Abstract
From the two organonickel(II) scaffolds [Ni(Phbpy)] + and [Ni(PyPhPy)] + (HPhbpy = 6-phenyl-2,2′-bipyridine≡HC ∧N ∧N and Py(HPh)Py = 2,6-di-2-pyridyl-benzene≡N ∧(HC) ∧N) the hydrido complexes [Ni(C ∧N ∧N)H] and [Ni(N ∧C ∧N)H] were studied in a combined experimental/theoretical approach. The hydrido complexes were prepared via the reaction of the halido derivatives [Ni(C ∧N ∧N)X] and [Ni(N ∧C ∧N)X] (X = Cl, Br) with Li(Et 3BH) (superhydride). The C ∧N ∧N complex undergoes rapid reductive elimination (RE) yielding HPhbpy and Ni particles even at the lowest temperatures, while the PyPhPy derivative is more stable. Low-temperature 1H nuclear magnetic resonance (NMR) spectroscopy allowed detection of a signal at δ = −2.86 ppm assignable to the hydrido ligand. The different stabilities can be directly correlated to the cis (Phbpy) and trans (PyPhPy) orientations of the carbanionic phen-2-ide group with the hydrido ligand, and rapid RE occurs from the cis position which is also supported by the density functional theory (DFT) calculations which are presented. A further TD-DFT/UV-vis absorption study is also reported to rationalize and confirm the fleeting existence of the Ni-H moiety, and proposals are made on the route of its decomposition.
Original language | English |
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Pages (from-to) | 2206-2215 |
Number of pages | 10 |
Journal | Organometallics |
Volume | 42 |
Issue number | 16 |
Early online date | 1 Aug 2023 |
DOIs | |
Publication status | Published - 28 Aug 2023 |
Keywords
- C-H BOND
- OXIDATIVE ADDITION
- PINCER COMPLEXES
- REACTIVITY
- ALKYLATION
- HYDROGEN
- NI
- POLYMERIZATION
- CATALYSTS
- EXCHANGE