page_title: Diphosphagermylene
section_title: Synthesis of P-Ge σ-Only Diphosphagermylenes
hierarchical_section_title: Diphosphagermylene / Preparation of Diphosphagermylenes / Synthesis of P-Ge σ-Only Diphosphagermylenes
caption_attribution_description: English: 1
context_page_description: Diphosphagermylenes are a class of compounds containing a divalent germanium atom bound to two phosphorus atoms. While these compounds resemble diamidocarbenes, such as N-heterocyclic carbenes, diphosphagermylenes display bonding characteristics distinct from those of diamidocarbenes. In contrast to NHC compounds, in which there is effective N-C p-p overlap between the lone pairs of planar nitrogens and an empty p-orbital of a carbene, systems containing P-Ge p-p overlap are rare. Until 2014, the geometry of phosphorus atoms in all previously reported diphosphatetrylenes are pyramidal, with minimal P-Ge p-p interaction. It has been suggested that the lack of p-p in Ge-P bonds is due to the high energetic barrier associated with achieving a planar configuration at phosphorus, which would allow for efficient p-p overlap between the phosphorus lone pair and the empty P orbital of Ge. The resulting lack of π stabilization contributes to the difficulty associated with isolating diphosphagermylene and the Ge-P double bonds.
context_section_description: Reactivity of sterically demanding lithium (fluorosilyl)silylphosphanides with GeI₂ yields green, cubic crystals in moderate yield. The identity of this species was investigated using only multinuclear NMR, elemental analysis, and UV-vis. Computational calculations (at the CIS level with the ab initio Los Alamos pseudopotential method (LAN L 1 DZ)) of the diphosphagermylene electronic structure was in agreement experimentally-derived electronic transition values. Due to disorder, the crystal structure of the diphosphagermylene could not be investigated.
caption: Synthesis of monomeric σ-only diphosphagermylenes.[4]
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