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Synthesis and Characterization of Dimethylbis(2-pyridyl)borate Nickel(II) Complexes: Unimolecular Square-Planar to Square-Planar Rotation around Nickel(II).

ABSTRACT: The syntheses of novel dimethylbis(2-pyridyl)borate nickel(II) complexes 4 and 6 are reported. These complexes were unambiguously characterized by X-ray analysis. In dichloromethane solvent, complex 4 undergoes a unique square-planar to square-planar rotation around the nickel(II) center, for which activation parameters of ?H (?) = 12.2(1) kcal mol(-1) and ?S (?) = 0.8(5) eu were measured via NMR inversion recovery experiments. Complex 4 was also observed to isomerize via a relatively slow ring flip: ?H (?) = 15.0(2) kcal mol(-1); and ?S (?) = -4.2(7) eu. DFT studies support the experimentally measured rotation activation energy (cf. calculated ?H (?) = 11.1 kcal mol(-1)) as well as the presence of a high-energy triplet intermediate (?H = 8.8 kcal mol(-1)).

SUBMITTER: Celaje JA

PROVIDER: S-EPMC4034079 | biostudies-other | 2014 Apr

REPOSITORIES: biostudies-other

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Synthesis and Characterization of Dimethylbis(2-pyridyl)borate Nickel(II) Complexes: Unimolecular Square-Planar to Square-Planar Rotation around Nickel(II).

Celaje Jeff A JA Pennington-Boggio Megan K MK Flaig Robinson W RW Richmond Michael G MG Williams Travis J TJ

Organometallics 20140407 8

The syntheses of novel dimethylbis(2-pyridyl)borate nickel(II) complexes 4 and 6 are reported. These complexes were unambiguously characterized by X-ray analysis. In dichloromethane solvent, complex 4 undergoes a unique square-planar to square-planar rotation around the nickel(II) center, for which activation parameters of ΔH⧧ = 12.2(1) kcal mol-1 and ΔS⧧ = 0.8(5) eu were measured via NMR inversion recovery experiments. Complex ...[more]

PMID: 24882919

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