| Autor: |
Kornev, Alexander N., Panova, Yulia S., Sushev, Vyacheslav V., Dorado Daza, Diego F., Novikov, Alexander S., Cherkasov, Anton V., Fukin, Georgy K., Abakumov, Gleb A. |
| Zdroj: |
Inorganic Chemistry; December 2019, Vol. 58 Issue: 23 p16144-16153, 10p |
| Abstrakt: |
The current study provides a clear understanding of the chemical properties of annelated 3a,6a-diaza-1,4-diphosphapentalenes (DDPs), which are best viewed as stabilized singlet phosphinidenes. It was found that DDPs undergo reversible oligomerization in solution, which provides 1,2,3-diazaphosphole-substituted cyclotetraphosphines, isolated and characterized by X-ray crystal structure analysis. Transformation of the 10-π-electron heteropentalene system into a stabilized phosphinidene occurs when the P–N bond is lengthened, which is facilitated by weak Lewis acids and bases. DFT calculations show that the lowest unoccupied molecular orbital of DDP has a high localization at the phosphorus atom when the N–P bond distance reaches the value of 2.53 Å. Oligomerization is a concentration-dependent process. Increasing the concentration of the monomer solution promotes tetramer formation, and vice versa: a strong dilution leads to a monomer. Tetramer solutions are photosensitive and yield monomers upon irradiation. The new annelated DDP 2and its dichloro precursor 4based on tetralone azine were synthesized. 4exists in the solid state as a 1,4-dichloro isomer, while in solution it gives an equilibrium mixture of 1,1- and 1,4-isomers. Cyclohexanone-annelated diazadiphosphapentalene 1forms a weak complex (1:1) with Ph3B, showing an elongated P–B bond (2.114(12) Å), which is noticeably larger than the sum of the covalent radii of the elements. |
| Databáze: |
Supplemental Index |
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