overnight this was then washed with methanol 4 u00d7 10 ml and 1 butanol 2 u00d7 5 ml to be certain of removing any traces of the sodium borohydride 1 butanol 10 ml 1 iodooctane 200 u03bcl 1 38 mmol and 2 2 azobisisobutyronitrile aibn were added and the reaction heated to 80 u00b0 c overnight the polymeric networks were filtered and the liquid collected for gas chromatography analysis samples were also sent for icp analysis to determine the degree of tin contamination percent loss relative to 1 molar equivalent of br 2 in general it can be observed from table 2 that a greater incorporation of the organic phase results in a material that possesses an enhanced resistance to chemical breakdown as a result of bromination the results in table 3 show that the material prepared assuming a 90 yield of digrignard ie 1 0 9 1 11 times excess was found to have the best active tin hydride content method b synthesis of phsn ch 2 n 3 2 11 u2032 type polymeric networks typically about 10 of x ch 2 n x where x u2550 br or i and n 6 8 10 or 12 in diethyl ether was added to the magnesium that.