Naphtho[2,1-e]-1,2-azaphosphorine 2-Oxide Derivatives: Synthesis, Optoelectronic Properties, and Self-Dimerization Phenomena

Abstract

A library of novel naphtho[2,1-e]-fused 1,2-azaphosphorine-2-oxides that contain electron-withdrawing and-donating substituents on the 3-phenyl groups have been designed, prepared and characterized. This new family of phosphorus-and nitrogencontaining heterocycles are found to be brightly fluorescent with tuneable emission wavelengths (em = 441−493nm, F = 0.19−0.93). Their strong self-dimerization behaviours through N−H and P=O hydrogen bond donors/acceptors were investigated experimentally and theoretically. It has been demonstrated that the pendant phenyl groups can be used to modify the intrinsic optoelectronic properties as well as the self-association of heterocycles. These results presented herein are expected to enable the development of new photofunctional materials and provide important insights in diverse areas of supramolecular chemistry.

Bumpy Roads Lead to Beautiful Places: The Twists and Turns in Developing a New Class of PN-Heterocycles

“…78 Building upon this linear extension of the aromatic backbone (b ring in Scheme 2), Chun-Lin's first study focused on the effect of its nonlinear extension (a and c rings). 79 Two families of PN-phenanthrene derivatives were prepared, where the first started with aminonaphthalenes 15 that were cyclized to 'bent-up' PN-phenanthrene imidates 16 and subsequently hydrolyzed to 'bent-up' amidates 17. The second was made starting from cyclization of aminonaphthalenes 18 to 'bent-down' PN-phenanthrene imidates 19 and hydrolysis to amidates 20 (Scheme 2 and Table 2).…”

Controlling Tautomerization in Pyridine‐Fused Phosphorus‐Nitrogen Heterocycles

“…Both the quantum yield and wavelength of emission can be tuned by alteration of the pendant functional groups as well as by fundamental changes to the acene backbone. [8][9][10][11] Use of strong electronwithdrawing groups as pendant moieties on derivatized scaffold 1 also resulted in dramatic enhancement of the heterocycle's dimerization in solution, affording dimerization constants that are one to two orders of magnitude stronger than the analogous lactam carbostyril. [3,4,12] Because of the phosphorus atom's decreased electronegativity compared to carbon, the phosphonyl motif has increased electron density on the oxygen and acts as a superior hydrogen-bond acceptor.…”

“…Structurally analogous to the popular fluorophores coumarin and carbostyril (Figure 1), the phosphaquinolinone motif exhibits notable photophysical properties. Both the quantum yield and wavelength of emission can be tuned by alteration of the pendant functional groups as well as by fundamental changes to the acene backbone [8–11] . Use of strong electron‐withdrawing groups as pendant moieties on derivatized scaffold 1 also resulted in dramatic enhancement of the heterocycle's dimerization in solution, affording dimerization constants that are one to two orders of magnitude stronger than the analogous lactam carbostyril [3,4,12] .…”

Golden Age of Fluorenylidene Phosphaalkenes–Synthesis, Structures, and Optical Properties of Heteroaromatic Derivatives and Their Gold Complexes

“…The incorporation of main group elements into π-conjugated materials has been identified as a promising path to new functional materials with outstanding optoelectronic properties. − In particular, phosphorus has led to a number of interesting optoelectronic materials that exploit its variable bonding situations and coordination modes . Over the past years, our group has been interested in utilizing the fluorene core as a strong acceptor unit by introducing supermesityl-phosphinidene or -arsinidene fragments (Mes*-P: or Mes*-As:, where Mes* = 2,4,6-tri- tert -butyl phenyl) at the bridgehead position (Figure , II and III ) .…”