ELECTRON BEHAVIOR AND STRUCTURAL CHARACTERIZATION OF NITROSYL PINCER-TYPE PNP RHODIUM COMPLEXES

JUAN PELLEGRINO; FABIO DOCTOROVICH; CARINA GAVIGLIO

Bariloche

Congreso; XV Reunión Anual de la Asociación Argentina de Cristalografía; 2019

Asociación Argentina de Cristalografía

REDOX BEHAVIOR AND STRUCTURAL CHARACTERIZATION OF NITROSYL PINCER-TYPE PNP RHODIUM COMPLEXESCarina Gaviglio1*; Fabio Doctorovich2; Juan Pellegrino21 Departamento de Física de la Materia Condensada, Gerencia de Investigación y Aplicaciones, Centro Atómico Constituyentes, CNEA.2 DQIAQF/INQUIMAE, FCEN-UBA/CONICET, Ciudad Universitaria, Pab. II, Buenos Aires, Argentina.* gaviglio@tandar.cnea.gov.arA topic of interest consists on exploring the combination of robust bulky pincer ligands that present high stability and steric protection with redox active ligands as NO in the reactivity of {RhNO}n complexes. Nitrosyl complexes are described as {MNO}n where n stands for the number of electrons in the metal d and π* NO orbitals. In a previous work the activation of carbon-halogen bonds by a paramagnetic complex {RhNO}9 with a PCP pincer type ligand was reported [1]. Herein the synthesis and characterization of a new paramagnetic complex {RhNO}9 1+. with a PNP pincer type ligand is presented.Reaction of {RhNO}8 12+ with 1 equivalent of Co(Cp)2 in trifluorotoluene resulted in quantitative formation of 1+. and [Co(Cp)2][BF4]. The paramagnetic nature of the one-electron reduced {RhNO}9 species 1+. was confirmed by EPR and by the broad resonances occurring in 1H NMR. Also by FTIR the expected change was observed in the NO upon the {RhNO}89 conversion from 12+ to 1+. (1911 to 1650 cm-1). Figure 1: ORTEP plot of complexes 12+ and 1+. at the 50% probability level. Hydrogen atoms and triflate counterions (CF3SO3-) are omitted for clarity.The molecular structure of both compounds 12+ and 1+. was confirmed by X-ray diffraction (Figure 1). In both structures the rhodium atom is located in the center of a square-planar geometry with the nitrosyl group occupying the position trans to the ipso carbon. In 12+ the Rh-N-O angle is 176.1(3)º while in 1+. is 145.5(2)º due to the more electron density on the NO ligand.Palabras clave: nitrosyl complexes; DRX; redox behavior.[1] J. Pellegrino, C. Gaviglio, D. Milstein, F. Doctorovich, Organometallics, 32 (2013) 6555?6564.