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Isolation of a 16π‐Electrons 1,4‐Diphosphinine‐1,4‐diide with a Planar C 4 P 2 Ring
Author(s) -
Rottschäfer Dennis,
Neumann Beate,
Stammler HansGeorg,
Sergeieva Tetiana,
Andrada Diego M.,
Ghadwal Rajendra S.
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202003617
Subject(s) - comproportionation , chemistry , lone pair , antiaromaticity , ring (chemistry) , crystallography , aromaticity , electron , molecular orbital , stereochemistry , molecule , organic chemistry , electrochemistry , physics , electrode , quantum mechanics
Herein, we report the first 1,4‐diphosphinine‐1,4‐diide compound [(ADC Ph )P] 2 ( 5‐Ph ) (ADC Ph =PhC{(NDipp)C} 2 ; Dipp=2,6‐ i Pr 2 C 6 H 3 ) derived from an anionic dicarbene (ADC Ph ) as a red crystalline solid. Compound 5‐Ph containing a 16π‐electron planar fused‐tricyclic ring system was obtained by the 4e reduction of [(ADC Ph )PCl 2 ] 2 ( 4‐Ph ) with Mg (or KC 8 ) in a quantitative yield. Experimental and computational results imply that the central 8π‐electrons C 4 P 2 ring of 5‐Ph , which is fused between two 6π‐electrons C 3 N 2 aromatic rings, is antiaromatic. Thus, each of the phosphorus atoms of 5‐Ph has two electron‐lone‐pairs, one in a p‐type orbital is in conjugation with the C=C bonds of the C 4 P 2 ring, while the second resides in a σ‐symmetric orbital. This can be shown with the gold complex [(ADC Ph )P(AuCl) 2 ] 2 ( 6‐Ph ) obtained by reacting 5‐Ph with (Me 2 S)AuCl. A mixture of 5‐Ph and 4‐Ph undergoes comproportionation in the presence of MgCl 2 to form the intermediate oxidation state compound [(ADC Ar )P] 2 (MgCl 4 ) ( 7‐Ph ), which is an aromatic species.