“…In recent years, cyclotri and cyclotetraphosphazenes have started to attract much attention due to their potential stereogenic properties, and biological activities such as antibacterial, antifungal and anti-cancer activities [8][9][10][11][12]. Our group has spent many years on designating and synthesizing novel partly substituted cyclotri and cyclotetraphosphazene derivatives with bidentate ligands {dibenzo-diaza-crown ethers [13][14][15][16][17], dibenzo N 2 O n (n =2-4) [18][19][20][21] and benzo NO [22][23][24][25][26][27][28] donor * Correspondence: sbilge@science.ankara.edu.tr type aminopodands, mono-and bis-ferrocenyldiamines [29][30][31][32][33][34][35][36][37], sodium (ferrocenylmethylamino)-1-alkoxide [38][39][40][41][42][43]}and multidentate N 2 O 2 -donor type dibenzo aminopodands [44][45][46]. Some interesting phosphazene derivatives such as monotopic and ditopic spiro-crypta phosphazenes, spirocyclic phosphaza (PNP-lariat) ethers, cyclophosphazenes possessing 6-membered spiro ring/rings, mono and bisferrocenylspirocyclophosphazenes, and spiro-ansa-spiro-, spiro-bino-spiro-and ansa-spiro-ansa-phosphazenes were synthesized.…”