The organic anionic radical 2-(4-carboxy-phenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl-3-oxide (NITpBA−) has two different types of potentially metal-coordinating sites. One is the carboxylate group, the other consists of the two oxygen atoms belonging to the nitronyl nitroxide part. The nitronyl nitroxides have generally revealed a rather weak coordinating ability and they have been found only to coordinate metal ions with a low electron density as in the case of hexafluoro-acetylecetonates. Howeverm, in the simple, carboxylate salt Mn(NITpBA)2(H2O)2, each MnII ion is coordinated simultaneously by water, carboxylate oxygens and radical oxygens with the NITpBA− ligands bridging the MnII ions such as to obtain a ladder-like structure. The NiII derivative has also been prepared and it was found to be isostructural with the Mn salt. Mn(NITpBA)2(H2O)2 crystallizes in the monoclinic system, P21/c (No. 14) space group, a = 12.644(2), b = 9.203(2), c = 13.598(2), β = 115.21 (1)°, V = 1431.6(4) Å3, Z = 2, refinement with 2150 reflections, 196 parameters, yielded R = 0.046 and Rw = 0.051. The magnetic susceptibility as a function of temperature of these compounds is readily accounted for on the basis of their structure. A chain model was adopted to reproduce the observed magnetic susceptibility of the NITpBAH free radical.
Scheda prodotto non validato
Scheda prodotto in fase di analisi da parte dello staff di validazione
|Titolo:||Structure and magnetism of Nickel(II) and Manganese(II) complexes of a nytronyl nitroxide carboxylic acid|
|Citazione:||Schiodt, N.C., FABRIZI DE BIANI, F., Caneschi, A., & Gatteschi, D. (1996). Structure and magnetism of Nickel(II) and Manganese(II) complexes of a nytronyl nitroxide carboxylic acid. INORGANICA CHIMICA ACTA, 248, 139-146.|
|Appare nelle tipologie:||1.1 Articolo in rivista|