SYNTHESIS OF STRAINED FERROCENYLORGANOCYCLOPHOSPHAZENES - X-RAY CRYSTAL-STRUCTURES OF N3P3(OCH2CF3)4(ETA-C5H4)2FE, N3P3(OPH)4(ETA-C5H4)2FE, AND N3P3PH2(OCH2CF3)2(ETA-C5H4)2FE

A series of transannular ferrocenylcyclotriphosphazenes were synthesized for studies of the relationship between molecular structure and polymerization behavior. Species N3P3(OCH2CF3)4(eta-C5H4)2Fe and N3P3(OPh)4(eta-C5H4)2Fe were synthesized by the reaction of N3P3F4(eta-C5H4)2Fe with NaOCH2CF3 and NaOPh, respectively. Cyclic trimers N3P3R(OCH2CF3)3(eta-C5H4)2Fe [R = OPh, R = Me, R = Ph (gem to Cp) and R = Ph (non-gem to Cp)] were prepared by reactions of the appropriate fluoroferrocenylphosphazene precursors [N3P3(OPh)F3(eta-C5H4)2Fe, N3P3MeF3(eta-C5H4)2Fe, N3P3PhF3(eta-C5H4)2Fe, and N3P3PhF3(eta-C5H4)2Fe] with NaOCH2CF3. The synthesis of N3P3Ph2(OCH2CF3)2(eta-C5H4)2Fe, (Ph groups non-gem to Cp) was achieved via the reaction of gem-N3P3F4Ph2 with dilithioferrocene to give N3P3Ph2F2(eta-C5H4)2Fe, followed by treatment with NaOCH2CF3. Treatment of N3P3Ph2F2(eta-C5H4)2Fe with NaOCH2CF3 yielded N3P3Ph2(OCH2CF3)2(eta-C5H4)2Fe (Ph groups gem to Cp). A 1-equiv amount of NaOPh reacts with N3P3F4(eta-C5H4)2Fe to form a mixture of cis- and trans-N3P3(OPh)F3(eta-C5H4)2Fe. The molecular structures of N3P3(OCH2CF3)4(eta-C5H4)2Fe, N3P3(OPh)4(eta-C5H4)2Fe, and N3P3Ph2(OCH2CF3)2(eta-C5H4)2Fe were determined by single-crystal X-ray diffraction. All were found to possess nonplanar, strained cyclotriphosphazene rings. Crystals of N3P3(OCH2CF3)4(eta-C5H4)2Fe are monoclinic with space group P2(1)/c, with a = 9.529 (5) angstrom, b = 14.515 (2) angstrom, c = 19.012 angstrom, beta = 97.94 (2)-degrees, V = 2605.8 angstrom 3, and Z = 4. Crystals of N3P3(OPh)4(eta-C5H4)2Fe are orthorhombic of space group P2(1)2(1)2(1) with a = 9.890 (2) angstrom, b = 15.962 (3) angstrom, c = 19.629(3) angstrom, V = 3098.8 angstrom 3, and Z = 4. The diphenyl species, N3P3Ph2(OCH2CF3)2(eta-C5H4)2Fe, crystallizes in the trigonal space group R3 (hexagonal axes) with a = 23.954 (8)angstrom, b = 23.94 (1) angstrom, c = 13.17 (1) angstrom, V = 6544 angstrom 3, and Z = 9.