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1.
The use of 2,2'-dithiodibenzaldehyde (DTDB) as a reactant for incorporating thiolate donors into the coordination sphere of a transition metal complex without the need for protecting groups is expanded to include the synthesis of complexes with pentadentate ligands. The ligand N,N'-bis(thiosalicylideneimine)-2,2'-thiobis(ethylamine) (tsaltp) is synthesized at a cobalt center by the reaction of DTDB with a Co complex of thiobis(ethylamine). The resulting Co complexes are thus coordinated by the N(2)S(3) pentadentate ligand through two imine N atoms, two thiolate S atoms, and one thioether S atom. A dimeric, bis-thiolate-bridged complex (1) is isolated and converted to a monomeric CN adduct (2) by treatment with KCN. The N(2)S(3) coordination environment provided by the tsaltp ligand is similar to that provided by the protein donors at the active site of the nitrile hydratase enzymes, with 2 being the first octahedral Co complex reported with such a coordination sphere. 相似文献
2.
Tamara R. Todorovi? Dušan M. Sladi? Tatjana T. Bo?i? Nenad R. Filipovi? Katarina K. An?elkovi? 《Inorganica chimica acta》2009,362(10):3813-3820
Five new complexes of Pt(II), Pd(II), Co(III) and Ni(II) with 2-pyridine(quinoline)carboxaldehyde selenosemicarbazones were synthesized and characterized. Crystal structures of Pt(II) complex with the pyridine derivative and Co(III) complex with the quinoline derivative were determined. In all complexes the ligands were coordinated through N2Se donor atom set forming either square-planar (Pt, Pd) or octahedral (Co, Ni) geometry. All complexes showed biological activity. 相似文献
3.
This article tries to rationalize the shortcomings of various model compounds and discusses requirements that a low-molecular compound must fulfill in order to become a potentially competitive catalyst for nitrogenases. For fundamental reasons, such a synthetic catalyst cannot be a precise structural duplicate of the active centers of nitrogenase. Results obtained with iron-sulfur carbonyl and diazene complexes further indicate that (1) the coupling and chronology of proton and electron transfer steps, (2) invariance of iron-sulfur distances within a wide range of electron density changes at the iron centers, and (3) Brönsted basic thiolate donors favoring the protonation of metal-sulfur cores and the formation of N–H···S bridges may be essential in order to reduce N2 via N2H2 and N2H4 to NH3 under mild conditions. 相似文献
4.
Andrea Melchior Roberto Portanova Claudio Tavagnacco Marilena Tolazzi 《Inorganica chimica acta》2004,357(12):3473-3482
The formation of Cd(II) and Co(II) complexes with N-methylethylenediamine (men) has been studied at 298 K in dimethylsulfoxide (dmso) in an ionic medium set to 0.1 mol dm−3 with Et4NClO4 in anaerobic conditions by means of potentiometric, UV-Vis, calorimetric and FT-IR technique. Mononuclear MLj (M=Cd, Co; j=1-3) complexes are formed in exothermic reactions, whereas the entropy changes oppose the complexes formation. The results are discussed in terms of different basicities and steric requirements and the whole of the thermodynamic data reported till now for the two ions with a number of diamines are summarized to visualize the selectivity of the ligands. The dioxygen uptake of Co(men)2 species has also been studied by means of UV-Vis and EPR techniques. The kinetic parameters and stability constants obtained for the formation of the superoxo and μ-peroxo species are discussed in terms of solvent effect and steric hindrance due to methyl group.Cyclic voltammetry was used to confirm the stability constant for the Co(dmen)2 (dmen=N,N′-dimethylethylenediamine) superoxo adduct formation but was not successful to investigate this Co(men)2-O2 system. 相似文献
5.
Subhendu Naskar Sumita Naskar Shyamal Kumar Chattopadhyay 《Inorganica chimica acta》2010,363(14):3641-18021
Five Ni(II) complexes of aroyl hydrazone ligands with 2,6-diacetyl pyridine monooxime are reported. X-ray crystal structure of the Ni(II) salicyloylhydrazone complex is also reported. In these complexes Ni(II) is in a distorted octahedral N4O2 coordination environment, with each of the two ligands coordinating through the pyridine nitrogen, imino-hydrazone nitrogen and the deprotonated oxygen of the hydrazone moiety. The iminooxime group remain uncoordinated in both the ligands and the planes containing the CH3-CN-OH groups are orthogonal to the adjacent pyridine rings. On excitation at 375 nm, the ligands as well as the Ni(II) complexes, show luminescence. However, the Ni(II) complexes have much lower quantum yield of emission than the free ligands. 相似文献
6.
P.M. Vimal Kumar 《Inorganica chimica acta》2011,375(1):84-92
The Schiff base ligand, 4-isopropylbenzaldehyde[N-(3-oxo-3,4-dihydro-2-quinoxalinyl)hydrazone] (Ipbh), the 1:1 condensation product of 4-isopropylbenzaldehyde and 2-hydroxy-3-hydrazinoquinoxiline, has been synthesized and characterized by X-ray crystallography. A series of complexes of Ipbh with Nickel(II), viz., [Ni(Ipbh)2]Cl2 (1), [Ni(Ipbh)2]Br2 (2), [Ni(Ipbh)2]I2 (3), [Ni(Ipbh)2·(CH3OH)2](NO3)2·(CH3OH)2 (4) and [Ni(Ipbh)2ClO4]ClO4 (5) have been synthesized. All the complexes were characterized by elemental analysis, molar conductivity, CHN analysis, spectroscopic studies, magnetic susceptibility measurements and TG/DTA methods. The solid-state structure of the complex 4 was established by single crystal X-ray crystallography. In all the complexes, Ipbh acts as a bidentate NO chelating agent, coordinated to the metal ion through the imine nitrogen and quinoxaline oxygen. In complex 4, Nickel(II) is in a distorted octahedral environment with an identical set of donor atoms, N2O4, coming from two imine nitrogen and two quinoxaline oxygen atoms of two Ipbh moieties as well as two oxygen atoms of the two methanol molecules. The crystal packing of Ipbh and the complex 4 exhibits 1D and 2D supramolecular networks, respectively through different intermolecular hydrogen-bonding interactions. 相似文献
7.
《Inorganica chimica acta》1987,128(2):231-237
Ni(II) dithiocarbamates (Ni(dtc)2) with various substituents on dtc were allowed to react with triphenylphosphine (PPh3). Mixed ligand complexes of the general formulae Ni(dtc)Cl(PPh3) and [Ni(dtc)(PPh3)2]ClO4 were prepared. The complexes were analysed by high resolution IR spectra. Comparison of the ν(C–N) frequencies of different complexes viz., Ni(dtc)2, Ni(dtc)Cl(PPh3) and [Ni(dtc)(PPh3)2]ClO4, showed the following order of decreasing v(C–N) values: [Ni(dtc)(PPh3)2]+> Ni(dtc)Cl(PPh3)> Ni(dtc)2. The observation showed the extent of contribution of the thiouride form in describing the structure of the complexes. The higher the contribution, larger is the value of ν(C–N). Cyclic voltammetric studies on the complexes showed the one electron reduction potentials to decrease in the following order: Ni(dtc)Cl(PPh3)>Ni(dtc)2> [Ni(dtc)(PPh3)2]+. The observations are explained with the nature of the substituents on the dtc moiety and other ligands present around Ni(II). Crystal structure of [Ni(dedtc) (PPh3)2]ClO4 (dedtc = diethyldithiocarbamate) was determined to study the effect of the introduction of PPh3 in place of Cl in the Ni(dtc)Cl(PPh3) complex. The complex is planar with NiS2P2 chromophore. The NiS distances are 2.190(2) and 2.239(2) Å and the NiP distances are 2.230(2) and 2.200(2) Å. The asymmetry in the NiS and NiP distances is ascribed to the steric effect due to bulky PPh3. The structural aspects are compared with those of the Ni(dtc)Cl(PPh3) complex. 相似文献
8.
The nickel(II) complexes of the compositions [Ni(hmidtc)(bpy)2]ClO4 (I), [Ni(hmidtc)(phen)2]ClO4 (II), [Ni(hmidtc)(phen)2]SCN (III), [Ni(hmidtc)(phen)2]PF6 (IV), [Ni(hmidtc)(phen)2]BPh4 (V), [Ni(hmidtc)(phen)2]AcO·2H2O (VI) and [Ni(hmidtc)(phen)2]Br·H2O (VII), involving a combination of one hexamethyleneimine-dithiocarbamate anion (hmidtc) and two bidentate N,N-donor ligands (2,2′-bipyridine (bpy) for I or 1,10-phenanthroline (phen) for II-VII), have been prepared. The compounds were characterized by elemental analysis, molar conductivity measurements, UV-Vis and IR spectroscopy, magnetochemical measurements and thermal analysis. A single-crystal X-ray analysis of the complex I revealed a distorted octahedral geometry with the nickel(II) ion coordinated by four nitrogen atoms (from two bidentate-coordinated bpy molecules) and two sulfur atoms (from one bidentate-coordinated hmidtc anion), together giving an NiN4S2 donor set. 相似文献
9.
One-pot metal promoted reactions between salicylaldehyde and 4-methyl-1,3-phenylenediamine in the presence of metal salts acting as template agents yield zinc(II) salicylaldimine complexes containing N,N′-bis(salicylidene)-4-methyl-1,3-phenylenediamine (H2L) as a result of the [2 + 1] Schiff base condensation. The complexes of formula [Zn(HL)Cl(H2O)2] · C2H5OH and [Zn(H2L)2Cl(NO3)(H2O)] · CH3OH were characterized as powder solids and in solution by spectroscopic methods (IR, 1H and 13C NMR, FAB-MS, ESI-MS, UV-Vis), thermogravimetric and elemental analysis, potentiometry, and tested for antimicrobial activity against Staphylococcusaureus in a minimum inhibitory concentration (MIC) experiment. In these two powder solid species, the salicylaldimine, formed in a self-assembly process, acts in two different coordination modes: as monodeprotonated bidentate chelator with an N,O donor set or as a neutral monodentate using exclusively oxygen as the donor atom without involving the nitrogen atoms in the coordination. However, crystals of these two complexes are isomorphous, with 1:2 metal:ligand stoichiometry, and display the latter, relatively rare coordination pattern. In solution, the presence of a 1:1 complex of monodeprotonated state is only detected. The complexes exhibit antimicrobial activity against S.aureus. 相似文献
10.
Reaction of nickel (II) perchlorate with the ligand N,N′-bis-(3,5-dipiperidin-1-yl-[2,4,6]triazin-1-yl)-pyridin-2-ylmethyl-ethane-1,2-diamine yields an octahedral Ni(II) high-spin complex 1 ([C40H56N14Ni(H2O)(CH3OH)](ClO4)2(CH3OH)2) with moderate zero-field splitting (ZFS) axial distortion parameter D/kB = 5.37 K. The ligand contributes a N4 donor set; the remaining two coordinating positions are occupied by coordinating solvents molecules. Exchange of the coordinating solvents molecules in complex 1 to thiocyanate moieties leads to formation of complex 2 ([C40H56N14Ni(NCS)2](CHCl)3) with an extended parameter D/kB = 8.80 K. The analysis of the structural and magnetic properties of complexes 1 and 2 led to the design of dinuclear complex 3 ([C40H56N14NiN3]2(ClO4)2(CH3OH)2), where two azido groups were utilized as bridging ligands. The double azido bridges in complex 3 cross each other to form a rarely observed non-coplanar (N3)2 structure. The magnetic behavior of complex 3 reveals ferromagnetic coupling interactions characterized by J/kB = 23.25 K, D1/kB = 7.90 K, D2/kB = 0.54 K. 相似文献
11.
Two Ni(II) complexes of the ligands N,N′-dipyridoxylethylenediimine (L1H2) and N,N′-dipyridoxyl-1,3-propanediimine (L2H2) were synthesized and their structures were determined by X-ray crystallography. The complexes are of formula Ni(L1). 3H2O (1·3H2O) and Ni(L2) (2). Both the complexes were found to be luminescent, but the quantum yields are significantly low compared to those of free ligands or their Zn(II) complexes. In 1·3H2O the metallo-organic fragment forms a staircase like network and three water molecules occupy the void space created by the staircase like network. The water molecules are strongly H-bonded between themselves forming a helical chain along ‘b’ axis. Complex 2, in spite of having same number of hydrogen bonding sites as that of 1, can not accommodate water clusters in their lattice. It is argued, that small steric factors, which may affect conformations of the hydrogen donor/acceptor sites, plays an important role in stabilization of water helices in lattices of metal complex. 相似文献
12.
Gerard C. Van Stein Gerard Van Koten Hans Passenier Olav Steinebach Kees Vrieze 《Inorganica chimica acta》1984,89(2):79-87
The reactions of the dianionic [(pyrrole-2-CHN)2R]2? ligands [(N′2N2)2?] (R = (R)(S)-1,2-cyclohexane or 1,2-ethane) with Zn(II) yield neutral dimeric [Zn2(N′2N2)2] complexes. The dimeric nature of the complexes was established by field-desorption mass spectrometry. 1H NMR studies show that these complexes have dimeric structures in solution in which the (N′2N2)2? ligands act as di-bidentates.The metal centres have tetrahedral geometries and bot have Δ or Λ configurations. The complex with the (R)(S)-1,2-cyclohexanediyl bridges has a rigid structure in solution. Neither intermolecular nor intramolecular exchange processes are observed The 1H NMR spectrum of the complex with the 1,2-ethanediyl bridging groups shows that at 213 K in CDCl3 a fast conformational movement is already taking place between two identical structures of the complex. It is not possible to determine whether in this complex intermolecular exchange processes are also taking place.The reactions of the anionic [pyrrole-2-CHNR′]? ligands [(N′N)?] (R′ = t-Bu, i-Pr, (S)-CHMePh or 2,6-xylyl) with Zn(II) yield the neutral Zn(N′N)2 complexes. These complexes were synthesized to study the coordination properties of the [pyrrole-2-CHNR′]? moieties with Zn(II). A 1H NMR study established that the zinc centres in the complexes containing the prochiral i-Pr or chiral (S)-CHMePh substituents have tetrahedral geometries with Δ or Λ configurations in CDCl3 at 213 K. These complexes undergo an intramolecular exchange process at higher temperatures (above 260 K when R′ = i-Pr) which involves inversion of the configuration of the zinc centre. A mechanism for this exchange process is proposed. 相似文献
13.
Miklós Czaun Simphiwe M. Nelana Ilia A. Guzei Mikael Håkansson George Lisensky Ebbe Nordlander 《Inorganica chimica acta》2010,363(12):3102-3112
The reactions of six diimine ligands with Cu(II) and Ni(II) halide salts have been investigated. The diimine ligands were Ph2CN(CH2)nNCPh2 (n = 2 (Bz2en, 1a), 3 (Bz2pn, 1b), 4 (Bz2bn, 1c)), N,N′-bis-(2-tert-butylthio-1-ylmethylenebenzene)-2,2′diamino-biphenyl (2), N,N′-bis-(2-chloro-1-ylmethylenebenzene)-1,3-diaminobenzene (3) and N,N′-bis-(2-chloro-1-ylmethylenebenzene)-1,2-ethanediamine (4). Reactions of 1a-c, 2-4 with CuCl2·2H2O in dry ethanol at ambient temperature led to complete or partial hydrolysis of the diimine ligands to ultimately form copper diamine complexes. The non-hydrolyzed complexes of 1b and 1c, [Cu(L)Cl2] (L = 1b, 1c), could be isolated when the reactions were carried out at low temperatures, and the half-hydrolyzed complex [Cu(Bzpn)Cl2] could also be identified via X-ray crystallography. Similarly, reactions of 1a or 1b with NiCl2·6H2O or [NiBr2(dme)] led to rapid hydrolysis of the imines and Ni complexes containing half-hydrolyzed 1a (Bzen; [trans-[Ni(Bzen)2Br2]) and 1b (Bzpn; [Ni(Bzpn)Br2] could be isolated and identified via single crystal X-ray analysis. Kinetic studies were made of the hydrolyses of 1a, 1b in THF and 2 in acetone, in the presence of Cu(II), and of 1a in acetonitrile, in the presence of Ni(II). Activation parameters were determined for the latter reaction and for the copper-catalyzed hydrolysis of 2; the relatively large negative activation entropies clearly indicate rate-determining steps of an associative nature. 相似文献
14.
Daniela Pucci Anna Bellusci Alessandra Crispini Mauro Ghedini Massimo La Deda 《Inorganica chimica acta》2004,357(2):495-504
Multifunctional Schiff base ligands Ln, namely the tetradentate N,N′-bis[2-hydroxy-5-(azopyridine)benzylidene]propylendiamine and the bidentate N-dodecyl-5-(azopyridine)salicylaldimine, both containing a flexible azo spacer, a metallation site and a terminal pyridine group, were synthetised and fully characterised. Mesogenic structures, analysed by polarised optical microscopy, DSC and powder X-ray diffraction, were obtained from self-assembly of the mono or bifunctional hydrogen-bond acceptors Ln with carboxylic acid donors. Ni(II) mono and bis-chelate, four- and six-coordinated, Ln derivatives were synthetised. The octahedral structure of the [Ni(py)2(L2)2] complex was confirmed by single crystal X-ray analysis. H-bonded self-assembly of Ni(II) complexes and carboxylic acids results in the formation of supramolecular networks whose structure and thermal stability were studied by DSC and powder X-ray diffraction analysis at variable temperatures. 相似文献
15.
16.
Wei Luo Xiang-Gao Meng Jiang-Feng Xiang Yun Duan Gong-Zhen Cheng Zhen-Ping Ji 《Inorganica chimica acta》2008,361(9-10):2667-2676
Four novel trinuclear copper(II)/nickel(II) complexes with four trianionic pentadentate ligands, N-(3-t-butylbenzoyl)-5-nitrosalicylhydrazide (H33-t-bbznshz), N-(3,5-dimethylbenzoyl)salicylhydrazide (H33,5-dmbzshz), N-(phenylacetyl)-5-bromosalicylhydrazide (H3pabshz) and N-(3-t-butylbenzoyl)salicylhydrazide (H33-t-bbzshz) have been synthesized and characterized by X-ray crystallography. These trinuclear compounds all have an M–N–N–M–N–N–M core formed by three metal ions and two ligands. The geometries of three Cu(II) ions in compound Cu3(3-t-bbznshz)2(H2O)(DMF)(py)2 · DMF (1) alternate between distorted square pyramidal and square planar, while in compound Cu3(3,5-dmbzshz)2(py)2 (2), they are all square planar. Three Ni(II) ions in compound Ni3(pabshz)2(DMF)2(py)2 (3) and Ni3(3-t-bbzshz)2(py)4 · 2H2O (4) follow square-planar/octahedral/square-planar coordination geometry. Compounds 1, 2 and 4 are bent trinuclear, with the bend angles of 156.4°, 141.49° and 127.1°, respectively, while the three nickel ions in compound 3 are strictly linear, with an angle of 180°. Studies on the trinuclear Ni(II) complexes show that the β-branched N-acylsalicylhydrazide ligands with sterically flexible Cα methylene groups are easier to yield linear trinuclear Ni(II) complexes, while α-branched N-acylsalicylhydrazides ligands tend to form bent trinuclear Ni(II) complexes. Antibacterial screening data indicate that the trinuclear Cu(II) compound 2 is more active than 1 and mononuclear Cu(II) compound, bent trinuclear Ni(II) compound 4 is more active than linear compound 3 and less active than tetranuclear nickel compound in the previous study. 相似文献
17.
《Inorganica chimica acta》1986,125(3):159-166
This paper describes the synthesis of compounds of Ni(II) with uracil, uridine and the nucleotides 5′UMP, 5′CMP, 5′GMP and 5′IMP, and their characterization, carried out by elemental analysis, by studying the infrared spectra, diffuse reflectance and conductivity measurement.In the complexes of NiURA (and NiURD) with acetate, direct coordination of the metal ion to the C4O group of the pyrimidine ring is inferred from the changes observed on the infrared spectrum of the corresponding bands at vCO. The variations in frequency of the vCOO symmetric and asymmetric bands of the acetate group together with the conductivity and reflectance results seem to indicate the dimer structure of the compounds.In the compounds of NiURA (and NiURD) with ethylenediamine indirect bonding of Ni(II)to the pyrimidine ring is inferred, probably established through hydrogen bonds involving the C4O groups in the base or nucleoside and the −NH2 groups in the ethylenediamine.In the complexes of Ni-nucleotide, bonding seems to occur through the heterocyclic ring (C4O for 5′UMP, N(3) for 5′CMP, N(7) for 5′GMP and 5′IMP) together with additional interactions through the phosphate group. 相似文献
18.
Three new chiral ligands bearing an O,O′,N donor set (OmethoxyOhydroxyNpyridine) were synthesised and coordinated to FeIII, FeII, NiII, CuII and ZnII to yield complexes with the general formula [M(OON)Clx]y. While the pyridine N and the hydroxy O atoms coordinate strongly to all applied metal ions, the methoxy donor seems not to be involved in coordination, although some evidence for a weak interaction between OMe and the ZnII were found in NMR spectra. In the bidentate O′,N coordination mode the new ligands exhibit several coordination geometries as analysed in the solid compounds by XRD, EXAFS and EPR and in solution by UV-Vis absorption, cyclic voltammetry, EXAFS, EPR or NMR spectroscopy. 相似文献
19.
Xanthates, like thiolates, form a variety of complexes with metals in which coordinating sulfur can serve as a hydrogen bond acceptor. Nickel tris xanthate complexes [Ni(xan)3]−, (xan = o-ethylxanthate, N-(carbamoylmethyl)ethylxanthate) have been synthesized and compared by a combination of X-ray crystallographic and spectroscopic measurements. Recent results from our studies of N-H?S hydrogen bonding interactions in metal-xanthate complexes shows N-S distances to be longer than those in related thiolate complexes, indicative of weaker hydrogen bonds for the xanthates. The complex (Et4N)[N-(carbamoylmethyl)ethylxanthate)] adopts an extended conformation in both the solid state and solution and lacks either intraligand or intermolecular N-H?S hydrogen bonds. The complex (CTA)[Ni(exa)3] exhibits N-H?S hydrogen bonds between the amide group of the counterion and the ligand sulfur. The amide-sulfur N-H?S distance is 3.567 Å. 相似文献
20.
Na3TMT · 9H2O (H3TMT=2,4,6-trimercaptotriazine) reacts with M(PPP)Cl2, PPP=PhP(CH2CH2PPh2)2, M=Ni, Pd, Pt, to give the compounds [M(PPP)(HTMT)]. The nickel and palladium complexes have been characterized by single-crystal X-ray diffraction analysis. PPP is tridentate in both complexes. The nickel complex has an irregular trigonal bipyramidal configuration in which the triazine is bidentate, coordinating through one sulfur and one nitrogen donor atom. The palladium complex has an approximately square planar geometry in which the triazine forms a strong Pd-S bond in the plane and also a very weak Pd-N interaction above the plane. The 31P NMR spectrum of the platinum complex is similar to that of the palladium complex, which is consistent with the Pt complex also having an approximately square-planar structure. Variable temperature NMR spectra show that two conformational isomers of the nickel complex are present in solution at low temperatures, though exchange is fast at room temperature. DFT calculations have confirmed the possible existence of two five-coordinate isomers of comparable stability. 相似文献