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New photoresponsive polyamides containing norbornadiene (NBD) residues in the main chain were synthesized in high yields by interfacial polycondensation between 2,5-norbornadiene-2,3-dicarboxylic acid dichloride (NBDC) and various primary or secondary diamines. The same polyamides were also obtained in high yields by direct polycondensation between 2,5-norbomadiene-2,3-dicarboxylic acid and various diamines using diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate and triethylamine as activating reagents. The degree of viscosity of the copolymers prepared by the reaction of NBDC and adipoyl chloride (ADC) with diamines increased with increasing ADC concentration, although the viscosities of homopolymers prepared by the reaction of NBDC with diamines were low. The photochemical properties of the resulting polyamides were examined in dichloromethane solution and in the film state. Polyamide 5 prepared with aromatic diamines showed higher photochemical reactivity than polyamides 1-4 prepared with aliphatic diamines both in dichloromethane solution and in the film state. Furthermore, it was also found that the rates of photochemical reaction of polyamide 1 sensitized with 5 mol % of Michler's ketone or 4-(N^V-dimethylamino)benzophenone were mostly the same as those of polyamide 5.

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KEY WORDSNew Photoresponsive Polyamide I Norbornadiene Residue in the Main Chain I Photochemical Valence Isomerization I Photosensitization I Photochemical valence isomerization between norbornadiene (NBD) and quadricyclane (QC) has been of interest1.2 from the view point of solar energy conversion and storage, because this reaction can convert solar energy into thermal energy through the strain energy in the molecule of QC. However, this solar energy conversion and storage system has so far been investigated mostly with relation to low molecular weight NBD derivatives.Recently, we reported synthesis of polymers containing pendant NBD moieties by the substitution reaction 3 -5 of poly(chloromethylstyrene) with NBD derivatives and by the selective cationic polymerization 6 of 2-(3-pheny 1-2,5-norbornadiene-2-carbony loxy )-ethyl vinyl ether. However, there is no report on the synthesis of any polymer containing NBDC (bp 85-87°Cj0.45 mmHg) was synthesized in 71% yield by the reaction of 2,5-norbornadiene-2,3-dicarboxylic acid with oxalyl chloride.A typical procedure for the synthesis of polyamide was as follows: 0.631 g (3 mmol) of I ,3-di(4-piperidyl)propane (DPP) and 9.67 mg (0.3 mmol) of tetrabutylammonium bromide were dissolved in 6ml of 4wt% aqueous sodium hydroxide solution. To the solution was added 0.651 g (3 mmol) of NBDC dissolved in 2HNO CH20NH2MDA 2HNo-O-oNH 2 ODA Scheme I. 1165