TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (claimed): The phenothiazine-containing polymeric metal complex is prepared by (A) dissolving 3-methyl thiophene in chloroform, stirring, slowly adding N-bromosuccinimide, stirring for 2-3 hours, heating and refluxing for 12-14 hours, cooling to room temperature, extracting with chloroform, extracting organic layer with water, washing for 3-5 times, drying overnight, rotationally evaporating the solvent with anhydrous magnesium sulfate, decompressing and distilling, and obtaining 2,5-dibromo-3-methyl thiophene; (B) mixing 2,5-dibromo-3-methyl thiophene and N-bromosuccinimide at a mole ratio of 1:1 in carbon tetrachloride, adding benzoyl peroxide as initiator, refluxing for 3-5 hours, cooling to room temperature, water washing the organic layer, drying with anhydrous magnesium sulfate, and decompressing and distilling to obtain 2,5-dibromo-3-(bromomethyl)thiophene; (C) under nitrogen atmosphere, mixing 2,5-dibromo-3-(bromomethyl)thiophene and triphenyl phosphorus dissolved in anhydrous xylene, refluxing for 24-28 hours, cooling to room temperature, filtering, using ether and acetone for washing, and vacuum drying to obtain 2,5-dibromo-3-(triphenyl phosphorus bromide methyl)thiophene; (D) dissolving 1,10-phenanthroline and potassium hydroxide in water, heating to boil, taking potassium permanganate solution, heating to 90-100 degrees C, slowly dropping the potassium permanganate solution into the reaction solution, boiling for 10-20 minutes, filtering, extracting with chloroform, drying the organic phase, and decompressing and distilling to obtain 4,5-diaza-fluoren-9 -one; (E) mixing 2,5-di-bromo-3-(triphenyl phosphorus bromide methyl)thiophene and 4,5-diaza-fluorene-9-one at a ratio of 1:1, placing in the ice water bath, slowly dripping ethanol sodium hydroxide solution, and drying in vacuum to obtain 2,5-dibromo-3-(4,5-diaza-fluorene-9-vinyl)thiophene; (F) mixing 2,5-dibromo-3-(4,5-diaza-fluorene-9-vinyl)thiophene and maleimide nitrile, slowly dripping solution of metal salt of methanol solution, heating to reflux, and reacting for 12-18 hours; (G) dissolving phenothiazine in N,N-dimethyl formamide, adding sodium hydride, ice cooling, adding bromotrithio-octane, reacting under room temperature for 2-5 hours, pouring the reaction liquid into distilled water, using n-hexane extraction, concentrating, drying, purifying, and leaching to obtain liquid to obtain N-octyl-3,7-bisphenothiazine aldehyde; (H) mixing ethylene dichloride and N,N-dimethyl formamide, ice water bath cooling, adding N-octyl-3,7-bisphenothiazine aldehyde, adding phosphorus oxychloride, heating to 90-100 degrees C, pouring the reaction liquid into distilled water, extracting, drying, evaporating solvent, and purifying; (I) mixing with bromo-methane, phosphorus ylide salt in anhydrous tetrahydrofuran, slowly adding sodium hydride, heating to reflux, reacting for 8-12 hours, adding methanol to the mixture, adding distilled water, extracting with methylene dichloride, drying overnight, concentrating, and purifying to obtain N-octyl-3,7-(phenyl-vinyl)phenothiazine; and (J) adding metal complex and N-octyl-3,7-bi-(phenyl-vinyl)phenothiazine into reaction container, adding refined triethylamine and palladium acetate, reacting at 90-100 degrees C for 36-40 hours, cooling to room temperature, filtering, washing, dissolving obtained crude product in tetrahydrofuran, and vacuum drying.