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1.
Self-assembly of flexible 1,3-bis(1,2,4-triazol-1-yl)propane (btp), inorganic Cu(II) salt and rigid benzene-based carboxylate coligand generates four complexes, {[Cu(btp)2(CH3OH)(H2O)]·H2O·2ClO4}n (1), {[Cu(btp)(Hbtc)2]·0.5H2O}n (2), [Cu(btp)2(H3btea)2]n (3), and [Cu(btp)(nb)2] (4) (H3btc = 1,3,5-benzenetricarboxylic acid, H4btea = 1,2,4,5-benzenetetracarboxylic acid, Hnb = p-nitrobenzoic acid), which are fully structural characterized by single-crystal X-ray crystallography, elemental analysis, IR, and TG-DTA techniques. Structural determinations reveal that the polymeric two-dimensional (2D) Cu-btp grid-like layer for 1, 1D linear single- and double-stranded chains for 2 and 3, as well as the discrete binuclear structure for 4, are jointly directed by the coordination polyhedrons of the Cu(II) ion and the exo-bidentate bridging btp core ligand with various conformations. The theoretical calculations suggest that the trans-trans btp is the most stable conformation, and the metal binding site is collectively determined by the electron density of N donors and the spatial orientation of the btp ligand. Unexpectedly, the polycarboxylate anions in 1-4 can only act as terminal coligands not popular bridging connectors. The thermal stability of the resulting complexes is also compared.  相似文献   

2.
Three complexes of the composition {[Cu(μ1,5-dca)2(mppca)2] · H2O}n (1), [Cu(μ1,5-dca)2(nppca)2]n (2) and [Cu(μ-Cl)2(mppca)2]n (3) (dca = dicyanamide, ; mppca = N-(4′-methylphenyl)-4-pyridinecarboxamide; nppca = N-(4′-nitrophenyl)-4-pyridinecarboxamide) have been synthesized and characterized by single crystal X-ray crystallography and magnetic susceptibility studies. Different supramolecular structures of the complexes have been constructed by different non-covalent motifs in the crystalline solids. In complex 1, adjacent copper(II) atoms are connected by double μ1,5-dca(end-to-end) bridges to form a chain-like structure. The chains are linked by π-π interactions and hydrogen bonds between the ligands and water molecules to form a 3D network. In complex 2, copper(II) atom has a coordination environment similar to 1, but water molecules have not been found. Weak C-H?N hydrogen bonding and π-π interaction yield a 3D supramolecular network which is different from that of complex 1. Complex 3 is a 1D polymeric chain in which Cu(II) ions are bridged by Cl, and only CH/π interactions had been found. Magnetic measurements revealed antiferromagnetic properties of 1, 3 and ferromagnetic behavior of 2.  相似文献   

3.
Three new ion-pair complexes, [4RBzDMAP]2[Cu(mnt)2] (mnt2− = maleonitriledithiolate; [4RBzDMAP]+ = 1-(4′-R-benzyl)-4-dimethylaminopyridinium, R = F(1), Cl(2) and Br(3)) were synthesized and characterized by elemental analyses, IR, UV, single crystal X-ray diffraction and magnetic measurements. The [Cu(mnt)2]2− anions and the cations stack alternately and form a 1D column via C-H···S, C-H···π or C-H···Cu interactions for 1 and 2. While the cations stack into a column though π···π or C-H···π interactions between pyridine and phenyl rings for 1 and 3. The change of the molecular topology of the counteraction when the 4-substituted group in the benzyl ring have been changed from F or Cl to Br atom, results in the difference in the crystal system, space group and the stacking mode of the cations and anions of 1, 2 and 3. Some weak hydrogen bonds between the adjacent columns further generate a 3D network structure. It is interesting that 1 and 2 exhibits antiferromagnetic coupling with θ = −2.372 K and θ = −14.732 K, while 3 shows weak ferromagnetic coupling feature with θ = 0.381 K.  相似文献   

4.
A 2D grid-like copper(II) complex [Cu(N3)2(pyz)](pyz = pyrazine) (1) has been synthesized and characterized by single crystal X-ray analysis and magnetic measurements. The 2D grid-like network of 1 consists of 1D chain of Cu-pyz units connected by end-on azido bridge. 1 crystallizes in the monoclinic space group C2 with a = 15.148(6) Å, b = 6.877(2) Å, c = 3.4591(12) Å and Z = 2. The magnetic investigation showed the presence of an antiferromagnetic interaction between the copper(II) ions mainly mediated through pyrazine bridge.  相似文献   

5.
Room temperature reaction of Cu(NO3)2 · 6H2O and pyrazine-2,3,5,6-tetracarboxylic acid (ptecH4) in the presence of pyridine (py) in water-methanol (1:1) mixture results in the formation of {[Cu2(ptec) · (py)2 · (H2O)3] · 4H2O}n (1). With pyridine-2,4,6-tricarboxylic acid (pytcH3) and Cu(NO3)2 · 6H2O, crystals of {[Cu(pytc)] · 1/2[Cu(H2O)6] · H2O}n (2) could be obtained hydrothermally at 180 °C. The structure of 1 consists of 2D polymeric sheets. These sheets are stacked on top of one another due to strong C-H?π interactions forming an overall 3D structure. The structure of 2, on the other hand, consists of twin-chain coordination polymers. The void spaces between two polymeric chains are occupied by [Cu(H2O)6]2+ ions which are H-bonded to the polymeric chains. The variable temperature magnetic measurements for 1 and 2 show weak antiferromagnetic interaction between Cu(II) centers. The EPR spectra of the compounds are consistent with their structures.  相似文献   

6.
Two tetranuclear copper(II) complexes with long rigid Schiff-base ligands [Cu4(bmsbd)2]·2DMF [H2bmsbd = N,N′-bis-(3-methoxy-salicylidene)benzene-1,4-diamine] (1) and [Cu4(besbd)2]·DMF·5H2O [H2besbd = N,N′-bis-(3-methoxy-salicylidene)benzene-1,4-diamine] (2) have been synthesised and characterized. Single X-ray diffraction analysis reveals that both complexes exhibit interesting [2 × 2] molecular grid-like configuration assembled by four organic ligands in a head-to-tail mode to bind four copper(II) ions. Magnetic property investigations reveal weak antiferromagnetic interaction viaσ-bond pathway of long rigid Schiff-base ligand between the neighboring copper(II) ions in both complexes.  相似文献   

7.
The synthesis, crystal structure and magnetic properties of manganese(III) binuclear complexes [MnIII2(L-3Н)2(CH3ОH)4]·2CH3ОH (1) and [MnIII2(L-3Н)2(Py)4]·2Py (2) (L = 3-[(1E)-N-hydroxyethanimidoyl]-4-methyl-1H-pyrazole-5-carboxylic acid) are reported. The ligand contains two distinct donor compartments formed by the pyrazolate-N and the oxime or the carboxylic groups. The complexes were characterized by X-ray single crystal diffraction, revealing that both 1 and 2 consist of dinuclear units in which the two metal ions are linked by double pyrazolate bridges with a planar {Mn2N4} core. Cryomagnetic measurements show antiferromagnetic interaction with g = 1.99, J = −3.6 cm−1, Θ = −2.02 K for 1 and g = 2.00, J = −3.7 cm−1, Θ = 1.43 K for 2.  相似文献   

8.
Four novel nicotinato-copper(II) complexes containing polybenzimidazole and polyamine ligands were synthesized with formula [Cu2(bbma)2(nic)2](ClO4)2·CH3OH·0.5H2O (1), [Cu2(dien)2(nic)2](ClO4)2·2CH3OH (2), [Cu(ntb)(nic)]ClO4·H2O (3) and [Cu(tren)(nic)]BPh4·CH3OH·H2O (4), in which bbma is bis(benzimidazol-2-yl-methyl)amine, dien is diethylenetriamine, ntb is tris(2-benzimidazolylmethyl)amine, tren is tris(2-aminoethyl)amine and nic is nicotinate anion. All of the complexes were characterized by elemental analysis, IR and X-ray diffraction analysis. Complexes 1 and 2 contain centrosymmetric dinuclear entity with the two Cu(II) atoms bridged by two nicotinate anions in an anti-parallel mode. The Cu···Cu separation is 7.109 Å for 1 and 6.979 Å for 2. Complexes 3 and 4 are mononuclear with nicotinate coordinated to Cu(II) ion by the carboxylate O atom in 3 and the pyridine N atom in 4. All of the complexes exhibit abundant hydrogen bonds to form 1D chain for 1, 3, 4 and 2D network for 2. Magnetic susceptibility measurements over the 2-300 K range reveal very weak ferromagnetic interaction between the two Cu(II) ions in 1 and antiferromagnetic interaction in 2 mediated by nicotinate ligand, with J value to be 0.15 and −0.19 cm−1, respectively.  相似文献   

9.
Two new binuclear radical complexes derived from a new long nitronyl nitroxide ligand, 2-[4-(5-pyrimidyl)phenyl]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (4-NITPhPyrim), and M(hfac)2 (M2+ = Cu2+, Mn2+; hfac = hexafluoroacetylacetonato), [Cu(hfac)2(4-NITPhPyrim)]2 · 4H2O (1) and [Mn(hfac)2(4-NITPhPyrim)]2 · 4H2O (2), were synthesized as well as characterized structurally and magnetically. X-ray analysis indicates that 1 and 2 are rectangle-like centrosymmetric dimer M2L2 complexes. Magnetic measurements indicate that there are two types of magnetic exchanges in 1: the ferromagnetic (FM) exchange between the Cu(II) ion and the directly bonded nitroxide unit (J1 = 24.20 cm−1) and the weak FM exchange of Cu-NIT through the pyrimidine and phenyl rings (J2 = 0.62 cm−1). Besides the strong antiferromagnetic (AFM) coupling between the Mn(II) ion and the directly bonded nitroxide unit (J = −87.61 cm−1), there is a weak FM interaction between the two Mn-NIT pairs (θ = 0.39 K) in 2.  相似文献   

10.
A novel copper(II)-radical complex [Cu(NITmPy)(PDA)(H2O)] · (H2O) (1) (NITmPy = 2-(3′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, H2PDA = 2,6-pyridinedicarboxylic acid) has been synthesized and structurally characterized by X-ray diffraction methods. It crystallizes in the triclinic space group . The Cu(II) ion exists in a distorted square pyramid environment. The molecules of [Cu(NITmPy)(PDA)(H2O)] · (H2O) are connected as a two-dimensional structure by the intermolecular hydrogen bonds. Magnetic measurements show intramolecular ferromagnetic interactions between NITmPy and Cu(II) ion and intermolecular antiferromagnetic interactions in 1.  相似文献   

11.
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   

12.
The template reaction between salicylaldehyde S-methyl-isothiosemicarbazone and 2-formylpyridine in presence of nickel(II) or copper(II) salts yields two new coordination compounds with general formula [NiL1]2(1) and [CuL2]2(2) (L1 = the dianionic (N1-salicylidene)(N4-(hydroxy(pyridin-2-yl)methyl) S-methyl-isothiosemicarbazide) ligand and L2 = the doubly deprotonated (N1-salicylidene)(N4-(picolinoyl) S-methyl-isothiosemicarbazide) ligand). In the complex 1, the formed L1 ligand appears as result of an addition reaction of the precursors, while for 2 a redox mechanism is implicated in the formation of L2. Despite the fact that the initial organic precursors are the same, the resulting ligands obtained in the template reaction are different. In 1, the Ni(II) metal ion adopts a square-planar geometry and the [NiL1] units are forming dimerized chains through weak Ni···Ni interactions (3.336 and 3.632 Å). In 2, the Cu(II) metal ions adopt a square-pyramidal geometry and form dinuclear species through weak Cu···O (phenoxo) interactions. The magnetic susceptibility measurements of the complexes reveal the diamagnetic nature of 1 as expected for a square planar Ni(II) complex and a paramagnetic behavior for 2 with weak intra-dimer antiferromagnetic interaction (J/kB = −2.1(1) K).  相似文献   

13.
Two new Co(II) coordination polymers with mixed ligands, {[Co(BTA)0.5(DBI)2]·DBI·H2O}n (1) and [Co(PDA)(DBI)(H2O)]n (2) (H4BTA = benzene-1,2,4,5-tetracarboxylic acid; H2PDA = 2,2′-(1,2-phenylene)diacetic acid; DBI = 5,6-dimethyl-1H-benzoimidazole) have been synthesized under hydrothermal conditions, respectively. Both of them are characterized by elemental analyses, powder X-ray diffraction, thermogravimetric analysis, single-crystal X-ray diffraction, and magnetic susceptibilities. In 1, the Co(II) ions are four-coordinated and lie in distorted tetrahedron coordination environment. 1D ladder-like chain structure is formed by the bridging BTA4− ligand. In 2, the Co(II) ions are in slightly distorted octahedral coordination geometry, and linked by PDA2− ligand exhibiting a 2D layer structure. Temperature-dependent magnetic susceptibility measurements of 1 and 2 revealed that there are antiferromagnetic interactions between Co(II) ions.  相似文献   

14.
A new perylene-pendent tridentate ligand, N-(3-perylenylmethyl)-N,N-bis(2-pyridylmethyl)amine (perbpa) 1 and its Cu(II) complex, [Cu(perbpa)Cl2] (2) were prepared and structurally characterized by the X-ray diffraction method. In the packing structure of ligand 1, perylene groups were aggregated to form a π-π stacked layer of dimerized pelylene moieties similar to the packing of pristine perylene. This result suggests both that the π-π interactions among the perylene moieties predominate for the arrangement of perbpa molecules in the crystal and that this ligand is a good candidate for constructing electron conducting path. A complex 2 was prepared from the ligand 1 and a copper(II) chloride dehydrate. Complex 2 had a mononuclear and 5-coordinate distorted square pyramidal structure with a perbpa and two coordinated chloride ions. The chemical oxidation of 2 by iodine resulted in the unprecedented binuclear Cu(II) species, [Cu2(μ-Cl)2(perbpa)2](I3)2, 3·(I3)2. An X-ray crystal structure analysis of 3·(I3)2 revealed the binuclear structure bridged by the chloride ions. A temperature dependent magnetic susceptibility measurement of 3 showed a weak ferromagnetic exchange interaction with S = 1 ground state, g = 2.12 and J = +1.17 cm−1, based on H = −2JS1 · S2. The UV-Vis absorption and the EPR spectra of 3 showed that the perylene groups are not oxidized. These results indicate a couple of Cu(II) constructed S = 1 ground state with intermolecular ferromagnetic interaction. The electrochemical study suggested that the crystallization of 3·(I3)2 was initiated by the oxidation of the N,N-bis-(2-pyridylmethyl)amino (bpa) groups of 2 by I2.  相似文献   

15.
A novel series of copper(II) complexes of formula [Cu(tren)(mpda)](ClO4)2 · 1/2H2O (1), [Cu2(tren)2(mpda)](ClO4)4 · 2H2O (2), and [Cu2(tren)2(ppda)](ClO4)4 · 2H2O (3) containing the tetradentate tris(2-aminoethyl)amine (tren) terminal ligand and the potentially bridging 1,n-phenylenediamine [n = 3 (mpda) and 4 (ppda)] ligand have been prepared and spectroscopically characterized. X-ray diffraction on single crystals of 1 and 3 show the presence of mono- (1) and dinuclear (3) copper(II) units where the mpda (1) and ppda (3) ligands adopt terminal monodentate (1) and bridging bis(monodentate) (3) coordination modes toward [Cu(tren)]2+ cations with an overall non-planar, orthogonal disposition of the phenylene group and the N-Cu-N threefold axis of the trigonal bipyramid of each copper(II) ion [values of the Cu-N-C-C torsion angle (?) in the range of 50.8(3)-79.2(2) (1) and 80.9(2)-86.5(2)° (3)]. Variable-temperature magnetic susceptibility measurements on the dinuclear complexes 2 and 3 show the occurrence of moderate ferromagnetic (J = +8.3 cm−1, 2) and strong antiferromagnetic (J = −51.4 cm−1, 3) couplings between the two copper(II) ions across the meta- and para-phenylenediamine bridges, leading to S = 1 (2) and S = 0 (3) ground spin states [H = −JS1 · S2 with S1 = S2 = SCu = 1/2]. Density functional theory (DFT) calculations on the triplet (2) and broken-symmetry (BS) singlet (3) ground spin states, support the occurrence of a spin polarization mechanism for the propagation of the exchange interaction through the predominantly π-type orbital pathway of the 1,n-phenylenediamine bridge. Finally, a new magneto-structural correlation between the magnitude of the magnetic coupling (J) and the Cu-N-C-C torsion angle (?) has been found which reveals the role of σ- versus π-type orbital pathways in the modulation of the magnetic coupling for m- and p-phenylenediamine-bridged dicopper(II) complexes.  相似文献   

16.
A three dimensional supramolecular network, {[Co(bpee)(H2O)4] · (tp) · 2(H2O)}n (1) [bpee = trans-1,2 bis(4-pyridyl)ethylene; tp = terephthalate dianion] has been synthesized and characterized by X-ray single crystal structure, magnetic measurement and thermal analysis. The structure determination reveals that the cobalt(II) ions, bridged by bpee and coordinated by four water molecules, give rise to covalently linked 1D polymeric chain. The parallel chains get involved in H-bonding with tp resulting in a 3D architecture. Upon heating 1, which is pink in color, transforms to [Co(bpee)(tp)] (1a, blue). The deaquated species (1a) reverts on keeping in humid atmosphere. Low temperature magnetic data indicate weak antiferromagnetic coupling.  相似文献   

17.
Tetranuclear Cu(II) complexes of N-(2-hydroxymethylphenyl)salicylideneimine (H2L1-H) and its homologues (5-CH3: H2L1-Me, 5-Cl: H2L1-Cl), [Cu(L1-H)]4 · 3H2O (1), [Cu(L1-Me)]4 · 2CH2Cl2 (2), and [Cu(L1-Cl)]4 · 2CH2Cl2 (3), have been characterized by X-ray crystal structure analyses and magnetic measurements. The structure analyses revealed that the complexes 1-3 have a defective double-cubane tetra copper(II) core connected by μ3-alkoxo bridges. The intramolecular Cu?Cu distances are in the range from 5.251(2)-5.256(3) Å for the longest to 3.0518(9)-3.092(2) Å for the shortest. Each Cu(II) ion has a square-pyramidal geometry and the dihedral angles between adjacent Cu(II) basal planes are almost right angles. Magnetic measurements of the present complexes indicate that weak antiferromagnetic interactions (J=−15 to −19 cm−1) between neighboring copper(II) ions are dominant in these tetracopper cores.  相似文献   

18.
Preparations, XPS and electronic spectroscopy, and magnetism of seven new one-dimensional cyano-bridged coordination polymers, chiral [Cu(RR-chxn)2][Pd(CN)4] · 2H2O (1), [Cu(trans-chxn)2][M(CN)4] · 2H2O (2, 4, and 6 for M = Pd, Ni, and Pt), and [Cu(cis-chxn)2][M(CN)4] · 2H2O (3, 5, and 7 for M = Pd, Ni, and Pt) (RR-chxn = cyclohexane-(1R,2R)-diamine, trans-chxn = racemic trans-cyclohexane-(1,2)-diamine, and cis-chxn = racemic cis-cyclohexane-(1,2)-diamine) have been reported in view of tuning of their electronic properties by stereochemistry of chxn ligands and metal-substitution. Comparison of Cu 2p1/2 and 2p3/2 peaks of XPS and broad d-d bands around 18 000 cm−1 of electronic spectra are described systematically for 1-7. Variable-temperature magnetic measurement shows that complexes 1-7 indicate weak antiferromagnetic interactions via cyano-bridges. Because of semi-coordination coupled with pseudo Jahn-Teller elongation and electrostatic interaction for 1, the axial Cu-N coordination bond distances of 2.330(7) and 3.092(8) Å are considerably longer than those of equatorial ones in the range from 2.016(6) to 2.030(6) Å. The former bond distances of 1 are intermediate values among the related Ni (2.324(6) and 3.120(8) Å) and Pt (2.34(1) and 3.09(1) Å) complexes.  相似文献   

19.
By pH-value adjustment, the reactions of zinc salt, 1,3,5-benzenetricarboxylic acid (H3btc) and 4,4′-bipyridine (bpy) yield three coordination polymers, formulated as [Zn3(btc)2(bpy)(H2O)2]n (1), [Zn(Hbtc)(bpy)(H2O)]n · 3nH2O (2) and [Zn(Hbtc)(bpy)(H2O)]n · 4nH2O (3), respectively. The structure of 1 is a 3D network containing channels filled with bpy ligands. Compound 2 consists of twofold interpenetrating (10,3)-b networks, while compound 3 is a 2D layer structure. The fluorescent studies reveal that they exhibit intense violet luminescence in solid state.  相似文献   

20.
A new one-dimensional (1D) copper(II) complex, [Cu2(dpk · CH2O)(N3)3]n (dpk · CH2OH = unimethylated diol of di-2-pyridyl ketone) (1), has been synthesized and characterized. X-ray crystal structure study reveals that 1 is composed of 1D copper(II) chain with alternating double EO-azido bridges and mixed EO-azido/alkoxo double bridges. The magnetic determination indicates that ferromagnetic interaction dominates in this new 1D S = 1/2 system.  相似文献   

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