3 years ago

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

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
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 +1.35V and three irreversible reduction processes at −1.38V, −2.03V and −2.30V. 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 295nm (ε =7.1×103 M−1 cm−1) and a shoulder around 350nm (ε =1.8×103 M−1 cm−1), which have been assigned to intraligand (ππ) and metal to ligand charge transfer (MLCT, dππ) transitions with the help of DFT/TDDFT. Excitation of RePNTfO in DCM at 350nm leads to an emission spectrum centered at 535nm. 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 , 50.8kJmol−1, −109.6JK−1 mol−1 and 83.5kJmol−1 respectively. The high negative entropy is indicative of a compact transition state, compatible with an associative mechanism, I a, for the exchange.

Publisher URL: www.sciencedirect.com/science

DOI: S0277538717305491

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.