Synthesis And Characterization Of Propargylphosphonamidates Helical Polymer

Phosphorus has a structure with five coordination, this compound is easy to form enantiomers and can hardly be separated. In this paper, four propargylphosphonamids monomers[HC≡CCH2NH(P=O)R1R2. monomerl: R1=OPh, R2=NC4H7COOCH3; monomer2:R1=OPh, R2=NC4H7COOCH2CH3; monomer3:R1=OPh, R2=NC4H7COOC(CH3)3; monomer4:R1=Ph, R2=NC4H7COOC(CH3)3] were designed and synthesized.1HNMR and 31PNMR shown that monomerl can only form optical enantiomer and can not be separated. But monomer2, monomer3 and monomer4 can be separated by split agent to form single P-chiral diastereomeric monomer. Polylmerization were carried out with (nbd)Rh+[η6-C6H5B-(C6H5)3] as catalyst in CHC13 giving four polymers with Moderate molecular weights (Mn) (0.4-0.7×104) and Mw/Mn (1.26-1.98) by GPC., Three factors (the pendent group, temperature, methanol content) were observed to affect the helix structure of polymers. The optical activity and secondary structure of the polymers were characterized by specific rotations ([α]D), circular dichroism (CD) spectra and UV-vis. It shows that the polymers have good optical activity and can form a single direction of the helical conformation.