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71.
The purpose of this paper is to provide the beginnings of an elementary theory for the category of loopless pointed matroids and strong maps. We propose a finite set of elementary axioms that is the beginning of an elementary axiomatic theory for this category.  相似文献   
72.
73.
The tripodal alcohol 1,1,1-tris(hydroxymethyl)ethane (H3thme) directs the formation of heptanuclear cobalt metallocycles in which the metal ions are coupled ferromagnetically.  相似文献   
74.
Dispersible, nearly isolated 6 nm nanoparticles of the CsNiCr(CN)6 Prussian blue analogue coated with polyvinylpyrrolidone (PVP) show superparamagnetic behaviour with a relatively high blocking temperature TB = 9 K.  相似文献   
75.
The reaction of phenylphosphonic acid (PhPO(3)H(2)) with the mixed-valent basic oxo-centered manganese triangle [Mn(3)O(O(2)CCMe(3))(6)(py)(3)] (1; where py=pyridine) in the presence of a suitable base gives four different manganese clusters depending on the identity of the base. The syntheses and structural characterization of [Mn(18)(mu(3)-O)(8)(PhPO(3))(14)(O(2)CCMe(3))(12)(py)(6)(H(2)O)(2)] (2), [Mn(7)(mu(3)-O)(3)(O(3)PPh)(3)(O(2)CCMe(3))(8)(py)(3)] (3), [Mn(9)Na(mu(3)-O)(4)(mu(4)-O)(2)(O(3)PPh)(2)(O(2)CCMe(3))(12)(H(2)O)(2)(H(2)O)(0.67)(Py)(0.33)] (4), and [Mn(13)(mu(3)-O)(8)(OMe)(8)(O(3)PPh)(4)(O(2)CCMe(3))(10)] (5) are described. Complexes 4 and 5 are homovalent Mn(III) cages, while 2 and 3 contain divalent, trivalent, and/or tetravalent ions. All the manganese centers are valence-localized, the octahedral Mn(III) sites being recognizable by marked Jahn-Teller distortions. The magnetic properties of compounds 2-5 have been investigated in the polycrystalline state by magnetic susceptibility and high-field magnetization measurements, which reveal that spin ground states vary from 0< or =S > or =8. AC susceptibility measurements performed on 4 and 5, in the 1.6-10.0 K ranges show the presence of out of AC susceptibility signal (chi(M)') for 4, and an effective energy barrier (U(eff)) for the re-orientation of the magnetization is found to be 17 K, but for 5, the chi(M)' maximum is found to be below 1.5 K.  相似文献   
76.
Several palladium(II) and platinum(II) complexes analogous to oxaliplatin, bearing the enantiomerically pure (1R,2R)‐(?)‐1,2‐diaminocyclohexane (DACH) ligand, of the general formula {MX2[(1R,2R)‐DACH]}, where M = Pd or Pt, X (COO)2, CH2(COO)2, , , {1,1′‐C5H8(CH2COO)2}, [1,1′‐C6H10(CH2COO)2], [1,1′‐(COO)2ferrocene], , , , MeCOO and Me3CCOO, were synthesized. All the complexes prepared were characterized physicochemically and spectroscopically. Some selected complexes were screened in vitro against several tumor cell lines and the results were compared with reference standard drug, oxaliplatin. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
77.
78.
The functionalisation of a Si(100) silicon wafer allows for the oriented grafting of a monolayer of Mn12 nanomagnets using a two-step procedure.  相似文献   
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80.
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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