diamidides

Analogues of acyclic carboxylic acid anhydrides in which =O has been replaced by =NR and –O– by –NR–: RC(=NR)NRC(=NR)R, N-imidoyl amidines. The name 1,3,5-triazapentadienes is sometimes applied as a class name to diamidides.
See: imidines
Source:
PAC, 1995, 67, 1307 (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1331