Reduction reactions of alkyne and butadiyne derived fluorinated cyclophosphazenes

Abstract

Alkyl derivatives of fluorinated cyclophosphazenes having phenyl or ferrocenyl units separated by two and four CH2 units from the cyclophosphazene ring are prepared by hydrogenation of the alkyne/butadiyne unit of the corresponding alkyne/dialkyne derived cyclic fluorophosphazenes. Hydrogenation of the ethynyl units in compounds [PhC≡C(F)PN](PNF2)2, [FcC≡C(F)PN](PNF2)2 and [(FcC≡C)2PN](PNF2)2 using Pd/C as catalyst resulted in compounds Ph(CH2)2P3N3F5 (1), Fc(CH2)2P3N3F5 (2) and [(FcCH2CH2)2PN](PNF2)2 (3) (Fc=ferrocenyl), respectively. Similar, hydrogenation reaction of the butadiynyl units in compounds [PhC≡C−C≡C(F)PN](PNF2)2, [FcC≡C−C≡C(F)PN](PNF2)2 and [(FcC≡C−C≡C)2PN](PNF2)2 using Pd/C as catalyst resulted in compounds Ph(CH2)4P3N3F5 (4), Fc(CH2)4P3N3F5 (5) and [{Fc(CH2)4}2PN](PNF2)2 (6), respectively. Hydrogenation of the butadiynyl and ethynyl units in the unsymmetrically substituted cyclophosphazene [(FcCC)(FcC≡C−C≡C)PN](F2PN)2 resulted in the alkyl derived cyclophosphazene [{Fc(CH2)4}{Fc(CH2)2}PN](F2PN)2 (7). Partial hydrogenation of [FcC≡C(F)PN](PNF2)2 using Lindlar catalyst resulted in the alkene derived cyclophosphazene [FcCHCH(F)PN](PNF2)2 (8) which was further reduced using Pd/C catalyst to give the alkyl derivative Fc(CH2)2P3N3F5 (2). An attempted hydrogenation of chlorinated phosphazene, [FcC≡C(Cl)PN](PNCl2)2 using Pd/C as catalyst resulted in compound [(FcCH2CH2)(OCH3)PN](PNCl2)2 (9) having methoxy substitution on the alkyl substituted phosphorus atom. All new compounds were characterized by IR, NMR [1H, 13C{1H}, 31P{1H}, and 19F{1H}] and HRMS studies. Compounds [FcC≡C(F)PN](PNF2)2 and 2 have also been structurally characterized.