Photochemically reactive polymers; the synthesis and photochemistry of amide polymers and model compounds containing metal-metal bonds and internal radical traps

摘要

The synthesis and photochemistry of a photochemically reactive polymer that has internal metal-radical traps (chlorine atoms) along its backbone is reported. Reaction of the organometallic 'diamine' (CpCH2CH2NH2)(2)Mo-2(CO)(6) with an activated mixed anhydride derivative of 3,4-dichlorohexanedioic acid gave the polymer [-CHClCH2C(O)NHCH2CH2(eta(5)-C5H4)(CO)(3)Mo-Mo(CO)(3)(eta(5)- C5H4)CH2CH2NHCOCH2CHCl-](n). The difunctional activated mixed anhydride was used because the Mo-Mo bond reacts with acyl chlorides to form oligomeric amides containing -Mo(CO)(3)Cl units. As an aid to the spectroscopic characterization of the polymers, model complexes were synthesized by reacting (CpCH2CH2NH2)(2)Mo-2(CO)(6) with activated mixed anhydrides of chloroacetic acid and 5-chlorovaleric acid. Thus, (eta(5)-C5H4R)(2)Mo-2(CO)(6) (R = -CH2CH2NHCOCH2Cl and -CH2CH2NHCO(CH2)(3)CH2Cl) were synthesized by reacting (CpCH2CH2NH2)(2)Mo-2(CO)(6) with CH3CH2OC(O)OC(O)CH2Cl and CH3CH2OC(O)OC(O)(CH2)(3)CH2Cl, respectively. Because of the metal-metal bonds along the backbone, the polyamide is photochemically reactive las are the model complexes), undergoing metal-metal bond photolysis reactions similar to the Cp2Mo2(CO)(6) dimer. The products contain CpMo(CO)(3)Cl units, indicative of 'self-trapping' by the chlorine atoms built into the polymer and model complexes. Photochemical decomposition also occurred in the solid state without external metal-radical traps. (C) 1998 Elsevier Science S.A. [References: 35]