A Neutral Tetraphosphacyclobutadiene Ligand in Cobalt(I) Complexes1. (4th December 2014)

• Record Type: Journal Article
• Authors: Yao, Shenglai; Lindenmaier, Nils; Xiong, Yun; Inoue, Shigeyoshi; Szilvási, Tibor; Adelhardt, Mario; Sutter, Jörg; Meyer, Karsten; Driess, Matthias
• Is Part Of: Angewandte Chemie. Volume 127:Number 4(2015)
• Page Start: 1266
• Page End: 1270
• Publication Date: 2014-12-04
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201409469
• Languages: English
• ISSNs: 0044-8249

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The unusual reactivity of the newly synthesized β‐diketiminato cobalt(I) complexes, [(L<sup>Dep</sup>Co)<sub>2</sub>] (<bold>2 a</bold>, L<sup>Dep</sup>=CH[C(Me)N(2, 6‐Et<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)]<sub>2</sub>) and [L<sup>Dipp</sup>Co<bold>⋅</bold>toluene] (<bold>2 b</bold>, L<sup>Dipp</sup>=CH[CHN(2, 6‐<sup>i</sup>Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)]<sub>2</sub>), toward white phosphorus was investigated, affording the first cobalt(I) complexes [(L<sup>Dep</sup>Co)<sub>2</sub>(μ<sub>2</sub>:η<sup>4</sup>, η<sup>4</sup>‐P<sub>4</sub>)] (<bold>3 a</bold>) and [(L<sup>Dipp</sup>Co)<sub>2</sub>(μ<sub>2</sub>:η<sup>4</sup>, η<sup>4</sup>‐P<sub>4</sub>)] (<bold>3 b</bold>) bearing the neutral cyclo‐P<sub>4</sub> ligand with a rectangular‐planar structure. The redox chemistry of <bold>3 a</bold> and <bold>3 b</bold> was studied by cyclic voltammetry and their chemical reduction with one molar equivalent of potassium graphite led to the isolation of [(L<sup>Dep</sup>Co)<sub>2</sub>(μ<sub>2</sub>:η<sup>4</sup>, η<sup>4</sup>‐P<sub>4</sub>)][K(dme)<sub>4</sub>] (<bold>4 a</bold>) and [(L<sup>Dipp</sup>Co)<sub>2</sub>(μ<sub>2</sub>:η<sup>4</sup>, η<sup>4</sup>‐P<sub>4</sub>)][K(dme)<sub>4</sub>] (<bold>4 b</bold>). Unexpectedly, the monoanionic Co<sub>2</sub>P<sub>4</sub> core in <bold>4 a</bold> and <bold>4 b</bold>, respectively, contains the two‐electron‐reduced cyclo‐P<sub>4</sub><sup>2−</sup> ligand with a square‐planar structure and mixed‐valent cobalt(I, II) sites. The electronic structures of <bold>3 a</bold>, <bold>3 b</bold>, <bold>4 a</bold>, and <bold>4 b</bold> were elucidated by NMR and EPR spectroscopy as well as magnetic measurements and are in agreement with results of broken‐symmetry DFT calculations.</p> </abstract>