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1.
The reaction of NiCl2 with excess potassium pivalate (KPiv) in ethanol affords the chainpolymeric compound KNi4(Piv)7(OH)2(EtOH)6. In the solid compound, the tetranuclear nickel fragments alternate with potassium atoms. The use of KNi4(Piv)7(OH)2(EtOH)6 in the reaction with Ni(hfac)2 (hfac is the hexafluoroacetylacetonate anion) gave the first polynuclear mixed-ligand complexes [K2Ni6(Piv)7(hfac)3(OH)4(HPiv)2(Me2CO)2]·1.5C7H16, [Ni6(Piv)4(hfac)4(OH)4(Me2CO)4], [K2Ni8(Piv)8(hfac)4(OH)6(H2O)2(Me2CO)6], [Ni8(Piv)10(hfac)2(OH)2(MeO)2(MeOH)2(HPiv)2]·C6H14, and [Ni16(Piv)10(hfac)6(OH)10(MeO)6(MeOH)8(H2O)6]·C6H14 containing both Piv and hfac as the anionic ligands. The molecular and crystal structures of all these compounds were established, and their magnetic properties were studied. All solids containing simultaneously Piv and hfac ligands tend to undergo ferromagnetic ordering with decreasing temperature. The solid [Ni8(Piv)10(hfac)2(OH)2(MeO)2(MeOH)2(HPiv)2]·C6H14 undergoes cooperative magnetic ordering below T c (2.5 K). Dedicated to the 90th anniversary of the L. Ya. Karpov Institute of Physical Chemistry. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1175–1182, June, 2008.  相似文献   

2.
Hydrolysis of [M4(hfac)4(MeO)4(MeOH)4] (М = Сo, Ni and hfac is hexafluoroacetylaceton ate) is a convenient way of obtaining polynuclear complexes [Ni7(hfac)6(OH)8(H2O)6]?2H2O, [Co12(hfac)10(OH)14(H2O)8]?2H2O?2MePh, [Co12(hfac)10(OH)14(H2O)4(Me2CO)4]?3PhMe, and [Co12(hfac)10(OH)14(H2O)6(Me2CO)2]?2H2O?2Me2CO, whose structures were confirmed by X-ray analysis.  相似文献   

3.
The heterospin mixed-ligand complex [Ni6(OH)4Piv4(hfac)4(NIT-Ph)2] (1) (NIT-Ph is 4,4,5,5-tetramethyl-2-phenyl-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide, hfac is hexafluoroacetylacetonate, and Piv is pivalate) was synthesized. The method for the synthesis of complex 1 is based on the replacement of acetone molecules in the hexanuclear complex containing the hexafluoroacetylacetonate and pivalate ligands [Ni6(OH)4Piv4(hfac)4(Me2CO)4] by NIT-Ph molecules. Two monodentate NIT-Ph molecules replace four acetone molecules, because the coordination of the O atom of the nitroxide group results in the blocking of one of the positions in the coordination environment of NiII the access to which is hindered by the phenyl ring of NIT-Ph. As a result, these ions are in a square-pyramidal environment unusual of NiII. In the low-temperature range, the dependence of the magnetization of 1 on the magnetic field is described by the Brillouin function. The reaction of [Ni6Piv4(hfac)4(OH)4(Me2CO)4] with the nitronyl nitroxide radicals 4,4,5,5-tetramethyl-2-(4-pyridyl)-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide (NIT-p-Py) or 4,4,5,5-tetramethyl-2-(1-methyl-1H-imidazol-5-yl)-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide (NIT-Iz) containing the pyridine or 1-methylimidazol-5-yl substituent, respectively, in the side chain is accompanied by the decomposition of the polynuclear fragment and affords the mononuclear complexes Ni(hfac)2(NIT-p-Py)2 and Ni(hfac)2(NIT-Iz)2, respectively. The reaction of 4,4,5,5-tetramethyl-2-(1-methyl-1H-imidazol-5-yl)-4,5-dihyd-ro-1H-imidazol-1-oxyl (Im-Iz), which is the imine analog of NIT-Iz, with [Ni6Piv4(hfac)4(OH)4(Me2CO)4] afforded the decanuclear complex [Ni10(OH)8Piv4(hfac)8(Im-Iz)2(H2O)6]. The molecular and crystal structures of all heterospin compounds were determined, and the magnetic properties of all compounds were investigated in the 2–300 K temperature range.  相似文献   

4.
《Mendeleev Communications》2021,31(5):628-630
Solid phase thermolysis of pivalate complex [Fe3O(Piv)6(HPiv)3]Piv generates the [Fe3O(Piv)6]+ complex cation due to a deficiency of ligands in the coordination sphere of the metal ions. Crystallization of [Fe3O(Piv)6]+ from THF–EtOH leads to the heteroleptic complex [Fe3O(Piv)6(THF)(EtOH)(OH)] · 0.5 THF · 0.5 H2O in 69% yield, while the reaction of [Fe3O(Piv)6]+ with AgNO3 in toluene results in the complex [Fe4Ag4O2(Piv)12] · 2 PhMe with a rare combination of FeIII and AgI atoms. Crystal structures of the two new complexes have been established.  相似文献   

5.
We synthesized 1-ethylimidazolyl-substituted nitronyl nitroxides, i.e., 2-(1-ethylimidazol-4-yl)- (L4Et) and 2-(1-ethylimidazol-5-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole 3-oxide-1-oxyl (L5Et). The stable radical L5Et is an ethyl analog of 2-(1-methylimidazol-5-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole 3-oxide-1-oxyl (L5Me) described earlier, the reaction of which with Cu(hfac)2 (hfac is 1,1,1,5,5,5-hexafluoropentane-2,4-dionate) leads to the formation of the [Cu(hfac)2(L5Me)2] jumping crystals. The reaction of Cu(hfac)2 with L5Et with reagent ratios 1: 2 and 1: 1 yields heterospin complexes [Cu(hfac)2(L5Et)2] and [Cu(hfac)2L5Et]2, respectively. X-ray diffraction study of the mononuclear complex [Cu(hfac)2(L5Et)2] determined that the compound has a packing similar to that of jumping crystals studied earlier, with the only difference being that the O...O contacts between neigh- boring nitroxide groups were found to be 0.3—0.5 Å longer than in [Cu(hfac)2(L5Me)2]. As a result of the lengthening of these contacts, [Cu(hfac)2(L5Et)2] crystals lack chemomechanical activi- ty. We found that when cooling crystals of binuclear complex [Cu(hfac)2L5Et]2 below 50 K, the antiferromagnetic exchange between unpaired electrons of the >N—?O groups of neighboring molecules leads to the full spin-pairing of the nitroxides, with only the Cu2+ ions contributing to the residual paramagnetism of the compound.  相似文献   

6.
Using single crystal X-ray diffraction the structure of polynuclear [Ni6(OH)4(Piv)7(HOC4H8O)(HPiv)4], {K4[Ni12(CO3)2(Piv)16(OH)8(HOC4H8OH)2]}HPiv, {[Ni6(OH)4(Piv)6(HOC4H8O)(Me2CO)(HOC4H8OH)2]4×(Piv)4}, and {K[Ni2L2(Piv)3]} complexes, where HOC4H8OH is 1,4-butanediol, HPiv is pivalic acid, and L is the anion of nitroxyl radical 2,2,5,5-tetramethyl-4-(3′,3′,3′-trifluoro-2′-oxy-1′-propenyl)-3-imidazolin-1-oxyl is determined.  相似文献   

7.
The Ce,Mn mixed-metal polynuclear compounds [Ce 3Mn6(O)5(OH)3Piv12Cl2(THF)3]·2THF, [Ce3Mn8(O)8Piv16Cl2(HPiv)2]·C7H16, [Ce10Mn4(O)6(OH)12Piv16Cl2(THF)2]·2THF·2H2O, [CeMn11Cl3(O)8Piv15(H2O)]·CH2Cl2, and [CeMn8(O)8Piv12(HPiv)2(THF)2] were prepared and structurally characterized. The possibility of synthesizing p,d,f-heterospin complexes by replacing coordinated THF molecules by nitroxide molecules was exemplified by the reaction of [Ce3Mn6(O)5(OH)3Piv12Cl2(THF)3]·2THF with nitronyl nitroxides (NIT-R is 2-R-4,4,5,5-tetramethyl-24midazoline-l-oxyl 3-oxide; R is Me or 4-Py). The X-ray diffraction study of these complexes showed that [Ce3Mn6(O)5(OH)3Piv12Cl2(HPiv)(NIT-Me)2] and [CeMn8(O)8Piv12(NIT4-Py) 4] · 2C6H14 have a molecular structure and [Ce3Mn6(O)5(OH)3-Piv12Cl2(NIT-Me)(H2O)] is an infinite chain.  相似文献   

8.
Joint thermolysis of the dinuclear pivalate complexes M2(μ-H2O)(μ-Piv)2(Piv)2(HPiv)4 (M = Co (1) and Ni (2), Piv- is the pivalate anion), in decane at 174 °C at the reactant ratio 1: 1 followed by treatment of the dry thermolysis product with methanol afforded crystals of a new cocrystallization product of the molecules containing the heterometallic cubane-like core M4(Co,Ni)O4. According to the X-ray diffraction data and the results of magnetic measurements, inductively coupled plasma atomic emission spectrometry (ICP-AES), and investigations of the solid-state thermal decomposition products, the isolated cocrystallization product has the general formula [Co1.6Ni2.43-OMe)42-Piv)2(pg2 -Piv)2(MeOH)4] ·4MeOH (3·4MeOH). Thermolysis of the crystals of the solvate 3·4MeOH is a destructive process accompanied by the intramolecular redox reaction. A mixture of metallic Ni and cobalt oxide (CoO) are the final solid decomposition products of 3 · 4MeOH in an argon atmosphere, whereas a mixture of the phases NiO, Co3O4, and NiCo2O4 is formed in air.  相似文献   

9.
The synthesis and structures of mononuclear Ni(II), Co(II), Mn(II), and Cu(II) pivalates isolated as complex salts NBu4[M(Piv)3] ((NBu4)+ is tetrabutylammonium cation, Piv is pivalate anion) and polynuclear complexes [Ni6(L)2(HL)2(Piv)6(HPiv)8], (NBu4)2[Co4(Piv)8(AcO)2(H2O)4], NBu4[Co2(Piv)5(H2O)2], and (NBu4)2[Cu4(Piv)8(AcO)2(H2O)2] (L2–, HL, and AcO is lactic acid dianion, lactic acid monoanion, and acetate anion, respectively) are discussed. The formation of the compounds is detected during the development of the synthesis of NBu4[M(Piv)3].  相似文献   

10.
New hexanuclear Fe(III)–Mn(II, III) pivalates [Fe2 III Mn4 II(O)2(Piv)10(HPiv)4] (I) or [Fe4 III Mn2 III(O)2(Piv)12(CH2O2)(HPiv)2] · Et2O (II) are synthesized using the solid-state thermolysis of [Fe2Mn(O)(Piv)6(HPiv)3] (90°С). Complexes I and II differ by the ratio of iron and manganese ions, which depends on the atmospheric composition during thermolysis. The structures of compounds I and II are determined by X-ray diffraction studies. According to the parameters of the Mössbauer spectrum, complex I contains the Fe3+ ions in the high-spin state in the octahedral environment of oxygen atoms.  相似文献   

11.
Three new metal–nitroxide complexes {[Ni(NIT4Py)2(obb)(H2O)2] · 1.5H2O}n ( 1 ), {[Co(NIT4Py)2(obb)(H2O)2] · 2H2O}n ( 2 ), and [Co(IM4Py)2(obb)2(H2O)2][Co(IM4Py)2(H2O)4] · 10H2O ( 3 ) with the V‐shaped 4,4′‐oxybis(benzoate) [NIT4Py = 2‐(4′‐pyridyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide, IM4Py = 2‐(4′‐pyridyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxide, and obb = 4, 4′‐oxybis(benzoate) anion] were synthesized and structurally characterized. Single‐crystal X‐ray analyses indicate that complexes 1 and 2 crystallize in neutral one‐dimensional (1D) zigzag chains, in which the nitroxide–metal–nitroxide units are linked by the V‐shaped 4,4′‐oxybis(benzoate) anions, whereas complex 3 consists of isolated mononuclear [Co(IM4Py)2(obb)2(H2O)2]2– anions and [Co(IM4Py)2(H2O)4]2+ ions. Magnetic measurements show that complexes 1 and 2 both exhibit weak antiferromagnetic interactions between the metal ions and the nitroxides.  相似文献   

12.
A dodecanuclear complex [Ni12Piv10(hfac)6(OH)8(EtOH)6]·C6H14 was isolated from various synthetic systems simultaneously containing NiII and the pivalate and hexafluoro-acetylacetonate anions. The structure of this complex was determined and the magnetic properties were investigated. The use of EtOH as the solvent or the presence of EtOH in the reagents is the decisive factor for the formation of this complex.  相似文献   

13.
A method was developed for the synthesis of mixed-metal heterospin compounds with the direct coordination of the nitroxide fragment based on the replacement of acetonitrile molecules in the heterotrinuclear complex [Co2Gd(NO3)Piv6(CH3CN)2] with nitroxide molecules. The molecular and crystal structure of the heterospin mixed-ligand heterotrinuclear CoII, GdIII, CoII complex [Co2Gd(NO3)Piv6(NIT-Me)2], where NIT-Me is stable nitronyl nitroxide, was established. The magnetic properties of this complex were investigated in the temperature range of 2–300 K. The coordination of nitroxide groups to CoII ions is responsible for strong exchange interactions between the unpaired electrons in the exchange clusters {>-·O-CoII}, resulting in the virtually complete spin coupling between each coordinated >N-·O group and one of the unpaired electrons of each CoII ion at temperatures below 200 K. Dedicated to Academician G. A. Abakumov on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1742–1745, September, 2007.  相似文献   

14.
The compounds [Ni(H2O)2(En)2][{Ni(En)2}Re6S8(OH)6] · 7H2O (I), [{Cu(En)2}Re6S8(H2O)2(OH)4] · 4H2O (II), and [Ni(H2O)2(En)2]0.5[Re6Se8(H2O)3(OH)3] · 10H2O (III) were synthesized by layering aqueous solutions of Ni(En)2Cl2 or Cu(En)2Cl2 (En is ethylenediamine) onto aqueous solutions of the potassium salts of the corresponding octahedral chalcohydroxo rhenium cluster complexes [Re6Q8(OH)6]4− (Q = S, Se). The structure of the obtained compounds was determined by X-ray diffraction analysis.  相似文献   

15.
As part of continuing studies of multispin compounds capable of exhibiting chemomechanical activity, a series of heterospin solids of the composition [Cu(hfac)2L x L′2?x ], [Cu(hfac)2L′], [Cu2(Piv)4L′2]·0.5C6H14, and [Cu2(hfac)2(Piv)2L′2], where hfac is the hexafluoroacetylacetonate anion, L is 4,4,5,5-tetramethyl-2-(1-methyl-1H-imidazol-5-yl)-4,5-dihydro-1H-imidazole-3-oxide-1-oxyl, L′ is the imino nitroxide analog of L, viz., 4,4,5,5-tetramethyl-2-(1-methyl-1H-imidazol-5-yl)-4,5-dihydro-1H-imidazole-1-oxyl, and Piv is the 2,2-dimethylpropionate anion, were synthesized and characterized. The packing of the synthesized crystals of the solid solutions [Cu(hfac)2L x L′2-x ], where L predominates, is similar to that for [Cu(hfac)2L2], and these crystals are able to undergo chemomechanical motion. On the contrary, the crystals of [Cu(hfac)2L x L′2?x ], where L′ predominates, have structural parameters similar to those of [Cu(hfac)2L′2] and do not exhibit thermally activated or photoactivated chemomechanical activity.  相似文献   

16.
Vaporization of cobalt(II) pivalate [Co(Piv)2] (1, HPiv = HO2CCMe3) and cobalt(II) oxopivalate [Co4O(Piv)6] (2) complexes has been studied by Knudsen effusion technique in combination with mass-spectral analysis of gas phase composition. The congruent sublimation of the prepared compounds has occurred, it has been accompanied by partial thermal decomposition in the case of complex 1. Saturated vapor over complex 1 has been found to consist mainly of monomeric Co(Piv)2, dimeric Co2(Piv)4, and small amount of tetrameric Co4(Piv)8 molecules, as well as Co4O(Piv)6, CO2, and 2,2,4,4-tetramethylpentanone ones. Saturated vapor over complex 2 contains only Co4O(Piv)6 species. The absolute values of partial pressure and sublimation enthalpies of gas phase components have been calculated.  相似文献   

17.
The heteronuclear complex [Fe4Li2(O)2(Piv)10(H2O)2] (1, Piv is the pivalic acid anion) was obtained by refluxing FeIII pivalates with LiI pivalates in toluene and isolated as the 1?PhCH3 solvate with a toluene molecule. According to X-ray diffraction data, complex 1 contains the {Fe4Li2O2} core. The Mössbauer spectroscopy data indicate that the core comprises para magnetic FeIII ions in the high-spin state located in the symmetric octahedral environment of oxygen atoms. Thermolysis of 1 studied by simultaneous thermal analysis demonstrated thermal stability of the complex up to 225 °С. The main end product of thermolysis at 600 °С is the mixed oxide LiFe5O8.  相似文献   

18.
Three new one‐dimensional (1D) chain metal–nitroxide complexes {[Cu(NIT4Py)2(suc)(H2O)] · 3H2O}n ( 1 ), {[Cd(NIT4Py)2(suc)(H2O)] · [Cd(NIT4Py)2(suc)(H2O)2] · 3H2O}n ( 2 ), and {[Zn(NIT4Py)(glu)(H2O)] · H2O}n ( 3 ) [NIT4Py = 2‐(4′‐pyridyl)‐4, 4, 5, 5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide, suc = succinate anion and glu = glutarate anion] were synthesized and structurally characterized. Single‐crystal X‐ray analyses indicate that the three complexes crystallize in neutral 1D chains in which the metal‐nitroxide units are linked by flexible dicarboxylate anions. The succinate anions only adopt trans configuration in complexes 1 and 2 , whereas the glutarate anion has gauche/anti conformation in complex 3 . Magnetic measurements show that complex 1 exhibits weak antiferromagnetic interactions between the copper ions and the nitroxides.  相似文献   

19.
利用水热法合成了两种过渡金属配合物为模板剂的含水硼酸盐晶体Co(en)3[B4O5(OH)4]Cl·3H2O(1) 和 [Ni(en)3][B5O6(OH)4]2·2H2O (2),并通过元素分析、X射线单晶衍射、红外光谱及热重分析对其进行了表征。化合物1晶体结构的主要特点是在所有组成Co(en)33+, [B4O5(OH)4]2–, Cl– 和 H2O之间通过O–H…O、O–H…Cl、N–H…Cl和N–H…O四种氢键连接形成网状超分子结构。化合物2晶体结构的特点是[B5O6(OH)4]–阴离子通过O–H…O氢键连接形成沿a方向有较大通道的三维超分子骨架,模板剂[Ni(en)3]2+阳离子和结晶水分子填充在通道中。  相似文献   

20.
New bi- and trihomonuclear Mn(II), Co(II), Ni(II), and Zn(II) complexes with sulfa-guanidine Schiff bases have been synthesized for potential chemotherapeutic use. The complexes are characterized using elemental and thermal (TGA) analyses, mass spectra (MS), molar conductance, IR, 1H-NMR, UV-Vis, and electron spin resonance (ESR) spectra as well as magnetic moment measurements. The low molar conductance values denote non-electrolytes. The thermal behavior of these chelates shows that the hydrated complexes lose water of hydration in the first step followed by loss of coordinated water followed immediately by decomposition of the anions and ligands in subsequent steps. IR and 1H-NMR data reveal that ligands are coordinated to the metal ions by two or three bidentate centers via the enol form of the carbonyl C=O group, enolic sulfonamide S(O)OH, and the nitrogen of azomethine. The UV-Vis and ESR spectra as well as magnetic moment data reveal that formation of octahedral [Mn2L1(AcO)2(H2O)6] (1), [Co2(L1)2(H2O)8] (2), [Ni2L1(AcO)2(H2O)6] (3), [Mn3L2(AcO)3(H2O)9] (5), [Co3L2(AcO)3(H2O)9] · 4H2O (6), [Ni3L2(AcO)3(H2O)9] · 7H2O (7), [Mn3L3(AcO)3(H2O)6] (9), [Co2(HL3)2(H2O)8] · 4H2O (10), [Ni3L3(AcO)3(H2O)9] (11), [Mn3L4(AcO)3(H2O)9] · H2O (13), [Co2(HL4)2(H2O)8] · 5H2O (14), and [Ni3L4(AcO)3(H2O)9] (15) while [Zn2L1(AcO)2(H2O)2] (4), [Zn3L2(AcO)3(H2O)3] · 2H2O (8), [Zn3L3(AcO)3(H2O)3] · 3H2O (12), and [Zn3L4(AcO)3(H2O)3] · 2H2O (16) are tetrahedral. The electron spray ionization (ESI) MS of the complexes showed isotope ion peaks of [M]+ and fragments supporting the formulation.  相似文献   

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