hydrogenchloride in tetrahydrofuran soln. of Pr compd. and dry HCl (1:6 mol) was shaken for 1 h at room temp.; formed ppt. of PrCl3 was filtered off, washed with THF and dried; org. layer was sepd. by distn in vac.;

hydrogenchloride in tetrahydrofuran soln. of Pr compd. and dry HCl (1:4 mol) was shaken for 1 h at room temp.; formed ppt. of PrCl3 was filtered off, washed with THF and dried; org. layer was sepd. by distn in vac.;

in benzene (vac.); soln. of Pr compd. and BrCH2CH2Br was heated at 120°C for 5 h; formed ppt. of PrBr3 was filtered off; org. layer was sepd. by distn.;

hydrogenchloride in tetrahydrofuran soln. of Pr compd. and dry HCl (1:6 mol) was shaken for 1 h at room temp.; formed ppt. of PrCl3 was filtered off, washed with THF and dried; org. layer was sepd. by distn in vac.;

hydrogenchloride in tetrahydrofuran soln. of Pr compd. and dry HCl (1:4 mol) was shaken for 1 h at room temp.; formed ppt. of PrCl3 was filtered off, washed with THF and dried; org. layer was sepd. by distn in vac.;