Inorganic Chemistry, Vol.39, No.4, 810-814, 2000
Synthesis and spectroscopy of N3P3X5OCH = CH2 (X = Cl, F, OCH3, OCH2CF3, N(CH3)(2)) and N3P3X4(OCH = CH2)(2) (X = Cl, N(CH3)(2)). Correlations of ultraviolet photoelectron spectroscopy and nuclear magnetic resonance data to electronic and geometrical structure
The syntheses of the vinyloxycyclotriphosphazene derivatives N3P3X5OCH=CH2 (X = OMe, OCH2CF3) and the N3P3(NMe2)(4)(OCH=CH2)(2) isomeric mixture along with improved preparations of N3P3X5OCH=CH2 (X = F, NMe2) are reported. The interactions between the vinyloxy function and the cyclophosphazene in these and the previously reported N3P3Cl5 (OCH=CH2) and N3P3F6-n(OCH=CH2)(n) (n = 1-4) have been examined by ultraviolet photoelectron spectroscopy (UPS) and NMR spectroscopy. The UPS data for the chloro and fluoro derivatives show a strong electron-withdrawing effect of the phosphazene on the olefin that is mediated with decreasing halogen substitution. The H-1 and C-13 NMR data for N3P3X5OCH=CH3 (X = F, Cl, OMe, OCH2CF3, NMe2) show significant changes as a function of the phosphazene substituent. There is a linear correlation between the beta-carbon chemical shift on the vinyloxy unit and the phosphorus chemical shift at the vinyloxyphosphorus centers. The chemical shifts of the different phosphorus centers on each ring are also related in a linear fashion. These relationships may be understood in terms of the relative electron donor-acceptor abilities of the substituents on the phosphazene ring. The H-1 NMR spectra of the N3P3(NMe2)(4)(OCH=CH2)(2) isomeric mixture allow for assignment of the relative amounts of cis and trans isomers. A model for the observed cis preference in the formation of N3P3Cl4(OCH=CH)(2) is presented.
Keywords:STEREOCHEMICAL CONTROL;CYCLOTRIPHOSPHAZENES;ORGANOPHOSPHAZENES;PHOSPHAZENES;POTENTIALS;SPECTRA