PHOTOCHEMICALLY REACTIVE POLYMERS - SYNTHESIS AND CHARACTERIZATION OF POLYURETHANES CONTAINING CP2MO2(CO)6 OR CP2FE2(CO)4 MOLECULES ALONG THE POLYMER BACKBONE

The syntheses of oligomeric urethanes containing Mo-Mo or Fe-Fe bonds along the backbone are reported. Reaction of the organometallic ''diol'' (eta-5-C5H4C(O)CH2OH)2Mo2(CO)6 with OCN(CH2)6NCO (hexamethylene diisocyanate; HMDI) gave [-OCH2C(O)C5H4(CO)3Mo-Mo(CO)3C5H4C(O)CH2OC(O)NH(CH2)6NHC(O)-]n (n = 4-5). Similarly, reaction of (eta-5-C5H4CH2CH2OH)2Mo2(CO)6 with HMDI gave [-OCH2CH2C5H4- (CO)3Mo-Mo(CO)3C5H4CH2CH2OC(O)NH(CH2)6NHC(O)-]n (n = 6-8) and reaction of (eta-5-C5H4CH2CH2OH)2Fe2(CO)4 with HMDI gave [-OCH2CH2CH2C5H4(CO)2Fe-Fe(CO)2C5H4CH2CH2OC(O)NH-(CH2)6NHC(O)-]n (n = 2-3). A copolymer with a lower density of metal-metal bonds along the backbone was synthesized by reacting (eta-5-C5H4CH2CH2OH)2Mo2(CO)6 and HO(CH2)4OH with HMDI. The polyurethanes were characterized by elemental analysis, by infrared, H-1 NMR, and electronic absorption spectroscopy, and by molecular weight. With certain preparations, MBAR(n) values up to 16000 (n congruent-to 20) were obtained. As an aid to the spectroscopic characterization of the complexes, model complexes were synthesized by reacting monoisocyanates with the metal-metal bonded diols. For example, [CH3(CH2)5NHC(O)OCH2CH2C5H4(CO)3Mo-Mo(CO)3C5H4CH2CH2)(O)NH(CH2)5CH3] was synthesized by reacting (eta-5-C5H4CH2CH2OH)2Mo2(CO)6 with CH3(CH2)5NCO. Because of the metal-metal bonds along the backbone, the polyurethanes are photochemically reactive, undergoing metal-metal bond photolysis reactions similar to the Cp2Mo2(CO)6 and Cp2Fe2(CO)4 dimers.