Synthical logo
Synthical
Your space
Profile
Activity
Favorites
Folders
Feeds
From chemRxiv
UC Irvine

Thermochemical Studies of Nickel Hydride Complexes with Cationic Ligands in Aqueous and Organic Solvents

Transition metal hydride complexes are key intermediates in a variety of catalytic processes. Transfer of a hydride, hydrogen atom, and proton are defined by the thermochemical parameters of hydricity, bond dissociation free energy (BDFE), and pKa, respectively. These values have been studied primarily in organic solvents to predict or understand reactivity. Despite growing interest in the development of aqueous metal hydride catalysis, BDFE measurements of transition metal hydrides in water are rare. Herein, we report two nickel hydride complexes with one or two cationic ligands that enable the measurement of BDFE values in both aqueous and organic solvents using their reduction potential and pKa values. The Ni(I/0) reduction potentials increase anodically as more charged groups are introduced into the ligand framework and are among the most positive values measured for Ni complexes. The complex with two cationic ligands, 2-Ni(II)–H, displays exceptional stability in water with no evidence of decomposition at pH 1 for at least 2 weeks. The BDFE of the nickel hydride bond in 2-Ni(II)–H was measured to be 53.8 kcal/mol in water, and between 50.9-56.2 kcal/mol in acetonitrile, consistent with prior work that indicates minimal solvent dependence for BDFEs of O-H and N-H bonds. These results indicate transition metal hydride BDFEs do not change drastically in water and inform future studies on highly cationic transition metal hydride complexes.
Upvote
Simplify
Published on June 28, 2022
Copy BibTeX
Loading...
Comments
Summary
There is no AI-powered summary yet, because we do not have a budget to generate summaries for all articles.
1. Buy subscription
We will thank you for helping thousands of people to save their time at the top of the generated summary.
If you buy our subscription, you will be able to summarize multiple articles.
Pay $undefined
≈10 summaries
Pay $undefined
≈60 summaries
2. Share on socials
If this article gets to top-5 in trends, we'll summarize it for free.
Copy link
Content
Summary