Design of organophosphorus materials for organic electronics and bio-applications

Asymmetrically Substituted Phospholes as Ligands for Coinage Metal Complexes

“…Within the diverse group of organophosphorus compounds phospholes play a prominent role [ 1 , 2 ]. Owing to their low HOMO-LUMO gap these five membered heterocycles show pronounced luminescence in form of fluorescence making them excellent materials for a wide range of applications [ 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. Recently, we explored the usage of phospholes as guest component in nanoimprint lithography and for the preparation of phosphole-silica hybrids [ 10 , 11 ].…”

Boron- and phosphorus-containing molecular/nano platforms: exploiting pathological redox imbalance to fight cancer

“…To this end, carbon-based homocyclic agents offer a relatively limited degree of tuneability due the intrinsic electronic properties of the carbon element. In contrast, boron [21][22][23][24][25][26] and phosphorus [27][28][29][30][31] heterocycles captivate due to their unique and wide regioselective chemistry (vide infra). This results in major advantages for rational drug design, which can selectively be attributed to either boron or phosphorus atom.…”

Two-Fold Intramolecular Phosphacyclization: From Fluorescent Diphosphapyrene Salts to Pentavalent Derivatives

“…The main benefit is that, once embedded, the phosphorus atom may be decorated with electrophiles, Lewis acids, and transition metals; most of these modifications at the phosphorus center are chemically reversible. , This provides unique possibilities not only to tune physical and chemical characteristics of individual molecules but also to influence the intermolecular interactions of bulk π-extended materials to meet the requirements of optoelectronic applications. Thus, π-systems particularly based on six-membered phosphorus heterocycles (6MPHs) have experienced a rapid evolution in the last years. − They have been used as fluorescent dyes for imaging and intracellular pH-sensors, liquid crystals, organic electronics, , and molecular motors …”

“…Currently, π-extended phosphonium salts based on 6MPHs, i.e., with a λ 4 ; σ 2 -endo , σ 2 -exo phosphorus center, are at the focus of organophosphorus chemistry; ,,− they provide a promising platform to conceive near-infrared fluorophores for bioimaging, electrofluorochromic systems, and viologen-like materials. , Quaternized phosphorus atoms strongly reduce the LUMO level of π-systems and thus decrease the optical band gap. A large variety of molecular motifs emerged to exploit this feature. ,,− However, the quaternized λ 4 ; σ 2 -endo , σ 2 -exo phosphorus centers from isolated 6MPHs have not been demonstrated to be reversible; i.e. the phosphorus substituents cannot be replaced by other moieties.…”

“…Consequently, they do not allow for further fine-tuning the physicochemical properties of the π-systems through the modification of the phosphorus atom as their functionalization remains locked after quaternization. This is in sharp contrast with, for instance, oxidized, pentavalent λ 5 ; σ 2 -endo , σ 2 -exo phosphorus atoms, which can be easily interconverted into trivalent λ 3 ; σ 2 -endo , σ 1 -exo once inserted into π-systems. ,, The trivalent form may be then postfunctionalized with oxidizing agents, transition metals, Lewis acids, etc., to tailor the properties of the π-system . Thus, the possibility of converting quaternized λ 4 ; σ 2 -endo , σ 2 -exo phosphorus atoms of π-extended 6MPHs into λ 5 ; σ 2 -endo , σ 2 -exo or trivalent λ 3 ; σ 2 -endo , σ 1 -exo centers would clearly revalue the π-extended phosphonium motifs for further purposes.…”