Showing papers on "Norbornadiene published in 2016"
TL;DR: The synthesis, characterization, and computational evaluation of a series of low molecular weight norbornadiene–quadricyclane systems indicate that the ethynyl moiety plays a critical role in obtaining the high oscillator strengths seen for these molecules.
Abstract: Molecular solar-thermal energy storage systems are based on molecular switches that reversibly convert solar energy into chemical energy. Herein, we report the synthesis, characterization, and computational evaluation of a series of low molecular weight (193-260 g mol(-1)) norbornadiene-quadricyclane systems. The molecules feature cyano acceptor and ethynyl-substituted aromatic donor groups, leading to a good match with solar irradiation, quantitative photo-thermal conversion between the norbornadiene and quadricyclane, as well as high energy storage densities (396-629 kJ kg(-1)). The spectroscopic properties and energy storage capability have been further evaluated through density functional theory calculations, which indicate that the ethynyl moiety plays a critical role in obtaining the high oscillator strengths seen for these molecules.
94 citations
TL;DR: The C-H polyaddition of dimethoxyarene moieties and 4,4'-dimethoxybiphenyl to unconjugated dienes such as norbornadiene and 1,4-divinylbenzene has been achieved for the first time by using cationic half-sandwich rare earth alkyl catalysts.
Abstract: The C–H polyaddition of dimethoxyarenes such as 1,4-dimethoxybenzene and 4,4′-dimethoxybiphenyl to unconjugated dienes such as norbornadiene and 1,4-divinylbenzene has been achieved for the first time by using cationic half-sandwich rare earth alkyl catalysts. This protocol afforded novel polymer materials consisting of dimethoxyarene moieties and nonpolar hydrocarbon structure motifs (cyclic, linear, and aromatic) in perfectly alternating sequences that are otherwise difficult to make. The reaction proceeded via C═C double bond insertion into a C–H bond ortho to each of the two methoxy groups in a step-growth polymerization fashion.
73 citations
TL;DR: The kinetics of the cycloreversion of QC to NBD, which is catalyzed by oxidizing equivalents, can be controlled by an applied electrode potential, which implies the ability to adjust in real time the release of thermal power stored in QC.
Abstract: We have investigated the electrochemically triggered cycloreversion of quadricyclane (QC) to norbornadiene (NBD), a system that holds the potential to combine both energy storage and conversion in a single molecule. Unambiguous voltammetric traces are obtained for pure NBD and pure QC, the latter a strained polycyclic isomer of the former. The difference in redox potentials is smaller than the energy difference between the neutral molecules. This is owing to a significant energy difference between the corresponding radical cations, as demonstrated by density functional theory (DFT) calculations. The vibrational modes of each pure compound are characterized experimentally in the fingerprint region and identified by DFT methods. Thermal and electrochemical transformations of NBD and QC are monitored in situ by IR spectroelectrochemical methods. The kinetics of the cycloreversion of QC to NBD, which is catalyzed by oxidizing equivalents, can be controlled by an applied electrode potential, which implies the ability to adjust in real time the release of thermal power stored in QC.
48 citations
TL;DR: A palladium-catalyzed arylboration of norbornene or norbornadiene with aryL halides and bis(pinacolato)diboron has been disclosed and is complementary to the existing methods and well tolerable with a variety of functional groups.
Abstract: A palladium-catalyzed arylboration of norbornene or norbornadiene with aryl halides and bis(pinacolato)diboron has been disclosed. Mechanistic studies suggest that the reaction proceeds under a Catellani-type coupling to render versatile multifunctionalized alkylboranes in good yields. This reaction is complementary to the existing methods and is well tolerable with a variety of functional groups and readily scaled-up to a gram scale without deteriorating the yield.
41 citations
TL;DR: One-pot protocols for the synthesis of previously unknown hybrid heterocyclic systems with the furoxanylpyridine core based on the tandem inverse-electron-demand hetero-Diels-Alder/retroDiels−Alder reactions of the tailor-made (1,2,4-triazin-3-yl)furoxans with 1-(pyrrolidino)cyclohexene and norbornadiene have been developed.
Abstract: Two convenient, facile, regioselective and highly effective one-pot protocols for the synthesis of previously unknown hybrid heterocyclic systems with the furoxanylpyridine core based on the tandem inverse-electron-demand hetero-Diels–Alder/retro-Diels–Alder reactions of the tailor-made (1,2,4-triazin-3-yl)furoxans with 1-(pyrrolidino)cyclohexene and norbornadiene have been developed. The methods comprise [4 + 2] cycloaddition of enamine or norbornadiene to the 1,2,4-triazine ring of (1,2,4-triazin-3-yl)furoxans followed by one-pot transformation of the formed intermediates and this affords an extensive series of polyheterocyclic ensembles combining furoxan and pyridine (tetrahydroisoquinoline, indenopyridine, terpyridine) rings in one molecule through a C–C bond in good to excellent yields.
39 citations
TL;DR: A palladium-catalyzed C-2 allylation of indoles and subsequent cyclization of the allylated indoles was reported in this article, where the resulting 2-allyl-3-chloroindoles were found to be suitable substrates for benzannulation reactions with alkynes and norbornadiene as an acetylene synthon.
Abstract: We report a palladium-catalyzed C-2 allylation of indoles and subsequent cyclization of the allylated indoles. The electronic effects of chloro and ester groups that can be readily installed at the C-3 position of indoles facilitated a highly efficient C–H allylation at the C-2 position. The resulting 2-allyl-3-chloroindoles were found to be suitable substrates for benzannulation reactions with alkynes and norbornadiene as an acetylene synthon. This approach, utilizing readily available indoles, allyl acetates, and norbornadiene, allows a rapid access to complex carbazoles.
24 citations
TL;DR: In this paper, the straightforward synthesis of two cationic iridium norbornadiene species bearing simple bidentate phosphines was reported, and the solid-state structures of these dimeric species were also discussed.
11 citations
TL;DR: A series of dinuclear copper(I) oxalate complexes were synthesized by the direct acid-base reaction of Cu2O with oxalic acid in ethanol with a ligand, or in neat ligand as mentioned in this paper.
11 citations
TL;DR: In this article, features of allylation of norbornadiene (NBD) with allyl formate were investigated in the presence of Pd catalysts and the products of secondary transformations, hydration and hydroformylation, have been found.
Abstract: Features of allylation of norbornadiene (NBD) with allyl formate were investigated in the presence of Pd catalysts In addition to the products of single or double allylation and hydroallylation of NBD, the products of secondary transformations, hydration and hydroformylation, have been found An effect of triphenylphosphine on the reaction direction was studied
10 citations
TL;DR: A prochiral bridged compound of C2v symmetry, the norbornadiene (NBD), oriented in a chiral liquid crystal composed of various mixtures of poly-γ-benzyl- l-glutamate and poly-ε-carboxy-l-lysine, two chiral homopolypeptides, is investigated using natural abundance deuterium 2D-NMR (NAD 2D -NMR) spectroscopy.
Abstract: A prochiral bridged compound of C2v symmetry, the norbornadiene (NBD), oriented in a chiral liquid crystal composed of various mixtures of poly-γ-benzyl-l-glutamate (PBLG) and poly-e-carboxy-l-lysine (PCBLL), two chiral homopolypeptides, is investigated using natural abundance deuterium 2D-NMR (NAD 2D-NMR) spectroscopy. In such chiral oriented solvents, enantiotopic directions are spectrally nonequivalent, and two distinct 2H quadrupolar doublets associated with enantioisotopomeric pairs of NBD are detected. As the two homopolypeptides have the same absolute configuration but distinct chemical functions in their side chains, the variation of residual quadrupolar couplings (RQC’s) allows the determination of the relative solute-fiber affinities toward the two polypeptides in these lyotropic bipolymeric systems. Besides the experimental measurement of RQC’s and the determination of their signs at each inequivalent 2H site, the elements of the second-rank order tensor, Sαβ, are calculated by assuming a model...
8 citations
TL;DR: In this article, the solar energy storage of four electron donating substituents, (push-push effect), X (X =−NH2,−OH) and four electron withdrawing substituent, (pull-pull effect) X(X = −CO2H,−CONH2, −NO2 and CN) were examined.
Abstract: The purpose of this research is to study the solar energy storage in norbornadiene (1)/quadricyclane (2) system by four direct attachments of substituents at two carbon atoms on both sides of the double bonds C2=C3 and C5=C6 in 1X and 2X; calculating the relative energies at B3LYP/6-311++G** level of theory. The solar energy storage of four electron donating substituents, (push-push effect), X (X =–NH2,–OH) and four electron withdrawing substituents, (pull-pull effect) X (X =–CO2H,–CONH2,–NO2 and CN) were examined. The solar absorption bands were calculated for 1X. The DFT calculations reveal that the bands were shifted to the visible spectrum region when the electron withdrawing substituents were used rather than the electron donating substituents.
TL;DR: Compounds 1 and 3 are proposed as intermediate species in the catalytic hydroacylation of norbornadiene with NCHO, and shows low stability in solution and undergoes slow ring closure isomerization toRhCl(NCO)(ntyl)(PR3)] after 12 hours.
Abstract: [RhCl(NCO)(nbyl)(PR3)] (nbyl = σ-norbornenyl; NCO = quinoline-8-acyl; R = p-F-C6H4) (1) has been synthesized by the reaction of [Rh(nbd)Cl]2 (nbd = norbornadiene) with 2 equivalents of NCHO (quinoline-8-carbaldehyde) and 2 equivalents of PR3. Compound 1 has been fully characterized in solution and also in the solid state by X-ray diffraction. Compound 1 shows low stability in solution and undergoes slow ring closure isomerization to [RhCl(NCO)(ntyl)(PR3)] (ntyl = σ-nortricyclyl) (2) after 12 hours. Reaction of 1 with an extra equivalent of aldehyde (NCHO) and PR3 led to the formation of [RhCl(H)(NCO)(PR3)2] (3) and an equivalent of ketone, which is a hydroacylation product. The catalytic activity of 3 in the hydroacylation of nbd with NCHO is reported as well as the catalytic activity of compound 1. Compounds 1 and 3 are proposed as intermediate species in the catalytic hydroacylation of norbornadiene with NCHO.
TL;DR: In this paper, the reaction of 4-fluoro-N-sulfinylaniline with norbornene and norbornadiene has afforded the Diels-Alder adducts of benzothiazine structure that have been oxidized into the corresponding benzothiaine sulfonamides.
Abstract: Reaction of 4-fluoro-N-sulfinylaniline with norbornene and norbornadiene has afforded the Diels–Alder adducts of benzothiazine structure that have been oxidized into the corresponding benzothiazine sulfonamides. Structure of the obtained compounds and stereochemistry of the diene addition and epoxidation of norbornene olefin bonds have established by means of X-ray diffraction method.
TL;DR: The interaction of P,N-containing cyclophanes containing two 1,5-diaza-3,7-diphosphacyclooctane fragments with tetracarbonyl(tetrahydrofuran)tungnsten(0) or tetracarbonel(norbornadiene)molybdenum(0,1) was studied in this paper.
Abstract: The interaction of P,N-containing cyclophanes containing two 1,5-diaza-3,7-diphosphacyclooctane fragments with tetracarbonyl(tetrahydrofuran)tungnsten(0) or tetracarbonyl(norbornadiene)molybdenum(0...
TL;DR: The ring opening metathesis polymerization (ROMP) of norbornadiene (NBD) in a non-degassed solution upon addition of ethyl diazoacetate (EDA) was reported in this article.
Abstract: The [RuCl3(PCy3)2] complex presented high reactivity toward ring opening metathesis polymerization (ROMP) of norbornadiene (NBD) in a non-degassed solution upon addition of ethyl diazoacetate (EDA). Quantitative yields of polyNBD were obtained instantaneously at 25 °C. ROMP of norbornene (NBE) occurred better at 50 °C for 60 min, with 95% of isolated polyNBE. Copolymers with different porous structures were obtained from ROMP of NBE in the presence of NBD with different starting [NBE]/[NBD] molar ratios at 25 °C. SEM micrographs showed a more organized porous structure as the NBD loading decreased. A well-defined honeycomb-like pattern was recorded for the copolymer from the run with an NBE : NBD molar ratio load of 5000 : 500. The Tg values varied from 37 °C in polyNBE to 90 °C in poly[NBE-co-NBD] as the NBD loading increased.
TL;DR: The first 3H-1,3-azaphospholo-pyridines 2a-c were synthesized as racemic mixtures in modest to medium yield by the reaction of N-(2-chloropyrid-3-yl)-trimethylacetimidoyl chloride 1 with RPLi2, and studied with respect to their suitability as ligands (L) in transition metal complexes.
Abstract: The first 3H-1,3-azaphospholo-pyridines 2a-c were synthesized as racemic mixtures in modest to medium yield by the reaction of N-(2-chloropyrid-3-yl)-trimethylacetimidoyl chloride 1 with RPLi2 (R = Ph, n-Bu, i-Bu), generated from RPH2 and BuLi in THF at -70 °C, and studied with respect to their suitability as ligands (L) in transition metal complexes. Reactions of 2a with group 6 metal(0) pentacarbonyls led to P-coordinated LM(CO)5 complexes 3a-5a (Cr, Mo, W) and the reaction of 2c with (norbornadiene)Mo(CO)4 surprisingly to 4c. [Rh(1,5-COD)Cl]2 and 2a,b, in metal/ligand ratio 1 : 1, furnished LRh(1,5-COD)Cl complexes 6a,b with P-coordination, 6b accompanied by a minor contamination by the bis-coordinated L[Rh(COD)Cl]2 complex 7b. Reactions of 2a,b with [(allyl)PdCl]2 proceeded in THF with dismutation of N-coordinated (allyl)PdCl and formed with 2a a labile crude product [(2a){(allyl)PdCl}1.2(PdCl2)0.8]·C4H8O, with the composition close to L[Pd(allyl)Cl]PdCl2 THF (8a·THF), which converted during crystallization to 9a, whereas 2b directly formed the N,N'-PdCl2-bridged bis[LPd(allyl)chloride] complex 9b. Conversion of 2b with equimolar amounts of Pd(CH3CN)2Cl2 in THF, or Na2PdCl4 in methanol, gave rise to the dimeric P,N-bridging complex 10b. Crystal structure analyses of 6a (rac), 9b·2CDCl3 (meso), 10b·4.5THF and 10b·2D6-acetone (rac) provided detailed structural information. 10b, but more efficiently complexes formed in situ from 2a,b and Pd2(DBA)3 or Pd(OAc)2, catalysed the arylamination of 2-bromopyridine with 2,4,6-trimethylaniline.
TL;DR: In this article, the authors employed density functional theory to study and characterize a new family of belt-shaped molecules which use the norbornadiene tether and aromatic molecules as linkers.
Abstract: We have employed density functional theory to study and characterize a new family of belt shaped molecules which use the norbornadiene tether and aromatic molecules as linkers. Our results indicated that the inclusion of the norbornadiene unit eliminates the strain commonly associated with the synthesis of belt-shaped molecules. Polymerization of the latter proved to be an effective method towards the bottom-up synthesis of organic nanotubes with uniform properties. The band gap of the infinite nanotubes proposed can be engineered by changing the molecule which links the norbornadiene tethers. In effect, the gap of the pyrene/norbornadiene and coronene/norbornadiene based nanotubes were 2.9 eV and 0.9 eV, respectively, as indicated by HSE calculations. Among the six belts assayed, two can be used to separate the magic fullerenes C180 and C240, given that large interaction energies were found upon complexation.
TL;DR: In this paper, the formation of the metallacycle has been found to occur through several steps, and the nbd displaces the cod in [(Ir(μ-Cl)(cod))2] to give the IrIII chloro-bridged complex, which bears a η4-C-coordinated nbd and a five-membered iridacycle formed by two half-coupled nbd moieties.
Abstract: The treatment of [(Ir(μ-Cl)(cod))2] (cod = 1,5-cyclooctadiene) with 2,5-norbornadiene (nbd) in the presence of triethylphosphane under an atmosphere of ammonia afforded the cation complex [Ir(κC,κC-C21H24)(NH3)3(PEt3)]Cl (1a) and complex [Ir(κC,κC-C21H24)Cl(NH3)2(PEt3)] (1b), the structures of which include a novel seven-membered iridacycle formed by three half-coupled nbd molecules. The formation of the metallacycle has been found to occur through several steps. First, the nbd displaces the cod in [(Ir(μ-Cl)(cod))2] to give the IrIII chloro-bridged complex [(Ir(κC,κC-C14H16)(μ-Cl)(η4-C7H8))2] (2), which bears a η4-C=C-coordinated nbd and a five-membered iridacycle formed by two half-coupled nbd moieties. Further reaction with PEt3 induces the C-C coupling between the iridacycle and the coordinated nbd to give the chloro-bridged complex [(Ir(κC,κC-C21H24)(μ-Cl)(PEt3))2] (4). Finally, 4 reacts with gaseous ammonia to split the chloro bridges and form species 1a and 1b. Also, complex 2 was found to react with several donor ligands to afford the corresponding mononuclear adducts [Ir(κC,κC-C14H16)Cl(η4-C7H8)(L)] [L = py (5), NH3 (6), PMe2Ph (7), tBuNC (8)]. The X-ray molecular structures of 5, 7 and 8 show the presence of a five-membered iridacycle, but their stereochemistries differ by virtue of the relative locations of the respective added ligand.
TL;DR: A palladium-catalyzed arylboration of norbornene or norbornadiene with aryL halides and bis(pinacolato)diboron has been disclosed and is complementary to the existing methods and well tolerable with a variety of functional groups.
Abstract: A palladium-catalyzed arylboration of norbornene or norbornadiene with aryl halides and bis(pinacolato)diboron has been disclosed. Mechanistic studies suggest that the reaction proceeds under a Catellani-type coupling to render versatile multifunctionalized alkylboranes in good yields. This reaction is complementary to the existing methods and is well tolerable with a variety of functional groups and readily scaled-up to a gram scale without deteriorating the yield.
TL;DR: In this article, a chiral bisoxazoline ligand based on norbornadiene was synthesized and used for the asymmetric Henry reaction, which yields high yields and moderate to acceptable enantioselectivities under the optimized reaction conditions.
Abstract: Novel chiral bisoxazoline ligands based on norbornadiene were synthesized and used for the asymmetric Henry reaction. Various aromatic aldehydes were converted into chiral $\beta $-nitro alcohols with high yields and moderate to acceptable enantioselectivities under the optimized reaction conditions.
Patent•
27 Apr 2016
TL;DR: In this paper, a preparation method of a norbornadiene dimer using a dimerization reaction was proposed, where a heterogeneous catalyst including a microporous zeolite catalyst and a mesoporous aluminosilicate catalyst was used.
Abstract: The present invention relates to a preparation method of a norbornadiene dimer using a dimerization reaction of norbornadiene (bicyclo(2.2.1) heptadiene-2,5, NBD). More particularly, the preparation method of the present invention prepares a norbornadiene dimer by promoting a dimerization reaction of norbornadiene using a heterogeneous catalyst including a microporous zeolite catalyst and a mesoporous aluminosilicate catalyst.
Patent•
30 Dec 2016
TL;DR: In this article, a series of compositions containing polymers of norbornadiene and maleic anhydride monomers which are useful in forming a variety of photopatternable structures are disclosed and claimed.
Abstract: Embodiments encompassing a series of compositions containing polymers of norbornadiene and maleic anhydride monomers which are useful in forming a variety of photopatternable structures are disclosed and claimed. The compositions are useful as permanent dielectric materials. More specifically, embodiments encompassing compositions containing a series of ter- and tetrapolymers of a variety of norbornadiene, maleic anhydride, maleimide and norbornene-type cycloolefinic monomers in which maleic anhydride is fully or partially hydrolyzed (i.e., ring opened and fully or partially esterified), and a photoactive compound are disclosed, which are useful in forming permanent dielectric materials having utility in a variety of electronic material applications, among various other uses.
TL;DR: The title salt, C12H16N3O2+·PF6−, was obtained by the dipolar cyclo-addition of norbornadiene to 2-azido-1,3-di-meth-oxy-imidazolium hexa-fluorido-phosphate.
TL;DR: One-pot protocols for the synthesis of previously unknown hybrid heterocyclic systems with the furoxanylpyridine core based on the tandem inverse-electron-demand hetero-Diels-Alder/retroDiels−Alder reactions of the tailor-made (1,2,4-triazin-3-yl)furoxans with 1-(pyrrolidino)cyclohexene and norbornadiene have been developed as discussed by the authors.
Abstract: Two convenient, facile, regioselective and highly effective one-pot protocols for the synthesis of previously unknown hybrid heterocyclic systems with the furoxanylpyridine core based on the tandem inverse-electron-demand hetero-Diels–Alder/retro-Diels–Alder reactions of the tailor-made (1,2,4-triazin-3-yl)furoxans with 1-(pyrrolidino)cyclohexene and norbornadiene have been developed. The methods comprise [4 + 2] cycloaddition of enamine or norbornadiene to the 1,2,4-triazine ring of (1,2,4-triazin-3-yl)furoxans followed by one-pot transformation of the formed intermediates and this affords an extensive series of polyheterocyclic ensembles combining furoxan and pyridine (tetrahydroisoquinoline, indenopyridine, terpyridine) rings in one molecule through a C–C bond in good to excellent yields.