Polymerization of 4-hydroxy-N-propargylpiperidine by transition metal catalysts

The polymerization of 4-hydroxy-N-propargylpiperidine, having 4-hydroxypipe ridine moiety, was carried out with various transition metal catalysts. The polymerizations proceeded well to give a relatively high yield of polymer (maximum polymer yield: 93%). Palladium, platinum, and ruthenum chlorides w ere found to be generally effective for this polymerization. On the other h and, the group 5 and 6 transition metal catalysts such as WCl6, MoCl5, WCl6 -organoaluminum compounds etc. fail to polymerize this monomer. The molecul ar structure of the resulting poly(4-hydroxy-N-propargylpiperidine) was cha racterized by the various instrumental analysis methods such as NMR (H-1- a nd C-13-), IR, and UV-visible spectroscopies. The IR spectrum of polymer sh ows neither the acetylenic hydrogen stretching (3197 cm(-1)) nor the carbon -carbon triple bond stretching (2113 cm(-1)) frequencies presented in the I R spectrum of monomer. Instead, the carbon-carbon double bond stretching fr equency at 1611 cm(-1) was newly observed. These polymers were mostly brown and black powders and were completely soluble in such polar solvents as fo rmic acid, DMF, DMSO, and tetrahydrofuran. X-ray diffraction analysis of th e resulting poly(4-hydroxy-N-propargylpiperidine) revealed that this polyme r is mostly amorphous.