Facile Synthesis and Properties of 2‐λ5‐Phosphaquinolines and 2‐λ5‐Phosphaquinolin‐2‐ones

Treatment of 2‐ethynylanilines with P(OPh)₃ gives either 2,2‐diphenoxy‐2‐λ⁵‐phosphaquinolines or 2‐phenoxy‐2‐λ⁵‐phosphaquinolin‐2‐ones under transition‐metal‐free conditions. This reaction offers access to an underexplored heterocycle, which opens up the study of the fundamental nature of the N?P^V double bond and its potential for delocalization within a cyclic π‐electron system. This heterocycle can serve as a carbostyril mimic, with application as a bioisostere for pharmaceuticals based on the 2‐quinolinone scaffold. It also holds promise as a new fluorophore, since initial screening reveals quantum yields upwards of 40 %, Stokes shifts of 50–150 nm, and emission wavelengths of 380–540 nm. The phosphaquinolin‐2‐ones possess one of the strongest solution‐state dimerization constants for a D–A system (130 M ^?1) owing to the close proximity of a strong acceptor (P?O) and a strong donor (phosphonamidate N? H), which suggests that they might hold promise as new hydrogen‐bonding hosts for optoelectronic sensing.     

1, 2λ5-azaphosphinines and a new 1λ5, 3λ5-. Diphosphinine

The 1,2-azaphosphinine, 9 , and the 1,3-diphosphinine, 10 , can be isolated from a mixture resulting from the reaction of 1,1,3,3-tetrakis(dimethylamino)-1λ⁵,3λ⁵-diphosphete, 1 , and ethyl isothiocyanate. The reaction of 1 with phenyl isothiocyanate yields the 1,2-azaphosphinine, 16 . Mechanisms for the formation of the compounds 9 , 10 , and 16 are suggested. The properties, the NMR, mass, and IR spectra, and the molecular and crystal structures of 9 and 10 are described and discussed.     

Substitutionsprodukte eines spirocyclischen anorganischen λ5PN-Systems aus Cyclotriphosphazen und Cyclodi(phosphadiazan)

Substitution Products of 4,4,6,6-Tetrachloro-6′-phenoxy-6′ -thioxo-cyclotriphosphazene-2-spiro-3′-cyclodi(phosphadiazane) Reactions of the spiro compound 4,4,6,6-Tetrachloro-6′-phenoxy-6′-thioxo-cyclotriphosphazene-2-spiro-3′-cyclodi(phosphadiazene) Cl₄N₃P₃(NH? NH)₂P(S)OC₆ H₅ with an excess of ammonia, cyclopropylamine, aziridine, and sodium phenolate were investigated. Fully or partially substitution of the chlorine atoms occurs. The reaction with two equivalents of the aziridine yields a mixture of isomers which consists of two geminal and two vicinal disubstituted products. The constitutions of the substituted compounds were confirmed by IR, NMR, MS and elemental analyses.     

1λ5,3λ5-Diphospholium ions

One example each is given for the reaction of bromoacetylenes and ethynyl-phenyliodonium tosylates with bis(diphenyl phosphino)methane. The yellow crystalline 1:1-addition products are diphospholium salts. They readily and selectively hydrolyze to give 2-phosphinoylethenyl phosphonium salts.