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E. N. Egorov E. A. Mikhalyova M. A. Kiskin V. V. Pavlishchuk A. A. Sidorov I. L. Eremenko 《Russian Chemical Bulletin》2013,62(10):2141-2149
New luminescent heterometallic complexes of Eu3+ and Zn2+ were synthesized: Zn2Eu(NO3)(Piv)6(L)2 (Piv is pivalate anion, L = MeCN (1), 2,3-lutidine (2), 2,2′-bpy (3)) and [Zn2(Piv)3(2,2′-bpy)2][ZnEu(NO3)3(Piv)3(2,2′-bpy)] (4). In the case of 2,2′-bpy, the order of mixing of the reagents ([Zn(Piv)2] n , Eu(NO3)3·6H2O, and 2,2′-bpy) affects the composition of the final reaction product: the reaction of [Zn(Piv)2] n and Eu(NO3)3·6H2O (in the ratio Zn : Eu = 3 : 1) in MeCN affords complex 1 and the subsequent addition of 2,2′-bpy (Zn : L = 1 : 1) affords complex 3. Complex 4 is formed in the reaction of [Zn(Piv)2] n and 2,2′-bpy (Zn : L = 1 : 1) in MeCN followed by the addition of Eu(NO3)3·6H2O (Zn : Eu = 3 : 1). The luminescence spectra of compounds 1–4 (Zn : Eu = 3 : 1) exhibit metal-centered luminescence of Eu3+. The most efficient ligand-antenna is 2,2′-bpy, which is due to the optimum position of the triplet level of this ligand. 相似文献
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A. V. Yakovenko L. Sorace E. A. Mikhalyova A. W. Addison V. V. Pavlishchuk 《Theoretical and Experimental Chemistry》2010,46(4):243-249
The temperature dependences of the magnetic susceptibilities for the complexes [Fe2III MIIO(p-NitPhCOO)6]∙MeCN (M = Co, Ni, p-NitPhCOO–= p-benzoatenitronyl nitroxide radical, MeCN = acetonitrile) revealed the existence of antiferromagnetic exchange coupling among
the metal ions in the trinuclear units, as well as between these units and the free radicals in the crystal lattices of the
complexes. 相似文献
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Mikhalyova EA Kolotilov SV Zeller M Thompson LK Addison AW Pavlishchuk VV Hunter AD 《Dalton transactions (Cambridge, England : 2003)》2011,40(41):10989-10996
Two lanthanide tetrafluoro-p-phthalate (L(2-)) complexes, Ln(L)(1.5)·DMF·H(2)O (Ln = Pr(3+) (1), Nd(3+) (2)), were synthesized using pyridine as a base. The compounds were found to be isostructural, and the structure of 1 has been determined by single crystal X-ray diffraction (monoclinic, space group C2, a = 22.194(2) ?, b = 11.4347(12) ?, c = 11.7160(12) ?, β = 94.703(2)°, V = 2963.3(5) ?(3), Z = 4). The crystal structure of 1 consists of dinuclear Pr(3+) units, which are connected by tetrafluoro-p-phthalate, forming separate 2D polymeric layers. The Ln(3+) ions in the dinuclear Ln(2) units are linked by two μ-O atoms and by two bridging O-C-O groups. The structure is porous with DMF and water molecules located between layers. Non-coordinated DMF molecules occupy about 27% of the unit cell volume. A systematic analysis of reported structures of Ln(III) polymers with p-phthalate and its derivatives shows that the ca. known 60 structures can be divided into six possible structural types depending on the presence of certain structural motifs. The magnetic properties of compounds 1 and 2 were studied. The dependence of χ(M)T on T (where χ(M) is magnetic susceptibility per dinuclear lanthanide unit) for 1 and 2 was simulated using two different models, based on: (i) the Hamiltonian ? = Δ?(z)(2)+ μ(B)g(J)H?, which utilises an axial splitting parameter Δ and temperature-independent paramagnetism (tip) and (ii) crystal field splitting. It was found that both models gave satisfactory fits, indicating that the Ln-Ln exchange interactions are small and the symmetry of the coordination environment is the main factor influencing the magnetic properties of these compounds. 相似文献
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H. Mühe Mc. Candless E. Valenta Utz Wilh Vaubel B. Ahlström O. Aschan J. Kondakow J. Schindelmeiser R. Böhme H. Herzfeld J. E. Teeple R. Adan J. Marcusson Darmois H. Wolff C. Piest R. Marcille EA. Parry M. Adams H. W. Fosse K. Ihnatowzcz 《Analytical and bioanalytical chemistry》1917,56(10-11):541-560
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RD Harris WS Baker Van Stipdonk MJ RM Crooks EA Schweikert 《Rapid communications in mass spectrometry : RCM》1999,13(14):1374-1380
A suite of keV polyatomic or 'cluster' projectiles was used to bombard unoxidized and oxidized self-assembled monolayer surfaces. Negative secondary ion yields, collected at the limit of single ion impacts, were measured and compared for both molecular and fragment ions. In contrast to targets that are orders of magnitude thicker than the penetration range of the primary ions, secondary ion yields from polyatomic projectile impacts on self-assembled monolayers show little to no enhancement when compared with monatomic projectiles at the same velocity. This unusual trend is most likely due to the structural arrangement and bonding characteristics of the monolayer molecules with the Au(111). Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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EA Mikhalyova SV Kolotilov O Cador M Zeller S Trofimenko L Ouahab AW Addison VV Pavlishchuk AD Hunter 《Dalton transactions (Cambridge, England : 2003)》2012,41(37):11319-11329
Six homodinuclear and two heteronuclear complexes Tp(Np)Co-C(2)O(4)-CoTp(Np) (1), Tp(Np)Co-C(2)O(4)-NiTp(Cy) (2), Tp(Cy)Ni-C(2)O(4)-NiTp(Cy) (3), Tp(Np)Co-C(2)O(2)(NH)(2)-CoTp(Np) (4), Tp(Cy)Ni-C(2)O(2)(NH)(2)-NiTp(Cy) (5), Tp(Np)Co-C(2)S(2)(NH)(2)-CoTp(Np) (6), Tp(Np)Co-C(2)S(2)(NH)(2)-NiTp(Cy) (7), Tp(Cy)Ni-C(2)S(2)(NH)(2)-NiTp(Cy) (8) (Tp(Np) = tris(3-neopentylpyrazolyl)borate, Tp(Cy) = tris(3-cyclohexylpyrazolyl)borate), were synthesized and characterized by mass spectrometry, electronic spectroscopy and X-ray crystallography. These compounds possess similar molecular structures, with the metal ions linked by bridging oxalate (1-3), oxamidate (4 and 5) or dithiooxamidate (6-8) ions. The heteronuclear nature of compounds 2 and 7 was additionally confirmed by high-resolution mass spectrometry. The magnetic properties of the Co(2+) complexes were modelled taking into account zero-field splitting of this ion, yielding D-values for Co(2+) in the range -17(1) to -50(1) cm(-1). All the metal ion pairs in compounds 1-8 are antiferromagnetically-coupled, with J values between -10.0(1) and -45.0(2) cm(-1) (via the exchange Hamiltonian ?(ex.) = -2J?(1)?(2)) and |J| increasing in the order oxalate < oxamidate < dithiooxamidate. This tendency can be attributed to greater M-S bond covalency compared to M-N or M-O bonds (M = Co(2+) and Ni(2+)). It was found that this antiferromagnetic coupling of Co(2+) and Ni(2+) ions through oxalate is more efficient for these tris(pyrazolyl)borate complexes than for similar oxalate-bridged systems with neutral aliphatic amine ligands. 相似文献