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′NCdouble bond; length as m-dashN(PhP(Se)SeP(Se)Ph, R=C6H5(CH2)1–3, 4-n-C10H21C6H4 and 4-BrC6H4CH2; R′=H, CH3, C2H5 and C(O)OC2H5 2a–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.