2‐(Dimethylamino)phosphinin: Ein phosphorhaltiges Anilinderivat

Abstract

Die bisher unbekannten 2‐Amino‐substituierten λ3,σ2‐Phosphinine sind phosphorhaltige Anilinderivate. Theoretische Studien zeigen, dass die starke Wechselwirkung der π‐donierenden NR2‐Gruppe mit dem aromatischen System zu einer erhöhten π‐Dichte am Phosphoratom führt. Ausgehend von einem 3‐N(CH3)2‐substituierten 2‐Pyron und (CH3)3SiC≡P wurden erstmalig 2‐N(CH3)2‐funktionalisierte Phosphinine synthetisiert. Deren Reaktionen mit CuBr⋅S(CH3)2 ergaben CuI‐Komplexverbindungen, in denen erstmalig ein neutrales Phosphinin als seltener μ2‐P‐4e‐Donor‐Ligand durch Verbrückung zweier CuI‐Zentren auftritt. Unsere experimentellen und theoretischen Untersuchungen zeigen, dass 2‐Aminophosphinine die Lücke in der Serie bekannter 2‐Donor‐funktionalisierter Phosphinine schließen.

Copper(I) and Gold(I) Complexes of Aminofunctionalized Phosphinines: Synthesis and Structural Characterization

“…The phosphorus heterocycles 5 – 7 show resonances in the 31 P{ 1 H} NMR spectra at δ(ppm)=238.0 ( 5 , CD 2 Cl 2 ), 244.0 ( 6 , CD 2 Cl 2 ) and 245.0 ( 7 , CD 2 Cl 2 ), respectively. Interestingly, these values are rather different to the shift observed for 2‐ N , N ‐dimethylaminosphosphinine (δ(ppm)=127.0) [11] . This indicates that the electronic properties of 5 – 7 vary significantly from its regioisomer.…”

“…Moreover, the nitrogen atom of the N , N ‐dimethylamino‐substituent is clearly pyramidalized in all three phosphinines. Consequently, we anticipate that the lone pair of the nitrogen atom only weakly contributes in conjugation with the aromatic phosphorus heterocycle, in contrast to the situation for 2 ‐N , N ‐dimethylaminophosphinine [11] …”

“…Having synthesized the novel 3‐ N , N ‐dimethylamino‐substituted phosphinines 5 – 7 , we were further interested in the electronic properties of the ligands, particularly with respect to the parent phosphinine C 5 H 5 P as well as the 2‐ N , N ‐dimethylamino‐functionalized regioisomer, recently reported by us [11] . As already demonstrated for phosphinine 6 , we also found an area of increased electron density close to the nitrogen atom in the electrostatic potential (ESA) maps of 5 and 7 , suggesting the presence of a lone pair that is not part of the aromatic phosphorus heterocycle (Figure 3).…”

“…The corresponding anionic phosphinin‐2‐olate, reported by Grützmacher and co‐workers, acts as a 4e − donor and bridges a cationic [Au(PPh 3 )] + as well as a neutral [AuCl] fragment ( D ) [10] . More recently, our group synthesized a neutral 2‐ N , N ‐dimethylamino‐substituted phosphinine [11] . The strong interaction between the lone‐pair of the nitrogen atom of the NMe 2 group and the aromatic system results in a high π‐density at the phosphorus atom.…”

Triple dehydrofluorination as a route to amidine-functionalized, aromatic phosphorus heterocycles

“…1. [2][3][4][5][6][7] In this respect, the specific functionalization of phosphinines is of particular importance in order to modify their stereoelectronic properties.…”