Showing papers on "Norbornadiene published in 2005"
TL;DR: The catalytic system derived from complex 4 d was found to afford high yields and good enantioselectivities in the reduction of various aryl alkyl ketones and is comparable or even superior to the best previously reported for prochiral nonaromatic ketones.
Abstract: The direct coupling of oxazolines and N-heterocyclic carbenes leads to chelating C,N ancillary ligands for asymmetric catalysis that combine both an "anchor" unit and a stereodirecting element. Reacting various N-substituted imidazoles with 2-bromo-4(S)-tert-butyl- and 2-bromo-4(S)-isopropyloxazoline gave the imidazolium precursors of the stereodirecting ancillary ligands. A library of ten different ligand precursors was obtained by using this simple procedure (65-97 % yield). These protioligands were metalated in a subsequent step by reaction with [{Rh(mu-OtBu)(nbd)}2] (nbd=norbornadiene), generated in situ from KOtBu and [{RhCl(nbd)}2] giving the corresponding N-heterocyclic carbene complexes [RhBr(nbd)(oxazolinyl-carbene)] 4 a-j in good yields. X-ray diffraction studies of two of the rhodium complexes, 4 d and 4 j, established a distorted square-pyramidal coordination geometry with the bromo ligand occupying the apical position. The rhodium-carbene bond length was found to be 2.070(4) A (4 d) and 2.012(3) A (4 j). Complexes 4 a-j were treated with AgBF4 in dichloromethane, giving the active cationic square-planar catalysts for the hydrosilylation of ketones. As a reference reaction for the catalyst optimisation, the hydrosilylation of acetophenone with diphenylsilane was studied and the system optimised with respect to the counterion (BF(4) (-)), solvent (THF) and the silane reducing agent (diphenylsilane). The reaction product (1-phenylethanol) was obtained with the highest enantiomeric excess (ee) by carrying out the reaction at -60 degrees C, whilst the enantioselectivity drops upon going both to lower and higher temperatures. The observation that the temperature dependence of the ee values goes through a maximum indicated a change in the rate-determining step as the temperature is varied. The determination of the initial reaction rate in the hydrosilylation of acetophenone upon varying the catalyst (4 d) and substrate concentrations at -55 degrees C established a rate law for the initial conversion which is first-order in both substrates as well as the catalyst (Vi = k[4][PhCOMe][Ph2SiH2]). The catalytic system derived from complex 4 d was found to afford high yields and good enantioselectivities in the reduction of various aryl alkyl ketones (acetophenone: 92 % isolated yield and 90 % ee, 2-naphtyl methyl ketone: 99 % yield, 91 % ee). The selectivity for the reduction of prochiral dialkyl ketones is comparable or even superior to the best previously reported for prochiral nonaromatic ketones; whereas cyclopropyl methyl ketone is hydrosilylated with an enantioselectivity of 81 % ee, the increase of the steric demand of one of the alkyl groups leads to improved ee's, reaching 95 % ee in the case of tert-butyl methyl ketone. Linear chain n-alkyl methyl ketones, which are particularly challenging substrates, are reduced in good asymmetric induction, such as 2-octanone (79 % ee) and even 2-butanone (65 % ee).
117 citations
TL;DR: In this paper, the authors show that the CD signal intensity depends on temperature and decreases reversibly with increasing temperature, although the energy difference between the right-handed and left-handed conformations of each other is almost zero.
Abstract: {4-[(3,5-Di-tert-butyl-4-hydroxyphenyl)(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dienylidene)methyl]phenyl}acetylene (abbreviated as (4-ethynylphenyl)hydrogalvinoxyl) was polymerized using [Rh(norbornadiene)Cl]2 catalyst in the presence of (R)-1-phenylethylamine or (S)-1-phenylethylamine to give red polymers. The circular dichroism (CD) spectra of polymers indicated that an excess of one-handed helical polyacetylene backbone was induced by helix-sense-selective polymerization under the asymmetric condition despite the achiral monomer. Results show that the CD signal intensity depends on temperature and decreases reversibly with increasing temperature, although the energy difference between the right-handed and left-handed conformations of each other is almost zero. The sign of the CD signal in the absorption region (420 nm) of the hydrogalvinoxyl chromophore, which was calculated from the polymer geometry, suggests that the excess of right-handed helix was induced by polymerization in the presence of (R)-1-ph...
71 citations
TL;DR: Observations suggest that an intramolecular triplet energy transfer occurs in Gn-NBD molecules, and it is proposed to proceed mainly via a through-space mechanism involving the closest donor (folding back conformation) and acceptor groups.
Abstract: A series of benzophenone (BP) and norbornadiene (NBD)-labeled poly(aryl ether) dendrimers (Gn-NBD), generations 1−4, were synthesized, and their photophysical and photochemical properties were examined. The phosphorescence of the peripheral BP (donor) chromophore was efficiently quenched by the NBD (acceptor) group attached to the focal point. Time-resolved spectroscopic measurements indicated that the lifetime of the triplet state of the BP chromophore was shortened due to the proximity of the NBD group. Selective excitation of the BP chromophore resulted in isomerization of the NBD group to quadricyclane (QC). All of these observations suggest that an intramolecular triplet energy transfer occurs in Gn-NBD molecules. The light-harvesting ability of these molecules increases with generation due to an increase in the number of peripheral chromophores. The energy transfer efficiencies are ca. 0.97, 0.54, 0.45, and 0.37 for generations 1−4, respectively, and the rate constant of the triplet−triplet energy t...
57 citations
TL;DR: Rh-catalyzed π-facial selective intermolecular hydroacylations of norbornenes with salicylaldehyde with endo- and exo-intermediates have been attained and the product formed in the reaction of 7-tert-butoxynorbornadiene was the endo,syn-product.
50 citations
TL;DR: In this paper, the synthesis, spectroscopic and structural characterisation, and electrochemical behaviour of some rhodium and iridium complexes of the form LM(X1)(X2)+, where L is a chelating bis(carbene) derived from an imidazolium-linked ortho-cyclophane, were described.
41 citations
TL;DR: In this paper, the aza-Diels-Alder reaction of 4-phosphinyl- and 4phosphonyl-1,2-diaza-1-3-butadienes with styrene, cyclopentadiene, dihydrofuran and norbornadiene is reported.
33 citations
TL;DR: A new phosphine-free palladacycle catalyst 4 was prepared from benzyl oxazoline in high yield and fully characterized, and hydrophenylation reactions of a wide range of bicyclic alkenes, not only norbornene and norbornadiene but also oxa- and aza-bicyclic al Kenes proceeded smoothly under aerobic condition without exclusion of water.
Abstract: A new phosphine-free palladacycle catalyst 4 was prepared from benzyl oxazoline in high yield and fully characterized. With it as catalyst, hydrophenylation reactions of a wide range of bicyclic alkenes, not only norbornene and norbornadiene but also oxa- and aza-bicyclic alkenes, with iodobenzene proceeded smoothly under aerobic condition without exclusion of water. Up to 1.7 x 10(6) TON as well as 1.2 x 10(5) TOF were achieved.
31 citations
TL;DR: F Fluoranthene 2 and heptacycle 3 are easily accessible from the reaction of diyne 1 and norbornadiene (NBD) in the presence of the rhodium catalyst.
22 citations
TL;DR: In this article, a high-stereospecific polymerization of a novel sulfur containing aromatic acetylenes, that is, (p-n-octylthiophenyl)acetylene (pOctSPA), was successfully performed using the Rh complex, [Rh(norbornadiene)Cl]2-TEA, catalyst in the presence of various solvents under mild conditions.
Abstract: Highly stereospecific polymerization of a novel sulfur containing aromatic acetylenes, that is, (p-n-octylthiophenyl)acetylene (pOctSPA), was successfully performed using the Rh complex, [Rh(norbornadiene)Cl]2-TEA, catalyst in the presence of various solvents under mild conditions. The resulting polymers were characterized in detail by 1H NMR, ESR, laser Raman, diffuse reflective UV-Vis (DRUV-Vis), and wide angle X-ray diffraction methods. The data showed that the resulting polymers bear cis-transoid form, which can induce the cis-to-trans isomerization when the cis polymers are subjected to pressure at room temperature under vacuum, breaking rotationally the cis CC bonds in the main-chain giving two kinds of π-radicals, the so-called cis radical and trans radical as the origin of a polymer magnet like a novel spin glass material. Further, the resulting cis poly(acetylene)s were found to have a helical main-chain, which is packed in pseudohexagonal crystal called π-conjugated columnar or nano π-conjugated columnar as a novel color controllable material. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2836–2850, 2005
18 citations
TL;DR: In this paper, the dicobalt(hexacarbonyl) complex of N-(2-butynoyl)-4,4-dimethyloxazolidinone (1) is treated with chiral cyclopentadienyl (tricarbonyls)molybdenum anions, and pairs of diastereomeric heterobimetallic (CoMo) complexes are obtained.
17 citations
TL;DR: The conformations of the chelate cycles in the X-ray structures of norbornadiene and cyclooctadiene-rhodium complexes of (R,R)-1,2-bis[(o-methylphenyl)phenylphosphino]ethane are dramatically different as discussed by the authors.
TL;DR: In this paper, a novel synthetic method for soluble precursor polymers of poly(p-phenylene vinylene) derivatives by the palladium-catalyzed three-component coupling polycondensation of aromatic diiodides, aromatic bis(boronic acid) derivatives, and norbornadiene is described.
Abstract: A novel synthetic method for soluble precursor polymers of poly(p-phenylene vinylene) (PPV) derivatives by the palladium-catalyzed three-component coupling polycondensation of aromatic diiodides, aromatic bis(boronic acid) derivatives, and norbornadiene is described. For example, the polymerization of 1,4-diiodo-2,5-dioctyloxybenzene, benzene-1,4-bis(boronic acid propanediol ester), and norbornadiene at 100 °C for 3 days provided a polymer consisting of the three monomer units in a 97% yield (number-average molecular weight = 3100, weight-average molecular weight/number-average molecular weight = 1.37). A derivative of PPV was produced smoothly by the retro Diels–Alder reaction of the polymer both in a dodecyloxybenzene solution and in a film at 200 °C in vacuo. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3403–3410, 2005
TL;DR: In this paper, the equilibrium constants at 21 °C in 1,2-dichloroethane are (2.4 ± 0.5) × 10-3 and 2.8 ± 0.4 ) × 10 −2 for cyclohexene and 1-octene, respectively.
TL;DR: In this paper, the solar energy storage in norbornadiene (1 )/quadricyclane (2 ) system was investigated using ab initio methods at HF/6-31G* and DFT/6 -31G * levels of theory.
Abstract: Electronic effects involved in the solar energy storage in norbornadiene ( 1 )/quadricyclane ( 2 ) system, are investigated using ab initio methods at HF/6-31G* and DFT/6-31G* levels of theory Substituents X, with various Hammett σ constants, are placed at the para carbon of a phenyl ring, attached to the C 2 of 1 and/or 2 A Hammett ρ value of −081 is encountered; indicating that electron donating substituents (–NMe 2 , –NH 2 , –OMe, –OH and –Me) induce storage of higher quantities of solar energy, than electron withdrawing groups (–NO 2 , –F, –Cl, –Br, –CF 3 and –COOH)
TL;DR: In this paper, a block copolymer of poly(5-ethynyl-2,2′-bipyridine) was obtained by the addition of 1 to a poly(phenylacetylene) containing a living end.
Abstract: 5-Ethynyl-2,2′-bipyridine (1; bpyC≡CH) polymerized in the presence of catalytic amounts of [RhF(COD)(PPh3)] or [Rh(μ-OH)(COD)]2 (COD = 1,5-cyclooctadiene) in 74–91% yields. In contrast, [Rh(μ-X)(NBD)]2 (X = Cl or OMe; NBD = norbornadiene) did not catalyze the polymerization of 1 or gave low yields of the polymer. The obtained polymer, poly(5-ethynyl-2,2′-bipyridine) [2; (bpyCCH)n], was highly stereoregular with a predominant cis–transoidal geometry. Random copolyacetylenes containing the 2,2′-bipyridyl group with improved solubility in organic solvents were obtained by the treatment of a mixture of 1 and phenylacetylene (3) or 1-ethynyl-4-n-pentyl-benzene with catalytic amounts of [RhF(COD)(PPh3)]. A block copolymer of 1 and 3 was prepared by the addition of 1 to a poly(phenylacetylene) containing a living end. The reaction of 2 with [Mo(CO)6] produced an insoluble polymer containing [Mo(CO)4(bpy)] groups, whereas with [RuCl2(bpy)2] or [Ru(bpy)2(CH3COCH3)2](CF3SO3)2, it gave soluble metal–polymer complexes containing [Ru(bpy)3]2+ groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43:3167–3177, 2005
TL;DR: In this paper, the rates of photoinduced electron transfer (ET) reactions across two oligo-norbornyl spacer groups (S), that is, structure 1 fused by two norbornadiene (NBD) units and structure 2 fused by three NBD units, are examined.
TL;DR: 5-Norbornene-2-carboxaldehyde and norbornadiene were respectively converted into norbornene derivatives functionalized with fluoroformamid inium hexafluorophosphate and 2-bromo-N-methylpyridinium tetrafluoroborate residues to produce ROMPgel and ROMPsphere peptide-coupling reagents.
TL;DR: In this paper, the authors investigated the performance of amine complex for ring-opening metathesis polymerization (ROMP) and showed that the yields are greater than 70% in CHCl 3 when [NBE]/[Ru] = 3000 (M n ∼ 10 4 to 10 5 and M w /M n = 1.2-2.0) at 50 ± 1 °C for 5 min.
TL;DR: In this paper, the activation barrier was calculated to be 34 kcal-mol−1 at the MCQDPT2/6-31G(d,p)/MCSCF(8,8)/6-6- 31G(D,p), consistent with the 33 kcal−1 experimental value of Frey [H.M. Frey, J. Chem. Soc.
Abstract: CASSCF calculations have been performed to understand the thermal isomerization of quadricyclane (Q) to norbornadiene (N) which occurs via a Woodward–Hoffmann forbidden pathway. The activation barrier is calculated to be 34 kcal mol−1 at the MCQDPT2/6-31G(d,p)//MCSCF(8,8)/6-31G(d,p) level, consistent with the 33 kcal mol−1 experimental value of Frey [H.M. Frey, J. Am. Chem. Soc. (1964) 365]. The transition state has high biradical character and the structure belongs to point group C1, whereas both Q and N belong to point group C2V. The reaction is found to be highly asynchronous with one bond cleaving entirely before the transition state and the second bond cleaving afterward on the intrinsic reaction coordinate.
TL;DR: The reaction of Cp*2V with 7-sila(germa) norbornadiene derivatives generated the first representatives of Schrock complexes of heavy carbene analogs with transition metals as mentioned in this paper.
Abstract: The reaction of Cp*2V with 7-sila(germa) norbornadiene derivatives generated the first representatives of Schrock complexes of heavy carbene analogs with transition metals. Decamethylvanadocene Cp*2V can be used as a paramagnetic trap for short-lived dimethylgermylene.
TL;DR: In this paper, a cyclic-dioxycarbene derivatives of general formula [Ir 4 (CO) 1 1 - n (L) (COCH 2 CH 2 O) n ] (L = P t Bu 3, n = 1 (2), PPh 3 : n = 2 (3), 2 (4)) were obtained by reaction of oxirane with the tetrairidium cluster derivatives.
TL;DR: In this paper, the presence of the nortricyclyl group and the structure of the complexes have been confirmed by NMR spectroscopy and, in one case, by single-crystal X-ray diffraction.
Abstract: [{Rh(Nbd)Cl}2] (Nbd = norbornadiene) reacts with o-(diphenylphosphane)benzaldehyde in benzene solution to give the rhodium(III) complex [Rh(Cl)(C7H9){o-PPh2(C6H4CO)}]n (1), where C7H9 is a nortricyclyl (Ntyl) group. Complex 1 reacts with various bidentate N-donors, such as biacetyldihydrazone, 2,2'-bipyridine, 8-aminoquinoline, 2-(aminomethyl)pyridine, or pyridine, to afford nortricyclyl [Rh(Cl){o-PPh2(C6H4CO)}(Ntyl)(NN)] complexes. The presence of the nortricyclyl group and the structure of the complexes have been confirmed by NMR spectroscopy and, in one case, by single-crystal X-ray diffraction. Nortricyclyl complexes containing bidentate N-donors are also formed by the reaction in benzene of PPh2(o-C6H4CHO) with the corresponding [Rh(Cl)(Nbd)(NN)] compounds prepared “in situ”. [Rh(Cl)(Nbd)(bipy)] prepared “in situ” reacts with PPh2(o-C6H4CHO) in methanol to give the complex [Rh(Cl){o-PPh2(C6H4CO)}(C7H9)(bipy)], where C7H9 is a norbornenyl (Nbyl) group. This compound has been fully characterized by NMR spectroscopy. A proposal for the selective production of the norbornenyl and the nortricyclyl derivatives is presented. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
TL;DR: It is shown that the X-ray absorption spectrum of 1,4-cyclohexadiene exhibits some particular spectral structures in the discrete energy region that evidence diene through-bond orbital interaction, whereas absorption peaks are identified in the norbornadiene and norbornadienone spectra that indicate effective through-space orbital interactions.
Abstract: Carbon and oxygen near-edge X-ray absorption fine structure (NEXAFS) spectra of 1,4-cyclohexadiene, p-benzoquinone, norbornadiene, norbornadienone, and cis-cis-[4,4,2]propella-3,8-diene-11,12-dione were calculated by means of Hartree-Fock and hybrid density functional theory using the static-exchange (STEX) approximation. The NEXAFS spectra are used as a probe to identify weak molecular interactions between the two non-conjugated ethylenic pi* orbitals present in these molecules. We show that the X-ray absorption spectrum of 1,4-cyclohexadiene exhibits some particular spectral structures in the discrete energy region that evidence diene through-bond orbital interaction, whereas absorption peaks are identified in the norbornadiene and norbornadienone spectra that indicate effective through-space orbital interactions. The molecular structure of the cis-cis-[4,4,2]propella-3,8-diene-11,12-dione isomer is such that the indirect through-bond or through-space diene orbital interactions are too weak to be assigned by its C1s NEXAFS spectrum.
TL;DR: The ring-opening copolymerization of donor-acceptor norbornadiene (D-A NBD) dicarboxylic acid monoglycidyl ester derivatives was performed with tetraphenylphosphonium bromide as a catalyst in toluene.
Abstract: The ring-opening copolymerization of donor–acceptor norbornadiene (D–A NBD) dicarboxylic acid monoglycidyl ester derivatives with D–A NBD dicarboxylic acid anhydride was performed with tetraphenylphosphonium bromide as a catalyst in toluene to produce new norbornadiene (NBD) polyesters containing D–A NBD moieties in the main chain and in the side chain in one step in good yields. The photoisomerization of the D–A NBD moieties in these polyesters proceeded very smoothly to give the corresponding quadricyclane groups. Because these NBD polyesters contained many NBD moieties in the polymer chain, they had the highest capacity for heat storage in the D–A NBD polymers reported so far. The stored thermal energy of the irradiated polyesters was evaluated by differential scanning calorimetry analysis to be approximately 150–190 J/g. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4412–4421, 2005
TL;DR: In this paper, an alternating copolymerization of CO with norbornadiene and ethylidenenorbornene is studied in the presence of Pd complex with (SS)-1, 5-methylbenzyl-3, 7-diphenyl-1,5-diaza-3-7-diphosphacyclooctane ligand, where the structure of cooligomers formed and cooligomerization rate depend on the catalytic system composition and comonomer structure.
Abstract: Alternating copolymerization of CO with norbornadiene and ethylidenenorbornene is studied in the presence of Pd complex with (SS)-1,5-methylbenzyl-3,7-diphenyl-1,5-diaza-3,7-diphosphacyclooctane ligand. The structure of cooligomers formed and cooligomerization rate are shown to depend on the catalytic system composition and comonomer structure. The obtained cooligomers are characterized by structural methods.
TL;DR: In this paper, trifluoromethanesulfonate promoted radical atom-transfer addition of 3-bromoacetyl-2-oxazolidinones to norbornadiene afforded stereoselectively the corresponding 5-exo-3-Bromo-5-nortricycleneacetic acid derivatives in good yields.
Abstract: Ytterbium trifluoromethanesulfonate promoted radical atom-transfer addition of 3-bromoacetyl-2-oxazolidinones to norbornadiene afforded stereoselectively the corresponding 5-exo-3-bromo-5-nortricycleneacetic acid derivatives in good yields. Following clean tri(trimethylsilyl)silane reduction of the bromides, 3-exo-nortricycleneacetic acid derivatives were obtained with excellent diastereoselectivities (90–96% de) when using the chiral 4-isopropyl- and 4-benzyl-substituted 2-oxazolidinone auxiliaries. The stereochemistry of the studied compounds was investigated by 1D and 2D NMR spectroscopy.
TL;DR: In this paper, a synthetic procedure was developed for preparation of exo-oriented di- and tetraamines of the norbornane series by 1,3-dipolar cycloaddition to norbornene and norbornadiene of generated in situ diazomethane followed by reduction of arising pyrazolines catalyzed by Raney nickel.
Abstract: Synthetic procedure was developed for preparation of exo-oriented di- and tetraamines of the norbornane series by 1,3-dipolar cycloaddition to norbornene and norbornadiene of generated in situ diazomethane followed by reduction of arising pyrazolines catalyzed by Raney nickel.
TL;DR: In this article, the vibrational frequencies and corresponding normal mode assignments of norbornadiene were examined theoretically using the gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one five types of motion predicted by a group theoretical analysis, utilizing the C 2 v symmetry of the molecule.
Abstract: The vibrational frequencies and corresponding normal mode assignments of norbornadiene are examined theoretically using the gaussian 98 set of quantum chemistry codes. All normal modes were successfully assigned to one five types of motion predicted by a group theoretical analysis (C C stretch, C–C stretch, C–H stretch, C–H bend, and C–C–C bend) utilizing the C 2 v symmetry of the molecule.
TL;DR: In this article, the results of nitrosation of norbornene and norbornadiene derivatives and dimethyl tricyclo[4.2.2] trifluoromethyl-cis-exo-2-chloro-3-nitrosobicycleclo were studied by X-ray diffraction.
Abstract: Studies of nitrosation of norbornene and norbornadiene derivatives and dimethyl tricyclo[4.2.2.02,5]deca-3,7-diene-9,10-cis-endo-dicarboxylate demonstrated that nitrosation of alkenes with EtONO-PHal3, EtONO-POHal3 (Hal = Cl or Br), and EtONO-SOCl2 systems can afford nitroso halides in high yields without the formation of by-products (ketones and oximes). The reactions with 5-substituted norbornenes are nonregioselective. The trans dimer of endo-5-trifluoromethyl-cis-exo-2-chloro-3-nitrosobicyclo[2.2.1]heptane was studied by X-ray diffraction.
TL;DR: In this article, the synthesis and photochemical valence isomerization of polymers containing donor-acceptor type norbornadiene (D-A NBD) residues in both main and side chains, by the polyaddition of 5-(4-methoxyphenyl)-1,4,6,7,7-pentamethyl-2,5-norbornadene-2-3-dicarboxylic acid diglycidyl ester with terephthaloyl chloride follows by substitution reactions of the resulting polymer with potassium
Abstract: The synthesis and photochemical valence isomerization of polymers containing donor–acceptor type norbornadiene (D–A NBD) residues in both main and side chains, by the polyaddition of 5-(4-methoxyphenyl)-1,4,6,7,7-pentamethyl-2,5-norbornadiene-2,3-dicarboxylic acid diglycidyl ester (D–A NDGE) with terephthaloyl chloride follows by substitution reactions of the resulting polymer with potassium 5-(4-methoxyphenyl)-1,4,6,7,7-pentamethyl-3-methylester-2,5-NBD-2-carboxylate, potassium 5-(4-methoxyphenyl)-1,4,6,7,7-pentamethyl-3-(N,N-dipropylcarbamoyl)-2,5-NBD-2-carboxylate, and potassium 5-(4-methoxyphenyl)-1,4,6,7,7-pentamethyl-3-(N-methyl-N-phenylcarbamoyl)-2,5-NBD-2-carboxylate, respectively. The photochemical valence isomerization of the synthesized poly(ester)s (P-1–P-4, and P-5a–c) was examined in tetrahydrofuran solution or in the film state upon irradiation with a 500-W xenon lamp, and it was found that each photochemical reaction proceeded very smoothly. It was also observed that the rate of the photochemical reaction of the NBD polymers increased efficiently by the addition of 4,4′-bis(diethylamino)benzophenone (BEBP) as a photo-sensitizer in the film state. The stored thermal energies of the irradiated polymers were evaluated by DSC analysis to be 75–153 J/g.