The Gold(I)‐Mediated Domino Reaction to Fused Diphenyl Phosphoniumfluorenes: Mechanistic Consequences for Gold‐Catalyzed Hydroarylations and Application in Solar Cells

Abstract

A domino sequence, involving a phosphinoauration and a gold-catalyzed 6-endo-dig cyclization step, was developed. Starting from modular and simple-to-prepare phosphadiynes, π-extended phosphoniumfluorenes were synthesized. The mechanistic proposal was supported by kinetic measurements and by the trapping of key intermediates. These led to important conclusions for the gold-catalyzed hydroarylation mechanism. Cyclic voltammetry (CV) and UV/Vis spectroscopy measurements indicated interesting properties for materials science. The phosphoniumfluorene structure was tested as a hole-blocking layer in perovskite solar cells of inverted architecture. Devices with the phosphoniumfluorene exhibited an efficiency of 14.2 %, which was much higher than that of devices without (10.7 %).

Intramolecular Phosphacyclization: Polyaromatic Phosphonium P‐Heterocycles with Wide‐Tuning Optical Properties

“…The reaction of 1 a with copper(II) triflate yielded two products in 30:70 ratio according to the 31 P NMR spectrum of the reaction mixture, which revealed two major signals at 23.8 and 4.4 ppm (Figure S1, Supporting Information). Based on the chemical shift, the main component with high field resonance is ascribed to the constitutional isomer with a six‐membered ring, whereas the low‐field singlet presumably corresponds to the phosphole‐type heterocyclic salt (Scheme ), for which the 31 P signals are typically found around 20–30 ppm in related hydrocarbon backbones . In addition, the mass spectrum of the mixture shows a single peak at m / z= 387.13, which matches the molecular mass of both proposed isomeric products.…”

“…The analysis of the previously reported metal‐mediated phosphacyclization reactions, which involve Au I , Ag I , Mn III , and Cu II species, allows us to assume a plausible reaction pathway presented in Scheme . Firstly, phosphoniumyl radical cation presumably forms from the parent phosphine in the presence of copper(II) triflate by means of a single‐electron transfer (SET).…”

“…The analysis of the previously reported metal-mediated phosphacyclization reactions, which involveA u I , [24][25] Ag I , [26] Mn III , [26a] and Cu II [20a, 27] species, allows us to assumeaplausible reactionp athway presented in Scheme4.F irstly,p hosphoniumyl radical cation [28] presumably forms from the parent phosphine in the presence of copper(II) triflate by means of a single-electron transfer (SET). In the next step, the highly reactive electrophilicP -cation produces the annulated radicali nter-mediate through PÀC PAH bond formation (PAH = polycyclic aromatic hydrocarbon).…”

Enhancing the Open‐Circuit Voltage of Perovskite Solar Cells by up to 120 mV Using π‐Extended Phosphoniumfluorene Electrolytes as Hole Blocking Layers

“…PEDOT:PSS was purchased from Heraeus Deutschland GmbH&Co. PCBM (99.5%) was purchased from Solenne BV. π‐extended phosphoniumfluorenes were synthesized based on the previous work . All other materials were purchased from Sigma‐Aldrich and used as received.…”

Cationic Organophosphorus Chromophores: A Diamond in the Rough among Ionic Dyes

“…The dialkynyl precursors of suitable stereochemistry undergo cascade process, where the first step of stoichiometric phosphinoauration is followed by a gold‐catalyzed cyclization to afford fused π‐extended salts 27 in up to quantitative yields (Scheme 8). [54] …”