Tuning the Optical Properties of 1,1′‐Biphospholes by Chemical Alterations of the P–P Bridge

Abstract

Keywords: Phosphorus heterocycles / Charge transfer / Conjugation / Pi interactions / Aromaticity 2,5-Di(1-naphthyl)-1-phenylphosphole (2) was prepared from phenylphosphine and dinaphthylbutadiyne in 70 % yield, and oxidized to its oxide 3. Treatment of 2 with a solution of potassium naphthalide results in selective formation of phospholide anion 4, which can be oxidized with iodine to afford biphosphole 5. The crystal structure of 5 exhibits an unusual s-trans conformation across the P-P bridge that is most stabilized by π-π stacking of the naphthyl substituents. Biphosphole 5 can be oxidized to its mono-oxidized 6 and dioxide 7. Generally, all phosphole oxidations lead to de-

Asymmetrically Substituted Phospholes as Ligands for Coinage Metal Complexes

“…The highest quantum yield was found for complex 4 which is still 11% lower than the quantum yield of the free phosphole ligand. The attenuation coefficients are comparable to those obtained for other phospholes [ 12 , 13 ].…”

“…Depending on their substitution pattern, the absorption and emission maxima can be tuned to lower or higher wavelengths and the quantum yield for emissive processes can be controlled to a certain extent [ 12 , 13 , 14 , 15 , 16 ]. In particular, asymmetrically substituted phospholes allow an even more precise adaption of the optical properties [ 10 , 17 ].…”

A Rational Synthetic Approach to 2,5‐Diphenyl‐β‐silyl Phospholes

“…[16] Recently, the scope of this reaction has been nicely extended. [17] These results inspired us to investigate whether β-lithiated phospholes may occur as intermediates in these reactions, and, if they exist, whether these intermediates could be a significant impact on the fluorescence properties of the phosphole system, leading to increased Stokes shifts and blueshifted absorption with redshifted emission. The key compounds have been characterized by multinuclear NMR spectroscopy, mass spectrometry, and, in part, by single-crystal X-ray diffraction analysis.…”

Catalytic Hydrofunctionalization Reactions of 1,3-Diynes

“…In this way, the final reaction products 88 are formed and the nucleophile PhPHLi regenerated. the same protocol, but using Li n Bu instead of LiPh, the synthesis of 2,5-di(1naphthyl)phosphole 89 [126], the chiral derivatives 90 [127] and 91 [128], and the ferrocenylsubstituted phospholes 92 [129][130][131] was later described by reacting the respective 1,3-diyne with a primary aryl phosphine (see Figure 12). Noncatalytic transformations allowing the access to phosphole derivatives from 1,3-diynes have additionally been described employing stoichiometric amounts of lithium-phosphide reagents [132][133][134].…”