[3+2] Fragmentation of a Pentaphosphido Ligand by Cyanide
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Abstract
White magic: White phosphorus can be selectively activated and functionalized at a low-valent α-diimine-cobalt complex. Treatment of the resulting pentaphosphido complexes (P5) with cyanide ions releases rare cyanodiphosphan-1-ide anions (P2) and forms an anionic cobalt complex with a triphosphido ligand (P3).
The activation of white phosphorus (P4) by transition-metal complexes has been studied for several decades, but the functionalization and release of the resulting (organo)phosphorus ligands has rarely been achieved. Herein we describe the formation of rare diphosphan-1-ide anions from a P5 ligand by treatment with cyanide. Cobalt diorganopentaphosphido complexes have been synthesized by a stepwise reaction sequence involving a low-valent diimine cobalt complex, white phosphorus, and diorganochlorophosphanes. The reactions of the complexes with tetraalkylammonium or potassium cyanide afford a cyclotriphosphido cobaltate anion 5 and 1-cyanodiphosphan-1-ide anions [R2PPCN]− (6-R). The molecular structure of a related product 7 suggests a novel reaction mechanism, where coordination of the cyanide anion to the cobalt center induces a ligand rearrangement. This is followed by nucleophilic attack of a second cyanide anion at a phosphorus atom and release of the P2 fragment.
The activation of white phosphorus (P4) by transition-metal complexes has been studied for several decades, but the functionalization and release of the resulting (organo)phosphorus ligands has rarely been achieved. Herein we describe the formation of rare diphosphan-1-ide anions from a P5 ligand by treatment with cyanide. Cobalt diorganopentaphosphido complexes have been synthesized by a stepwise reaction sequence involving a low-valent diimine cobalt complex, white phosphorus, and diorganochlorophosphanes. The reactions of the complexes with tetraalkylammonium or potassium cyanide afford a cyclotriphosphido cobaltate anion 5 and 1-cyanodiphosphan-1-ide anions [R2PPCN]− (6-R). The molecular structure of a related product 7 suggests a novel reaction mechanism, where coordination of the cyanide anion to the cobalt center induces a ligand rearrangement. This is followed by nucleophilic attack of a second cyanide anion at a phosphorus atom and release of the P2 fragment.
Details
Original language | Undefined |
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Journal | Angewandte Chemie International Edition |
Volume | 58 |
Issue number | 52 |
Publication status | Published - 2019 |
Peer-reviewed | Yes |
External IDs
WOS | 000494840300001 |
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Scopus | 85074833515 |