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1.
Summary Halogenation of Ln III, Ce IV and ZrO II -diketone/-ketoester derivatives and their mixed ligand complexes of the types Ln(AA) 2(Sal) and Ln(AA)(Sal) 2 by NCS, NBS and PyHBr 3 yield different isomeric products depending on the nature of the solvent medium, the reagent and the reaction time. The halogenation, if carried out in glacial acetic acid, irrespective of the reagent, yields the stable S-hall, product wherein the three chelate rings remain imperturbed in respect of metal coordination. When the reaction is carried out in 5% v/v DMF-CHCl 3 employing N-halosuccinimide and maintaining correct reaction times, it is possible to isolate individually three other isomeric products. The isomers prepared are Ln(OO) 3, Ln(OO) 2(OX), Ln(OO)(OX) 2 and Ln(OX) 3 where (OO) represents diketone oxygen linkage and (OX) represents diketone oxygen and substituted halogen linkage to the central metal ion. The four linkage isomers have been identified by a comparison of the number of observed 3H n.m.r. or 13C n.m.r. signals with those expected for a given isomer on the basis of symmetry considerations in the tris-chelated octahedral structures. 相似文献
2.
The use of the [Fe III(AA)(CN) 4] ? complex anion as metalloligand towards the preformed [Cu II(valpn)Ln III] 3+ or [Ni II(valpn)Ln III] 3+ heterometallic complex cations (AA=2,2′‐bipyridine (bipy) and 1,10‐phenathroline (phen); H 2valpn=1,3‐propanediyl‐bis(2‐iminomethylene‐6‐methoxyphenol)) allowed the preparation of two families of heterotrimetallic complexes: three isostructural 1D coordination polymers of general formula {[Cu II(valpn)Ln III(H 2O) 3(μ‐NC) 2Fe III(phen)(CN) 2 {(μ‐NC)Fe III(phen)(CN) 3}]NO 3 ? 7 H 2O} n (Ln=Gd ( 1 ), Tb ( 2 ), and Dy ( 3 )) and the trinuclear complex [Cu II(valpn)La III(OH 2) 3(O 2NO)(μ‐NC)Fe III(phen)(CN) 3] ? NO 3 ? H 2O ? CH 3CN ( 4 ) were obtained with the [Cu II(valpn)Ln III] 3+ assembling unit, whereas three isostructural heterotrimetallic 2D networks, {[Ni II(valpn)Ln III(ONO 2) 2(H 2O)(μ‐NC) 3Fe III(bipy)(CN)] ? 2 H 2O ? 2 CH 3CN} n (Ln=Gd ( 5 ), Tb ( 6 ), and Dy ( 7 )) resulted with the related [Ni II(valpn)Ln III] 3+ precursor. The crystal structure of compound 4 consists of discrete heterotrimetallic complex cations, [Cu II(valpn)La III(OH 2) 3(O 2NO)(μ‐NC)Fe III(phen)(CN) 3] +, nitrate counterions, and non‐coordinate water and acetonitrile molecules. The heteroleptic {Fe III(bipy)(CN) 4} moiety in 5 – 7 acts as a tris‐monodentate ligand towards three {Ni II(valpn)Ln III} binuclear nodes leading to heterotrimetallic 2D networks. The ferromagnetic interaction through the diphenoxo bridge in the Cu II?Ln III ( 1 – 3 ) and Ni II?Ln III ( 5 – 7 ) units, as well as through the single cyanide bridge between the Fe III and either Ni II ( 5 – 7 ) or Cu II ( 4 ) account for the overall ferromagnetic behavior observed in 1 – 7 . DFT‐type calculations were performed to substantiate the magnetic interactions in 1 , 4 , and 5 . Interestingly, compound 6 exhibits slow relaxation of the magnetization with maxima of the out‐of‐phase ac signals below 4.0 K in the lack of a dc field, the values of the pre‐exponential factor ( τo) and energy barrier ( Ea) through the Arrhenius equation being 2.0×10 ?12 s and 29.1 cm ?1, respectively. In the case of 7 , the ferromagnetic interactions through the double phenoxo (Ni II–Dy III) and single cyanide (Fe III–Ni II) pathways are masked by the depopulation of the Stark levels of the Dy III ion, this feature most likely accounting for the continuous decrease of χM T upon cooling observed for this last compound. 相似文献
3.
Abstract α-Hydroxyiminophosphonic acid derivatives are widely known not only as intermediates in the synthesis of the important aminophosphonic acids, 1,2 but also as phosphorylating agents, 3 potential metalloenzyme inhibitors, 4 and as compounds having fungicidal activity. 5 In this work the scope of these compounds has been extended considerably by the synthesis of a number of novel dialkyl derivatives. Novel lanthanide (La III, Pr III, Nd III, Gd III and Dy III) and transition metal (Co II and Ni III) complexes of dialkyl α-hydroxyiminophosphonates (RO) 2P(O)C(R')N(OH) where R = Et. Pr i and R′ = Me, Et have been prepared and the NMR shift properties of the Pr III complex (R = Et; R′ = Et) indicate the potential of these compounds as NMR shift reagents for the analysis of geometric isomers. 6,7 X-ray crystal structure analysis of [Ni(L 1) 2C1 2] (L 1: R = Et; R′ = Et) shows a distorted cis octahedral coordination at the nickel atom giving two symmetry related diethyl-(E)-α-hydroxyiminopropanephosphonate ligands and two chlorine donors, and those of [Pr(L 2) 3Cl 3] and [Nd(L 2) 2(NO 3) 3(H 2O)] (L 2: R = Pr i; R′ = Et) show nine-coordination geometries with asymmetric bidentate and monodentate L 2 bonding respectively. Thus the metal complexes show unusual coordination ambivalence, changing from symmetrically bidentate to asymmetrically bidentate and then to monodentate bonding modes, to accommodate the different steric requirements of the coordinating anions in facilitating neutral complex formation. 相似文献
4.
The exchange coupling constants ( J) were calculated and the spin density distributions were analyzed in the B3LYP/TZV approximation for the complex anions [L 2M(1) IIILM(2) IIL 2]
n−, where L is ligand (L is oxalate, oxamide, dithiooxamide, hydroxamate) and M(1) and M(2) are atoms of the tri- and divalent
3d-transition metals, respectively, and n- is the charge of the anion. The largest J values were found for the complexes formed by the Cr III-Ni II and Cr III-Co II pairs with the dithiooxamide ligands. Differences between the calculated and experimental J values are at most a few cm −1. 相似文献
5.
The interaction of BSA and Fe III complexes ([Fe III(gly)(H 2O) 4] 2+, [Fe III(ida)(H 2O) 3] +, and [Fe III(nta)(H 2O) 2], gly—glyane, ida—iminodiacetic acid, nta—triglycolamic acid) as well as the sonocatalytic damage to BSA was studied by UV-vis
and fluorescence spectra. In addition, the influences of ultrasonic irradiation time and Fe III complex concentration were also examined on the sonocatalytic damage to BSA. The results showed that the fluorescence quenching
of BSA solution caused by the Fe III complexes belonged to the static quenching process. The BSA and Fe III complexes interacted with each other mainly through weak interaction and coordinate actions. The binding association constants
( K) and binding site numbers ( n) were calculated. The results were as follows: K
1 = 0.5353 × 10 4 l mol −1 and n
1 = 0.9812 for [Fe III(gly)(H 2O) 4] 2+, K
2 = 1.4285 × 10 4 l mol −1 and n
2 = 1.0899 for [Fe III(ida)(H 2O) 3, and K
3 = 0.4411 × 10 4 l mol −1 and n
3 = 0.9471 for [Fe III(nta)(H 2O) 2]. Otherwise, under ultrasonic irradiation the BSA were obviously damaged by the Fe III complexes. The damage degree rose up with the increase of ultrasonic irradiation time and Fe III complex concentration. And that, [Fe III(nta)(H 2O) 2] exhibited in a way higher sonocatalytic activity than [Fe III(gly)(H 2O) 4] 2+ and [Fe III(ida)(H 2O) 3] +. 相似文献
6.
The possible isomers of [ Mg( NH3) n = 1 − 10] + clusters have been investigated using both M06-2X/6-31++G(d,p) and MP2/6-31++G(d,p) levels of theory. The isomeric distribution for each n size has been studied as a function of temperatures ranging from 25 to 400 K. To the best of our knowledge, for clusters size n > 6, this is the first theoretical study available in the literature. From the calculated values in the considered clusters and using a fitting procedure, we have evaluated the binding energies (−14.0 kcal/mol), clustering energies (−10.1 kcal/mol), clustering free energies (−2.8 kcal/mol), and clustering enthalpies (−10.3 kcal/mol). On the basis of our structural and infrared (IR) spectroscopy outcomes, we find that the first solvation shell can hold up to six ammonia molecules. © 2019 Wiley Periodicals, Inc. 相似文献
7.
Cyanide‐bridged metal complexes of [Fe 8M 6(μ‐CN) 14(CN) 10 (tp) 8(HL) 10(CH 3CN) 2][PF 6] 4? n CH 3CN? m H 2O (HL=3‐(2‐pyridyl)‐5‐[4‐(diphenylamino)phenyl]‐1 H‐pyrazole), tp ?=hydrotris(pyrazolylborate), 1 : M=Ni with n=11 and m=7, and 2 : M=Co with n=14 and m=5) were prepared. Complexes 1 and 2 are isomorphous, and crystallized in the monoclinic space group P2 1/ n. They have tetradecanuclear cores composed of eight low‐spin (LS) Fe III and six high‐spin (HS) M II ions (M=Ni and Co), all of which are bridged by cyanide ions, to form a crown‐like core structure. Magnetic susceptibility measurements revealed that intramolecular ferro‐ and antiferromagnetic interactions are operative in 1 and in a fresh sample of 2 , respectively. Ac magnetic susceptibility measurements of 1 showed frequency‐dependent in‐ and out‐of‐phase signals, characteristic of single‐molecule magnetism (SMM), while desolvated samples of 2 showed thermal‐ and photoinduced intramolecular electron‐transfer‐coupled spin transition (ETCST) between the [(LS‐Fe II) 3(LS‐Fe III) 5(HS‐Co II) 3(LS‐Co III) 3] and the [(LS‐Fe III) 8(HS‐Co II) 6] states. 相似文献
8.
Lanthanide‐based extended coordination frameworks showing photocontrolled single‐molecule magnet (SMM) behavior were prepared by combining highly anisotropic Dy III and Ho III ions with the carboxylato‐functionalized photochromic molecule 1,2‐bis(5‐carboxyl‐2‐methyl‐3‐thienyl)perfluorocyclopentene (H 2dae), which acts as a bridging ligand. As a result, two new compounds of the general formula [{Ln III2(dae) 3(DMSO) 3(MeOH)} ? 10 M eOH] n (M=Dy for 1 a and Ho for 2 ) and two additional pseudo‐polymorphs [{Dy III2(dae) 3(DMSO) 3(H 2O)} ? x MeOH] n ( 1 b ) and [{Dy III2(dae) 3(DMSO) 3(DMSO)} ? x MeOH] n ( 1 c ) were obtained. All four compounds have 2D coordination‐layer topologies, in which carboxylate‐bridged Ln 2 units are linked together by dae 2? anions into grid‐like frameworks. All four compounds exhibited a strong reversible photochromic response to UV/Vis light. Moreover, both 1 a and 2 show field‐induced SMM behavior. The slow magnetic relaxation of 1 a is influenced by the photoisomerization reaction leading to the observation of the cross‐effect: photocontrolled SMM behavior. 相似文献
9.
Complexation of Fe II and Fe III with azaheterocyclic ligands L (L = phen or bipy) were studied in the presence and in the absence of boron cluster anions [B nH n] 2– ( n = 10, 12). The reactions were carried out in air at room temperature in organic solvents and/or water. In all the solvents used, well known [FeL 3] An ( An = 2Cl – or SO 42–) ferrous complexes were formed from Fe II salts. Composition of ferric complexes with L ligands depends on the nature of solvent: either dinuclear oxo‐iron(III) chlorides [L 2ClFe III–O–Fe IIIL 2Cl]Cl 2 or ferric ferrates(III) [Fe IIIL 2Cl 2][Fe IIICl 4], or [Fe IIIL 2Cl 2][Fe IIICl 4L] were isolated from Fe III salts. Introduction of the closo‐borate anions to a Fe 3+(or Fe 2+)/L/solv. mixture stabilizes ferrous cationic complexes [FeL 3] 2+ in all the solvents used: only ferrous [FeL 3][B nH n] ( n = 10, 12) complexes were isolated from all the reaction mixtures in the presence of boron cluster anions. 相似文献
10.
Study on the stoichiometry and affinity of the arsenicals bound to HSA is an important step toward a better understanding of arsenic toxic effects. After incubation of AsIII or AsV with HSA at the physiological conditions (pH 7.43 and 37 °C), the free arsenicals and arsenic-HSA complexes were separated and detected by the combined techniques of microdialysis and liquid chromatography with hydride generation atomic fluorescence spectroscopy (MD–LC–HGAFS). The decrease of AsIII peak response rather than AsV indicated that HSA reacted with AsIII but not AsV. The binding plots indicated that the binding between HSA and AsIII was in Scatchard pattern when the concentration ratios of AsIII to HSA were ≤1:1. The strong binding sites (n
1) were 1.6 and the stability constant (K
1) was 1.54 × 106 M−1. When the concentration ratios of AsIII to HSA were >1:1, the binding was in Plasvento pattern with the stability constant K
2 ≅ 0 and no specific binding of AsIII with HSA. On the contrary, AsV did not show binding with HSA. The results showed that AsIII reacted with HSA more readily than AsV, which provides a chemical basis for arsenic toxicity. 相似文献
11.
Summary The single-step electrochemical synthesis of neutral transition metal complexes of imidazole, pyrazole and their derivatives has been achieved at ambient temperature. The metal was oxidized in an Me 2CO solution of the diazole to yield complexes of the general formula: [M(Iz) 2] (where M = Co, Ni, Cu, Zn; Iz = imidazolate); [M(MeIz) 2] (where M = Co, Ni, Cu, Zn; MeIz = 4-methylimidazolate); [M(Pr iIz) 2] (where M = Co, Ni, Cu, Zn; Pr iIz = 2-isopropylimidazolate); [M(pyIz) n] (where M = Co III, Cu II, Zn II; pyIz = 2-(2-pyridyl)imidazolate); [M(Pz) n] (where M = Co III, Ni II, Cu II, Zn II; Pz = pyrazolate); [M(ClPz) n] and [M(IPz) n] (where M = Co III, Ni II, Cu II, Zn II; ClPz = 4-chloropyrazolate; IPz = 4-iodopyrazolate); [M(Me 2Pz) n] (where M = Co II, Cu I, Zn II; Me 2Pz = 3,5-dimethylpyrazolate) and [M(BrMe 2Pz) n] (where M = Co II, Ni II, Cu I, Zn II; BrMe 2Pz = 3,5-dimethyl-4-bromopyrazolate). Vibrational spectra verified the presence of the anionic diazole and electronic spectra confirmed the stereochemistry about the metal centre. Variable temperature (360-90 K) magnetic measurements of the cobalt and copper chelates revealed strong antiferromagnetic interaction between the metal ions in the lattice. Data for the copper complexes were fitted to a Heisenberg ( S=
) model for an infinite one-dimensional linear chain, yielding best fit values of J=–62––65cm –1 and g = 2.02–2.18. Data for the cobalt complexes were fitted to an Ising ( S=
) model with J=–4.62––11.7cm –1 and g = 2.06–2.49. 相似文献
12.
Summary Mn II forms a yellow mononuclear species with the title ligand having a 12 stoichiometry and whose conditional stability constant is 8.9 × 10 10
m
–2. The c.v. of this complex shows an oxidation at +0.78V versus s.c.e. Controlled-potential electrolysis at +0.80V versus s.c.e. yields a binuclear species of Mn III with a 12 metal:ligand stoichiometry.The addition of Mn III(urea) 6(ClO 4) 3 to a solution of the ligand produces a mononuclear complex of Mn III if the concentration of the metal ion is less than 1 mM. At higher concentrations a binuclear species is obtained. The latter is reduced in two steps, at +0.24 and –0.58 V versus s.c.e. Controlled-potential electrolysis at 0.0 V produces a dark green complex after the transfer of 0.5 equivalents of charge per mole of Mn. This binuclear L 2Mn II-Mn IIIL 2 mixed-valence complex can be obtained only by electrolysis of the binuclear L 2Mn IIIMn IIIL 2 species. Attempts to prepare the complex chemically were unsuccessful - the binuclear Mn III species was obtained in every case.Author to whom all correspondence should be directed. 相似文献
13.
Reaction of K 3[M(CN) 6] (M?=?Cr III, Fe III, Co III ) with [Cu(en) 2](ClO 4) 2 in water gives three cyanide-bridged supramolecular complexes, {[Cu(en) 2][KM(CN) 6]} n [M?=?Cr III ( 1), Fe III ( 2), Co III ( 3); en?=?ethylenediamine], which have been characterized by elemental analysis, ICP analysis, IR spectra, TGA-DTA analysis and X-ray diffraction. Complex 1 crystallizes in the monoclinic, space group C2/ c with cell dimensions a?=?0.85237(12), b?=?1.7014(3), c?=?1.2103(2)?nm, β =?98.70(2)° and Z?=?4, and 2 crystallizes in the same space group with a?=?0.8401(2), b?=?1.6844(5) Å, c?=?1.1859(2)?nm, β =?98.98(2)° and Z?=?4. The crystal structures of 1 and 2 reveal a novel three-dimensional porous framework in which [Cu(en) 2] 2+ acts as a template, [M(CN) 6] 3? as a building block and K + as a connecting unit. 相似文献
14.
Summary The structures of the volatile bimetallic iso-propoxides of later 3d metals with the general formula, [M{Al(OPr- i)4} n] where M=Cr III, Mn II, Fe III, Co II, Ni II and Cu II have been investigated by visible reflectance and electron spin resonance spectroscopy as well as magnetic measurements. 相似文献
15.
Isomeric mixtures of compounds Me nM(CH?CHMe) 4?n (M=Si, Pb; n=0?3) have been prepared and studied, as well as pure Me 3M(CMe?CH 2) and mixtures containing propenyl isopropenyl residues bonded to silicon and lead. 1H, 13C, 29Si and 207Pb NMR data are presented; as previously observed for the corresponding tin compounds, the 29Si and 207Pb shifts for the Me 3MC 3H 5 isomers can be used to calculate the shifts expected for the other isomers; while for lead the agreement is good, calculated and observed values for silicon diverge with decreasing n due, at least in part, to steric factors. 相似文献
16.
Five rare earth heterospin complexes [ Ln(hfac) 3(NIT ptBuPh) 2], [ LnIII = Eu ( 1 ), Tb ( 2 ), Dy ( 3 ), Ho ( 4 ), Er ( 5 )] (hfac = hexafluoroacetylacetonate), were synthesized with the radical ligand NIT ptBuPh [2‐(4′‐ tert‐butylphenyl)‐4, 4,5, 5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide]. These complexes exhibit similar structures. All of them crystallize in the monoclinic space group P2 1/ c, and consist of discrete mononuclear molecules. The central LnIII ion is eight‐coordinate with a distorted dodecahedral environment. The NIT ptBuPh radical acts as monodentate ligand towards LnIII ion through the NO group. The magnetic studies suggested weak antiferromagnetic interactions between LnIII ion and radicals in 1 , 3 , 4 , and 5 , but weak ferromagnetic interaction in 2 . 相似文献
17.
In absolute ethanol and in the presence of triethylorthoformate, reactions of metal(II) nitrates with linear tridentate amines afforded metal complexes of the formula M(NNN)(NO 3) 2, where M = Ni 2+, Cu 2+ and Zn 2+, and NNN = dien and Medpt. The compounds fall into three categories in accordance with their stereochemistry and mode of binding of the nitrato ligands. Compounds I, [Ni(dien)(O 2NO)(ONO 2)] and III, [Zn(dien)(O 2NO)(ONO 2)] are isomorphous and isostructural. They crystallize in the monoclinic space group P2 1/ n with nearly identical cell constants. The stereochemistry of these two compounds is such that the terdentate dien ligand forms a fac MN 3 moiety with the two oxygens of the bidentate nitrato ligand trans to the terminal NH 2. These ligands form the base of the octahedral arrangement in which the sixth position, trans to the secondary nitrogen of the dien, is an oxygen of the monodentate nitrato ligand. Compound IV, [Ni(Medpt)(O 2NO)(ONO 2)] falls into the same category as I and III despite the fact that the two rings in the Ni-Medpt moiety are six-membered rings, unlike those in compounds I and III which are five-membered rings. Nevertheless, the nickel-amine arrangement is fac. The bidentate nitrato-oxygens are trans to the terminal NH 2 of the amine ligand, and the oxygen of the monodentate nitrato ligand is trans to the tertiary amine-nitrogen. Such stereochemistry is prevalent for nickel and zinc compounds. Interestingly, compound IV crystallizes as a conglomerate (space group P2 12 12 1). Compound II, {[Cu(dien)(μ-ONO 2)]NO 3} ∞ belongs to the second category and has a polymeric structure. The repeating fragment in the polymeric chain is a Cu(dien)-O fragment with the monodentate nitrato ligand occupying an equatorial position of the base. A second oxygen of the equatorial nitrate becomes an axial ligand for an adjacent Cu-N 3O fragment. In this way the substance propagates into an infinite chain. The repeating unit has an effective square pyramidal, five-coordinate, configuration. Finally, the compound crystallizes as a racemate. The second nitrate necessary for charge compensation of this copper(II) compound is ionic and its function is to hold the infinite chains of the lattice. The third category represented by compound V, [Cu(Medpt)(ONO 2) 2] contains two molecules in the asymmetric unit of the racemic lattice (monoclinic, space group P2 1/ a). The structure of Cu-Medpt is unlike that of IV in that both species present in the asymmetric unit have the amine ligand in a mer configuration which together with a monodentate oxygen of a nitrato ligand form a base plane of a square pyramid. The fifth ligand of both Cu 2+ ions is a second monodentate nitrato ligand. The stereochemical differences between the two Cu 2+ ions are insignificant for the Cu-Medpt fragment, which share the same conformation and configuration. The major difference between the two species is the torsional angles defined by the Cu-O-N-O angles. The difference arises from variation in the hydrogens of the primary amine moieties selected by nitrato-oxygens to form intramolecular hydrogen bonds. Finally, there is a little variation in the equatorial Cu-ONO 2 stereochemistry because of steric hindrance, imposed by the Medpt, preventing large torsional angles by these nitrato ligands. This is evident by comparing the two copper species shown in Finally, nitrate-to-Br ligand exchange was found to take place when KBr pellets are prepared for IR spectral measurements. 相似文献
18.
Redox-inactive metal ions are one of the most important co-factors involved in dioxygen activation and formation reactions by metalloenzymes. In this study, we have shown that the logarithm of the rate constants of electron-transfer and C−H bond activation reactions by nonheme iron(III)–peroxo complexes binding redox-inactive metal ions, [(TMC)Fe III(O 2)] +-M n+ (M n+=Sc 3+, Y 3+, Lu 3+, and La 3+), increases linearly with the increase of the Lewis acidity of the redox-inactive metal ions (Δ E), which is determined from the g zz values of EPR spectra of O 2.−-M n+ complexes. In contrast, the logarithm of the rate constants of the [(TMC)Fe III(O 2)] +-M n+ complexes in nucleophilic reactions with aldehydes decreases linearly as the Δ E value increases. Thus, the Lewis acidity of the redox-inactive metal ions bound to the mononuclear nonheme iron(III)–peroxo complex modulates the reactivity of the [(TMC)Fe III(O 2)] +-M n+ complexes in electron-transfer, electrophilic, and nucleophilic reactions. 相似文献
19.
The geometries, successive binding energies, vibrational frequencies, and infrared intensities are calculated for the [Li(H 2O) n] + and [K(H 2O) n] + ( n = 1?4) complexes. The basis sets used are 6-31G* and LANL 1DZ (Los Alamos ECP +DZ ) at the SCF and MP 2 levels. There is an agreement for calculated structures and frequencies between the MP 2/6-31G* and MP 2/LANL 1DZ basis sets, which indicates that the latter can be used for calculations of water complexes with heavier ions. Our results are in a reasonable agreement with available experimental data and facilitate experimental study of these complexes. © 1995 John Wiley & Sons, Inc. 相似文献
20.
Four cyano‐bridged 1D bimetallic polymers have been prepared by using the paramagnetic building block trans‐[Ru(acac) 2(CN) 2] ? (Hacac=acetylacetone): {[{Ni(tren)}{Ru(acac) 2(CN) 2}][ClO 4]?CH 3OH} n ( 1 ) (tren=tris(2‐aminoethyl)amine), {[{Ni(cyclen)}{Ru(acac) 2(CN) 2}][ClO 4]? CH 3OH} n ( 2 ) (cyclen=1,4,7,10‐tetraazacyclododecane), {[{Fe(salen)}{Ru(acac) 2(CN) 2}]} n ( 3 ) (salen 2?= N, N′‐bis(salicylidene)‐ o‐ethyldiamine dianion) and [{Mn(5,5′‐Me 2salen)} 2{Ru(acac) 2(CN) 2}][Ru(acac) 2(CN) 2]? 2 CH 3OH ( 4 ) (5,5′‐Me 2salen= N,N′‐bis(5,5′‐dimethylsalicylidene)‐ o‐ethylenediimine). Compounds 1 and 2 are 1D, zigzagged NiRu chains that exhibit ferromagnetic coupling between Ni II and Ru III ions through cyano bridges with J=+1.92 cm ?1, z J′=?1.37 cm ?1, g=2.20 for 1 and J=+0.85 cm ?1, z J′=?0.16 cm ?1, g=2.24 for 2 . Compound 3 has a 1D linear chain structure that exhibits intrachain ferromagnetic coupling ( J=+0.62 cm ?1, z J′=?0.09 cm ?1, g=2.08), but antiferromagnetic coupling occurs between FeRu chains, leading to metamagnetic behavior with TN=2.6 K. In compound 4 , two Mn III ions are coordinated to trans‐[Ru(acac) 2(CN) 2] ? to form trinuclear Mn 2Ru units, which are linked together by π–π stacking and weak Mn???O* interactions to form a 1D chain. Compound 4 shows slow magnetic relaxation below 3.0 K with ?=0.25, characteristic of superparamagnetic behavior. The Mn III???Ru III coupling constant (through cyano bridges) and the Mn III???Mn III coupling constant (between the trimers) are +0.87 and +0.24 cm ?1, respectively. Compound 4 is a novel single‐chain magnet built from Mn 2Ru trimers through noncovalent interactions. Density functional theory (DFT) combined with the broken symmetry state method was used to calculate the molecular magnetic orbitals and the magnetic exchange interactions between Ru III and M (M=Ni II, Fe III, and Mn III) ions. To explain the somewhat unexpected ferromagnetic coupling between low‐spin Ru III and high‐spin Fe III and Mn III ions in compounds 3 and 4 , respectively, it is proposed that apart from the relative symmetries, the relative energies of the magnetic orbitals may also be important in determining the overall magnetic coupling in these bimetallic assemblies. 相似文献
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