排序方式: 共有83条查询结果,搜索用时 15 毫秒
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Rogez G Marvilliers A Sarr P Parsons S Teat SJ Ricard L Mallah T 《Chemical communications (Cambridge, England)》2002,(14):1460-1461
The rational design of the organic ligand allows to finely tune the degree of delocalization of mixed-valence Prussian blue-like molecules. 相似文献
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Marcos Rubín-Osanz Franois Lambert Feng Shao Eric Rivire Rgis Guillot Nicolas Suaud Nathalie Guihry David Zueco Anne-Laure Barra Talal Mallah Fernando Luis 《Chemical science》2021,12(14):5123
We report the existence of a sizeable quantum tunnelling splitting between the two lowest electronic spin levels of mononuclear Ni complexes. The level anti-crossing, or magnetic “clock transition”, associated with this gap has been directly monitored by heat capacity experiments. The comparison of these results with those obtained for a Co derivative, for which tunnelling is forbidden by symmetry, shows that the clock transition leads to an effective suppression of intermolecular spin–spin interactions. In addition, we show that the quantum tunnelling splitting admits a chemical tuning via the modification of the ligand shell that determines the crystal field and the magnetic anisotropy. These properties are crucial to realize model spin qubits that combine the necessary resilience against decoherence, a proper interfacing with other qubits and with the control circuitry and the ability to initialize them by cooling.We have directly monitored spin level anti-crossings, or “clock transitions”, in Ni(ii) molecular monomers and shown that the quantum tunnelling gap admits a chemical tuning. 相似文献
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H. Kazemian M. H. Mallah M. Ghannadi Maragheh 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(3):619-623
This study deals with durable borosilicate glasses for the immobilizing of radioisotopes from nuclear waste streams generated
by a radiopharmaceutical production unit. In this regard, different boron frits (glasses) and waste-loaded glasses were prepared
under various experimental conditions. The effects of some parameters such as melting temperature, cooling procedure and various
raw materials were investigated. The best composition of the frits as well as the best glass/waste ratio was determined to
optimize the immobilization process. All experiments were performed in non-active bench scale.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Carrasco R Cano J Mallah T Jones LF Collison D Brechin EK 《Inorganic chemistry》2004,43(17):5410-5415
The reaction of the trimetallic species [Fe(3)O(PhCOO)(6)(H(2)O)(3)]NO(3) with 1,1,1-tris(hydroxymethyl)ethane (H(3)thme) affords either the octametallic species [Fe(8)(PhCOO)(12)(thme)(4)] 1 or the hexadecametallic species [Fe(16)(EtO)(4)(PhCOO)(16)(Hthme)(12)](NO(3))(4) 2, depending on the nature of the solvent used for crystallization. The structure of 1 can be described as a nonplanar wheel of eight Fe(III) ions bridged by a combination of PhCOO(-) and thme(3)(-) ligands, and 2 as a nonplanar wheel of sixteen Fe(III) ions bridged by PhCOO(-), Hthme(2)(-), and EtO(-) ligands. Both compounds can be broken down into simple units of two metal ions and the bridging ligands that connect them. The best fits of the chi vs T curves in the 300-10 K temperature range were obtained with the parameters g = 2.0, J(1) = -24.0 cm(-1), and J(2) = -8.59 cm(-1) for [Fe(8)] and g = 2.0, J(1) = -25.0 cm(-1), J(2) = -11.73 cm(-1), and J(3) = -69.3 cm(-1) for [Fe(16)]. Density functional theory (DFT) calculations show that the antiferromagnetic interactions between the metals in the dinuclear units decrease when two types of bridging ligands are present, as expected for an orbital counter-complementarity effect. 相似文献
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Karmakar TK Ghosh BK Usman A Fun HK Rivière E Mallah T Aromí G Chandra SK 《Inorganic chemistry》2005,44(7):2391-2399
The preparation of a series of multidentate pyridyl-imine ligands, L1-L3, and their reactivity with the Mn(II)/N3- system is described (L1 = [N,N-bis(pyridine-2-yl)benzylidene]ethane-1,2-diamine; L2 = [N,N-bis(pyridine-2-yl)benzylidene]propane-1,3-diamine, and L3 = [N,N-bis(pyridine-2-yl)benzylidene]butane-1,4-diamine). Complexes comprising dinuclear end-on bis(mu-azido)-bridged manganese(II) units of formulas [Mn2(L1)2(N3)4][Mn2(L1)2(N3)2(CH3OH)2](ClO4)2 (two cocrystallized dinuclear units, 1.2), [Mn2(L2)2(N3)2](ClO4)2 (3), and [Mn2(L3)2(N3)2](ClO4)2 (4) have been synthesized. The crystal structures of complexes 1-4 as well as their magnetic properties are presented. Each manganese atom of cocrystallized complexes in compound 1.2 is heptacoordinated, displaying Mn-N-Mn angles, theta, of 102.53(12) and 101.70(12) degrees and Mn...Mn distances of 3.5091(7) and 3.4680(7) A. On the other hand, each manganese center in compounds 3 and 4 is located within an octahedral coordination environment, the complexes displaying theta angles of 104.29(11) and 103.60(18) degrees , respectively, and Mn...Mn vectors of 3.5371(7) and 3.5338(10) A, respectively. Magnetic susceptibility studies revealed the presence of intramolecular ferromagnetic superexchange, yielding an S = 5 spin ground state in all complexes. Fitting of the experimental data led to coupling constants, intermolecular exchange values, and g factors (in the J/zJ'/g format) of 0.77 cm(-1)/0.01 cm(-1)/2.20 (1.2), 2.04 cm(-1)/0.01 cm(-1)/1.99 (3), and 1.75 cm(-1)/-0.05 cm(-1)/2.04 (4), respectively (using H = -2JS1S2 as the convention for the Heisenberg spin-Hamiltonian). These results are consistent with predictions from recent DFT calculations performed on end-on bis(mu-N3-)-bridged Mn(II) dinuclear complexes. A plot of experimental J vs theta, including data from the only preexisting compound of this kind, reveals a linear relationship, which could be the first evidence of a possible magneto-structural correlation between these two parameters. 相似文献
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Volatron F Catala L Rivière E Gloter A Stéphan O Mallah T 《Inorganic chemistry》2008,47(15):6584-6586
Spin-crossover coordination nanoparticles of the cyanide-bridged three-dimensional network Fe(pyrazine){Pt(CN) 4} were prepared at three different sizes using a microemulsion. The 14 nm particles present a transition centered around 265 K with a hysteresis of 6 K. 相似文献