Synthesis of New Photoresponsive Polymers Containing Trifluoromethyl-Substituted Norbornadiene Moieties

Abstract

Polymers containing trifluoromethyl (CF 3 )-substituted donor-acceptor NBD moieties in the side chain or in the main chain were synthesized by substitution or addition with CF r NBD-carboxylic acid derivatives, or by polycondensation of CFrNBD-dicarboxylic acid derivatives, and the durability of the resulting polymers was examined.Photochemical valence isomerization between norbomadiene (NBD) and quadricyclane (QC) is of interest as a solar energy conversion and storage system, I because photoenergy can be stored as strain energy (about 20 kcal/mol) in a QC molecule (Scheme I). Recently, this photochemical reaction has also been investigated as an optical waveguide utilizing photoinduced refractive index changes 2a . b or as a photochromic system potentially applicable to data storage. 2cTaking these unique characteristics of NBD into account, polymers containing NBD moieties have been investigated. However, the photoreactivity and the fatigue resistance of these polymers were insufficient for practical use as advanced materials. 3 Recently, we reported the synthesis of CF 3 -substituted donor-acceptor NBD (CFrNBD) derivatives which not only absorb visible light efficiently but also exhibit efficient fatigue resistance.4 Therefore; we now synthesized new photoreactive polymers containing CFrNBD moieties.The NBDmonomers, namely, NBD carboxylic acid I and NBD dicarboxylic acid 2, were synthesized from eyclopentanedione derivative 3 as shown in Scheme 1. 5 Polymers containing CFrNBD moieties in the side chain were synthesized according to Scheme 2. 5 The reactions of NBD carboxylic acid I with poly(chloromethylstyrene),3b poly(2-chloroethyl vinyl ether) 3c, and poly(glycidyl methacrylate) 3d proceeded smoothly using tetrabutylammonium bromide as a catalyst in DMF to give the corresponding polymers P·I, P·2, and P-3 in 80,83, and 82% yields, respectively. To P-I, P·2, and P-3, NBD carboxylic acid was found to be introduced in 100,93, and 100% yield, respectively. 6 These results show that CFrNBD moieties could be readily introduced in the side chain of many polymers.Next, we synthesized polymers containing CFrNBD moieties in the main chain as shown in Tables I and 2. 5 Polyamide P-4 was synthesized by polycondensation of the bis(4-nitrophenyl) ester 4, obtained from NBD dicarboxlic acid 2, with trans-I,4-diaminocyclohexane as diamine. 7 The yield and the M n of P-4 were 82% and 17800, respectively. 8 This polyamide was also synthesized from 2 with diarnine using DPPA as condensation reagent; the yield and the M n were 88% and 42,900, respectively. Polyester was synthesized by polycondensation of 2 with diol using hafnium chloride as the Lewis acid catalyst. 9 The yield and the M n of p-s were 82% and 39,300, respectively. On the other hand, when the reaction was canied out using WSCD

Synthesis and photochemical properties of novel pentamethylated norbornadiene containing polyimides

“…As shown in Figure 4 for polymer P1b, the absorption maximum at 278 nm decreases gradually on irradiation indicating a good conversion of the NBD into QC after 20 min. In addition, and as it is reported in the literature,19, 21, 31, 32 an isosbestic point at 228 nm was observed. This phenomenon, which was observed for all the samples means that the photochemical valence isomerization of the NBD units of polymer chains to the corresponding QC groups occurred selectively without side reactions.…”

Advanced materials based on polymer cocrystalline forms

“…Photoisomerizations of organic dyes have been widely used as a means to record optical data. In particular, photoisomerization of norbornadiene and its derivatives (N, see scheme ) leading to quadricyclane and its derivatives (Q, see scheme ) has been deeply studied169–172 and polymeric materials containing N derivatives (both as covalently bonded pendant groups or simply added to transparent amorphous phases) have been investigated for optical waveguides (utilizing photoinduced refractive index changes) and for data storage 173–177. However, in all these optical materials there is a complete disorder in the spatial disposition of the photoisomerizing molecules.…”

Development of Novel Photo-Functional Materials Based on Cyclic Oligomers

“…[10][11][12][13] Nishikubo et al [14][15][16][17] reported that polymers containing certain norbornadiene (NBD) moieties in the main and side chains showed high photochemical reactivity, and had a high photo-energy storage capability. NBD is converted to quadricyclane (QC) under UV irradiation, and the resulting polymers are expected to be good photo-energy transformation systems.…”