Abstract: The syntheses of MeN= P (MeNCH# H&N(4),[HRNP (MeNCH2CH2) 3N](CF3C02)(R= Ph, S (CF3-C02); R= Me, 6 (CF3C02)),[MePhNP (MeNCH2CH2) 3N] I (7 (I)), the stable azide adduct MeN3P (MeNCH2CH2) 3N (S), and [HRNP (NMe2) 3](CF3C02)(R= Ph, 9 (CF $02) are reported. Equilibria measured by 31P NMR spectroscopy reveal the relative ordering of basicity: t-BuN= P [N= P (NMe2) 3] 3> P (MeNCH2CH2) sN ( ...