Dynamic Properties of Methyl(trimethylphosphane)nickel Complexes Containing (2‐Diphenylphosphanyl)phenylamido Ligands

<jats:title>Abstract</jats:title><jats:p>P,N‐chelates of nickel NiCl[2‐(Ph<jats:sub>2</jats:sub>P)C<jats:sub>6</jats:sub>H<jats:sub>4</jats:sub>NR](PMe<jats:sub>3</jats:sub>) (<jats:bold>1</jats:bold>: R = H; <jats:bold>2</jats:bold>: R = SiMe<jats:sub>3</jats:sub>) have been obtained from NiCl<jats:sub>2</jats:sub>(PMe<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub> and 2‐(Ph<jats:sub>2</jats:sub>P)C<jats:sub>6</jats:sub>H<jats:sub>4</jats:sub>NRLi. Reaction with MeLi affords methylnickel compounds NiMe[2‐(Ph<jats:sub>2</jats:sub>P)C<jats:sub>6</jats:sub>H<jats:sub>4</jats:sub>NR](PMe<jats:sub>3</jats:sub>) (<jats:bold>3</jats:bold>: R = H; <jats:bold>4</jats:bold>: R = Me; <jats:bold>5</jats:bold>: R = SiMe<jats:sub>3</jats:sub>). By the same route NiMe[2‐(R<jats:sup>1</jats:sup>R<jats:sup>2</jats:sup>P)C<jats:sub>6</jats:sub>H<jats:sub>4</jats:sub>NR](PMe<jats:sub>3</jats:sub>) (<jats:bold>6</jats:bold>: R<jats:sup>1</jats:sup> = R<jats:sup>2</jats:sup> = CHMe<jats:sub>2</jats:sub>) was synthesized. Solutions in THF contain <jats:italic>cis</jats:italic> and <jats:italic>trans</jats:italic> isomers of square‐planar complexes, and dynamic NMR spectroscopy shows dissociation of trimethylphosphane to be more rapid in the <jats:italic>trans</jats:italic> isomers. In a crystal of <jats:bold>5</jats:bold> the molecular structure is <jats:italic>cis</jats:italic>‐<jats:bold>5</jats:bold>. Out of these complexes only <jats:bold>3</jats:bold> and <jats:bold>4</jats:bold> add trimethylphosphane to form pentacoordinate compounds NiMe[2‐(Ph<jats:sub>2</jats:sub>P)C<jats:sub>6</jats:sub>H<jats:sub>4</jats:sub>NR](PMe<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub> (<jats:bold>7</jats:bold>, <jats:bold>8</jats:bold>) in the crystal as shown by the molecular structure of <jats:bold>7</jats:bold> while in THF equilibria <jats:bold>7</jats:bold> ⇄ <jats:italic>cis</jats:italic>‐<jats:bold>1</jats:bold> and <jats:bold>8</jats:bold> ⇄ <jats:italic>cis</jats:italic>‐<jats:bold>2</jats:bold> are observed by NMR spectroscopy. The same solution properties are found with NiMe[2‐(R<jats:sup>1</jats:sup>R<jats:sup>2</jats:sup>P)C<jats:sub>6</jats:sub>H<jats:sub>4</jats:sub>NR](PMe<jats:sub>3</jats:sub>)<jats:sub>2</jats:sub> (<jats:bold>9</jats:bold>: R<jats:sup>1</jats:sup> = CMe<jats:sub>3</jats:sub>, R<jats:sup>2</jats:sup> = Ph). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)</jats:p>