Redox reaction of red phosphorus with hydrosulfide anions in DMSO

A wet etching method for few-layer black phosphorus with an atomic accuracy and compatibility with major lithography techniques

“…RP and BP have very close standard enthalpy of formation and standard molar entropy. Common reactions with RP published from 1920's can be classified into five categories: 1) reactions with oxygen or high oxidative oxyacid 30,31 , 2) reactions with high oxidative metal ions or some kind of metals, [32][33][34][35] 3) reactions with halogens 36-38 , 4) strong Lewis base reactions [39][40][41][42][43] and 5) organic addition or substitution reactions 39,[42][43][44][45] . However, common photoresist used in lithography process is incompatible with the solution used in Lewis base reactions and organic addition/substitution reactions, and metal contact materials used for BP devices are incompatible high oxidative metal ion reactions.…”

Elemental phosphorus in strongly basic media as phosphorylating reagent: a dawn of halogen-free ‘green’ organophosphorus chemistry

“…36 Red phosphorus reacts with NaSH in DMSO (100-116°C, 4.5 h) via redox P-P bond cleavage with hydrosulfide anions to form intermediate species with P-H and P-S bonds, and finally leading to phosphine and trisodium phosphotrithioite. The latter are readily oxidized with air oxygen and elemental sulfur to form S,S,S-trisodium phosphotrithioate and trisodium phosphotetrathioate, respectively.…”

“…The treatment of the reaction mixture with alkyl halides leads to a ~1:1 mixture of S,S,S-trimethyl phosphorotrithioate and trimethyl phosphorotetrathioate in a total yield of 10% (Scheme 19). 36 Sulfur-centered nucleophiles produced from thiols in the KOH/DMSO system disassemble (125-128°C, 4 h) the crosslinked macromolecule of red phosphorus to form finally (in 13-15% yields) potassium S,S-dialkyl trithiophosphates. The latter are readily alkylated with organic halides to give S,S,S-trialkyl trithiophosphates (Scheme 20).…”