Kinetics and photophysical behavior of the P,N-ReI complex [P,N-{(C6H5)2(C5H4N)P}Re(CO)3(O-O3SCF3)]: A directly coordinated (and labile) triflate

Gaspar Prado, María Belén Ibañez, Alison Acosta, Eduardo Chamorro, Patricio Hermosilla-Ibáñez, Germán Günther, Nancy Pizarro, Andrés Vega

Resultado de la investigación: Contribución a una revistaArtículorevisión exhaustiva

1 Cita (Scopus)

Resumen

The reaction of [P,N-{(C6H5)2(C5H4N)P}Re(CO)3Br] (RePNBr) with silver triflate leads to the complex [P,N-{(C6H5)2(C5H4N)P}Re(CO)3(O-CF3SO3)] (RePNTfO) with moderate yield. This new P,N-ReI triflate compound contains the anion directly coordinated to the metal, completing an octahedral environment. RePNTfO displays in dichloromethane (DCM) solution an irreversible oxidation about +1.35 V and three irreversible reduction processes at −1.38 V, −2.03 V and −2.30 V. Oxidation has been attributed to the ReI/ReII couple, while the reduction corresponds to PN-ligand processes, which is consistent with those computed by means of DFT. The absorption spectrum of RePNTfO in DCM displays a maximum at 295 nm (ε = 7.1 × 103 M−1 cm−1) and a shoulder around 350 nm (ε = 1.8 × 103 M−1 cm−1), which have been assigned to intraligand (π → π) and metal to ligand charge transfer (MLCT, dπ → π) transitions with the help of DFT/TDDFT. Excitation of RePNTfO in DCM at 350 nm leads to an emission spectrum centered at 535 nm. The analysis of the variation of the absorption and emission spectra in coordinating solvents compared to non-coordinating DCM, DFT/TDDFT calculations modeling and ELF analysis suggests for coordinating solvents that triflate ligand is replaced in the coordination sphere of ReI in solution. Kinetics of the exchange of triflate by bromide measured in DCM at different temperatures allowed to estimate the Eyring parameters: ΔH, ΔS and ΔG, 50.8 kJ mol−1, −109.6 J K−1 mol−1 and 83.5 kJ mol−1 respectively. The high negative entropy is indicative of a compact transition state, compatible with an associative mechanism, Ia, for the exchange.

Idioma originalInglés
Páginas (desde-hasta)222-230
Número de páginas9
PublicaciónPolyhedron
Volumen137
DOI
EstadoPublicada - 24 nov 2017

Áreas temáticas de ASJC Scopus

  • Química física y teórica
  • Química inorgánica
  • Química de los materiales

Huella

Profundice en los temas de investigación de 'Kinetics and photophysical behavior of the P,N-Re<sup>I</sup> complex [P,N-{(C<sub>6</sub>H<sub>5</sub>)<sub>2</sub>(C<sub>5</sub>H<sub>4</sub>N)P}Re(CO)<sub>3</sub>(O-O<sub>3</sub>SCF<sub>3</sub>)]: A directly coordinated (and labile) triflate'. En conjunto forman una huella única.

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