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1.
Reaction of CdCl2 with N-alkylaminopyrazole ligands 1-[(2-ethylamino)ethyl]-3,5-dimethylpyrazole (deae), 1-[(2-(tert-butylamino)ethyl)]-3,5-dimethylpyrazole (deat), bis-[(3,5-dimethylpyrazolyl)methyl]ethylamine (bdmae), and bis-[(3,5-dimethylpyrazolyl)ethyl]ethylamine (ddae) in absolute ethanol yields [CdCl2(NN′)] (NN′ = deae (1), deat (2)), [CdCl2(bdmae)] (3), and [CdCl(ddae)]2[CdCl4] (4). The Cd(II) complexes have been characterised by elemental analyses, conductivity measurements, IR, 1H, 13C{1H} and 113Cd NMR spectroscopies, and X-ray diffraction methods. 1H and 113Cd NMR experiments at variable temperature for 3 and 4 show that dynamic processes are taking place in solution. We report the measurements of 113Cd NMR chemical shift data for complexes 1-4 in solution. X-ray crystal structures for complexes 2 and 3 have been determined. The Cd(II) is coordinated to the deat ligand, in 2, by one nitrogen atom of the pyrazolyl group and one nitrogen atom of the amine. It finishes a tetrahedral geometry with two chlorine atoms. The bdmae ligand is linked to Cd(II), in 3, by two nitrogens atoms of the pyrazolyl groups and one amine nitrogen, along with two chlorine atoms, in a distorted trigonal bipyramidal geometry.  相似文献   

2.
Four different mononuclear octahedral Ni(II) complexes with protonated and deprotonated form of the same ligand have been synthesized by controlling reaction conditions and structurally characterized. The complexes are [Ni(HLl-his)(benzoate)(MeOH)] (1), [Ni(HLl-his)(SCN)(MeOH)] (2), [Ni(HLl-his)2] (3) and [Ni(Ll-his)(imidazole)2] (4) where H2Ll-his is (S)-2-(2-hydroxybenzylamino)-3-(1H-imidazol-4-yl)-propionic acid. The ligand behaves as a monobasic tetradentate ligand in 1 and 2, monobasic tridentate ligand in 3 and dibasic tetradentate ligand in 4. Ni(II) coordinated phenolic proton of the ligand in the complexes 1-2 shows strong intra-molecular H-bonding with benzoate in 1 and lattice water in 2, whereas 3 shows intermolecular H-bonding between uncoordinated phenols with neighbouring carboxylate. The pH titration of the complexes revealed that metal coordination and H-bond in complexes 1 and 2 considerably lowers the acidity of ligand phenol (pKa 6.8 and 7.0 respectively) compared to phenol (pKa 10). The complex 4 does not show any proton loss due to the absence of phenolic proton. All the complexes show extensive H-bonded network in the crystals including narrow (7.8 × 5.2 Å) water filled one dimensional channel in 2.  相似文献   

3.
The synthesis, structure and spectral and redox properties of the copper(II) complexes [Cu(pmtpm)Cl2] (1) and [Cu(pmtpm)2](ClO4)2 (6), where pmtpm is the linear tridentate ligand 2-pyridyl-N-(2′-methylthiophenyl)methyleneimine containing a thioether and two pyridine donors, are described. Also, the mixed ligand complexes [Cu(pmtpm)(diimine)](ClO4)2 (2-5), where the diimine is 2,2′-bipyridine (bpy) (2), 1,10-phenanthroline (phen) (3), 2,9-dimethyl-1,10-phenanthroline (2,9-dmp) (4) or dipyrido-[3,2-d:2′,3′-f]-quinoxaline (dpq) (5), have been isolated and studied. The X-ray crystal structures of the complexes 1, [Cu(pmtpm)(2,9-dmp)](ClO4)24 and 6 have been successfully determined. The complex 1 possesses a trigonal bipyramidal distorted square based pyramidal (TBDSBP) coordination geometry in which three corners of the square plane are occupied by two nitrogens and thioether s of pmtpm ligand and the remaining equatorial and the axial positions by two chloride ions. The complex 4 contains a CuN4S chromophore also with a TBDSBP coordination geometry in which two nitrogens and the thioether sulfur of pmtpm ligand occupy three corners of the square plane. One of the two nitrogens of 2,9-dmp ligand is equatorially coordinated and the other axially to copper. On the other hand, the complex 6 is found to possess a square based pyramidal distorted trigonal bipyramidal (SPDTBP) coordination geometry. The CuN2S trigonal plane in it is comprised of the pyridine and imine nitrogens and the thioether sulfur of the pmtpm ligand. The pyridine nitrogens of the ligand occupy the axial positions and the second thioether sulfur remains uncoordinated. On long standing in acetonitrile solution the mixed ligand complexes 2 and 3 undergo ligand disproportionation to provide the corresponding bis-complexes of bpy and phen, respectively, and 6. The electronic and EPR spectral parameters and the positive redox potential of complex 4 are consistent with the equatorial location of the thioether sulfur in the square-based coordination geometry around copper(II). On the other hand, the higher g and lower A values and lower E1/2 values for the complexes 2, 3 and 5 are consistent with the axial coordination of the thioether sulfur. Also, the Cu(II)/Cu(I) redox potentials increase with increase in number of aromatic rings of the diimine ligand. The steric and electronic effects of the bidentate diimine ligands in orienting the thioether coordination to axial or equatorial position are discussed.  相似文献   

4.
Three new supramolecular complexes based on a 2-(pyrazin-2-yl)-1H-benzimidazole (Hpbi) and a series of Cd(II) salts have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction analysis. Reaction of CdCl2·2.5H2O with Hpbi afforded a one-dimensional chain [Cd(Hpbi)Cl2] (1), which exhibits a three-dimensional (3-D) supramolecular architecture through intermolecular X-H···Cl (X = N and C) hydrogen bonds and π-π stacking interactions. When using CdBr2·4H2O instead of CdCl2·2.5H2O under similar reaction conditions, a bisnuclear complex [Cd(Hpbi)2Br2] (2) is obtained, which obviously exhibits intermolecular X-H···Br (X = N and C) hydrogen bonds and π-π stacking interactions. When CdI2 take place of CdCl2·2.5H2O, a mononuclear complex, [Cd(Hpbi)2I2] (3), is isolated, which shows a 3D supramolecule framework formed by intermolecule hydrogen bonds and π-π packing interactions. Interestingly, the Hpbi ligand exhibits the same coordination modes in complexes 1-3. It is noteworthy that the radius of anions plays an important role in affecting the structures and luminescent intensity of the final products. The TGA for 1-3 have been investigated and discussed in detail.  相似文献   

5.
Two phenoxo bridged dinuclear Cu(II) complexes, [Cu2L2(NO2)2] (1) and [Cu2L2(NO3)2] (2) have been synthesized using the tridentate reduced Schiff-base ligand 2-[(2-dimethylamino-ethylamino)-methyl]-phenol (HL). The complexes have been characterized by X-ray structural analyses and variable-temperature magnetic susceptibility measurements. The structures of the two compounds are very similar having the same tridentate chelating ligand (L) and mono-dentate anionic ligand nitrite for 1 and nitrate for 2. In both complexes Cu(II) is penta-coordinated but the square pyramidal geometry of the copper ions is severely distorted (Addison parameter (τ) = 0.33) in 1 while the distortion is quite small (average τ = 0.11) in 2. These differences have marked effect on the magnetic properties of two compounds. Although both are antiferromagnetically coupled, the coupling constants (J = −140.8 and −614.7 cm−1 for 1 and 2, respectively) show that the coupling is much stronger in 2.  相似文献   

6.
A tridentate NNO donor Schiff base ligand [(1Z,3E)-3-((pyridin-2-yl)methylimino)-1-phenylbut-1-en-1-ol = LH] in presence of azide ions coordinates with cobalt(II) and copper(II) ions giving rise to three new coordination complexes [Co2(L)21,1-N3)2(N3)2] (1), [Cu2(L)21,3-N3)]·ClO4 (2) and [(μ1,1-N3)2Cu5(μ-OL)21,1-N3)41,1,1-N3)2]n (3). The complexes have been characterized by elemental analysis, FT-IR, UV-Vis spectral studies, and single crystal X-ray diffraction studies. These complexes demonstrate that under different synthetic conditions the azide ions and the Schiff base ligand (LH) show different coordination modes with cobalt(II) and copper(II) ions, giving rise to unusual dinuclear and polynuclear species (1, 2 and 3) whose structural variations are discussed. Magneto-structural correlation for the very rare singly μ1,3-N3 bridged CuII-Schiff base dinuclear species (2) has been studied. In addition, the catalytic properties of 1 for alkene oxidation and the general catalase-like activity behavior of 2 have been discussed.  相似文献   

7.
Neutral, hexacoordinated “3 + 2” mixed ligand oxorhenium (1) and oxotechnetium (2) complexes of the general formula MO[SNO][NN], where M = Re or 99Tc, SNO is 2-mercaptoethyl-N-glycine and NN is 2,2′-bipyridine (bpy), were synthesized by simultaneous action of the tridentate SNO and the bidentate NN ligand on ReOCl3(PPh3)2 or 99TcO-gluconate precursors in a 1:1:1 molar ratio. Both complexes were characterized by elemental analysis, IR and NMR spectroscopy. X-ray structure determination of rhenium complex 1 revealed a distorted octahedral coordination geometry where the SNO donor atoms of the tridentate ligand and one bpy nitrogen atom occupy the equatorial positions of the octahedron, whereas the second bpy nitrogen atom and the oxo-group fill the apical positions.  相似文献   

8.
Formation of three Cd(II)-ethylenediamine (en) complexes ([Cd(en)n]2+, n = 1-3) in aqueous solution and in DMSO solvent has been established by means of 113Cd NMR spectroscopy. It is clearly shown that Cd(II)-en complexes form primarily in basic solutions. A correlation between the 113Cd NMR chemical shifts and the ethylenediamine (en) coordination number has been observed and discussed. Two single crystals with the composition [Cd2(en)5](ClO4)4 (1) and [Cd(en)3](ClO4)2 (2) were prepared from aqueous solution, and their structures were determined by single crystal X-ray diffraction. Cd(II) ions are coordinated by six atoms in both compounds, 1 and 2: via five N-donor atoms and one O-donor atom forming a bimetallic complex 1, and via six N-donor atoms forming a distorted octahedral monometallic complex 2. Raman spectra of complexes 1 and 2 also provide additional evidence that the cis-form of the bridging en is present in complex 1.  相似文献   

9.
Four cadmium(II) complexes of the semirigid tridentate ligand 8-[(pyridin-4-yl)methylthio] quinoline (TQMP4, L), namely, [CdL2](ClO4)2 (1), [Cd(L)Br2] (2), [Cd2(L)2(NO3)4] (3), and [Cd2(L)2I4] (4), have been prepared by the methods of layering and the diffusing of diethyl ether. The structures of the complexes have been identified by elemental analysis (EA), infrared spectra (IR) and single-crystal diffraction. The different coordination modes of the ligands and counter anions result in a 2D (4, 4) net structure in complex 1, a 1D polymer chain in complex 2, and 0D binuclear rings in complexes 3 and 4. Their antibacterial and antifungal activities were also tested.  相似文献   

10.
One monomeric neutral Cu(II) complex [(pmtpm)CuCl2] (1) is reported by Lindoy and Livingstone [8]. Two new complexes namely, μ-Cl bridged binuclear Cu(II) complex [{(pmtpm)Cu(Cl)}2 μ-Cl](ClO4) (2) and a bis μ-Cl bridged binuclear Cu(II) complex [{(pmtpm)Cu}2(μ-Cl)2](ClO4)2 (3) derived from a tridentate Schiff base ligand, 2-pyridyl-N-(2′-methylthiophenyl)methyleneimine (pmtpm) were synthesized and characterized by various spectroscopic methods and by X-ray crystallography. (N2S)CuCl2 chromophore(s) of distorted square pyramidal coordination geometries around Cu(II) ion(s) have been observed for all the complexes 1-3. The equatorial sites of the square plane comprise two N and a thioether S donor atoms of the pmtpm ligand as well as one Cl ion (terminal in 1 and 2, and bridging in 3) while the remaining axial site is occupied by a terminal Cl ion (for 1) or a bridging Cl ion (for 2 and 3). The equatorial Cu-Cl distances are much shorter [1: 2.2511(4) Å, 2: 2.2307(12) Å, 3: 2.2513(12) Å] than the axial Cu-Cl distances [1: 2.4394(4) Å, 2: 2.5597(9) Å, 3: 2.7037(12) Å]. The correlation of an axial Cu-Cl bond elongation with a lower g|| value in the solid state EPR spectrum and a blue shifted ligand field transition in the solid and solution phase absorption spectrum has been observed.  相似文献   

11.
The condensation of 2-formyl-pyridine with Girard’s T reagent yields a new hydrazone in the form of an ammonium quaternary salt: [H(2-PyGT)]Cl. This tridentate ligand is readily soluble in water and reacts with iron(III) or copper(II) chlorides to give [Fe(2-PyGT)Cl3] (1) or [Cu(2-PyGT)Cl2]·(H2O) (2) complexes, respectively. Single-crystal X-ray studies in 1 and 2 reveal that the coordination reaction gives rise to the deprotonation of the organic ligand that is coordinated using its NNO donor atoms in the form of a zwitterion species. The coordination spheres around the transition metal ions in complexes 1 and 2 are quite different. In 1, the iron site adopts a distorted octahedral coordination sphere, while the Cu(II) ions in 2 show a distorted tetragonal-pyramid geometry. As expected, the magnetic properties of these compounds reveal only weak antiferromagnetic interaction between spin carriers.  相似文献   

12.
Eight mononuclear Pd(II) complexes containing salicylaldiminato thiosemicarbazones (saltsc-R; where R = H (1), 3-OMe (2), 3-tBu (3) and 5-Cl (4)) as dinegative tridentate ligands were prepared by the reaction of the corresponding thiosemicarbazone with the precursor Pd(L)2Cl2 (L = phosphatriazaadamantane or 4-picoline) in the presence of a weak base. These complexes (9-16) were characterised by a range of spectroscopic and analytical techniques including NMR spectroscopy and X-ray diffraction. These complexes along with four other Pd(II) analogues (5-8) were screened for activity in vitro against the Trichomonas vaginalis parasite. Preliminary results show that the type of ancillary ligand as well as the substituents on the aromatic ring of the salicylaldiminato thiosemicarbazone ligand influences the antiparasitic activity of these complexes.  相似文献   

13.
The complexes of Cu(I), Cu(II), Ni(II), Zn(II) and Co(II) with a new polypyridyl ligand, 2,3-bis(2-pyridyl)-5,8-dimethoxyquinoxaline (L), have been synthesized and characterized. The crystal structures of these complexes have been elucidated by X-ray diffraction analyses and three types of coordination modes for L were found to exist in them. In the dinuclear complex [Cu(I)L(CH3CN)]2·(ClO4)2 (1), L acts as a tridentate ligand with two Cu(I) centers bridged by two L ligands to form a box-like dimeric structure, in which each Cu(I) ion is penta-coordinated with three nitrogen atoms and a methoxyl oxygen atom of two L ligands, and an acetonitrile. In [Cu(II)L(NO3)2]·CH3CN 2, the Cu(II) center is coordinated to the two nitrogen atoms of the two pyridine rings of L which acts as a bidentate ligand. The structures of [Ni(II)L(NO3)(H2O)2]·2CH3CN·NO3 (3), [Zn(II)L(NO3)2 (H2O)]·2CH3CN (4) and [Co(II)LCl2(H2O)] (5) are similar to each other in which L acts as a tridentate ligand by using its half side, and the metal centers are coordinated to a methoxyl oxygen atom and two bipyridine nitrogen atoms of L in the same side. The formation of infinite quasi-one-dimensional chains (1, 4 and 5) or a quasi-two-dimensional sheet (2) assisted by the intra- or intermolecular face-to-face aryl stacking interactions and hydrogen bonds may have stabilized the crystals of these complexes. Luminescence studies showed that 1 exhibits broad, structureless emissions at 420 nm in the solid state and at 450 nm in frozen alcohol frozen glasses at 77 K. Cyclic voltammetric studies of 1 show the presence of an irreversible metal-centered reduction wave at approximately −0.973 V versus Fc+/0 and a quasi-reversible ligand-centered reduction couple at approximately −1.996 V versus Fc+/0. The solution behaviors of these complexes have been further studied by UV-Vis and ESR techniques.  相似文献   

14.
A new NNS tridentate ligand, S-allyl-3-(2-pyridyl-methylene)dithiocarbazate (HL) has been prepared. Three coordination complexes, Mn(L)2 (1), [Co(L)2]NO3 (2) and Ni(L)2 (3) (L is the deprotonated monoanionic form of HL) have been synthesized and characterized by elemental analysis, molar conductivity, FT-IR, 1H NMR and UV-Vis spectroscopy. 1 and 3 are neutral complexes, while 2 is cationic with nitrate as the counter ion. Single crystal X-ray diffraction analysis shows that bis-chelate complexes have a distorted octahedral geometry in which two ligands in thiolate tautomeric form coordinate to the metal center through N atoms of the pyridine and imino moieties and one S atom. Molecular geometry from X-ray analysis, molecular geometry optimization, atomic charges distribution and bond analysis of the ligand and complexes have been performed using the density functional theory (DFT) with the B3LYP functional.  相似文献   

15.
Neutral tris(trimethylsilylmethyl) complexes [Ln(CH2SiMe3)3(L)] (Ln = Sc (1), Lu (2)) and cationic bis(trimethylsilylmethyl) complexes [Ln(CH2SiMe3)2(L)(THF)]+[BPh4], (Ln = Sc (3), Lu (4)) that contain bis(2-methoxyethyl)(trimethylsilyl)amine (L = Me3SiN(CH2CH2OMe)2) as a neutral, tridentate ligand were synthesized and characterized by NMR spectroscopy. X-ray structural analysis was performed for the scandium complex 1 and exhibited a distorted octahedral coordination geometry with a facially arranged ligand at the neutral scandium center. NMR spectroscopy corroborated the coordination of the tertiary amine function of the ligand to the metal. Complexes 3 and 4 expand the still limited range of cationic rare-earth metal alkyl complexes with known neutral, multidentate ligands.  相似文献   

16.
Six new 1-3D coordination polymers of an unsymmetrical angular ligand 3-pyridin-4-ylbenzoate (L), namely, [Ni(L)2(C2H6O2)]n (1), [Cd(L)2(H2O)2]n·4H2O (2), [Zn2(OH)(L)3]n (3), [Fe2(OH)(L)3]n (4), [Ni(L)2(H2O)]n (5) and [Cd(L)2(H2O)]n (6) were hydro(solvo)thermally synthesized. They have abounding structure chemistry ranging from one-dimensional ribbons (1 and 2), and two-dimensional novel helical double-layered frameworks (3 and 4) to three-dimensional CdSO4-topological porous interpenetrating architectures with hydrophilic and hydrophobic channels regularly arraying (5 and 6). The labile conformations and coordination modes of ligand L, which were finely tuned by reaction conditions, perhaps play the key role in the construction of various architectures. Very interestingly, the slight difference in solvent system or temperature resulted in the distinct architectures of nickel(II) complexes 1 and 5 or cadmium(II) complexes 2 and 6. As expected, the unsymmetrical ligand L has a trend to construct metal-organic helixes as observed in 3 and 4. Thermogravimetric analysis of 5 shows the main framework retains stability until a higher temperature 379 °C. The 3D microporous network of 5 can slightly absorb for N2 and Ar. Compounds 2, 3 and 6 emit ligand-centered photoluminescence but with obviously different intensities owing to the structural diversities and coordinating water molecules.  相似文献   

17.
Reaction of HgCl2 with trans-(±)2-(2,5-di(pyridin-2-yl)-4,5-dihydro-1H-imidazol-4-yl)pyridine (L1) and cis-(±)-(phenyl(2,4,5-tri(pyridin-2-yl)-4,5-dihydroimidazol-1- yl)methanone (L2) gives mononuclear complexes, 1 and 2. In these complexes L1 and L2 behave as tridentate and bidentate chelating ligands, giving distorted trigonal bipyramidal and tetrahedral coordination geometries, respectively. X-ray diffraction studies revealed a series of N-H?Cl, C-H?Cl, C-H?N and C-H?π interactions in 1 giving a 3D network, and N-H?Cl, C-H?Cl, C-H?π and π?π interactions in 2 giving a 2D network in the crystal lattice. Since both ligands should have a similar binding capacity to the mercury ions, the variations observed for coordination number and geometry should be a consequence of supramolecular stabilizing effects.  相似文献   

18.
Four new coordination complexes, NiII(L)2 (1), [CoIII(L)2]ClO4 (2), [Zn(HL)(L)]ClO4 · H2O (3) and [Zn(L)2][Zn(L)(HL)]ClO4 · 7H2O (4) (where L is a monoanion of a Schiff base ligand, N′-[(2-pyridyl)methylene]salicyloylhydrazone (HL) with NNO tridentate donor set), have been synthesised and systematically characterised by elemental analysis, spectroscopic studies and room temperature magnetic susceptibility measurements. Single crystal X-ray diffraction analysis reveals that 1 is a neutral complex, while 2-4 are cationic complexes. Among them, 4 is a rare type of cationic complex with two molecules in the asymmetric unit. The ligand chelates the metal centre with two nitrogen atoms from the pyridine and imino moieties and one oxygen atom coming from its enolic counterpart. All the reported complexes show distorted octahedral geometry around the metal centres, with the two metal-N (imino) bonds being significantly shorter than the two metal-N (Py) bonds.  相似文献   

19.
A series of coordination polymers have been prepared by the combination of flexible ligand 1,1′-biphenyl-2,2′-dicarboxylic acid (H2dpa) and different types of nitrogen-containing ligands, with various metal ions such as Co(II), Zn(II) and Cd(II). The single-crystal structure analyses reveal that the above complexes possess different structure features with the introduction of different nitrogen-containing ligands. When auxiliary linear ligand 4,4′-bipyridine (4,4′-bpy) is introduced, two-dimensional layered complex, [Co2(dpa)2(4,4′-bpy)2(H2O)]n (1) is formed. Whereas if chelating ligand, 1,10-phenanthroline (1,10′-phen) and 2,2′-bipyridine (2,2′-bpy) are introduced, one-dimensional complex [Zn(dpa)(1,10′-phen)]n (2) and discrete complexes [Co2(dpa)2(2,2′-bpy)2(H2O)2] (3), [Co3(dpa)3(1,10′-phen)6(H2O)2] (4), [Cd(dpa)(1,10′-phen)2][(H2dpa)2(H2O)2] (5) are synthesized. To our interest, 1 and 2 crystallize in homochiral spacegroup. Furthermore, the magnetic property of complex 1 and the fluorescent properties of complexes 2 and 5 are studied.  相似文献   

20.
A chiral Schiff base N-(S)-2-(6-methoxylnaphthyl)-propanoyl-N′-(2-hydroxylbenzylidene)hydrazine (H2L) has been synthesized. Reaction of H2L with Cu(OAc)2 · H2O led to the formation of a metal complex {[CuL] · H2O · 2DMF} (1). In complex 1, the potential dinegative tridentate L2− ligand acting as tetradentate bridging ligand coordinate to two metal ions so as to form a novel infinite metal-organic coordination chain structure. The enantiomerically pure ligand H2L presents two different sets of signals in the 1H NMR spectrum either in chloroform solution or in dimethylsulfoxide solution, showing the presence of both (E) and (Z) isomers. The X-ray structural investigations of H2L revealed that it is the fully extended E-configuration in the solid state.  相似文献   

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