Synthesis and properties of cyclophosphazenes appended with covalently linked porphyrin-ferrocene conjugates

摘要

Cyclotriphosphazene and cyclotetraphosphazene appended with six and eight covalently linked porphyrin-ferrocene conjugates respectively were synthesized by treating N_3P_3Cl_6 and N_4P _4Cl_8 with appropriate equivalents of ferrocene linked porphyrin containing meso-hydroxyphenyl group in THF in the presence of Cs _2CO_3 followed by column chromatographic purification. NMR and absorption studies indicated a weak interaction between adjacent porphyrin-ferrocene conjugates. Electrochemical studies supported electrochemical equivalence of ferrocenyl and porphyrinyl moieties in these multi-porphyrin-ferrocene conjugate assemblies. The fluorescence studies showed significant quenching of porphyrin fluorescence due to photo-induced electron transfer from ferrocene to singlet state of porphyrin unit in these assemblies.