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1.
《Journal of Coordination Chemistry》2012,65(7):543-551
The oxalato-bridged dinickel(II) complex with the title ligand, [Ni2(L a H)2(μ-ox)](ClO4)2·2H2O (1), was prepared and its structure was determined by X-ray crystallography, as well as that of the monomeric nickel(II) complex, [Ni(L a H)ox]ClO4·3H2O (2). In Complexes 1 and 2, the ligand, L a , is folded along the N(4)–Ni(1)–N(11) axis. The antiferromagnetic coupling between the two nickel(II) centers in 1 was revealed and the coupling constant, J?=??17.4?cm?1, and g?=?2.11 were estimated. It was found that the oxalato-bridged dimer 1 was readily converted to the mononuclear cis-nickel(II) complex [NiL a (OH2)](ClO4)2 (3a), in basic aqueous solution. In [NiL a (CH3CN)]I2 (3b), which was derived from 3a, the aminomethyl pendant arm is coordinated to the Ni(II) ion and L a is folded along the N(1)–Ni(1)–N(8) axis. 相似文献
2.
Reaction of nickel(II) thiocyanate and pyridazine (pdz) as organic spacer ligand leads to the formation of the ligand‐rich 1:2 (1:2 = metal to ligand ratio) trinuclear nickel(II) complex of composition [Ni3(NCS)6(pdz)6]. Depending on the reaction solvent, different polymorphic modifications are obtained: Reaction in acetonitrile leads to the formation of the new modification 1I and reaction in ethanol leads to the formation of modification 1II reported recently. In their crystal structures discrete [Ni3(NCS)6(pdz)6] units are found, in which each of the Ni2+ cations exhibits a NiN6 distorted octahedral arrangement. The central Ni2+ cation is coordinated by four bridging pdz ligands and two thiocyanato anions in trans positions. Both thiocyanato anions exhibit the end‐on bridging mode. The peripheral Ni2+ cations are bridged by one thiocyanato anion and by two pdz ligands with the central Ni2+ cation. Further they are coordinated by two terminal N‐bonded thiocyanato anions and one terminal N‐bonded pdz ligand. The structure of 1I was determined by X‐ray single crystal structure investigation and emphasized by infrared spectroscopy. Magnetic measurements revealed a quasi Curie behavior with net ferromagnetic interactions for 1I and net antiferromagnetic interactions for 1II . Solvent‐mediated conversion experiments clearly show that modification 1I represents the thermodynamic most stable form at room temperature and that modification 1II is metastable. On thermal decomposition, both modification transform quantitatively in a new ligand‐deficient intermediate. Elemental analysis revealed a 3:4 compound of composition [Ni3(NCS)6(pdz)4]. A structure model supported by IR spectroscopic investigations was assumed, in which three coordination modes of the thiocyanato anion exist, resulting in a 2D polymeric network. 相似文献
3.
Wang Li Cai Jiwen Mao Zon-Wang Feng Xiao-Long Huang Jin-Wang 《Transition Metal Chemistry》2004,29(4):411-418
Four novel dinickel complexes, coordinated by mixed ligands of tren and racemic amino acids, namely [Ni2(tren)2(dl-alaninato)(H2O)]I3·2H2O (1), [Ni2(tren)2(dl-leucinato)(H2O)]I3·2.5H2O (2), [Ni2(tren)2(dl-phenylalaninato)(H2O)]I3·H2O (3), and {[Ni2(tren)2(dl-histinato)](ClO4)3·1.5H2O}
n
(4), have been synthesized and structurally characterized by X-ray crystallography, FTIR, u.v. and e.s. spectra. They represent the first series of dinickel(II) complexes bridged by the unusual (N,O,O)-coordinated -amino acids. In complexes (1–3), one of the nickel(II) centers is coordinated by four N-atoms of the tren ligand, one O-atom of the carboxylate group of the amino acidato ligand and one H2O molecule. The other nickel(II) center is also coordinated by the four N-atoms of the tren ligand, one carboxylic O-atom and the amino N-atom of the amino acidato ligand, resulting in an asymmetric dinuclear core with chromophores of NiN4O2 and NiN5O. In the polymeric {[Ni2(tren)2(dl-histinato)](ClO4)3·1.5H2O}
n
(4), the imidazole N-atom is also involved in ligation with nickel(II) and both nickel(II) centers have the same chromophore described as NiN5O. The Ni...Ni distances are in the 5.5199(10)–5.5807(15)Å range. Analyses of the magnetic properties of complexes (1), (3) and (4) show that a weak ferromagnetic interaction exists between the two nickel(II) centers. 相似文献
4.
Hana Bashir Shawish Mohammadjavad Paydar Chung Yeng Looi Yi Li Wong Elaheh Movahed Siti Nadiah Abdul Halim Won Fen Wong Mohd-Rais Mustafa Mohd Jamil Maah 《Transition Metal Chemistry》2014,39(1):81-94
Nickel(II) complexes with 2,3-dihydroxybenzaldehyde N4-substituted thiosemicarbazone ligands (H3L1–H3L4) have been synthesized and characterized with the aim of evaluating the effect of N4 substitution in the thiosemicarbazone moiety on their coordination behavior and biological activities. Two series of nickel(II) complexes with the general formulae [Ni(H3L)(H2L)]ClO4 and [Ni2(HL)2] were characterized by analytical and spectral techniques. The molecular structure of one of the complexes, namely, [Ni(H3L4)(H2L4)]ClO4 was established by single crystal X-ray diffraction studies. The crystal structure of this complex revealed that two H3L4 ligands are coordinated to nickel(II) in different modes; one as a neutral tridentate ONS ligand and the other is as a monoanionic tridentate (ONS?) ligand. The antimicrobial activities of the compounds were tested against 25 bacterial strains via the disc diffusion method, and their minimum inhibitory concentration (MIC) and minimum microbicidal concentration were evaluated using microdilution methods. With a few exceptions, most of the compounds exhibited low-to-moderate inhibitory activities against the tested bacterial strains. However, the complexes [Ni2(HL3)2] (7) and [Ni2(HL4)2] (8) indicated higher inhibitory activity against Salmonella enterica ATCC 9068 (MIC values 15.7 and <15.7 μg/ml, respectively), compared with gentamicin as the positive control (MIC 25 μg/ml). Complex (7) also inhibited Streptococcus pneumoniae more efficiently (MIC 31.2 μg/ml), compared with gentamicin (MIC > 50 μg/ml). The toxicities of the compounds were tested on brine shrimp (Artemia salina), where no meaningful toxicity level was noted for both the free ligands and the complexes. The cytotoxicities of the compounds on cell viability were determined on MCF7, PC3, A375, and H413 cancer cells in terms of IC50; complexes [Ni(H3L3)(H2L3)]ClO4 (3), [Ni2(HL3)2] (7) and [Ni2(HL4)2] (8) exhibited significant cytotoxicity on the tested cell lines. 相似文献
5.
Henrike Gehring Ramona Metzinger Christian Herwig Julia Intemann Prof. Dr. Sjoerd Harder Prof. Dr. Christian Limberg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(5):1629-1636
After the lithiation of PYR‐H2 (PYR2?=[{NC(Me)C(H)C(Me)NC6H3(iPr)2}2(C5H3N)]2?), which is the precursor of an expanded β‐diketiminato ligand system with two binding pockets, its reaction with [NiBr2(dme)] led to a dinuclear nickel(II)–bromide complex, [(PYR)Ni(μ‐Br)NiBr] ( 1 ). The bridging bromide ligand could be selectively exchanged for a thiolate ligand to yield [(PYR)Ni(μ‐SEt)NiBr] ( 3 ). In an attempt to introduce hydride ligands, both compounds were treated with KHBEt3. This treatment afforded [(PYR)Ni(μ‐H)Ni] ( 2 ), which is a mixed valent NiI? μ‐H? NiII complex, and [(PYR‐H)Ni(μ‐SEt)Ni] ( 4 ), in which two tricoordinated NiI moieties are strongly antiferromagnetically coupled. Compound 4 is the product of an initial salt metathesis, followed by an intramolecular redox process that separates the original hydride ligand into two electrons, which reduce the metal centres, and a proton, which is trapped by one of the binding pockets, thereby converting it into an olefin ligand on one of the NiI centres. The addition of a mild acid to complex 4 leads to the elimination of H2 and the formation of a NiIINiII compound, [(PYR)Ni(μ‐SEt)NiOTf] ( 5 ), so that the original NiII(μ‐SEt)NiIIX core of compound 3 is restored. All of these compounds were fully characterized, including by X‐ray diffraction, and their molecular structures, as well as their formation processes, are discussed. 相似文献
6.
Sonia B. Jimnez-Pulido Ftima M. Linares-Ordez Miguel N. Moreno-Carretero 《Polyhedron》2009,28(13):2641-2648
The XRD structure and the influence of the conformation in the molecular orbitals of the pteridine-benzoylhydrazone ligand (BZLMH = benzoylhydrazone of 6-acetyl-1,3,7-trimethyllumazine, lumazine = (1H,3H)-pteridin-2,4-dione) have been studied. Complexes of BZLMH with nickel(II), zinc(II) and mercury(II) have been prepared and spectroscopically characterized by IR, NMR and fluorescence spectroscopy; also XRD studies have allowed to establish two different coordinative patterns in the complexes [Ni3(BZLMH)3(OH)(H2O)(CH3CN)2](ClO4)5 · 2H2O · CH3CN (2) and [Zn(NO3)(BZLMH)(H2O)](NO3) (3). Compound (2) is a trinuclear hydroxo-centered complex with a central hydroxo group bridging the three nickel(II) ions. The [Ni3(μ3-OH)]5+ core is planar with the benzoylhydrazone ligands coordinated in the bis-bidentate [O(4),N(5)]-[N(61),O(63)] mode. The zinc(II) compound displays a BPT coordination geometry in which the BZLMH ligand acts in a tridentate fashion using N(5), N(61) and O(63) donor atoms. Fluorescence spectroscopic properties of benzoylhydrazone (BZLMH) are studied and the fluorescence band shift and changes in intensity is modulated by complexation with different metal ions (Ni2+, Zn2+ and Hg2+), so the binding is signaled such a possible cause. 相似文献
7.
Michael Böhme Adrian E. Ion Benjamin Kintzel Axel Buchholz Helmar Görls Winfried Plass 《无机化学与普通化学杂志》2020,646(13):999-1009
The pentanuclear nickel(II) complex [Ni5(saltagBr)2(tptz)4] ( Ni5 ) with the tritopic triaminoguanidine-derived Schiff-base ligand H5saltagBr (1,2,3-tris[(5-bromosalicylidene)amino]guanidine) and tptz (2,4,6-tris(2-pyridyl)-1,3,5-triazine) as capping ligands is reported. Ni5 crystallizes in the triclinic space group P1 with the central nickel(II) ion linking two triangular arrangements of nickel(II) ions supported by two tritopic triaminoguanidine ligands. The octahedral coordination of the four peripheral nickel(II) ions is complemented by capping tridentate tptz ligands. By variation of the synthesis also the corresponding trinuclear nickel(II) complex [Ni3(saltagBr)(tptz)3]NO3 ( Ni3 ) is accessible. Magnetic measurements for Ni3 and Ni5 reveal a singlet ground state with antiferromagnetic coupling between the nickel(II) ions, which in the case of Ni5 can only be simulated assuming a two-J exchange coupled spin topology. For both complexes significant zero-field splitting for the nickel(II) ions is evident from the measured magnetic data, which can be verified by theoretical studies revealing a magnetic anisotropy with strong rhombic distortion due to the presence of the tptz co-ligands in both compounds. 相似文献
8.
Jun Zhou Jie Yang Li Qi Xuan Shen Dunru Zhu Yan Xu You Song 《Transition Metal Chemistry》2007,32(6):711-715
A novel dinuclear nickel(II) complex, [Ni2(MOBPT)2Cl2(H2O)2]Cl2 · 7H2O (MOBPT = 4-(p-methoxyphenyl) −3,5-bis(pyridine-2-yl)-1,2,4-triazole), has been synthesized and characterized by elemental analysis, IR and single crystal X-ray
diffraction methods. The crystal structure determination shows that the dinuclear Ni2N8 unit is almost planer in which each NiII ion is coordinated by four nitrogen atoms from MOBPT equatorially and a water molecule and a chloride ion axially in a distorted
octahedral geometry. Magnetic measurements reveal a relatively weak antiferromagnetic exchange in the complex. 相似文献
9.
Iaki Muga Pablo Vitoria Antonio Luque Juan M. Gutirrez‐Zorrilla Carmen Guzmn‐Miralles Pascual Romn 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):m81-m83
The title compound, [Ni2(C2O4)(C4H13N3)2(H2O)2](PF6)2·‐2H2O, contains a dinuclear oxalato‐bridged nickel(II) complex cation. The structure determination reveals the presence of a centrosymmetric binuclear complex where the oxalate ligand is coordinated in a bis‐bidentate mode to the Ni atoms. The distorted octahedral environment of each Ni atom is completed by the three N atoms of the diethylenetriamine ligand in a fac arrangement and by one O atom from a water molecule. PF6? acts as counter‐anion. A two‐dimensional network of hydrogen bonds links the cations and anions and stabilizes the structure. 相似文献
10.
Xiao‐Hua Chen Qiong‐Jie Wu Zhi‐Yu Liang Chun‐Rong Zhan Jian‐Bin Liu 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(5):m190-m194
In the complex (morpholine)[2‐hydroxy‐N′‐(5‐nitro‐2‐oxidobenzylidene)benzohydrazidato]nickel(II), [Ni(C14H9N3O5)(C4H9NO)], (I), the NiII center is in a square‐planar N2O2 coordination geometry. The complex bis[μ‐2‐hydroxy‐N′‐(2‐oxidobenzylidene)benzohydrazidato]bis[(morpholine)zinc(II)], [Zn2(C14H10N2O3)2(C4H9NO)2], (II), consists of a neutral centrosymmetric dimer with a coplanar Zn2(μ2‐O)2 core. The two ZnII centers are bridged by phenolate O atoms. Each ZnII center exhibits a distorted square‐pyramidal stereochemistry, in which the four in‐plane donors come from the O,N,O′‐tridentate 2‐hydroxy‐N′‐(2‐oxidobenzylidene)benzohydrazidate(2−) ligand and a symmetry‐related phenolate O atom, and the axial position is coordinated to the N atom from the morpholine molecule. There are intramolecular phenol–hydrazide O—H...N hydrogen bonds present in both (I) and (II). In (I), square‐planar nickel complexes are linked by intermolecular morpholine–morpholine N—H...O hydrogen bonds, leading to a one‐dimensional chain, while in (II) an infinite two‐dimensional network is formed via intermolecular hydrogen bonds between the coordinated morpholine NH groups and the uncoordinated phenolate O atoms. 相似文献
11.
A new ligand incorporating a dioxime moiety, (2E,3E)-3-[(2-{[(1E,2E)-2-(hydroxyimino)-1-methylpropylidene]amino}phenyl)imino]butan-2-one oxime, (H2Phmdo) (3) has been prepared by reacting 2,3-butanedionemono-{O-[4-(1-methyl-2-oxo-propylideneaminooxy)-2,3-bis-(1-methyl-2-oxo-propylideneaminooxy-methyl)-but-2-enyl]-oxime} (2) with 1,2-phenylenediamine. Mono-, di- and trinuclear copper(II) and/or nickel(II) complexes of H2Phmdo were characterized by elemental analyses, magnetic moments, 1H-n.m.r. and 13C-n.m.r., i.r. and mass spectral studies. The mononuclear copper(II) and nickel(II) complexes of H2Phmdo were found to have a 1:1 metal:ligand ratio. Elemental analyses, stoichiometric and spectroscopic data of the metal
complexes indicated that the metal ions are coordinated to the oxime and imine nitrogen atoms (C=N). In the dinuclear complexes,
in which the first Cu(II) or Ni(II) ion was complexed with nitrogen atoms of the oxime and imine groups, the second Cu(II) ion is ligated with dianionic oxygen atoms of the oxime groups and are linked to the 1,10-phenanthroline nitrogen atoms.
The data support the proposed structure of H2Phmdo and its complexes. 相似文献
12.
Cengiz Arici Filiz Ercan Raif Kurtaran Orhan Atakol 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(7):812-814
In the title compounds, {2,2′‐[2,2‐dimethyl‐1,3‐propanediylbis(nitrilomethylidyne)]diphenolato‐κ4N,N′,O,O′}nickel(II), [Ni(C19H20N2O2)], and {2,2′‐[2,2‐dimethyl‐1,3‐propanediylbis(nitrilomethylidyne)]diphenolato‐κ4N,N′,O,O′}copper(II), [Cu(C19H20N2O2)], the NiII and CuII atoms are coordinated by two iminic N and two phenolic O atoms of the N,N′‐bis(salicylidene)‐2,2‐dimethyl‐1,3‐propanediaminate (SALPD2?, C17H16N2O22?) ligand. The geometry of the coordination sphere is planar in the case of the NiII complex and distorted towards tetrahedral for the CuII complex. Both complexes have a cis configuration imposed by the chelate ligand. The dihedral angles between the N/Ni/O and N/Cu/O coordination planes are 17.20 (6) and 35.13 (7)°, respectively. 相似文献
13.
Michael Böhme Dirk Schuch Axel Buchholz Helmar Görls Winfried Plass 《无机化学与普通化学杂志》2020,646(3):166-174
The trinuclear nickel(II) complex [Ni3(saltagtBu)(bpy)3(H2O)3]Cl (H5saltagtBu = 1,2,3-tris[(5-tert-butylsalicylidene)amino]guanidine) was synthesized and characterized by experimental as well as theoretical methods. The complex salt crystallizes with three molecules of dimethylformamide (dmf) and water as [Ni3(saltagtBu)(bpy)3(H2O)3]Cl · 3dmf · 3H2O ( 1 ) in the trigonal space group P3 , with the complex located on a threefold rotation axis, which is consistent with the molecular C3 symmetry of the complex cation. Magnetic measurements reveal an antiferromagnetic coupling (J = –35.9 cm–1) between the nickel(II) ions leading to a diamagnetic ground state for the trinuclear complex cation. Theoretical investigations based on broken-symmetry DFT confirm the antiferromagnetic exchange within the complex cation of 1 . Additional single-ion CASSCF ab initio studies reveal that magnetic anisotropy is present in the system. The experimental and theoretical results for 1 are compared with those of a structurally similar nickel(II) complex that is based on the bromo-substituted derivative of the triaminoguanidine ligand. The differences in their magnetic properties can be attributed to the stronger elongation of the pseudo-octahedral coordination sphere at the nickel(II) centers in case of 1 . The analysis of the magnetic properties of 1 clearly shows that for such exchange coupled systems reliable parameters for the magnetic anisotropy cannot be extracted from experimental data alone. 相似文献
14.
Montserrat Alfonso Antonia Neels Helen Stoeckli-Evans 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(10):1144-1146
The new nickel(II) coordination polymer poly[diaquanickel(II)-μ-(pyrazine-2,3,5,6-tetracarboxylato)-tetraaquanickel(II)], {[{Ni(C8N2O8)(H2O)2}Ni(H2O)4]}n, has been synthesized and characterized both spectroscopically and crystallographically, by X-ray powder diffraction analysis. In this two-dimensional coordination polymer, NiII ions are bridged by pyrazine-2,3,5,6-tetracarboxylic acid, coordinating in a bis-bidentate manner, so forming one-dimensional polymeric chains. The chains are linked by a second NiII ion, via an O atom of the coordinated carboxylate group, resulting in the formation of a two-dimensional layer-like polymer. The remaining coordination sites of the two independent octahedral NiII ions are occupied by water molecules. The layers are connected via hydrogen bonds involving all six coordinated water molecules. 相似文献
15.
Zi‐Lu Chen Yu‐Zhen Zhang Fu‐Pei Liang 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(2):m48-m50
The title nickel(II) coordination polymer, viz. poly[[bis(1,10‐phenanthroline)tris(μ3‐1,4‐phenylenediacetato)trinickel(II)] dihydrate], {[Ni3(C10H8O4)3(C12H8N2)2]·2H2O}n, consists of linear trinuclear building blocks with two crystallographically unique Ni atoms. One NiII atom and the geometric centre of one 1,4‐phenylenediacetate ligand in the trinuclear unit both lie on inversion centres, while the other unique NiII atom lies near the inversion centre, together with another 1,4‐phenylenediacetate ligand. Each pair of adjacent trinuclear units is bridged by 1,4‐phenylenediacetate ligands, forming two kinds of infinite chains along the a and b axes, respectively. These two kinds of chains crosslink to yield a two‐dimensional network in the ab plane. The two‐dimensional sheets further stack along the c axis viaπ–π stacking interactions and hydrogen bonds, forming a three‐dimensional supramolecular structure. 相似文献
16.
《Acta Crystallographica. Section C, Structural Chemistry》2017,73(11):880-884
Macrocyclic ligand systems with a variety of (different) donor sites oftentimes give rise to very exciting and unexpected multinuclear metal complexes. We report herein the structure of a trinuclear mixed imidazolylidene/imidazolium nickel N‐heterocyclic carbene (NHC) complex, namely di‐μ‐chlorido‐bis{μ‐calix[2]imidazolium[2]imidazolylidene[2]pyrazolate}trinickel(II) tetrakis(hexafluoridophosphate) acetonitrile tetrasolvate, [Ni3(C24H24N12)2Cl2](PF6)4·4CH3CN or [Ni3(L Me)2Cl2](PF6)4·4CH3CN, that can be understood as a trapped reaction intermediate during the synthesis of the respective [Ni2L Me](PF6)2 product. The structure not only contains protonated next to deprotonated imidazole heterocycles, but also Ni2+ ions with fundamentally different coordination modes within one molecule. Two of the three metal atoms are coordinated in a square‐pyramidal fashion by half a ligand molecule and one chloride ligand, whereas the third Ni2+ ion is bound octahedrally by four pyrazolate moieties and two chloride anions. 相似文献
17.
The reaction of nickel(II)chloride with γ-mercapto-propylamine in ethanolic solution gives the complex [Ni3(MPA)4]Cl2(MPA=NH2-(CH2)3-S). The complexes [Ni3(MPA)4]X2(X=Br, I, ClO4) can be synthesized from the chloride complex by addition of the sodium salt in aqueous solution. The crystal structure consists of discrete divalent trinuclear cations and chloride anions. Each sulphur atom of the ligand acts as a bridge between two nickel atoms, and the nitrogen atoms complete the coordination around the terminal nickel atoms. The geometry around the metal atoms is square-planar. The electronic and IR spectra of the complexes [Ni3(MPA)4]X2(X=Br, I, ClO4) indicate that all these compounds are composed of the [Ni3(MPA)4]2+ and X? ions. 相似文献
18.
Anja Burkhardt Dr. Eike T. Spielberg Sascha Simon Helmar Görls Dr. Axel Buchholz Dr. Winfried Plass Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(5):1261-1271
The reaction of benzyl 2-amino-4,6-O-benzylidene-2-deoxy-α-D -glucopyranoside (HL) with the metal salts Cu(ClO4)2 ⋅ 6 H2O and Ni(NO3)2 ⋅ 6 H2O affords via self-assembly a tetranuclear μ4-hydroxido bridged copper(II) complex [(μ4-OH)Cu4(L)4(MeOH)3(H2O)](ClO4)3 ( 1 ) and a trinuclear alcoholate bridged nickel(II) complex [Ni3(L)5(HL)]NO3 ( 2 ), respectively. Both complexes crystallize in the acentric space group P21. The X-ray crystal structure reveals the rare (μ4-OH)Cu4O4 core for complex 1 which is μ2-alcoholate bridged. The copper(II) ions possess a distorted square-pyramidal geometry with an [NO4] donor set. The core is stabilized by hydrogen bonding between the coordinating amino group of the glucose backbone and the benzylidene protected oxygen atom O4 of a neighboring {Cu(L)} fragment as hydrogen-bond acceptor. For complex 2 an [N4O2] donor set is observed at the nickel(II) ions with a distorted octahedral geometry. The trinuclear isosceles Ni3 core is bridged by μ3-alcoholate O3 oxygen atoms of two glucose ligands. The two short edges are capped by μ2-alcoholate O3 oxygen atoms of the two ligands coordinated at the nickel(II) ion at the vertex of these two edges. Along the elongated edge of the triangle a strong hydrogen bond (244 pm) between the O3 oxygen atoms of ligands coordinating at the two relevant nickel(II) ions is observed. The coordinating amino groups of the these two glucose ligands are involved in additional hydrogen bonds with O4 oxygen atoms of adjacent ligands further stabilizing the trinuclear core. The carbohydrate backbones in all cases adopt the stable 4C1 chair conformation and exhibit the rare chitosan-like trans-2,3-chelation. Temperature dependent magnetic measurements indicate an overall antiferromagnetic behavior for complex 1 with J1=−260 and J2=−205 cm−1 (g=2.122). Compound 2 is the first ferromagnetically coupled trinuclear nickel(II) complex with JA=16.4 and JB=11.0 cm−1 (g1,2=2.183, g3=2.247). For the high-spin nickel(II) centers a zero-field splitting of D1,2=3.7 cm−1 and D3=1.8 cm−1 is observed. The S=3 ground state of complex 2 is consistent with magnetization measurements at low temperatures. 相似文献
19.
《Journal of Coordination Chemistry》2012,65(11):961-966
A new dinuclear nickel(II) compound, [Ni2(TPA)2(μ-C2O4)](H2O)0.75(ClO4)2 [TPA = tris(2-pyridylmethyl) amine], was synthesized and characterized by electronic spectroscopy and X-ray methods. In the complex, the oxalate ion acts as a bis-bidentate ligand and the two Ni(II) ions are six coordinated with a distorted octahedral structure. The complex crystallizes in the triclinic space group Pi , with a = 13.203(4), b = 16.574(5), c = 21.802(6) Å, α = 78.644(5), β = 80.299(5), γ = 72.446(5)°, V = 4429 Å3, Z = 2; R 1 = 0.0615, wR 2 = 0.1639. In the temperature range 4-300 K, magnetic measurements show that the exchange interaction between the two metal ions is antiferromagnetic with J = ? 18.74 cm?1, g = 2.10. 相似文献
20.
Alfonso Castieiras Ricardo Domínguez Lourdes Gmez‐Rodríguez Joaquín Borrs 《无机化学与普通化学杂志》2003,629(6):1096-1103
A copper(II) and two nickel(II) dinuclear oxalato‐bridged compounds of formulae [{Cu(bpdto)}2(μ‐ox)](ClO4)2 ( 1 ), [{Ni(bpdto)]2(μ‐ox)](ClO4)2( 2 ), and [{Ni(bpdto)}2(μ‐ox)](NO3)2·2H2O ( 3 ), where bpdto = 1, 8‐bis(2‐pyridyl)‐3, 6‐dithiaoctane and ox = oxalate = C2O42— anion, have been synthesized and characterized. The crystal structure of 3 was determined by single‐crystal X‐ray analysis. It is a dinuclear complex with i symmetry in which the oxalate ligand is coordinated in bis(didentate) fashion to the inversion centre‐related nickel atoms. The distorted octahedral environment of each nickel atom is completed by two sulphur atoms in the equatorial plane and by two pyridyl nitrogen atoms in axial positions. Magnetic susceptibility measurements over the range 5 — 299K, show antiferromagnetic interactions that are weak in 1 (J = —12.8 cm—1) and strong in 2 and 3 (J = —37.8 and —40.9 cm—1, respectively), which in the case of 3 is in keeping with the observed structural parameters. 相似文献