Synthesis of New Photoresponsive Polyamides Containing Norbornadiene Residues in the Main Chain

Abstract

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

Synthesis of New Photoresponsive Polymers Containing Trifluoromethyl-Substituted Norbornadiene Moieties

“…Next, we synthesized polymers containing CF 3 −NBD moieties in the main chain as shown in Schemes and and in Tables and . Polyamide P-4 was synthesized by polycondensation of the bis(4-nitrophenyl) ester 15 , obtained from NBD−dicarboxlic acid 2 , with trans -1,4-diaminocyclohexane as diamine. , The yield and the M n of P-4 were 82% and 17 800, respectively. This polyamide was also synthesized from 2 with diamine using DPPA as condensation reagent; the yield and the M n were 88% and 42 900, respectively.…”

“…Taking these unique characteristics of NBD into account, Nishikubo et al have investigated the synthesis and photochemical reaction of various photoresponsive polymers containing NBD moieties in the side chain − or in the main chain. , However, the photoreactivity and fatigue resistance of these polymers were insufficient for practical use as advanced materials. To improve the photoreactivity of these polymers, they recently synthesized polyesters containing donor−acceptor (D−A) NBD moieties and found these polyesters had high photoreactivity and good durability for repeated cycles of interconversion .…”

Photo-optical effect of polymers containing norbornadiene moieties.

“…The preparation of a polymer containing NBD residue in main-chain, P(NBDA/mXDA) was prepared according to the procedure reported elsewhere [3]. Films were tasted from trifluoroacetic acid solution of the prepared polymer, and dried at 50°C for 12 hours before measurements.…”

Synthesis and photochemical property of polymers with pendant donor–acceptor‐type norbornadiene moieties

“…From these points, Nishikubo et al3–8 reported the synthesis of various NBD polymers and their photochemical and thermal properties. Polyamides3 containing NBD residues in the main chain were synthesized by the polycondensation reaction of 2,5‐NBD‐2,3‐dicarboxylic acid derivatives with diamines and diisocyanates.…”

“…From these points, Nishikubo et al3–8 reported the synthesis of various NBD polymers and their photochemical and thermal properties. Polyamides3 containing NBD residues in the main chain were synthesized by the polycondensation reaction of 2,5‐NBD‐2,3‐dicarboxylic acid derivatives with diamines and diisocyanates. Polyesters4 containing NBD residues in the main chain were prepared by the polyaddition reaction of 2,5‐NBD‐2,3‐dicarboxylic acid with bis(epoxide)s. Various polymers containing pendant NBD moieties were also synthesized by the substitution reaction5 of poly[(chloromethyl)styrene] with NBD carboxylic acids with a phase‐transfer catalyst (PTC), by the addition reaction6 of poly(glycidyl methacrylate)s with the same NBD compounds, by the selective cationic polymerization7 of vinyl ether monomers containing NBD moieties, and by the ring‐opening copolymerization8 of glycidyl compounds containing NBD residues with cyclic carboxylic anhydrides.…”