Publications by authors named "Cherif Balde"

The purpose of this work is to study the influence of the substitution of Fe(ii) by Mn(ii) on the spin crossover behaviour of [FexMn1-x(L222N3O2)(CN)2]·H2O solid solutions where L222N3O2 is a macrocyclic ligand = 2,13-dimethyl-6,9-dioxa-3,12,18-triazabicyclo[12.3.1]-octadeca-1(18),2,12,14,16-pentaene.

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Crystalline [Fe(bppSMe)2][BF4]2 (1; bppSMe = 4-(methylsulfanyl)-2,6-di(pyrazol-1-yl)pyridine) undergoes an abrupt spin-crossover (SCO) event at 265±5 K. The crystals also undergo a separate phase transition near 205 K, involving a contraction of the unit-cell a axis to one-third of its original value (high-temperature phase 1; Pbcn, Z = 12; low-temperature phase 2; Pbcn, Z = 4). The SCO-active phase 1 contains two unique molecular environments, one of which appears to undergo SCO more gradually than the other.

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The effects of metal dilution on the spin-crossover behavior of iron(II) in the mixed crystal series [Fe(x)Zn(1-x)(bpp)2](NCSe)2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) have been studied using magnetic susceptibility, photomagnetism and diffuse reflectivity measurements. For each mixed-crystal system, the thermal spin transition temperature, T(1/2), and the relaxation temperature of the photo-induced high-spin state, T(LIESST), have been systematically determined. It appears that T(1/2) decreases with the metal dilution while T(LIESST) remains unchanged.

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We report the spin state photo-switching dynamics in two polymorphs of a spin-crossover molecular complex triggered by a femtosecond laser flash, as determined by combining femtosecond optical pump-probe spectroscopy and picosecond X-ray diffraction techniques. The light-driven transformations in the two polymorphs are compared. Combining both techniques and tracking how the X-ray data correlate with optical signals allow understanding of how electronic and structural degrees of freedom couple and play their role when the switchable molecules interact in the active crystalline medium.

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An iron(II) complex [Fe(L5)2][ClO4]2 of a new nonplanar tridentate ligand [L5 = 2-[3-(2'-pyridyl)pyrazol-1-ylmethyl](1-methylimidazole)] has been synthesized and its spin-transition properties have been investigated. X-ray structural analysis of the solvated compound [Fe(L5)2][ClO4]2.CH3CN at 100 K and at 298 K revealed a mononuclear Fe(II)N6 pseudooctahedron with the tridentate ligand in the meridional coordination mode.

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Bottoms up! A discrete metallo-supramolecular nanoball (see picture), synthesized by using "bottom-up" methodologies, uniquely undergoes a solvent-sensitive, physically addressable electronic spin switching. The switching occurs by thermal, light, or solvent perturbation, where importantly it can be switched "on" or "off" by green or red laser irradiation, respectively.

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The thermal and light-induced spin transitions in [Fe(x)Zn(1-x)(phen)2(NCS)2] (phen = 1,10-phenantholine) have been investigated by magnetic susceptibility, photomagnetism and diffuse reflectivity measurements. These complexes display a thermal spin transition and undergo the light-induced excited spin state trapping (LIESST) effect at low temperatures. For each compound, the thermal spin transition temperature, T1/2, and the relaxation temperature of the photo-induced high-spin state, T(LIESST), have been systematically determined.

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The title compound [Fe (II)(L) 2][ClO 4] 2.C 7H 8 (L = 2-[3-(2'-pyridyl)pyrazol-1-ylmethyl]pyridine) has been isolated while attempting to grow single crystals of the spin-transition (continuous-type) compound [Fe (II)(L) 2][ClO 4] 2, published earlier ( Dalton Trans. 2003, 3392-3397).

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A comprehensive study of the photomagnetic behavior of the [Fe(L222N5)(CN)2].H2O complex has been carried out. This complex is characterized by a low-spin (LS) iron(II)-metal center up to 400 K and exhibits at 10 K the well-known Light-Induced Excited Spin State Trapping (LIESST) effect.

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Malaria coma induced by P.falciparum was diagnosed in 51 of 390 adult African patients who had been admitted to the therapeutical unit of the Donk Central Hospital and were receiving parenteral quinine at day 1 of the onset of coma. Examining some clinical and laboratory manifestations of malaria coma indicated that fatal outcome was significantly recorded among the patients with severe concomitant anemia and among the patients who had not or had received inadequate liquid parenterally on the first day of coma.

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