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1.
D.A. Brown W.K. Glass T.J. Kemp H. Müller-Bunz H. Nimir 《Inorganica chimica acta》2005,358(9):2755-2762
Reaction between the dinuclear model hydrolases [M2(μ-OAc)2(OAc)2(μ-H2O)(tmen)2]; M = Ni (1); M = Co (2) and trimethylsilyltrifluoromethanesulphonate (TMS-OTf) under identical reaction conditions gives the mononuclear complex [Ni(OAc)(H2O)2(tmen)][OTf] · H2O (3) in the case of nickel and the dinuclear complex [Co2(μ-OAc)2(μ-H2O)2(tmen)2][OTf]2 (4) in the case of cobalt.Reaction of (3) with urea gives the previously reported [Ni(OAc)(urea)2(tmen)][OTf] (5), whereas (4) gives [Co2(OAc)3(urea)(tmen)2][OTf] (6) previously obtained by direct reaction of (2) with urea. Both (3) and (4) react with monohydroxamic acids (RHA) to give the dihydroxamate bridged dinuclear complexes [M2(μ-OAc)(μ-RA)2(tmen)2][OTf]; M = Ni (7); M = Co (8) previously obtained by the reaction of (1) and (2) with RHA, illustrating the greater ability of hydroxamic acids to stabilize dinuclear complexes over that of urea by means of their bridging mode, and offering a possible explanation for the inhibiting effect of hydroxamic acids by means of their displacing bridging urea in a possible intermediate invoked in the action of urease. 相似文献
2.
Three new copper(II) complexes of 5,5-diethlybarbiturate (barb), [Cu(barb)2(dmen)]·0.5H2O (dmen = N,N-dimethylethylenediamine) 1, [Cu(barb)2(bapa)] (bapa = bis(3-aminopropyl)amine) 2, and [Cu(barb)(apen)](barb)·2H2O (apen = N,N′-bis(3-aminopropyl)ethylenediamine) 3, have been synthesized and characterized by chemical, spectroscopic and thermal methods. Single crystal X-ray diffraction studies revealed that all complexes are mononuclear. The copper(II) ion exhibits a square-pyramidal coordination geometry in 1 and 3, but a trigonal-bipyramidal geometry in 2. The barb ligand shows different coordination modes. 1 presents the unequal coordination of the barb ligands: one is monodentate (N) and the other one is bidentate (N, O). In 2, both barb ligands are N-coordinated, whereas in 3, one barb ligand is N-coordinated, while the second barb ligand behaves as a counter-ion. The dmen, bapa and apen ligands act as bi-, tri- and tetradentate ligands, respectively. All complexes display a hydrogen-bonded network structure. The IR spectroscopic analysis shows that the ν(CO) stretching frequencies do not correlate predictably with the coordination mode of the barb ligand in 1. Thermal analysis data for 1-3 are in agreement with the crystal structures. 相似文献
3.
By using the hindered tris(pyrazolyl)borate ligand TpiPr2 (hydrotris(3,5-diisopropyl-1-pyrazolyl))borate, both mono- and binuclear complexes of cobalt [TpiPr2Co](X) (X = NO3 and OBz) and [TpiPr2Co]2(μ-X)(μ-OBz) (X = OH, N3) were synthesized. The nitrato complex, [TpiPr2Co](NO3) (1), which could be converted to (2), was prepared by reaction of KTpiPr2 with hydrated Co(NO3)2 and its molecular structure was determined by X-ray crystallography. The dinuclear di(μ-hydroxo) complex, [TpiPr2Co]2(μ-OH)2 (2), which was obtained by treatment of 1 with aqueous NaOH, reacted with one equivalent of benzoic acid to give the (μ-benzoato)(μ-hydroxo) complex, [TpiPr2Co]2(μ-OH)(μ-OBz) (3). X-ray crystallography shows the presence of both hydroxy and carboxylate group as bridging ligands and both cobalt metals are in five coordination environment in 3. The μ-azido complex, [TpiPr2Co]2(μ-N3)(μ-OBz) (5), was prepared by reaction of 3 with one equivalent of aqueous sodium azide. The spectroscopic studies suggested μ-1,1-bridging nature of group in this complex. The reaction of 2 with excess amount of benzoic acid resulted in the destruction of the bimetallic core to give the mononuclear carboxylato complex, [TpiPr2 Co](OBz) (4), which was characterized by X-ray crystallography. 相似文献
4.
Xavier FR Peralta RA Bortoluzzi AJ Drago V Castellano EE Haase W Tomkowicz Z Neves A 《Journal of inorganic biochemistry》2011,105(12):1740-1752
In this work we report on the synthesis, crystal structure, and physicochemical characterization of the novel dinuclear [FeIIICdII(L)(μ-OAc)2]ClO4·0.5H2O (1) complex containing the unsymmetrical ligand H2L = 2-bis[{(2-pyridyl-methyl)-aminomethyl}-6-{(2-hydroxy-benzyl)-(2-pyridyl-methyl)}-aminomethyl]-4-methylphenol. Also, with this ligand, the tetranuclear [Fe2IIIHg2II(L)2(OH)2](ClO4)2·2CH3OH (2) and [FeIIIHgII(L)(μ-CO3)FeIIIHgII(L)](ClO4)2·H2O (3) complexes were synthesized and fully characterized. It is demonstrated that the precursor [FeIII2HgII2(L)2(OH)2](ClO4)2·2CH3OH (2) can be converted to (3) by the fixation of atmospheric CO2 since the crystal structure of the tetranuclear organometallic complex [FeIIIHgII(L)(μ-CO3)FeIIIHgII(L)](ClO4)2·H2O (3) with an unprecedented {FeIII(μ-Ophenoxo)2(μ-CO3)FeIII} core was obtained through X-ray crystallography. In the reaction 2 → 3 a nucleophilic attack of a FeIII-bound hydroxo group on the CO2 molecule is proposed. In addition, it is also demonstrated that complex (3) can regenerate complex (2) in aqueous/MeOH/NaOH solution. Magnetochemical studies reveal that the FeIII centers in 3 are antiferromagnetically coupled (J = − 7.2 cm− 1) and that the FeIII-OR-FeIII angle has no noticeable influence in the exchange coupling. Phosphatase-like activity studies in the hydrolysis of the model substrate bis(2,4-dinitrophenyl) phosphate (2,4-bdnpp) by 1 and 2 show Michaelis-Menten behavior with 1 being ~ 2.5 times more active than 2. In combination with kH/kD isotope effects, the kinetic studies suggest a mechanism in which a terminal FeIII-bound hydroxide is the hydrolysis-initiating nucleophilic catalyst for 1 and 2. Based on the crystal structures of 1 and 3, it is assumed that the relatively long FeIII…HgII distance could be responsible for the lower catalytic effectiveness of 2. 相似文献
5.
Rupam Sarma 《Inorganica chimica acta》2011,377(1):50-55
A 1D-coordination polymer [{Mn3(C6H5COO)6(BPNO)2(MeOH)2}(MeOH)2]n (1) having benzoate as the anionic ligand and 4,4′-bipyridyl-N,N′-dioxide (BPNO) as bridging ligand is synthesized by reacting benzoic acid with manganese(II) acetate tetrahydrate followed by reaction with 4,4′-bipyridyl-N N′-dioxide. The bridging bidentate BPNO ligands in this coordination polymer along with the benzoate bridges hold the repeated units. The chain like structure in one dimension by benzoate bridges are connected to each other through the μ3-η2:η1 bridges of BPNO ligands. This coordination polymer can be transformed to a molecular complex [Mn(H2O)6](C6H5COO)2.4BPNO (2). In this complex the BPNO remains outside the coordination sphere but they are hydrogen bonded to water molecules to form self assembled structure. The reaction of 3,5-pyrazoledicarboxylic acid (L1H2) and BPNO with manganese(II) acetate or zinc(II) acetate led to molecular complexes with composition [M2(L1)2(H2O)6].BPNO·xH2O {where M = Mn(II) (3), Zn(II)(4)}. These molecular complexes of BPNO are characterised by X-ray crystallography. The complexes 3-4 are binuclear carboxylate complexes having M2O2 core formed from carboxylate ligands with two metal ions. 相似文献
6.
Two new nickel(II) complexes with the composition [Ni(L+H)(CH3CN)2](ClO4)3 (1) and [Ni(L)(tp)]·6H2O (2), (L = 3,10-bis{3-(1-imidazolyl)propyl}-1,3,5,8,10,12-hexaazacyclotetradecane, tp = terephthalate) have been synthesized and structurally characterized by a combination of analytical, spectroscopic and X-ray diffraction methods. The structure of 1 consists of monomeric cations of the formula [Ni(L+H)(CH3CN)2]3+ and perchlorate ions. The nickel(II) ion is six-coordinate with bonds to the four nitrogen atoms of the macrocycle and two nitrogen atoms of the axial acetonitrile ligands. One of the protonated imidazole pendants of the macrocycle is hydrogen bonded to the imidazole group of the neighboring nickel(II) macrocycle, forming an undulated 1D supramolecule. Then, the two 1D supramolecular chains are further interconnected by C-H···π interactions between the methyl group of the acetonitrile ligand and one of the imidazole groups to form a 2D double stranded supramolecular polymer. In the structure of 2, the 1D coordination polymer is formed with nickel(II) macrocycles and bridging terephthalate ions, where each 1D chain is interconnected with π-π interactions of pendant imidazole moieties of the macrocycles, resulting in the formation of a 2D supramolecule. 相似文献
7.
The reaction of [Ti(cp∗)2(BTMSA)] (1) (cp∗ = η5-C5Me5, BTMSA = bis(trimethylsilyl)acetylene) with malonic acids ((HOOC)2CR2, R = H, Me) and N,N-dimethylglycine resulted in the formation of titanium(IV) dicarboxylato complexes [Ti(cp∗)2{(OOC)2CR2}] (R = H, 2; R = Me, 3) and an α-amino acid titanium(III) complex [Ti(cp∗)2(OOCCH2NMe2)] (4). The identities of complexes 2-4 were confirmed by microanalysis, 1H and 13C NMR spectroscopy (2, 3), ESI-MS and CID experiments (2, 3) as well as by ESR and magnetic measurements (μeff = 1.81, 298 K) for 4. Single X-ray diffraction analyses of 2 and 4 exhibited monomolecular complexes in which the titanium atom is distorted tetrahedrally coordinated by two η5-C5Me5 rings and by the chelating bound malonato-κ2O,O′ (2) and N,N-dimethylglycinato-κ2O,O′ ligand (4). 相似文献
8.
The complexes [Cu2(o-NO2-C6H4COO)4(PNO)2] (1), [Cu2(C6H5COO)4(2,2′-BPNO)]n (2), [Cu2(C6H5COO)4(4,4′-BPNO)]n (3), [Cu(p-OH-C6H4COO)2(4,4′-BPNO)2·H2O]n (4), (where PNO = pyridine N-oxide, 2,2′-BPNO = 2,2′-bipyridyl-N,N′-dioxide, 4,4′-BPNO = 4,4′-bipyridyl-N,N′-dioxide) are prepared and characterized and their magnetic properties are studied as a function of temperature. Complex 1 is a discrete dinuclear complex while complexes 2-4 are polymeric of which 2 and 3 have paddle wheel repeating units. Magnetic susceptibility measurements from polycrystalline samples of 1-4 revealed strong antiferromagnetic interactions within the {Cu2}4+ paddle wheel units and no discernible interactions between the units. The complex 5, [Cu(NicoNO)2·2H2O]n·4nH2O, in which the bridging ligand to the adjacent copper(II) ions is nicotinate N-oxide (NicoNO) the transmitted interaction is very weakly antiferromagnetic. 相似文献
9.
Sumitra Das Soumi Chattopadhyay Hoong-Kun Fun Joan Ribas 《Inorganica chimica acta》2010,363(7):1513-498
One 0D monomer trans-[Ni(pn)2(dca)2] (1), one neutral 2D polymer [Ni(pn)(dca)2]n (2) and one polycationic 1D polymer [Ni(pn)2(dca)]n(PF6)n (3) (pn = 1,3-propanediamine; dca = dicyanamide) have been synthesized and X-ray crystallographically characterized. 1 has terminal trans-Ni(dca)2 unit, 2 contains both double bridged Ni-(NCNCN)2-Ni and single bridged Ni-(NCNCN)-Ni units in alternate fashion and 3 consists of single Ni-(NCNCN)-Ni bridge by covalent bonds. The nickel(II) centers are six-coordinated with distorted octahedral geometry. Multiple lateral N-H···N, C-H···N, N-H···F and C-H···F hydrogen bondings promote dimensionality. Variable-temperature magnetic measurements indicate weak antiferromagnetic interactions through μ1,5 bridge(s). 相似文献
10.
To compare the cytotoxicities and the DNA-binding properties in tetranuclear complexes with different bridging ligands, two tetracopper(II) complexes with formulae of [Cu4(oxbe)2Cl2(bpy)2]·4H2O (1) and [Cu4(oxbm)2Cl2(bpy)2]·2H2O (2) were synthesized, where H3oxbe and H3oxbm stand for N-benzoato-N′-(2-aminoethyl)oxamide and N-benzoato-N′-(1,2-propanediamine)oxamide, respectively, and bpy is 2,2′-bipyridine. Complex 1 was characterized by elemental analyses, IR and electronic spectra and single-crystal X-ray diffraction. The crystal structure reveals the presence of the circular tetranuclear copper(II) cations which are assembled by a pair of cis-oxamido-bridged dinuclear copper(II) units through carboxyl bridges. The crystal structure of complex 2 has been reported in our previous paper. However, the bioactivities were not studied. Cytotoxicities experiments reveal that both the two complexes exhibit cytotoxic effects against human hepatocellular carcinoma cell SMMC-7721 and human lung adenocarcinoma cell A549, and complex 1 has the better activities than those of complex 2. The results of the interactions between the two complexes and herring sperm DNA (HS-DNA) suggest that the two complexes interact with HS-DNA in the mode of intercalation with the intrinsic binding constants of 3.93 × 104 M−1 (1) and 2.48 × 104 M−1 (2). These results indicated that the bridging ligands may play an important role in the cytotoxicities and the DNA-binding properties of tetranuclear complexes. 相似文献
11.
Supriti Paul Corine Mathonière Rodolphe Clérac Debashis Ray 《Inorganica chimica acta》2011,370(1):108-116
Reaction of the imidazolidinyl phenolate-based ligand, H3L [(2-(2′-hydroxyphenyl)-1,3-bis[4-(2-hydroxyphenyl)-3-azabut-3-enyl]-1,3-imidazolidine)] with Cu(ClO4)2·6H2O produces an aqua-bridged cationic reactant complex [Cu2(μ-H2O)(μ-L)][ClO4]·1.5H2O (1·1.5H2O). Solution phase interaction of 1·1.5H2O with SCN− anions in 1:1 molar ratio leads to [Cu2(μ-L)(NCS)]·2H2O (2·2H2O) that does not possess anymore the reactive aqua bridge but instead a terminal SCN− anion coordinated only to one CuII ion. Whereas in 1:2 molar ratio, partial extrusion of the CuII ions takes place to generate in situ [Cu(NCS)3(OH2)]− anions. These complex anions then quantitatively replace anions in 1·1.5H2O via ‘anion metathesis’ and concurrently remove the aqua bridge by coordination of linear MeCN to one of the CuII ions to give [Cu2(μ-L)(CH3CN)][Cu(NCS)3(OH2)] (3). The literature unknown [Cu(NCS)3(OH2)]− anion forms an intimate H-bonded assembly with the cationic part of 3 to yield a novel [Cu3] isosceles triangle. The precursor complex is known as antiferromagnetic whereas in 2·2H2O, the CuII (S = 1/2) ions in a dinuclear entity exhibit ferromagnetic interactions (J/kB = +15.0 K and g = 2.22) to yield an ST = 1 spin ground state in good agreement with the M versus H data below 8 K. 相似文献
12.
Aurkie Ray Guillaume Pilet Carlos J. Gómez-García Sebastián Bellú 《Inorganica chimica acta》2011,375(1):20-30
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)2(μ1,1-N3)2(N3)2] (1), [Cu2(L)2(μ1,3-N3)]·ClO4 (2) and [(μ1,1-N3)2Cu5(μ-OL)2(μ1,1-N3)4(μ1,1,1-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
13.
Christiane Fernandes Adolfo Horn Jr. Vagner M. de Assis Luciana da S. Mathias Adailton J. Bortoluzzi João Carlos Aquino Almeida 《Journal of inorganic biochemistry》2010,104(11):1214-1223
We synthesized iron(III), cobalt(II), copper(II) and zinc(II) complexes [FeIII(HBPClNOL)Cl2]·H2O (1), [CoII(H2BPClNOL)Cl2] (2), [CuII(H2BPClNOL)Cl]Cl·H2O (3), and [ZnII(HBPClNOL)Cl] (4), where H2BPClNOL is the ligand (N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)[(3-chloro)(2-hydroxy)]propylamine). The complexes obtained were characterized by elemental analysis, IR and UV-visible spectroscopies, electrospray ionization mass spectrometry (ESI-MS), tandem mass spectrometry (MS/MS), and cyclic voltammetry. X-ray diffraction studies were performed for complexes (3) and (4) revealing the presence of mononuclear and dinuclear structures in solid state for (3). However, the zinc complex is mononuclear in solid state. Biological studies of complexes (1)-(4) were carried out in vitro for antimicrobial activity against nine Gram-positive bacteria (Staphylococcus aureus strains RN 6390B, COL, ATCC 25923, Smith Diffuse, Wood 46, enterotoxigenic S. aureus FRI-100 (SEA+), FRI S-6 (SEB+) and SEC FRI-361) and animal strain S. aureus LSA 88 (SEC/SED/TSST-1+). The following sequence of inhibition promoted by the complexes was observed: (4) > (2) > (3) > (1), showing the effect of the metal on the biological activity. To directly observe the morphological changes of the internal structure of bacterial cells after the treatment, transmission electron microscopy (TEM) was employed. For the most active complex [ZnII(HBPClNOL)Cl] (4), granulation deposits around the genetic material and internal material leaking were clearly detected. 相似文献
14.
Two novel Co(II) coordination polymers {[Co(H2O)2(CH3OH)2(4-bpfp)](NO3)2}n1 (4-bpfp=N,N′-bis(4-pyridylformyl)piperazine) and [Co(NCS)2(CH3OH)2(3-bpfp)]n2 (3-bpfp=N,N′-bis(3-pyridylformyl)piperazine) have been synthesized and characterized by single crystal X-ray diffraction. Both the polymers consist of one-dimensional chains constructed by bridging bpfp ligands and Co(II) ions. The existence of O?H-O hydrogen bond in 1 and S?H-O hydrogen bond in 2 play important roles in creating interesting supramolecular structures. Their third-order nonlinear optical (NLO) properties in DMF solution have been studied by Z-scan technique. The results reveal that polymers 1 and 2 exhibit strong NLO absorption effects (α2=9.00×10−11 m W−1 for 1; 1.41 × 10−10 m W−1 for 2) and self-focusing performance (n2=3.24×10−16 esu for 1; 3.05 × 10−16 esu for 2) in DMF solutions. The corresponding effective NLO susceptibilities χ(3) values are 3.08 × 10−12 esu (1) and 4.70 × 10−12 esu (2). All of the values are comparable to those of the reported good NLO materials. Additionally, the TG-DTA results of the two polymers are in agreement with the crystal structures. 相似文献
15.
Five new complexes, [Co3(HL1)2(Py)8]·4CH3OH (1), [Ni3(HL1)2(Py)4]2·2DMF (2), [Co3(H2L2)2(Py)8]·2NO3 (3), [Ni2(HL2)(Py)6] (4) and [Cu4(HL2)2(Py)4]·4DMF (5) (H4L1 = N-propionyl-4-hydroxysalicylhydrazide, H44-hopshz; H5L2 = N-(3-carboxy-cis-2-propenoyl)-4-hydroxysalicylhydrazide, H54-hocpshz) have been obtained from two N,N′-diacylhydrazide ligands and characterized by elemental analysis, FT-IR, X-ray diffraction and antimicrobial activities. These di-, tri-, and tetrameric complexes are connected into three-dimensional supramolecular architectures with interesting topologies through O-H?O, C-H?O and C-H?π interactions. 1-3 are linear trimeric complexes with the ligands triply-deprotonated. Topological analysis indicates that they exhibit 2D (4,4), 3D (6,8)-connected (3349526)(3441257647) and 8-connected (42563) net, respectively. 4 and 5 possess dimeric and tetrameric structures, which are extended into 7-connected (33413536) and 4-connected (4,4) net, respectively. 相似文献
16.
The synthesis and crystal structure of four new copper(I) and copper(II) supramolecular amine, and amine phosphonate, complexes is reported. Reaction of copper(I) with 2-,9-dimethyl-1-10-phenanthroline (dmp) produced a stable 4-coordinate Cu(I) species, [Cu(I)(dmp)2]Cl · MeOH · 5H2O (2), i.e., the increased steric hindrance in the ‘bite’ area of dmp did not prevent interaction with the metal and provided protection against oxidation which was not possible for the phen analogue [R. Clarke, K. Latham, C. Rix, M. Hobday, J. White, CrystEngCommun. 7(3) (2005), 28-36]. Subsequent addition of phenylphosphonic acid to (2) produced two structures from alternative synthetic routes. An ‘in situ’ process yielded red block Cu(I) crystals, [Cu(I)(dmp)2] · [C6H5PO3H2 · C6H5PO3H] (4), whilst recrystallisation of (2) prior to addition of the acid (‘stepwise’ process) produced a green, needle-like Cu(II) complex, [Cu(II)(dmp) · (H2O)2 · C6H5PO2(OH)] [C6H5PO2(OH)] (3). However, addition of excess dmp during the ‘stepwise’ process forced the equilibrium towards product (4) and resulted in an optimum yield (99%). The structure of (4) was similar to the phen analogue, [Cu(II)Cl(phen)2] · [C6H5PO2(OH) · C6H5PO(OH)2] (1) [R. Clarke, K. Latham, C. Rix, M. Hobday, J. White, CrystEngCommun. 7(3) (2005), 28-36], but the presence of dmp exerted some influence on global packing, whilst (3) exists as a polymeric layered material. In contrast, reaction of copper(I) with di-2-pyridyl ketone (dpk), followed by phenylphosphonic acid produced purple/blue Cu(II) species, [Cu(II)(dpk · H2O)2] Cl2 · 4H2O (5), and [Cu(II)(dpk · H2O)2] · [C6H5PO2(OH)2 · C6H5PO(OH)2] (6), respectively, i.e., in both cases oxidation of copper occurred. Solid-state luminescence was observed in (2) and (4). The latter showing a 5-fold enhancement in intensity. 相似文献
17.
Mixed ligand complexes: [Co(L)(bipy)] · 3H2O (1), [Ni(L)(phen)] · H2O (2), [Cu(L)(phen)] · 3H2O (3) and [Zn(L)(bipy)] · 3H2O (4), where L2− = two -COOH deprotonated dianion of N-(2-benzimidazolyl)methyliminodiacetic acid (H2bzimida, hereafter, H2L), bipy = 2,2′ bipyridine and phen = 1,10-phenanthroline have been isolated and characterized by elemental analysis, spectral and magnetic measurements and thermal studies. Single crystal X-ray diffraction studies show octahedral geometry for 1, 2 and 4 and square pyramidal geometry for 3. Equilibrium studies in aqueous solution (ionic strength I = 10−1 mol dm−3 (NaNO3), at 25 ± 1 °C) using different molar proportions of M(II):H2L:B, where M = Co, Ni, Cu and Zn and B = phen, bipy and en (ethylene diamine), however, provides evidence of formation of mononuclear and binuclear binary and mixed ligand complexes: M(L), M(H−1L)−, M(B)2+, M(L)(B), M(H−1L)(B)−, M2(H−1L)(OH), (B)M(H−1L)M(B)+, where H−1L3− represents two -COOH and the benzimidazole N1-H deprotonated quadridentate (O−, N, O−, N), or, quinquedentate (O−, N, O−, N, N−) function of the coordinated ligand H2L. Binuclear mixed ligand complex formation equilibria: M(L)(B) + M(B)2+ ? (B)M(H−1L)M(B)+ + H+ is favoured with higher π-acidity of the B ligands. For Co(II), Ni(II) and Cu(II), these equilibria are accompanied by blue shift of the electronic absorption maxima of M(II) ions, as a negatively charged bridging benzimidazolate moiety provides stronger ligand field than a neutral one. Solution stability of the mixed ligand complexes are in the expected order: Co(II) < Ni(II) < Cu(II) > Zn(II). The Δ log KM values are less negetive than their statistical values, indicating favoured formation of the mixed ligand complexes over the binary ones. 相似文献
18.
Two oxime-functionalized diazamesocyclic derivates, namely, N,N′-bis(acetophenoneoxime)-1,4-diazacycloheptane (H2L1) and N,N′-bis(acetophenonoxime)-1,5-diazacyclooctane (H2L2), have been prepared and characterized. Both ligands (obtained in the hydrochloride form) can form stable metal complexes with CuII and NiII salts, the crystal structures of which were determined by X-ray diffraction technique. The reactions of H2L1 with Cu(ClO4)2 and Ni(ClO4)2 afford a penta-coordinated mononuclear complex [Cu(H2L1)Cl] · ClO4 (1) and a four-coordinated monomeric [Ni(HL1)] · ClO4 (2), in which the ligand is monodeprotonated. The ligand H2L2 also forms a quite similar mononuclear [Ni(HL2)] · ClO4 complex with Ni(ClO4)2, according to our previous work. However, reactions of different CuII salts [Cu(ClO4)2, CuCl2 and Cu(NO3)2 for 3, and CuSO4 for 4] with H2L2 in the presence of NaClO4 yield two unusual mono-μ-Cl dinuclear CuII complexes [Cu2(HL2)2Cl] · (ClO4) (3), and [Cu2(H2L2)(HL2)Cl] · (ClO4)2 · (H2O)(4). These results indicate that the resultant CuII complexes (1, 3 and 4) are sensitive to the backbones of diazamesocycles and even auxiliary anions. 相似文献
19.
Daewon Hong 《Inorganica chimica acta》2005,358(7):2303-2311
The scope of formation and structures of tungsten-iron-sulfur clusters has been explored using reactions based on [(Tp*)WS3]1− (1) as the ultimate precursor. The reaction system 1/FeCl2/NaSEt/S affords the cubane cluster [(Tp*)WFe3S4Cl3]1− (2), which with NaSEt is converted to [(Tp*)WFe3S4(SEt)3]1− (3).Clusters 2 and 3 contain the cubane [WFe3(μ3-S)4]3+ core.Complex 1 with FeCl2/NaSEt forms [(Tp*)WFe2S3Cl2(SEt)]1− (4) with the cuboidal [WFe2(μ2-S)2(μ3-S)(μ2-SR)]2+ core.Treatment of 2 with excess Et3P yields the edge-bridged double [(Tp*)2W2Fe6S8(PEt3)4] (5) with the [W2Fe6(μ3-S)6(μ4-S)2] core. Reaction of 2 with excess leads a mixture of products, from which [(Tp*)2W2Fe5S9Na(SH)(MeCN)]3−(6) was identified.This cluster, as closely related [(Tp)2Mo2Fe6S9(SH)2]3−, exhibits a core topology [W2Fe5Na(μ2-S)2(μ3-S)6(μ6-S)] very similar to the PN cluster of nitrogenase. All reactions were carried out in acetonitrile. The structures of 2-6 were established crystallographically as Et4N+ salts. In the cubane series, substitution of tungsten for molybdenum decreases the [MFe3S4]3+/2+ redox potential by ca. 0.20 V but has a negligible effect on electron distribution. This work expands the small set of previously known weak-field W-Fe-S clusters, demonstrates the existence of tungsten-containing edge-bridged double cubanes and clusters with the PN core topology, and introduces a new cuboidal core structure as found in 4 (Tp = hydrotris(pyrazolyl)borate, Tp* = hydrotris(3,5-dimethylpyrazolyl)borate). 相似文献
20.
New hydrogen-bonding assemblies were synthesized from the reaction of a metalloligand, [Cu(2,4-pydca)2]2− (LCu) (2,4-pydca = 2,4-pyridinedicarboxylate), with a FeII ion or an imidazole in an aqueous medium and crystallographically characterized. The obtained compounds, [Fe(H2O)6][Cu(2,4-pydca)2] (1) and [Cu(2,4-pydca)(imidazole)2] · 2H2O (2), have metalloligand dimer units, [Cu2(2,4-pydca)4]4− and [Cu2(2,4-pydca)2(imidazole)4], respectively, each of which assembles by π-π (1) and hydrogen-bonding (2) interactions to form 1-D metalloligand arrays. The 1-D metalloligand arrays are linked by rich hydrogen-bonding interactions via H2O molecules. 相似文献