Novel heterocyclic selenazadiphospholaminediselenides, zwitterionic carbamidoyl(phenyl)-phosphinodiselenoic acids and selenoureas derived from cyanamides

2,4-Bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide (Woollins’ reagent, WR) reacts with cyanamides (1a-h) in refluxing toluene to afford a series of novel selenazadiphospholaminediselenides (RR′NCN(PhP(Se)SeP(Se)Ph, R=C₆H₅(CH₂)_1-3, 4-n-C₁₀H₂₁C₆H₄ and 4-BrC₆H₄CH₂; R′=H, CH₃, C₂H₅ and C(O)OC₂H₅2a-g). Post-treatment of the reaction mixture with water led to the formation of carbamidoyl(phenyl)phosphinodiselenoic acids (RR′NC(NH₂)P(SeH)₂Ph, R=C₆H₅(CH₂)_2-3, 4-n-C₁₀H₂₁C₆H₄ and 4-BrC₆H₄CH₂; R′=H and CH₃, 3b, 3c, 3e and 3f) and selenoureas (RR′NC(Se)NH₂, R=C₆H₅(CH)_1-2; R′=CH₃ and OC(O)C₂H₅, 4f and 4h) in moderate to excellent yields. All new compounds are characterised spectroscopically and five X-ray crystal structures are reported.