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1.
The reaction of trans(N)-[Co(d-pen)2]− (pen = penicillaminate) with HgCl2 or HgBr2 in the molar ratios of 1:1 gave the sulfur-bridged heterodinuclear complex, [HgX(OH2){Co(d-pen)2}] (X = Cl (1a) or Br (1b)). A similar reaction in the ratio of 2:1 produced the trinuclear complex, [Hg{Co(d-pen)2}2] (1c). The enantiomers of 1a and 1c, [HgCl(OH2){Co(l-pen)2}] (1a′) and [Hg{Co(l-pen)2}2] (1c′), were also obtained by using trans(N)-[Co(l-pen)2]− instead of trans(N)-[Co(d-pen)2]−. Further, the reaction of cis · cis · cis-[Co(d-pen)(l-pen)]− with HgCl2 in the molar ratio of 1:1 resulted in the formation of [HgCl(OH2){Co(d-pen)(l-pen)}] (2a). During the formations of the above six complexes, 1a, 1b, 1c, 1a′, 1c′, and 2a, the octahedral Co(III) units retain their configurations. On the other hand, the reaction of cis · cis · cis-[Co(d-pen)(l-pen)]− with HgCl2 in the molar ratio of 2:1 gave not [Hg{Co(d-pen)(l-pen}2] but [Hg{Co(d-pen)2}{Co(l-pen)2}] (2c), accompanied by the ligand-exchange on the terminal Co(III) units. The X-ray crystal structural analyses show that the central Hg(II) atom in 1c takes a considerably distorted tetrahedral geometry, whereas that in 2c is of an ideal tetrahedron. The interconversion between the complexes is also examined. The electronic absorption, CD, and NMR spectral behavior of the complexes is discussed in relation to the crystal structures of 1c and 2c. 相似文献
2.
The reaction of the octahedral mononuclear complex, trans(N)-[Co(l-pen-N,O,S)2]− (pen = penicillaminate), with [PtCl2(bpy)] (bpy = 2,2′-bipyridine) stereoselectively gave an optically active S-bridged dinuclear complex, [Pt(bpy){Co(l-pen)2}]Cl · 3H2O (2Cl · 3H2O), whose structure is enantiomeric to the previously reported [Pt(bpy){Co(d-pen)2}]Cl · 3H2O (1Cl · 3H2O). The mixture of equimolar amounts of 1Cl · 3H2O and 2Cl · 3H2O in H2O crystallizes as [Pt(bpy){Co(d-pen)2}]0.5[Pt(bpy){Co(l-pen)2}]0.5Cl · 7H2O (3Cl · 7H2O), in which the enantiomeric complex cations 1 and 2 are included in the ratio of 1:1. The crystal structures of 2Cl · 3H2O and 3Cl · 7H2O were determined by X-ray crystallography, and compared with that of 1Cl · 3H2O. The structural feature for 2 is essentially consistent with that for 1, except for the absolute configurations around the octahedral Co(III) center. The optically active complex cation 2 exists as a monomer, accompanied by no intermolecular interactions in the π-electronic systems of bpy moieties. In the crystals of 3Cl · 7H2O, on the other hand, the enantiomeric complex cations, [Pt(bpy){Co(d-pen)2}]+ and [Pt(bpy){Co(l-pen)2}]+, are arranged alternately while overlapping the bpy planes along a axis, and the π electronic system of the bpy framework in [Pt(bpy){Co(d-pen)2}]+ interacts with those in [Pt(bpy){Co(l-pen)2}]+. Differences between the crystal structures of 2Cl · 3H2O and3Cl · 7H2O significantly reflect their diffuse reflectance spectra. In aqueous solution, each cation in both 2Cl · 3H2O and 3Cl · 7H2O is comparatively put on a free environment without such intermolecular interactions. 相似文献
3.
Alper Tolga Çolak Ferda? Çolak Demet Akduman Mehmet Tümer 《Inorganica chimica acta》2010,363(10):2149-198
The mer-[Co(pydca)(H2O)3(ina)]·H2O (1), (2a3mpyH)2[Co(pydca)2(H2O)2]·2H2O (2) and (2a6mpyH)2[Co(pydca)2(H2O)2]·2H2O (3) complexes (H2pydca: pyridine-2,5-dicarboxylic acid, ina: isonicotinamide, 2a3mpy = 2-amino-3-methylpyridine and 2a6mpy = 2-amino-6-methylpyridine) were synthesised and characterised by elemental analysis, magnetic and spectroscopic measurements (UV-Vis and IR spectra) and single crystal X-ray diffraction technique. The thermal behaviour of the complexes was also studied by simultaneous thermal analysis techniques (TG, DTG and DTA). In complex 1, Co(II) ion was coordinated by one bidentate pydca, one isonicotinamide and three aqua ligands to generate a CoN2O4 distorted octahedral geometry. Complexes 2 and 3 crystallise in the triclinic system and space group and the structures consist of one complex anion [Co(pydca)2(H2O)2]2−, two protonated aminomethylpyridinium cations, ampyH+ and two crystal water molecules. In the anions, the Co(II) ions have a distorted octahedral configuration and are coordinated by two bidentate pydca and two trans-aqua ligands. The pydca ligand is coordinated to the Co(II) by both the heterocyclic N atom and the adjacent carboxylate group O atom, creating a chelate ring, while protonated ampy ions behave as counter ion. 相似文献
4.
The preparation and variable temperature-magnetic investigation of three squarate-containing complexes of formula [Fe2(OH)2(C4O4)2(H2O)4]·2H2O (1) [Cr2(OH)2(C4O4)2(H2O)4]·2H2O (2) and [Co(C4O4)(H2O)4]n (3) [H2C4O4 = 3.4-dihydroxycyclobutene-1,2-dione (squaric acid)] together with the crystal structures of 1 and 3 are reported. Complex 1 contains discrete centrosymmetric [Fe2(OH)2(C4O4)2(H2O)4] diiron(II) units where the iron pairs are joined by a di-μ-hydroxo bridge and two squarate ligands acting as bridging groups through adjacent oxygen atoms. Two coordinated water molecules in cis position complete the octahedral environment at each iron atom in 1. The iron-iron distance with the dinuclear unit is 3.0722(6) Å and the angle at the hydroxo bridge is 99.99(7)°, values which compare well with the corresponding ones in the isostructural compound 2 (2.998 Å and 99.47°) whose structure was reported previously. The crystal structure of 3 contains neutral chains of squarato-O1,O3-bridged cobalt(II) ions where four coordinated water molecules complete the six-coordination at each cobalt atom. The cobalt-cobalt separation across the squarate bridge is 8.0595(4) Å. A relatively important intramolecular antiferromagnetic coupling occurs in 1 whereas it is very weak in 2, the exchange pathway being the same [J = −14.4 (1) and −0.07 cm−1 (2), the spin Hamiltonian being defined as ]. A weak intrachain antiferromagnetic interaction between the high-spin cobalt(II) ions occurs in 3 (J = −0.30 cm−1). The magnitude and nature of these magnetic interactions are discussed in the light of their respective structures and they are compared with those reported for related systems. 相似文献
5.
Four new three-dimensional materials built from reduced molybdenum(V) phosphates as building blocks and transitional metal (Co, Zn and Cd) complexes as linkers, (Hbpy)2[Co(bpy)(H2O)]2[Co(H2PO4)2 (HPO4)6(MoO2)12(OH)6] (1), [Co(H2O)4]2[Co(Hbpy)(H2O)]2[Co(bpy)][Co(HPO4)4(PO4)4(MoO2)12(OH)6] · 6H2O (2), Na2[Zn(Hbpy)(H2O)2]2[Zn(Hbpy)]2[Zn(HPO4)2(PO4)6(MoO2)12(OH)6] · 4H2O (3), (H2bpy)2[Cd(bpy)(H2O)]2[Cd(bpy)(H2O)2]2[Cd(HPO4)4(PO4)4(MoO2)12(OH)6] · 2H2O (4) (bpy = 4,4′-bipyridine), have been synthesized and characterized by elemental analyses, IR, TG, and single crystal X-ray diffraction. The 3-D framework of 1 is constructed from Co[P4Mo6]2 dimers bonded together with [Co(bpy)]n coordination polymer chains. In compound 2, the Co[P4Mo6]2 dimers are linked by both [Co(bpy)] complex chains and the cobalt dimers to form a 3-D framework. Compounds 1 and 2 represent the first examples of reduced molybdenum(V) phosphates decorated with transition metal complexes chains. The 3-D framework of 3 is constructed from Zn[P4Mo6]2 dimers bonded together with [Zn(bpy)] coordination complexes and [Zn(bpy)(H2O)2] complexes. In compound 4, the Cd[P4Mo6]2 dimers are coordinated with [Cd(bpy)(H2O)] and [Cd(bpy)(H2O)2] complexes to construct a 3-D structure. To our best knowledge, it is the first time that linear ligand 4,4′-bpy molecules have been grafted into the backbone of reduced molybdenum phosphates. Furthermore, the magnetic properties of compounds 1 and 2 are reported. 相似文献
6.
Wilson Jacob 《Inorganica chimica acta》2006,359(14):4565-4573
We have prepared and structurally characterized six-coordinate Fe(II), Co(II), and Ni(II) complexes of types [MII(HL1)2(H2O)2][ClO4]2 (M = Fe, 1; Co, 3; and Ni, 5) and [MII(HL2)3][ClO4]2 · MeCN (M = Fe, 2 and Co, 4) of bidentate pyridine amide ligands, N-(phenyl)-2-pyridinecarboxamide (HL1) and N-(4-methylphenyl)-2-pyridinecarboxamide (HL2). The metal centers in bis(ligand)-diaqua complexes 1, 3 and 5 are coordinated by two pyridyl N and two amide O atoms from two HL1 ligands and six-coordination is completed by coordination of two water molecules. The complexes are isomorphous and possess trans-octahedral geometry. The metal centers in isomorphous tris(ligand) complexes 2 and 4 are coordinated by three pyridyl N and three amide O atoms from three HL2 ligands. The relative dispositions of the pyridine N and amide O atoms reveal that the pseudo-octahedral geometry have the meridional stereochemistry. To the best of our knowledge, this work provides the first examples of structurally characterized six-coordinate iron(II) complexes in which the coordination is solely by neutral pyridine amide ligands providing pyridine N and amide O donor atoms, with or without water coordination. Careful analyses of structural parameters of 1-5 along with that reported in the literature [MII(HL1)2(H2O)2][ClO4]2 (M = Cu and Zn) and [CoIII(L2)3] have allowed us to arrive at a number of structural correlations/generalizations. The complexes are uniformly high-spin. Spectroscopic (IR and UV/Vis) and redox properties of the complexes have also been investigated. 相似文献
7.
A new bis(macrocycle) ligand, 7,7′-(2-hydoxypropane-1,3-diyl)-bis{3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),13,15-triene} (HL), and its dicopper(II) ([Cu2(HL)Cl2](NO3)2 · 4H2O (4a), [Cu2(HL)I2]I2 · H2O (4b)) and dinickel(II) ([Ni2(L)(OH2)](ClO4)3 (5a), [Ni2(L)(OH2)]I3 · 2H2O (5b), [Ni2(L)N3](N3)2 · 7H2O (5c)) complexes have been synthesized. The alkoxide bridged face-to-face structure of the dinickel(II) complex 5c has been revealed by X-ray crystallography, as well as the “half-opened clamshell” form of the bis(macrocyclic) dicopper(II) complex 4b. Variable temperature magnetic susceptibility studies have indicated that there exists intramolecular antiferromagnetic coupling (J=−33.8 cm−1 (5a), −32.5 cm−1 (5b), and −29.7 cm−1 (5c)) between the two nickel(II) ions in the nickel(II) complexes. 相似文献
8.
Hong-Lin Zhu 《Inorganica chimica acta》2011,366(1):27-38
Four butane-1,2,3,4-tetracarboxylato bridged supramolecular complexes [Co2(H2O)5(BTC)]·2H2O 1, [Co2(H2O)5(BTC)]·2H2O 2, [Co2(H2O)6(bpy)2(BTC)]·4H2O 3 and [Co2(H2O)2(bpy)2(BTC)] 4, (H4BTC = butane-1,2,3,4-tetracarboxylic acid, 2,2-bpy = 2,2-bipydine) are synthesized and characterized by single-crystal X-ray diffraction. IR spectroscopy, TG-DTA analyses, elemental analyses, powder X-ray diffraction and magnetic measurements for 3 and 4 are carried out. The dinuclear Co unit in 2 is bridged by BTC4− anions into 2D layers, which are assembled via interlayer hydrogen bonds into a 3D (44·62)(45·65)2(46·68·8) topological supramolecular architecture. In 3, the [Co2(H2O)6(bpy)2(BTC)] molecules are aggregated to 2D layers via π-π stacking interactions, the resulting layers are engaged in hydrogen bonding leading to a novel 3D supramolecular architecture with the schläfli symbol of (102.12)2(4.102)2(42.102.122). The Co atoms in 4 are linked by BTC4− anions into a 1D chain, then the hydrogen bonding and π-π stacking interactions result in formation of a 3D novel (43.62.8)2(46.66.83)(63)2 topological networks. The variable temperature magnetic characterizations on 3 and 4 suggest weak antiferromagnetic or ferromagnetic coupling exchange via π···π stacking interactions (J = -0.03 cm−1 for 3, J = 0.11 cm−1 for 4). 相似文献
9.
The cobalt(II) complexes [Co(TPA)Cl]ClO4 (1), [Co(TPA)Br]ClO4 (2), [Co(TPA)(H2O)]Cl(ClO4) (3) and [Co2(TPA)2(μ-tp)](ClO4)2 · 2H2O (4) (TPA = tris(2-methylpyridyl)amine and tp = terephthalate dianion) were synthesized and structurally characterized by UV-vis and IR spectroscopy. The molecular structures of complexes 1 and 4 were determined by X-ray crystallography and their magnetic properties were measured over the temperature range 2-300 K. The coordination geometry around the central Co(II) in these compounds has a distorted trigonal bipyamidal geometry with four nitrogen atoms from the TPA ligand and the fifth coordination site is occupied by Cl− ion in 1, Br− ion in 2, coordinated oxygen atom from H2O in 3 and by an oxygen atom supplied by the carboxylate group of the bridged terephthalato ligand in 4. The visible spectra of the complexes 1-3 in MeOH show strong distortion toward tetrahedral geometry. For complex 4, analysis of the infrared spectral data for the ν(COO−) stretching frequencies of the tp-carboxalato groups reveals the existence of the bis(monodentate) coordination mode for the bridged tp. X-ray data for 1 and 4 show that the former is mononuclear while the latter is dinuclear. The electronic spectrum of 4 in MeOH is in complete agreement with the assigned X-ray geometry around the Co(II) centers. The magnetic behavior of the mononuclear complex 1 is indicative of a high-spin compound with zero-field splitting. The best fit was obtained with ∣D∣ = 7.3 cm−1, g = 2.25. The dinuclear complex 4 exhibits weak antiferromagnetic coupling with a coupling constant J = −0.8 cm−1. The magnetic properties and the structural parameters of 4 are discussed in relation to the other related μ-terephthalato dinuclear Co(II) compounds. The geometry of the coordination sphere around 4 is unique - the CSD compilation listing only one other compound with such a geometry around the dinuclear Co(II) complex and its composition is far different from that in 4. However, they share a common feature of having a weakly antiferromagnetic coupling between Co(II) centers. 相似文献
10.
Two new cobalt(II) complexes of symmetric hexadentate mixed-ligand N,O [1,12-bis(2-pyridyl)-5,8-dioxa-2,11-diazadodecane (pydado)] and N,S [1,12-bis(2-pyridyl)-5,8-dithia-2,11-diazadodecane (pydadt)] donor atoms have been synthesized as perchlorate salts. The crystal structures show that [Co(pydado)](ClO4)2 · H2O (1) crystallizes in the triclinic space group and [Co(pydadt)](ClO4)2 (2) crystallizes in the monoclinic space group P21/c. The cation [Co(pydado)]2+ is pseudo-octahedral with the two pyridyl groups in trans position. However, in [Co(pydadt)]2+ complex, the size of thioether sulfur atoms imposes a distorted octahedral geometry; the pyridyl groups and the sulfur atoms are in trans position. The reaction of the complex 2 and hydrogen peroxide resulted to the oxidation of CoII into CoIII and the thioether groups of the ligand to sulfinate groups with elimination of the central ethylenic group of pydadt. Thus, complex 2 was converted to bis[3-(2-pyridylmethylamino)ethanesulfinate] cobalt(III) complex (3) {[Co(pynso)2](ClO4) · 0.5H2O}. The X-ray crystal structure reveals that the compound 3 crystallizes in the triclinic space group with the same donor atoms (Npyridyl, Namine and S) belonging to the two ligands in cis-position. In aqueous solution, the stability constants of the Co(II) chelates with these two ligands, determined by potentiometry, show the formation of [Co(LH)]3+ and [CoL]2+ species in all cases. The chelating power of pydadt ligand is slightly greater than that of pydado. 相似文献
11.
Red or orange crystals of [Co(NH3)6]2Cl2[Fe(CN)6] · 4H2O (1), [Co(en)3]2Cl2[Fe(CN)6] · 2H2O (2) and [Co(en)3]4[Fe(CN)6]3 · 21.6H2O (3) were isolated from the aqueous systems Co3+-LN-[Fe(CN)6]4− (LN = NH3, en = 1,2-diaminoethane). In all isolated samples the combination of Mössbauer (δ values were from the range −0.07 to −0.08 mm/s) and IR spectra (ν(CN) stretching vibrations in the range 2015-2047 cm−1) confirms the presence of low spin Fe(II) in [Fe(CN)6]4− anions. X-ray structure analyses corroborate the ionic character of all studied compounds. These contain diamagnetic [Co(NH3)6]3+ (1) or [Co(en)3]3+ (2 and 3) complex cations and diamagnetic [Fe(CN)6]4− complex anions. In compounds 1 and 2 chloride anions are present, too. All three compounds contain water of crystallization, in compound 3 as many as 21.6 molecules per formula unit. 相似文献
12.
Herein, we report the syntheses, spectral and structural characterization, and magnetic behavior of four new dinuclear terephthalato-bridged copper(II) complexes with formulae [Cu2(trpn)2(μ-tp)](ClO4)2 · 2H2O (1), [Cu2(aepn)2(μ-tp)(ClO4)2] (2), [Cu2(Medpt)2(μ-tp)(H2O)2](ClO4)2 (3) and [Cu2(Et2dien)2(μ-tp)(H2O)](ClO4)2 (4) where tp = terephthalate dianion, trpn = tris(3-aminopropyl)-amin, aepn = N-(2-aminoethyl)-1,3-propanediamine, Medpt = 3,3′-diamino-N-methyldipropylmine and Et2dien = N,N-diethyldiethylenetriamine. The structures of these complexes consist of two μ-tp bridging Cu(II) centers in a bis(monodentate) bonding fashion. The coordination geometry of the Cu(II) ions in these compounds may be described as close to square-based pyramid (SP) with severe significant distortion towards trigonal bipyramid (TBP) stereochemistry in 1. The visible spectra of the complexes in aqueous solutions are in complete agreement with the assigned X-ray geometry around the Cu(II) centers. Also, the solid infrared spectral data for the stretching frequencies of the tp-carboxalato groups, the ν(COO−) reveals the existence of bis(monodentate) coordination mode for the bridged terephthalate ligand. The susceptibility measurements at variable temperature over the range 2-300 K are reported. Despite the same bonding mode of the tp bridging ligand, there has been observed slight antiferromagnetic coupling for the compounds 1 and 4 with J values of −0.5 and −2.9 cm3 K mol−1, respectively, and very weak ferromagnetic coupling for 2 and 3 with J values of 0.8 and 10.1 cm3 K mol−1, respectively. The magnetic results are discussed in relation to other related μ-terephthalato dinuclear Cu(II) published compounds. 相似文献
13.
Monika Moszner 《Inorganica chimica acta》2004,357(12):3613-3620
The decaaqua-di-rhodium(II) cation has been found to be an interesting starting material in the preparation of dioxygen complexes with different N-donor ligands. Treatment of aqueous HClO4 solution of [Rh2(H2O)10]4+ with NH4OH/NH3, py and/or en results in water exchange and the formation of corresponding [Rh2II(H2O)10−m(base)n(OH)m](4−m)+ derivatives. Reaction of the latter with dioxygen afforded superoxo and/or peroxo complexes, depending on reaction conditions: [Rh2III(O2 −)(NH3)8(OH)2](ClO4)3 (1), [Rh2III(O2 −)(NH3)8(OH)(H2O)](ClO4)4 (2), [Rh2III(O2 2−)(NH3)10](ClO4)4 · 6H2O (3), [Rh2III(O2 −)(py)8(H2O)2](ClO4)5 (4), [Rh2III(O2 2−)(en)4(H2O)2](ClO4)4 (5) and [Rh2III(O2 −)(en)4(H2O)2](ClO4)5 (6). All the obtained complexes were characterized by elemental analysis, mass spectrometry, UV-Vis, IR and ESR spectroscopies and magnetic measurements. 相似文献
14.
Kinetics and mechanism for reduction of halo- and haloam(m)ine platinum(IV) complexes by l-ascorbate
Kelemu Lemma Donald A. HouseNegussie Retta Lars I. Elding 《Inorganica chimica acta》2002,331(1):98-108
Reduction of the model platinum(IV) complexes cis-[PtCl4(NH3)2] (1), trans-[PtCl4(NH3)2] (2), trans-[PtCl2(en)2]2+ (3), trans-[PtBr2(NH3)4]2+ (4), [PtCl6]2− (5), and [PtBr6]2− (6) with l-ascorbic acid (H2Asc) in 1.0 M aqueous medium at 25 °C in the region 1.75≤pH≤7.20 has been investigated using stopped-flow spectrophotometry. The redox reactions follow the rate law: −d[Pt(IV]/dt=k[H2Asc]tot[Pt(IV)] where k is a pH-dependent second-order rate constant and [H2Asc]tot, the total concentration of ascorbic acid. The pH-dependence of k is attributed to parallel reduction of Pt(IV) by the protolytic species HAsc− and Asc2−. Analysis of the kinetics data reveals that the ascorbate anion Asc2− is up to seven orders of magnitude more reactive than HAsc− while H2Asc is unreactive. Electron transfer from HAsc−/Asc2− to the Pt(IV) compounds is suggested to take place by a mechanism involving a reductive attack on any one of the mutually trans-halide ligands by Asc2− and/or HAsc− forming a halide-bridged activated complex. The rapid reduction of these complexes supports the assumption that ascorbate Asc2− might be an important reductant at physiological conditions for anticancer active Pt(IV) pro-drugs capable of undergoing reductive trans elimination. The parameters ΔH≠ and ΔS≠ for reduction of Pt(IV) with Asc2− have been determined from the study of the temperature dependence of k. 相似文献
15.
Wilson Jacob 《Inorganica chimica acta》2008,361(5):1231-1238
Synthesis and crystal structure of two coordination polymers of composition [MnII(H2bpbn)1.5][ClO4]2 · 2MeOH · 2H2O (1) and [CoII(H2bpbn)(H2O)2]Cl2 · H2O (2) [H2bpbn = N,N′-bis(2-pyridinecarboxamido)-1,4-butane], formed from the reaction between [Mn(H2O)6][ClO4]2/CoCl2 · 4H2O with H2bpbn in MeCN, are described. In 1 each MnII ion is surrounded by three pyridine amide units, providing three pyridine nitrogen and three amide oxygen donors. Each MnII center in 1 has distorted MnN3O3 coordination. In 2 each CoII ion is coordinated by two pyridine amide moieties in the equatorial plane and two water molecules provide coordination in the axial positions. Thus, the metal center in 2 has trans-octahedral geometry. In both 1 and 2, the existence of 1D zigzag network structure has been revealed. Owing to π-π stacking of pyridine rings from adjacent layers 1 forms 2D network; 2 forms 2D and 3D network assemblies via N-H?Cl and O-H?Cl secondary interactions. Both the metal centers are high-spin. 相似文献
16.
Reactions of 2-(arylazo)pyridine (La-c) with [IrCl3(PPh3)2] in two different solvents, viz. ethanol and toluene are reported. In refluxing toluene two new isomeric (mer and fac geometries) iridium complexes, having molecular formula [IrCl3(PPh3)(L)] (1 and 2) have been isolated. The reaction in refluxing ethanol yielded two new hydrido complexes of molecular formula [IrHCl2(PPh3)(L)] (3) and [IrHCl(PPh3)2(L)]Cl (4) along with the compound 2. All the complexes have been thoroughly characterized by NMR, UV-Vis spectroscopy, cyclic voltammetry and X-ray crystallographic analysis. The 1H NMR spectra of the hydrido complexes 3 and 4 showed a doublet and a triplet signals at δ −20.43 and −14.82 respectively due to coupling with magnetically equivalent phosphorous nuclei. Strong trans influence of the π-acceptor ligands guided the X-ray structural parameters; bonds trans to the these ligands are unusually long. Similar elongation effect was also noted for the bonds trans to the coordinated hydrido ligand. UV-Vis-NIR spectrum consisted of multiple transitions in the UV and visible regions. Cyclic voltammetry of each of these complexes has exhibited a reductive response between −0.25 and −0.55 V, which has been assigned to azo-ligand reduction. The compound 3, however, showed a quasireversible oxidative wave near 1.45 V, due to IrIII/IrIV couple. 相似文献
17.
Rojalin Sahu 《Inorganica chimica acta》2010,363(14):4008-4016
Four new hetero-bimetallic Co3+-Na+ and Co3+-K+ coordination polymers having the molecular formulae [Na(H2O)Co(L)(N3)3]n (1), [Na2Co(L)(N3)3(H2O)5][Co(L)(N3)3] (2), K[Co(L)(NCS)3]·H2O (3) and K[Co(L)2][Co(NCS)4]·0.5H2O (4), were synthesized. Compounds 1-4 were characterized by single crystal X-ray diffraction, IR, UV-Vis, and thermogravimetric methods. These bimetallic systems have EE, EO azide bridge (1, 2) as well as bent (1, 2, 3) and linear (1, 4) aquo bridges. Important features observed among them were: a Z-shaped and diamond-shaped Co2Na2 clusters in 1, a centrosymmetric double ladder like polymer based on Na4 cluster in 2, and a linear KOK core having paddle-wheel structure in 4. 相似文献
18.
The reactions of CoCl2 with three equivalents of 2-(phenylimino)pyrrolyl sodium salts, performed under a nitrogen atmosphere, lead to the formation of the Co(III) complexes [Co(κ2N,N′-NC4H3C(H)N-C6H5)3] (2a), [Co(κ2N,N′-NC4H3C(CH3)N-C6H5)3] (2b) and [Co(κ2N,N′-NC16H9C(H)N-C6H5)3] (2c), accommodating three chelating iminopyrrolyl ligands. Complexes 2a-c were obtained in moderate yields, and their characterisation by 1H, 13C NMR and X-ray diffraction show they are diamagnetic and have an octahedral geometry about the cobalt centre, respectively. Uncharacterised products were obtained in the same reaction involving ligand precursors such as 2-(2,6-dimethylphenylimino)pyrrolyl sodium salts, which is attributed to a greater steric hindrance in the coordination of three of these bulkier ligands. The redox behaviour of complexes 2a-c shows an irreversible reduction wave with a peak potential in the range −3.2 to −3.7 V. Upon reduction, the complexes decompose giving rise, in the case of 2a, to a redox pattern compatible with the formation of [Co(κ2N,N′-NC4H3C(H)N-C6H5)2]. 相似文献
19.
Three novel cadmium(II) complexes [Cd2(tbpo)(O2CC6H4-p-NO2)2]ClO4·3CH3OH (1) [Cd2(bbap)(O2CC6H4-p-NO2)2]ClO4·4.5CH3OH·0.75H2O (2) and [Cd(ntb)(O2CC6H4-p-NO2)]ClO4·4CH3OH (3) have been synthesized and characterized by IR, elemental analysis, 1H NMR and X-ray crystallography, where tbpo− and bbap− are anions of N,N,N′,N′-tetrakis(2-benzimidazolylmethyl)-2-hydroxo-1,3-diaminopropane and 2,6-bis[bis(2-benzimidazolylmethyl)aminomethyl]-4-methylphenol, respectively; ntb is tris(2-benzimidazolymethyl)amine. Complexes 1 and 2 contain μ-phenolate-bridged and μ-alkoxo-bridged dicadmium(II) cores with the Cd1?Cd2 separation of 3.671 Å for complex 1 and 3.718 Å for 2. One of the 4-nitrobenzoate anions bridged the two cadmium(II) ions in syn-anti mode through its carboxylate group, the other 4-nitrobenzoate is only coordinated with Cd2 in bidentate chelating mode. The two central cadmium(II) atoms are in trigonal bipyramidal and pentagonal bipyramidal geometry. In complex 3, the cadmium(II) atom is coordinated with four nitrogen atoms of ntb and one carboxylate oxygen atom of 4-nitrobenzoate in distorted trigonal bipyramidal geometry. Experiment shows that there is a higher affinity of 4-nitrobenzoate anion as coligand with the dinuclear [Cd2(tbpo)]3+ and [Cd2(bbap)]3+ cores than that with the mononuclear [Cd(ntb)]2+ core. 相似文献
20.
Four cobalt(III) complexes containing the polypyridine pentadentate ligands N,N-bis(2-pyridylmethyl)amine-N′-ethyl-2-pyridine-2-carboxamide (PaPy3H), N,N-bis(2-pyridylmethyl)amine-N′-[1-(2-pyridylethyl)acetamide (MePcPy3H), and N,N-bis(2-pyridylmethyl)amine-N′-(2-pyridylmethyl)acetamide (PcPy3H), have been synthesized. All three ligands bind the Co(III) center in the same fashion with the exception of loss of conjugation between the carboxamide moiety and the pyridine ring in the latter two. The structures of [(PaPy3)Co(OH)][(PaPy3)Co(H2O)](ClO4)3 · 3H2O (1), [(PaPy3)Co(NO2)](ClO4) · 2MeCN (2), [(MePcPy3)Co(MeCN)](ClO4)2 · 0.5MeCN (3), and [(PcPy3)Co(Cl)](ClO4) · 2MeCN (4) have been determined. These ligands with strong-field carboxamido N donor stabilize the +3 oxidation state of the Co center as demonstrated by the facile oxidation of the corresponding Co(II) complexes (prepared in situ) by H2O2, [Fe(Cp)2](BF4), or nitric oxide (NO). The Co-Namido bond distances of 1-4 lie in the narrow range of 1.853-1.898 Å. 1H NMR spectra of these complexes confirm the low-spin d6 ground states of the metal centers. 相似文献