Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/75775
Type: Artigo de periódico
Title: Ruthenium nitrosyl complexes with N-heterocyclic ligands
Author: Borges, SDS
Davanzo, CU
Castellano, EE
Z-Schpector, J
Silva, SC
Franco, DW
Abstract: A new route was developed for preparing a series of trans nitrosyl complexes of general formula trans-[Ru(NH3)4(L)(NO)](BF4)(3), where L = imidazole: L-histidine, pyridine, or nicotinamide. The complexes have been characterized by elemental analysis, molar conductance measurements, UV-visible, infrared, proton nuclear magnetic, and electron paramagnetic resonance spectroscopies, and electrochemical techniques. The compounds possess relatively high v(NO) stretching frequencies indicating that a high degree of positive charge resides on the coordinated nitrosyl group. The nitrosyl complexes react with OH-according to the equation trans-[Ru(NH3)(4)L(NO)](3+) + 20H(-) reversible arrow trans-[Ru(NH3)(4)L(NO2)](+) + H2O, with a K-eq (at 25.0 degrees C in 1.0 mol/L NaCl) of 2.2 x 10(5), 5.9 x 10(7), 9.7 x 10(10), and 4.6 x 10(13) L-2 mol(-2) for the py, nic, imN, and L-hist complexes, respectively. Only one redox process attributed to the reaction [Ru-II(NH3)(4)L(NO+)](3+) + e(-) reversible arrow trans-[Ru-II(NH3)(4)L(NO0)](2+) was observed in the range -0.45 to 1.20 V for all the nitrosyl complexes. Linear correlations are observed in plots of v(NO) versus E-1/2 and of E-1/2 versus Sigma E-L showing that the oxidizing strength of the coordinated NO increases with increase in L pi-acidity. The crystal structure analysis of trans-[Ru(NH3)(4)nicNO](2)(SiF6)(3) shows that the mean Ru-N-O angle is very close to 180 degrees (177 +/- 1 degrees) and the mean N-O distance is 1.17 +/- 0.02 Angstrom, thus confirming the presence of the Ru-II-NO+ moiety in the nitrosyl complexes studied.
Country: EUA
Editor: Amer Chemical Soc
Rights: fechado
Identifier DOI: 10.1021/ic951563s
Date Issue: 1998
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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