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1.
The reactions of Cu(ClO4)2·6H2O with 6-(benzylamino)purine derivatives in a stoichiometric 1:2 metal-to-ligand ratio led to the formation of penta-coordinated dinuclear complexes of the formula [Cu2(μ-L18)4(ClO4)2](ClO4)2·nsolv, where L1 = 6-(2-fluorobenzylamino)purine (complex 1), L2 = 6-(3-fluorobenzylamino)purine (2), L3 = 6-(4-fluorobenzylamino)purine (3), L4 = 6-(2-chlorobenzylamino)purine (4), L5 = 6-(3-chlorobenzylamino)purine (5), L6 = 6-(4-chlorobenzylamino)purine (6), L7 = 6-(3-methoxybenzylamino)purine (7) and L8 = 6-(4-methoxybenzylamino)purine (8); n = 0–4 and solv = H2O, EtOH or MeOH. All the complexes have been fully characterized by elemental analysis, FTIR, UV–Vis and EPR spectroscopy, and by magnetic and conductivity measurements. Variable temperature (80–300 K) magnetic susceptibility data of 18 showed the presence of a strong antiferromagnetic exchange interaction between two Cu(II) (S = 1/2) atoms with J ranging from −150.0(1) to −160.3(2) cm−1. The compound 6·4EtOH·H2O was structurally characterized by single crystal X-ray analysis. The Cu?Cu separation has been found to be 2.9092(8) Å. The antiradical activity of the prepared compounds was tested by in vitro SOD-mimic assay with IC50 in the range 8.67–41.45 μM. The results of an in vivo antidiabetic activity assay were inconclusive and the glycaemia in pre-treated animals did not differ significantly from the positive control.  相似文献   

2.
1-(Phenylselenomethyl)-1H-benzotriazole (L1) and 1-(4-methoxyphenyltelluromethyl)-1H-benzotriazole (L2) have been synthesized by reacting 1-(chloromethyl)-1H-benzotriazole with in situ generated nucleophiles PhSe and ArTe, respectively. The complexes of L1 and L2 with Pd(II) and Ru(II)(η6-p-cymene) have been synthesized. Proton, carbon-13, Se-77 and/or Te-125 NMR spectra authenticate both the ligands and their complexes. The single crystal structures of L1, L2 and [RuCl(η6-p-cymene)(L)][PF6] (L = L1: 3, L = L2: 4) have been solved. The Ru-Se and Ru-Te bond lengths have been found 2.4801(11) and 2.6183(10) Å, respectively. The palladium complexes, [PdCl2(L)] (L = L1: 1, L = L2: 2) have been explored for Heck and Suzuki-Miyaura C-C coupling reactions. The TON values are upto 95,000. The Ru-complexes have been found promising for catalytic oxidation of alcohols (TON ∼ 7.8-9.4 × 104). The complexes of telluroether ligands are as efficient catalysts as those of selenoether ones and in fact better for catalytic oxidation.  相似文献   

3.
Four azide bridged dinuclear copper(II) complexes, [Cu2(LX)2(N3)2](ClO4)2, with LX = substituted N,N-bis[(3,5-dimethylpyrazole-1-yl)-methyl]benzylamine, [X = H (1), OMe (2), Me (3) and Cl (4)] have been synthesized, out of which complexes 1 and 2 have been characterized structurally. In Complex 1 the two bridging azide ligands have connected the two metal centers in an end-on (EO) fashion with aSP (asymmetric Square Pyramidal) geometry and showed an weak antiferromagnetic interaction (J = −3.34 cm−1). On the contrary, in complex 2, the two metal centers have been connected in end-to-end (EE) fashion exhibiting moderately strong ferromagnetic interaction (J = +19.7 cm−1). Cyclic voltammetric studies performed on all the four complexes show a reasonably good correlations when E1/2 for CuIICuII → CuIICuIII and CuIICuIII → CuIIICuIII oxidations are plotted against σ (substituent constants) with ρ = −0.182 (R= 0.92) and −0.684 (R= 0.99) respectively.  相似文献   

4.
1,8-Naphthyridine (napy) and terpyridine-analogous (N,N,C) tridentate ligands coordinated ruthenium (II) complexes, [RuL(napy-κ2N,N′) (dmso)](PF6)2 (1: L=L1=N″-methyl-4′-methylthio-2,2′:6′,4″-terpyridinium, 2: L = L2 = N″-methyl-4′-methylthio-2,2′:6′,3″-terpyridinium) were prepared and their chemical and electrochemical properties were characterized. The structure of complex 1 was determined by X-ray crystallographic study, showing that it has a distorted octahedral coordination style. The cyclic voltammogram of 1 in DMF exhibited two reversible ligand-localized redox couples. On the other hand, the CV of 2 shows two irreversible cathodic peaks, due to the Ru-C bond of 2 containing the carbenic character. The IR spectra of 1 in CO2-saturated CH3CN showed the formation of Ru-(η1-CO2) and Ru-CO complexes under the controlled potential electrolysis of the solution at −1.44 V (vs. Fc/Fc+). The electrochemical reduction of CO2 catalyzed by 1 at −1.54 V (vs. Fc/Fc+) in DMF-0.1 M Me4NBF4 produced CO with a small amount of HCO2H.  相似文献   

5.
Eight new organoantimony(V) complexes with 1-phenyl-1H-tetrazole-5-thiol [L1H] and 2,5-dimercapto-4-phenyl-1,3,4-thiodiazole [L2H] of the type RnSbL5 − n (L = L1: n = 4, R = n-Bu 1, Ph 2, n = 3, R = Me 3, Ph 4; L = L2: n = 4, R = n-Bu 5, Ph 6, n = 3, R = Me 7, Ph 8) have been synthesized. All the complexes 1-8 have been characterized by elemental, FT-IR, 1H and 13C NMR analyses. Among them complexes 2, 6 and 8 have also been confirmed by X-ray crystallography. The structure analyses show that the antimony atoms in complexes 2 and 6 display a trigonal bipyramid geometry, while it displays a distorted capped trigonal prism in complex 8 with two intramolecular Sb?N weak interactions. Furthermore, the supramolecular structure of 2 has been found to consist of one-dimensional linear molecular chain built up by intermolecular C-H?N weak hydrogen bonds, while a macrocyclic dimer has been found in complex 6 linked by intermolecular C-H?S weak hydrogen bonds with head-to-tail arrangement. Interestingly, one-dimensional helical chain is recognized in complex 8, which is connected by intermolecular C-H?S weak hydrogen bonds.  相似文献   

6.
The synthesis of two oxoverdazyls based compounds, the 1,5-dimethyl-3-(2′-hydroxyphenyl)-6-oxoverdazyl 1 and the perchlorate salt of 1,5-dimethyl-3-(2′-imidazolium)-6-oxoverdazyl 2 are reported. The structural analysis of 1 reveals that radicals are closely packed in regular columns by way of π-stacking. In contrast, the packing in 2 is definitely influenced by the protonation state of the radical substituent and shows strong lateral staggering of the organic radicals. The organisation in the solid state strongly influences the intermolecular exchange interaction between π-stacked radicals which goes from J = −113 cm−1 (H = −J∑SiSi+1) in 1 to J = −1.0 cm−1 and J′ = −0.67 cm−1 in 2.  相似文献   

7.
Three new copper(II) complexes [CuL1]2(ClO4)2 (1), [CuL2]ClO4 (2) and [CuL3] (3) with three Schiff base ligands [HL1 = 1-phenyl-3-{3-[(pyridin-2-ylmethylene)-amino]-propylimino}-butan-1-one, HL2 = 1-phenyl-3-[3-(1-pyridin-2-yl-ethylideneamino)-propylimino]-butan-1-one and H2L3 = 3-[3-(1-methyl-3-oxo-3-phenyl-propylideneamino)-propylimino]-1-phenyl-butan-1-one] have been synthesized and structurally characterized by X-ray crystallography. The mono-negative tetradentate asymmetric Schiff base ligands (L1) and (L2) are chelated in complexes 1 and 2 to form square planar copper(II) complexes. In complex 1, the two units are associated weakly through ketonic oxygen of benzoylacetone fragment to form the dimeric entity. The square planar geometry of complex 3 is unusually distorted towards tetrahedral one. All three complexes exhibit reversible cyclic voltammetric responses in acetonitrile solution corresponding to the CuII/CuI redox process. The E1/2 (−0.47 V versus SCE) of 3 shows significant anodic shift due to the tetrahedral distortion around Cu(II) compare to that of 1 and 2 (−0.82 and −0.87 V versus SCE, respectively).  相似文献   

8.
Two series of complexes of the types trans-[CoIII(Mebpb)(amine)2]ClO4 {Mebpb2− = N,N-bis(pyridine-2-carboxamido)-4-methylbenzene dianion, and amine = pyrrolidine (prldn) (1a), piperidine (pprdn) (2a), morpholine (mrpln) (3a), benzylamine (bzlan) (4a)}, and trans-[CoIII(cbpb)(amine)2]X {cbpb2− = N,N-bis(pyridine-2-carboxamido)-4-chlorobenzene dianion, and amine = pyrrolidine (prldn), X = PF6 (1b), piperidine (pprdn), X = PF6 (2b), morpholine (mrpln), X = ClO4 (3b), benzylamine (bzlan), X = PF6 (4b)} have been synthesized and characterized by elemental analyses, IR, UV–Vis, and 1H NMR spectroscopy. The crystal structure of 1a has been determined by X-ray diffraction. The electrochemical behavior of these complexes, with the goal of evaluating the effect of axial ligation and equatorial substitution on the redox properties, is also reported. The reduction potential of CoIII, ranging from −0.53 V for (1a) to −0.31 V for (3a) and from −0.48 V for (1b) to −0.22 V for (3b) show a relatively good correlation with the σ-donor ability of the axial ligands. The methyl and chloro substituents of the equatorial ligand have a considerable effect on the redox potentials of the central cobalt ion and the ligand-centered redox processes.  相似文献   

9.
The synthesis of two mononuclear precursor copper complexes, [(HL2)2Cu], 1, and [(HL3)2Cu]·H2O, 2, and three dinuclear Cu–Ln complexes, [(HL1)2Cu(CH3CN)2Gd(NO3)3], 3, [(HL3)2CuGd(NO3)3]·2(H2O), 4, and [(HL3)2CuTb(NO3)3]·2(H2O), 5, based on the ligands H2L1 (4-bromo-2-[1-(5-bromo-2-hydroxy-3-methoxybenzyl)-1H-benzimidazol-2-yl]-6-methoxyphenol), H2L2 (2-(1H-benzimidazol-2-yl)-4-bromo-6-methoxyphenol) and H2L3 (2-(1H-benzimidazol-2-yl)-6-methoxyphenol) are described in this contribution. The X-ray crystal structures of H2L2, 1, 3, 4, and 5 have been solved. The novel ligand H2L2 crystallizes with two independent molecules in the asymmetric unit; several intermolecular hydrogen contacts connect alternate independent H2L2 molecules into chains developing along c. In complex 1, two (HL2) ligands chelate the copper ion through their imidazolyl nitrogen and phenoxo oxygen atoms, in a relative head to tail arrangement. The molecular structure of 3 is similar to those of the previously reported Cu–Ln complexes of H2L1. In the isostructural complexes 4 and 5, two HL3 ligands sandwich one Cu2+ ion through their N,O sites and one Ln3+ ion through their O2 site, implying a relative head to head arrangement, at variance with the relative head to tail arrangement of HL2 in the mononuclear copper precursor 1. The magnetic properties of 1, 3, 4, and 5 have been investigated. Extended intermolecular antiferromagnetic interactions operate in complex 1 ((JChain = −0.8(1) cm−1). Ferromagnetic interactions between Gd (S = 7/2) and Cu (S = 1/2) centers operate in complexes 3 and 4, leading to an S = 4 ground state (JCuGd = 7.2(2) cm−1 for 3 and JCuGd = 6.5(2) cm−1 for 4). Depopulation of the Tb Stark levels, preclude obtaining reliable information on the presence and sign of the Cu–Tb interaction in 5. These new complexes are complementary to those previously reported: the Cu–O2–Gd core is planar while deformations are borne by the ligands at variance with previous examples where the constraints were located at the Cu–O2–Gd core. The presence of two independent ligands in the Cu,Gd coordination spheres confers a degree of freedom greater than that allowed by a unique tetradentate ligand. As a result, the strength of the magnetic interaction is not solely related to the dihedral angle between the CuOO and GdOO planes in the central core.  相似文献   

10.
Four cyclometalated Pt(II) complexes, i.e., [(L2)PtCl] (1b), [(L3)PtCl] (1c), [(L2)PtCCC6H5] (2b) and [(L3)PtCCC6H5] (2c) (HL2 = 4-[p-(N-butyl-N-phenyl)anilino]-6-phenyl-2,2′-bipyridine and HL3 = 4-[p-(N,N′-dibutyl-N′-phenyl)phenylene-diamino]-phenyl-6-phenyl-2,2′-bipyridine), have been synthesized and verified by 1H NMR, 13C NMR and X-ray crystallography. Unlike previously reported complexes [(L1)PtCl] (1a) and [(L1)PtCCC6H5] (2a) (HL1 = 4,6-diphenyl-2,2′-bipyridine), intense and continuous absorption bands in the region of 300-500 nm with strong metal-to-ligand charge transfer (1MLCT) (dπ(Pt) → π(L)) transitions (ε ∼ 2 × 104 dm3 mol−1 cm−1) at 449-467 nm were observed in the UV-Vis absorption spectra of complexes 1b, 1c, 2b and 2c. Meanwhile, with the introduction of electron-donating arylamino groups in the ligands of 1a and 2a, complexes 1b and 2b display stronger phosphorescence in CH2Cl2 solutions at room temperature with bathochromically shifted emission maxima at 595 and 600 nm, relatively higher quantum yields of 0.11 and 0.26, and much longer lifetimes of 8.4 and 4.5 μs, respectively. An electrochromic film of 1b-based polymer was obtained on Pt or ITO electrode surface, which suggests an efficient oxidative polymerization behavior. An orange multilayer organic light-emitting diode with 1b as phosphorescent dopant was fabricated, achieving a maximum current efficiency of 11.3 cd A−1 and a maximum external efficiency of 5.7%. The luminescent properties of complexes 1c and 2c are dependent on pH value and solvent polarity, which is attributed to the protonation of arylamino units in the C^N^N cyclometalating ligands.  相似文献   

11.
A series of organotin(IV) complexes with O,O-diethyl phosphoric acid (L1H) and O,O-diisopropyl phosphoric acid (L2H) of the types: [R3Sn · L]n (L = L1, R = Ph 1, R = PhCH22, R = Me 3, R = Bu 4; L = L2, R = Ph 9, R = PhCH210, R = Me 11, R = Bu 12), [R2Cl Sn · L]n (L = L1, R = Me 5, R = Ph 6, R = PhCH27, R = Bu 8; L = L2, R = Me 13, R = Ph 14, R = PhCH215, R = Bu 16), have been synthesized. All complexes were characterized by elemental analysis, TGA, IR and NMR (1H, 13C, 31P and 119Sn) spectroscopy analysis. Among them, complexes 1, 2, 3, 5, 8, 9 and 11 have been characterized by X-ray crystallography diffraction analysis. In the crystalline state, the complexes adopt infinite 1D infinite chain structures which are generated by the bidentate bridging phosphonate ligands and the five-coordinated tin centers.  相似文献   

12.
The present work illustrates the versatile coordination modes of the amide-based ligands towards copper(II) ion. The reaction of the deprotonated form of the ligand, [L1]2− with CuCl2 affords a linear trinuclear complex, [Cu3(L1)2(Cl)2(H2O)] (1) which has been characterized thoroughly including single crystal structure analysis. The structure of 1 shows that one of the arm of the flexible ligand flips to coordinate second copper(II) centre, resulting in the formation of a trinuclear complex. On the other hand, ligand H2L2 in its deprotonated form reacts with Cu(II) ion to give complex 2 with general formula, [Cu(L2)]n (2). The crystal structure of the complex 2 shows that each copper is square-pyramidal with 5th coordination coming from the O-atom of the amide group from a neighbouring complex. This results in the generation of an one-dimensional zig-zag chain. The variable temperature magnetic measurements of the complexes, 1 and 2 show that while Cu ions in the former are antiferromagnetically coupled (J = −110.34 cm−1), a weak ferromagnetic interaction (J = +3.08 cm−1) exists in the later. A rationale, based on the orbital overlap from the copper ions and associated ligands, is provided for the observed magnetic coupling between the copper ions.  相似文献   

13.
HSCH2CONHCH3 and HSCH2CON(CH3)2 containing a peptide bond are prepared for the synthesis of DNICs with/without intra-molecular hydrogen bonding, respectively. The IR ν(NO) bands of [(NO)2Fe(SCH2CONHCH3)2] (2) appears at 1751, 1700 cm−1. In complex 2, the presence of intramolecular [NH?S] hydrogen bonding was verified by the observation of IR spectroscopy with N−H stretching frequency 3334 cm−1 (CDCl3) and subsequently confirmed by single-crystal X-ray diffraction showing N−S distance of 2.94 Å. Complex 2 displays the rhombic EPR spectrum with g1 = 2.039, g2 = 2.031 and g3 = 2.013 at in frozen H2O. Complexes 2 and 3 rapidly release NO when exposed to light. The time needed for photolysis reactions of 2 is two times faster than that of 3 in less polar solvent. Representative time courses for the photolability of 2 and 3 in THF display the NO-off ability: 2 > 3.  相似文献   

14.
The syntheses and structures of a series of metal complexes, namely Cu2Cl4(L1)(DMSO)2·2DMSO (L1 = N,N′-bis(2-pyridinyl)-1,4-benzenedicarboxamide), 1; {[Cu(L2)1.5(DMF)2][ClO4]2·3DMF} (L2 = N,N′-bis(3-pyridinyl)-1,4-benzenedicarboxamide), 2; {[Cd(NO3)2(L3)]·2DMF} (L3 = N,N′-bis-(2-pyrimidinyl)-1,4-benzenedicarboxamide), 3; {[HgBr2(L3)]·H2O}, 4, and {[Na(L3)2][Hg2X5]·2DMF} (X = Br, 5; I, 6) are reported. All the complexes have been characterized by elemental analysis, IR spectra and single crystal X-ray diffraction. Complex 1 is dinuclear and the molecules are interlinked through S?S interactions. In 2, the Cu(II) ions are linked through the L2 ligands to form 1-D ladder-like chains with 60-membered metallocycles, whereas complexes 3 and 4 form 1-D zigzag chains. In complexes 5 and 6, the Na(I) ions are linked by the L3 ligands to form 2-D layer structures in which the [Hg2X5] anions are in the cavities. The L2 ligand acts only as a bridging ligand, while L1 and L3 show both chelating and bridging bonding modes. The L1 ligand in 1 adopts a trans-anti conformation and the L2 ligand in 2 adopts both the cis-syn and trans-anti conformations, whereas the L3 ligands in 36 adopt the trans conformation.  相似文献   

15.
A new water-soluble metal-free phthalocyanine, 2,9,16,23-tetrakis(4-(1-naphthoxy-4-sulfonic acid sodium salt))phthalocyanine NhtH2Pc, where Nht indicates naphthoxy-4-sulfonic acid sodium salt, was synthesized and its aggregation, electrochemical and spectroelectrochemical properties were investigated in non-aqueous solutions. The aggregation study of NhtH2Pc showed that NhtH2Pc had both aggregated and non-aggregated mono phthalocyanine forms in the case of the 1:1 ratio of methanol and water, while it exhibited only the characteristic UV–Vis absorption of monomeric phthalocyanine in methanol and DMSO. NhtH2Pc displayed three reversible one-electron reductions waves, assigned to Pc3−/Pc2−, Pc4−/Pc3− and Pc5−/Pc4− couples, respectively. The electrochemical half-wave potentials of the reduction processes were located at E1/2 = −0.510, −0.924 and −1.24 V, respectively while the anodic potential of the oxidation process was displayed at E1/2 = 0.590 V versus pseudo Ag/AgCl. The half-wave potentials of the first and second reductions were positively shifted by 0.150 and 0.136 V compared with those of the unsubstituted metal-free phthalocyanine (H2Pc). These shift values are almost the same as those observed for [(SO3)4H2Pc]. The electrochemical studies showed that the electron-withdrawing sulfonated-naphthoxy groups on the macrocycle core made the reduction processes of NhtH2Pc easier in DMSO solution. The well-defined UV–Vis spectra of the electro-reduced species [NhtH2Pc] were obtained with an applied potential (Eapp = −0.70 V) in a thin-layer cell. The spectroelectrochemical results showed that the first reduction product exhibited characteristic spectral changes corresponding to mono-anionic species of metal-free phthalocyanines, having long-term stability during the reduction process.  相似文献   

16.
The reactions of organoantimony chlorides L1,2SbCl21 and 2 ([2,6-(ROCH2)2C6H3], R = Me; L1 and R = t-Bu; L2) with silver salts of selected carboxylic acids resulted to corresponding organoantimony carboxylates L1,2Sb(OOCR′)2, 1a-c (for L1) and 2a-c (for L2), where R′ = CH3 for 1a, 2a; R′ = CHCH2 for 1b, 2b and R′ = CF3 for 1c, 2c. All compounds were characterized by the help of elemental analysis, ESI-MS, 1H and 13C NMR spectroscopy. The solid state structure investigation using single crystal X-ray diffraction techniques (2a, c) and IR spectroscopy revealed significant differences in coordination mode of both O,C,O chelating ligand and carboxylic groups in this set of compounds. The structure of all compounds in solution of non-coordinating solvent (CDCl3) was determined by means of variable temperature 1H, 13C, 19F NMR spectroscopy and IR spectroscopy.  相似文献   

17.
Two neutral ligands, L1 · 2H2O and L2 · H2O, and seven complexes, [Cu(pmb)2(L1)] (1), [Cu(pmb)2(L2)] (2), [Cu(Ac)2(L2)] · 4H2O (3), [Cu(4-aba)2(L2)] (4), [Ag(4-ts)(L1)(H2O)] (5), [Ag2(epes)2(L1)] · 2H2O (6), [Ag(1,5-nds)0.5(L2)] · 0.5C2H5OH · H2O (7) [where L1 = 1,1′-(1,4-butanediyl)bis(2-methylbenzimidazole); L2 = 1,1′-(1,4-butanediyl)bis(2-ethylbenzimidazole), pmb = p-methoxybenzoate anion; Ac = acetate anion; 4-aba = 4-aminobenzoate anion; 4-ts = p-toluenesulfonate anion; epes = N-(2-hydroxyethyl)piperazine-N′-(2-ethanesulfonate) anion; 1,5-nds = 1,5-naphthalenedisulfonate anion], have been synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. The L1 and L2 ligands in compounds 17 act as bridging ligands, linking metal ions into chain structures. The chains in compounds 3, 4 and 6 interlace with each other by hydrogen bonds to generate 3D supramolecular structures. In compound 5, π–π interactions between adjacent L1 ligands hold the chains to a supramolecular layer. In compound 7, the sulfonate anions act as counterions in the framework. The thermal stabilities of 3, 6 and 7, and the luminescent properties for 57 in the solid states are also discussed.  相似文献   

18.
The mononuclear high-spin iron(III) complexes [Fe(3-MeOsalpn)Cl(H2O)] (1) and [Fe(3-MeOsalpn)(NCS)(H2O)]·0.5CH3CN (2) and the tetranuclear oxo-bridged compound [{Fe(3-MeOsalpn)Gd(NO3)3}2(μ-O)]·CH3CN (3) [3-MeOsalpn2− = N,N′-propylenebis(3-methoxysalicylideneiminate)] have been prepared and magneto-structurally characterised. The iron(III) ion in 1 and 2 is six-coordinated in a somewhat distorted octahedral surrounding with the two phenolate-oxygens and two imine-nitrogens from the Schiff-base building the equatorial plane and a water (1 and 2) and a chloro (1)/thiocyanate-nitrogen (2) in the axial positions. The neutral mononuclear units of 1 and 2 are assembled into centrosymmetric dinuclear motifs through hydrogen bonds between the axially coordinated water molecule of one iron centre and methoxy-oxygen atoms from the Schiff-base of the adjacent iron atom. The values of the intradimer metal-metal distance within the supramolecular dimers are 4.930 (1) and 4.878 Å (2). The tetranuclear of 3 can be described as two {FeIII(3-MeOsalpn)} units connected through an oxo-bridge, each one hosting a [GdIII(NO3)3] entity in the outer cavity defined by the two phenolate- and two methoxy-oxygen atoms. The values of the intramolecular Fe?Fe and Fe?Gd distances in 3 are 3.502 and 3.606 Å, respectively. The analysis of the magnetic data of 1-3 in the temperature range 1.9-300 K shows the occurrence of weak intermolecular antiferromagnetic interactions in 1 and 2 [J = −0.76 (1) and −0.75 cm−1 (2) with the Hamiltonian defined as H = −JSFe1·SFe1] whereas two intramolecular antiferromagnetic interactions coexist in 3, one very strong between the two iron(III) ions (J1) through the oxo bridge and the other much weaker between the iron(III) and the Gd(III) ions (J2) across the double phenoxo oxygens [J1 = −275 cm−1 and J2 = −3.25 cm−1, the Hamiltonian being defined as H=-J1SFe1·SFe1-J2(SFe1·SGd1+SFe1·SGd1)]. These values are analysed in the light of the structural data and compared with those of related systems.  相似文献   

19.
Two new manganese complexes, [Mn3(L1)4(NO3)2]n (1, HL1=nicotinate N-oxide acid) and [MnL2Cl]n (2, HL2=isonicotinate N-oxide acid)], have been hydrothermally synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction. In 1, the L1 ligands take two different coordinated modes bridging four and three MnII ions. The nitrate anions take chelating coordination modes, leading one type of the MnII ions as a 4-connected node. The whole net can be viewed as a 3, 4, 6-connected 4-nodal net with Schläfli notation {43}2{44; 62}4{46; 66; 83}. Complex 2 has a honeycomb layer mixed bridged by chlorine, N-oxide and carboxylate. The adjacent layers are linked by the phenyl ring of L2 ligand, giving a 3D framework with a {34; 54} {32;4;56;66} 4, 6-connect net. Magnetic studies indicate that 1 is an antiferromagnet with low-dimensional characteristic, in which a -J1J1J2- coupled alternating chain is predigested. Fitting the data of 1 gives the best parameters J1=−2.77, J2=−0.67 cm−1. The magnetic properties of complex 2 represent the character of the 2D honeycomb layer with the J1=−2.05 and J2=0.55 cm−1, which results in a whole antiferromagnetic state.  相似文献   

20.
Ruthenium complexes with bipyridine-analogous quaternized (N,C) bidentate ligands [RuL(bpy)2](PF6)2 (bpy = 2,2′-bipyridine, (1), L = L1 = N′-methyl-2,4′-bipyridinium; (2), L = L2 = N′-methyl-2,3′-bipyridinium) were synthesized and characterized. The structure of complex 2 was determined by the X-ray structure analysis. The 13C{1H} NMR spectroscopic and cyclic voltammetric studies indicate that the coordination modes of these ligands are quite different, that is, the C-coordinated rings of (N,C)-ligands in 1 and 2 are linked to ruthenium(II) with a pyridinium manner and a pyridinylidene one, respectively. The ligand-localized redox potentials of 1 and 2 also revealed the substantial difference in the electron donating ability of both ligands.  相似文献   

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