the oxygen atom is retained in the coordination sphere of the metal.     

First row transition metal complexes of (E)-2-(2-(2-hydroxybenzylidene) hydrazinyl)-2-oxo-N-phenylacetamide complexes

Manganese(II), iron(II), cobalt(II), nickel(II), copper(II), and chromium(III) complexes of (E)-2-(2-(2-hydroxybenzylidene)hydrazinyl)-2-oxo-N-phenylacetamide were synthesized and characterized by elemental and thermal (TG and DTA) analyses, IR, UV-vis and (1)H NMR spectra as well as magnetic moment. Mononuclear complexes are obtained with 1:1 molar ratio except [Mn(HOS)(2)(H(2)O)(2)] and [Co(OS)(2)](H(2)O)(2) complexes which are obtained with 1:2 molar ratios. The IR spectra of ligand and metal complexes reveal various modes of chelation. The ligand behaves as a monobasic bidentate one and coordination occurs via the enolic oxygen atom and azomethine nitrogen atom. The ligand behaves also as a monobasic tridentate one and coordination occurs through the carbonyl oxygen atom, azomethine nitrogen atom and the hydroxyl oxygen. Moreover, the ligand behaves as a dibasic tridentate and coordination occurs via the enolic oxygen, azomethine nitrogen and the hydroxyl oxygen atoms. The electronic spectra and magnetic moment measurements reveal that all complexes possess octahedral geometry except the copper complexes possesses a square planar geometry. From the modeling studies, the bond length, bond angle, HOMO, LUMO and dipole moment had been calculated to confirm the geometry of the ligands and their investigated complexes. The thermal studies showed the type of water molecules involved in metal complexes as well as the thermal decomposition of some metal complexes. The protonation constant of the ligand and the stability constant of metal complexes were determined pH-metrically in 50% (v/v) dioxane-water mixture at 298 K and found to be consistent with Irving-Williams order. Moreover, the minimal inhibitory concentration (MIC) of these compounds against Staphylococcus aureus, Escherechia coli and Candida albicans were determined.     

Synthesis and spectroscopic studies of mixed-ligand and polymeric dinuclear transition metal complexes with bis-acylhydrazone tetradentate ligands and 1,10-phenanthroline

Two types of dinuclear copper(II) and nickel(II) complexes with two tetradentate N2O2 donor ligands 1,4-bis(1-anthranoylhydrazonoethyl)benzene (L1), 1,4-bis(1-salicyloylhydrazonoethyl)benzene (L2) and N,N'-bidentate heterocyclic base [1,10-phenonthroline (phen)] have been synthesized and characterized by elemental analysis, infrared spectra, UV-vis electronic absorption spectra and magnetic susceptibility measurements. The reaction of metal(II) acetates with the solution containing ligand and 1,10-phenonthroline in methanol gives mixed-ligand dinuclear metal(II) complexes with general formula [M2L(phen)2]Cl2 (L=L1 or L2), whereas, the ligands react with metal(II) acetates to form polymeric dinuclear complexes with general formula [(M2L2)n] (L=L1 or L2). In the complexes, the ligands act as dianionic tetradentate and coordination takes place in the enol tautomeric form with the enolic oxygen and azomethine nitrogen atoms while the phenolic hydroxyl and amino groups of aroylhydrazone moiety do not participate in coordination. The effect of varying pH and solvent on the absorption behavior of both ligands and complexes has been investigated.     

Synthesis of cobalt(II), nickel(II) and copper(II) complexes with 2-(2-hydroxyphenyliminomethyl)-1-(4-methyl-phenylsulfonamido)benzene and crystal structures of {bis(methanol)[2-(2′-N-tosylaminophenyl)iminomethyl]phenolato}nickel(II) and {bis(2,2′-bipyridine)[2-(2′-N-tosylaminophenyl)iminomethyl]phenolato}copper(II)

Electrochemical oxidation of metal anodes (cobalt, copper and nickel) in acetonitrile solutions of 2-(2-hydroxyphenyliminomethyl)-1-(4-methyl-phenylsulfonamido)benzene (H₂L) gave [CoL], [CuL] and [NiL] complexes. When 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) was added to the electrolytic cell, the mixed complexes [MLL′] (M=Co, Cu, L′=bipy or M=Ni, L′=phen) were obtained. A binuclear compound of composition [Ni₂L₂(MeOH)₄] (1) was synthesized by reaction of the ligand H₂L and nickel(II) acetate in methanol. X-ray structure determination showed the compound to be binuclear, with each nickel atom coordinated to two nitrogen and two bridging phenol oxygen atoms of two dianionic ligands and two methanol molecules, in an octahedral environment. The crystal structure of [CuLbipy] (2) was determined by X-ray diffraction; with the copper atom in a distorted bipyramidal environment defined by the two bipyridine nitrogen atoms and by the phenolic oxygen and the nitrogen atoms of the dianionic ligand. The electronic and vibrational spectral data of the complexes are discussed and related to the structure.     

Diastereopure Fe(II) and Zn(II) complexes derived from a tridentate N,N',N-bis(methyl-L-prolinate)-substituted pyridine ligand

A series of mononuclear iron(II) and zinc(II) complexes of the new chiral Py(ProMe)2 ligand (Py(ProMe)2 = 2,6-bis[[(S)-2-(methyloxycarbonyl)-1-pyrrolidinyl]methyl]pyridine) have been prepared. The molecular geometry in the solid state (X-ray crystal structures) of the complexes [FeCl2(Py(ProMe)2)] (1), [ZnCl2(Py(ProMe)2)] (2), [Fe(OTf)2(Py(ProMe)2)] (3), [Fe(Py(ProMe)2)(OH2)2](OTf)2 (4), and [Zn(OTf)(Py(ProMe)2)](OTf) (5) are reported. They all show a meridional NN'N coordination of the Py(ProMe)2 ligand. The bis-chloride derivatives 1 and 2 represent neutral isostructural five-coordinated complexes with a distorted geometry around the metal center. Unusual seven-coordinate iron(II) complexes 3 and 4 having a pentagonal bipyramidal geometry were obtained using weakly coordinating triflate anions. The reaction of Zn(OTf)2 with the Py(ProMe)2 ligand afforded complex 5 with a distorted octahedral geometry around the zinc center. All complexes were formed as single diastereoisomers. In the case of complexes 3-5, the oxygen atoms of both carbonyl groups of the ligand are also coordinated to the metal. The stereochemistry of the coordinated tertiary amine donors in complexes 3-5 is of opposite configuration as in complexes 1 and 2 as a result of the planar penta-coordination of the ligand Py(ProMe)2. Complexes 1, 2, and 5 have an overall -configuration at their metal center, while the Fe(II) ion in complexes 3 and 4 has the opposite delta-configuration (crystal structures and CD measurements). The magnetic moments of iron complexes 1, 3, and 4 correspond to that of high-spin d6 Fe(II) complexes. The solution structures of complexes 1-5 were characterized by means of UV-vis, IR, conductivity, and CD measurements and their electrochemical behavior. These studies showed that the coordination environment of 1 and 2 observed in the solid state is maintained in solution. In coordinating solvents, the triflate anion (3, 5) or water (4) co-ligands of complexes 3-5 are replaced by solvent molecules with retention of the original pentagonal bipyramidal and octahedral geometry, respectively.     

Transition metal complexes of bidentate Schiff base ligands

New Schiff base ligands derived from vanillin (HL¹), 4-dimethylaminobenzaldehyde (HL²) and 3,5-di-t-butyl-4-hydroxybenzaldehyde (HL³) with N-(pyridyl)-3-methoxy-4-hydroxy-5-aminobenzylamine (2) and their copper(II), cobalt(II), nickel(II), oxovanadium(IV) and zinc(II) transition metal complexes have been synthesized and characterized by elemental analyses, electronic and i.r. spectra, molar conductance data and by 1H and ¹³C n.m.r. spectra. The results indicate that the ligands coordinate through azomethine nitrogen and phenolic oxygen to the metal ions. In like manner, it was found that the pyridine and amine nitrogen atoms are not coordinated to the metal ions. The ¹H and ¹³C n.m.r. spectral data confirmed the suggested structure for the Schiff base ligands, and the mass spectra results confirmed the proposed structure of the ligands. The antimicrobial activity properties of the ligands and their metal complexes have been studied.     

Synthesis and characterization of some pyrimidine, purine, amino acid and mixed ligand complexes

Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes of barbital, thiouracil, adenine, amino acids (methionine, lysine and alanine) and some mixed ligands were prepared and characterized by elemental analyses, IR, electronic spectra, magnetic susceptibility and ESR spectra. Coordination of the metallic centre to the oxygen and nitrogen atoms of barbital, thiouracil, amino acids and coordinate to amino group and nitrogen atom of adenine occurred. Electronic spectra and magnetic susceptibility measurements were utilized to infer the structure of the complexes which are octahedral for Mn(II), Fe(III), Co(II), Ni(II) and Cd(II) and tetrahedral for Mn(II), Cu(II), Zn(II) complexes. ESR spectra were observed for copper complexes with a d(x2)-(y2) ground state with small g(||) values indicating strong interaction between the ligands and their metal ions.     

Metal complexes with pyridone-based radicals: Preparation and properties of a dinuclear paddle-wheel copper(II) complex and a mononuclear palladium(II) complex

We prepared and characterized dinuclear copper(II) and mononuclear palladium(II) complexes coordinated with a pyridine-based open-shell ligand, 5-(4′,4′,5′,5′-tetramethylimidazoline-3′-oxide-1′-oxyl)-2(1H)-pyridone (=HL). In the copper(II) dinuclear complex [Cu₂(L)₄(DMF)₂] (1), four deprotonated ligands are coordinated as bridging ligands to form a paddle-wheel type unit. In the palladium(II) complex trans-[PdCl₂(HL)₂] (2), two HL ligands in the neutral hydroxypyridine form are coordinated to the trans positions of the metal ion via the nitrogen atoms. The hydroxyl groups of the ligands are hydrogen-bonded to the chlorine atoms of neighboring molecules, thereby creating a hydrogen-bonded double-chain molecular arrangement. Magnetic susceptibilities of these complexes were measured and analyzed. The small intramolecular antiferromagnetic interaction in the latter complex may originate from superexchange through the diamagnetic metal center.     

Di- and tetranuclear copper(II) complexes of a novel binucleating tetrathioether-tetrathiol ligand

A novel bi-tetradentate polythioether ligand, 6,6-methylene-bis(5- mercapto-3-thiahexyl)-4,8-dithiaundecane-1, 11-dithiol (H4L) was synthesized, and its di- and tetranuclear copper(II) complexes were prepared, and characterized by elemental analyses, magnetic moments, 1H-n.m.r., i.r., and Uv/vis spectra. The i.r. data show that the ligand acts in a tetradentate manner and coordinates via one S atom of the thioether and thiol groups. The geometry of the metal chelates is discussed with the help of magnetic and spectroscopic measurements. The elemental analyses, stoichiometry, and spectroscopic data of the complexes indicate that the copper(II) ions are coordinated to the bi-dianion of the ligand. The function of the thiol ligand is to release protons to form copper(II) complexes, (Cu2L).     

cis-[Ni(NCS)_2tren]的镜面对称性破缺: 螯环的特殊手性构象

为了探究cis-[Ni(NCS)2tren][tren:三(2-氨基乙基)胺]的手性来源,本文采用单晶X射线衍射、溶液紫外-可见-近红外(UV-Vis-NIR)光谱、固体紫外圆二色(CD)光谱和粉末X射线衍射(XRD)等对cis-[Ni(NCS)2tren]的一对手性晶体进行了表征.研究结果表明:该手性晶体由结晶过程中的镜面对称性破缺而形成;三角架型配体tren配位后的特殊手性构象(δδλ,λλδ)是cis-[Ni(NCS)2tren]的主要手性来源.络合物固体紫外CD谱所呈现的Cotton效应可能来自其螯环手性构象以及手性金属中心对NCS-配体的π-π*跃迁和荷移跃迁生色团的手性微扰.对20批次合成产物进行固体CD检测的统计结果表明:它们的对映体过量(ee)值在39%-100%之间.     

Investigations into the synthesis and fluorescence properties of Tb(III) complexes of a novel bis-beta-diketone-type ligand and a novel bispyrazole ligand

A novel bis-beta-diketone organic ligand, 1,1'-(2,6-bispyridyl)bis-3-(p-methoxyphenyl)-1,3-propanedione (L1) and its derivatives, a novel bispyrazole ligand, 2,6-bis(5-(4-methoxyphenyl)-1H-pyrazol-3-yl)pyridine (L2) were designed and synthesized and their complexes with Tb(III) ion were successfully prepared. The ligands and the corresponding metal complexes were characterized by elemental analysis, infrared, proton nuclear magnetic resonance spectroscopy and TG-DTA. Analysis of the IR spectra suggested that the lanthanide metal ion Tb(III) coordinated to the ligands via the nitrogen atom of the pyridine ring and the carbonyl oxygen atoms for ligand L1 and the nitrogen atom of the pyrazole ring for ligand L2. The fluorescence properties of the two complexes in solid state were investigated and it was discovered that the Tb(III) ions could be sensitized by both the ligand (L1) and ligand (L2) to some extent. In particular, the complex of ligand (L2) is a better green luminescent material that could be used as a candidate material in organic light-emitting devices (OLEDs) since it could be much better sensitized by the ligand (L2), and the fluorescence intensity of Tb(III) complex of L2 are almost as twice strong as L1's.     

OPTICAL ROTATION STUDIES OF COPPER (II)-TRIPEPTIDE COMPLEXES

Abstract

Copper(II) complexes of various optically active di- and tripeptides have been studied with the aid of optical rotatory dispersion (ORD) and circular dichroism (CD) techniques. The magnitudes of the molecular rotations related to the d-d transitions of the complexes fall into three different ranges, depending on the positions of asymmetric carbon atoms of the ligands. The molecular rotations of GAG and GLG complexes are greater than those of GGA, GGL, and GGV complexes, which are again greater than those of AGG, LGG, and VGG complexes (G, A, L, and V are glycine, alanine, leucine, and valine residues, respectively, in the tripeptides investigated, the N-terminal residue being the first residue in each abbreviation). The structures of these complexes, deduced from their potentiometric equilibrium curves and from the known crystal structure of the copper(II)-triglycine complex, show that the asymmetric carbon atoms of the second and third amino acid residues (counting from the N-terminal amino acid residue) are in the plane composed of the central metal ion, the nitrogen atoms of the amino and peptide groups, and the oxygen atom of the carboxylate group. The magnitude of the Cotton effect increases with the planarity of the chelate rings which include the asymmetric carbon atom and the metal ion, and with increasing strength of the coordinate bonds that form these chelate rings. Further support for this interpretation is found in the CD spectra of the copper(II) and nickel(II) complexes of AGG, GAG, GGA, and AAA. Analysis of the CD spectra of LL and DL alanylalanine complexes also demonstrate the influence of planarity and coordinate bond strength on the magnitude of the Cotton effect. Schiff base formation of aldehydes and ketones with dialanines causes fundamental changes in the geometries of the copper(II) complexes and reverses the relative contributions of the chelate rings to the total CD absorption intensities of the complexes.     

A new cytosine-copper paramagnetic complex spectroscopic study

Two different copper complexes with cytosine molecules are formed in the process of crystal growth from the aqueous solution with traces of copper. One of them is diamagnetic, turning into paramagnetic upon ionizing irradiation (complex I). The other, the subject of the present study, is paramagnetic (complex II) as prepared. For complex II, EPR spectra demonstrate that the copper ion is coordinated with one nitrogen atom and three oxygen atoms. On the basis of the detailed EPR spectroscopic analysis and quantum-chemical calculations (in the DFT approach) the model of the complex has been proposed. Both experimental data and the theoretical results support the model with the copper atom, located between the two cytosine ribbons, ligated to a nitrogen and an oxygen atom from two opposing cytosine molecules and two oxygen atoms from water molecules. For complex II the Raman spectra demonstrated concerted restructuring of the hydrogen bonding in the cytosine crystal matrix upon insertion of copper ions.     

Synthesis and characterization of bis(N,N-diethylnicotinamide) <Emphasis Type="Italic">m</Emphasis>-hydroxybenzoate complexes of Co(II), Ni(H), Cu(II), and Zn(II)

Four novel mixed-ligand complexes of Co(II), Ni(II), Cu(II), and Zn(II) with m-hydroxybenzoate (m-Hba) and N,N-diethylnicotinamide (Dena) were synthesized and characterized on the basis of elemental analysis, FT-IR spectroscopic study, and solid state UV-Vis spectrophotometric and magnetic-susceptibility data. The thermal behavior of the complexes was studied by combined TG-DTA methods in static air atmosphere, and the mass spectra were recorded. The Co(II), Ni(II), and Zn(II) complexes, except for the Cu(II) complex, contain two molecules of coordinated water, two m-Hba, and two Dena ligands per formula unit. In these complexes, the m-Hba and Dena behave as monodentate ligands via acidic oxygen and nitrogen of the pyridine ring. In the Cu(II) complex, the m-Hba is coordinated as monoanionic bidentate ligand through acidic oxygen and carbonyl oxygen. Dena is bonded with Cu²⁺ as monodentate ligand by the nitrogen atom of the pyridine ring. The decomposition pathways and the stability of the complexes are interpreted in terms of the proposed structural data. The final decomposition products were found to be the respective metal oxides. The article was submitted by the authors in English.     

Spectral studies on cobalt(II), nickel(II) and copper(II) complexes of naphthaldehyde substituted aroylhydrazones

A series of new coordination complexes of cobalt(II), nickel(II) and copper(II) with two new aroylhydrazones, 2-hydroxy-1-naphthaldehyde isonicotinoylhydrazone (H(2)L(1)) and 2-hydroxy-1-naphthaldehyde-2-thenoyl-hydrazone (H(2)L(2)) have been synthesized and characterized by elemental analysis, conductance measurements, magnetic susceptibility measurements, (1)H NMR spectroscopy, IR spectroscopy, electronic spectroscopy, EPR spectroscopy and thermal analysis. IR spectra suggests ligands acts as a tridentate dibasic donor coordinating through the deprotonated naphtholic oxygen atom, azomethine nitrogen atom and enolic oxygen atom. EPR and ligand field spectra suggests octahedral geometry for Co(II) and Ni(II) complexes and a square planar geometry for Cu(II) complexes.     

Coordination Chemistry of Acrylamide. 6 Synthesis and Coordination Compounds of N‐Pyrazolylpropanamide – a Versatile Acrylamide‐derived Ligand

The syntheses, spectroscopy and single crystal X‐ray structures of the multifunctional acrylamide‐derived ligand N‐pyrazolylpropanamide (= L) ( 1 ), and its complexes [L₂CuCl₂] ( 2 ) and [L₄Co₃Cl₆] ( 3 ) with copper(II) and cobalt(II) chlorides, respectively, are described. The ligand 1 is easily obtained in one step by the reaction of pyrazole with acrylamide in a 1:1 molar ratio in the presence of trimethylbenzylammonium hydroxide as a basic catalyst. The reaction of CuCl₂·2H₂O with 1 in a 1:2 metal salt:ligand molar ratio in ethanol/‐triethylorthoformate solution gave coordination compound 2 . The crystal structure of 2 contains two seven‐membered chelate rings formed by two nitrogen atoms of the pyrazolyl groups and two weakly coordinated carbonyl oxygen atoms of the substituted amide moieties. Two chloride ions in the axial positions complete a distorted octahedral coordination environment around the Cu^II atom. The reaction of CoCl₂·6H₂O with 1 in a 1:2 metal salt:ligand molar ratio afforded the unusual zwitterionic complex 3 . The crystal structure of 3 contains a central cobalt atom in an octahedral coordination surrounded by four ligands in which two of them act as chelate ligands and the other two, coordinated via the carbonyl oxygen atoms of the amide moieties to this metal center, act as bridging ligands bonded to two CoCl₃^? units.     

Raman spectroscopic studies on tropolone complexes with La, Nd, Sm, Yb

The complexes of tropolone (HL) with different lanthanide metals of lanthanum (La), neodymium (Nd), samarium (Sm), ytterbium (Yb) have been prepared respectively in the non-aqueous solution by the direct electrochemical oxidation of sacrificial metal anodes, and characterized by normal Raman spectroscopy. By comparing the spectra of the ligands and their complexes, the stretching vibrational band of OH disappeared in complexes, and the frequencies shifts of some relevant bands were observed, particularly for the stretching vibration of CO. In the low frequency region, new metal ion sensitive bands at 400-700 cm(-1) were observed, which could be assigned to the stretching vibrational mode of the bonding of lanthanide with oxygen. The stretching vibration of lanthanide-oxygen of tropolonate complexes showed a metal ion sensitivity. All the obvious change in spectral feature of Raman spectra revealed that CO and OH were coordinated with the center metal ions through oxygen atoms. Based on Raman results, the structures of the above complexes were proposed.