1620886-35-2Relevant academic research and scientific papers
Phosphorus centers of different hybridization in phosphaalkene-substituted phospholes
Oeberg, Elisabet,Orthaber, Andreas,Lescop, Christophe,Reau, Regis,Hissler, Muriel,Ott, Sascha
, p. 8421 - 8432 (2014)
Phosphole-substituted phosphaalkenes (PPAs) of the general formula Mes P=C(CH3)-(C4H2P(Ph))-R 5a-c (Mes=2,4,6-tBu 3Ph; R=2-pyridyl (a), 2-thienyl (b), phenyl (c)) have been prepared from octa-1,7-diyne-substituted phosphaalkenes by utilizing the Fagan-Nugent route. The presence of two differently hybridized phosphorus centers (σ2,λ3 and σ3, λ3) in 5 offers the possibility to selectively tune the HOMO-LUMO gap of the compounds by utilizing the different reactivity of the two phosphorus heteroatoms. Oxidation of 5a-c by sulfur proceeds exclusively at the σ3,λ3-phosphorus atom, thus giving rise to the corresponding thioxophospholes 6a-c. Similarly, 5a is selectively coordinated by AuCl at the σ3,λ3-phosphorus atom. Subsequent second AuCl coordination at the σ2, λ3-phosphorus heteroatom results in a dimetallic species that is characterized by a gold-gold interaction that provokes a change in π conjugation. Spectroscopic, electrochemical, and theoretical investigations show that the phosphaalkene and the phosphole both have a sizable impact on the electronic properties of the compounds. The presence of the phosphaalkene unit induces a decrease of the HOMO-LUMO gap relative to reference phosphole-containing π systems that lack a P=C substituent.
