The 2H-azaphosphirene complex 1 reacts with triorgano-stannyl(ethoxy)a
cetylenes 2a,b to yield bifunctional eta(1)-1-phosphaallene 5a,b and 1
H-phosphirene complexes 6a,b; 5a,b and 6a,b are characterized by NMR s
pectroscopy (C-13, P-31) and complex 6b by single crystal X-ray diffra
ction.