Showing papers on "Norbornadiene published in 1991"
TL;DR: The results of studies on intramolecular interconversions in systems of norbornadiene quadricyclane and their derivatives are classified and discussed in this article, where the mechanisms of the forward photoreaction and reverse thermal process in relation to the nature of the substituents and carbocycles, type of sensitiser and catalyst, and properties of the medium are discussed in detail and classified.
Abstract: The results of studies on intramolecular interconversions in systems of norbornadiene quadricyclane and their derivatives are classified and discussed. The mechanisms of the forward photoreaction and reverse thermal process in relation to the nature of the substituents and carbocycles, type of sensitiser and catalyst, and properties of the medium are discussed in detail and classified. An analysis is made of the influence of these factors on the spectroscopic, kinetic, and thermodynamic properties of this system as an accumulator and converter of light energy. Methods of improving its characteristics — light absorption, the quantum yield of the photoreaction, and stability of the photoproduct — have been established. The bibliography includes 188 references.
148 citations
TL;DR: Amorphous cis-transoidal poly(phenylacetylene) was obtained by [Rh(norbornadiene)Cl] 2 /triethylamine-catalyzed polymerization as discussed by the authors.
Abstract: Amorphous cis-transoidal poly(phenylacetylene) was obtained by [Rh(norbornadiene)Cl] 2 /triethylamine-catalyzed polymerization. The polymer was found to change into crystalline polymer with cis-cisoidal structure when it was poured into toluene or chloroform.
102 citations
TL;DR: A series of fluxional intramolecular η2-bound arene complexes, (C7H8Ar)Pdl(PPh3), 1a-1d, and 2 may be isolated from the catalytic reactions of norbornadiene (or norbornene) with aryl iodides in the presence of Zn and PdCl2(pPh3)2(eqn. 1) and their structures have been determined by X-ray crystallography and NMR spectroscopy.
Abstract: A series of fluxional intramolecular η2-bound arene complexes, (C7H8Ar)Pdl(PPh3), 1a–1d, and 2 may be isolated from the catalytic reactions of norbornadiene (or norbornene) with aryl iodides in the presence of Zn and PdCl2(PPh3)2(eqn. 1) and their structures have been determined by X-ray crystallography and NMR spectroscopy.
67 citations
Patent•
27 Nov 1991TL;DR: In this article, a shelf stable heat curable mixtures of vinyl substituted organopolysiloxane fluid and siloxane hydride are provided, where one part polyorganosiloxane mixtures are catalyzed with an inclusion compound of a cyclodextrin and a complex of cyclopentadiene, 1,5-cyclooctadiene or norbornadiene.
Abstract: Shelf stable heat curable mixtures of vinyl substituted organopolysiloxane fluid and siloxane hydride are provided. The one part polyorganosiloxane mixtures are catalyzed with an inclusion compound of a cyclodextrin and a complex of a cyclopentadiene, 1,5-cyclooctadiene or norbornadiene and a platinum group metal material, such as a C.sub.(1-4) alkyl substituted platinum or a rhodium halide.
60 citations
TL;DR: In this paper, the series of phosphonium phosphines [Ph2P(CH2)nPMe3]X (n = 2, 3, 6, 10; X = NO−3, Cl−, PF−6), henceforth II-, III-, VI-, and X-phosphos, respectively, have been prepared and characterized.
45 citations
TL;DR: In this article, the palladium(II) acetate catalyzed hydroarylation of norbornene and norbornadiene (bicyclo[2.2.1] hepta-2,5-diene) with aryl iodides, triethylamine and formic acid was rendered enantioselective by using optically active phosphine ligands as co-catalysts.
Abstract: The palladium(II) acetate catalyzed hydroarylation of norbornene and norbornadiene (bicyclo[2.2.1]hept-2-ene and bicyclo[2.2.1] hepta-2,5-diene) with aryl iodides, triethylamine and formic acid was rendered enantioselective by using optically active phosphine ligands as co-catalysts. The screening of 5 aryl iodides and 19 optically active phosphine ligands gave the corresponding exo-2-arylbicyclo[2.2.1]heptanes and exo-5-arylbicyclo[2.2.1]hept-2-enes with enantioselectivities of up to 40.6% ee
42 citations
42 citations
39 citations
TL;DR: Chiral cationic and neutral Rh complexes are highly active and excellent catalysts for enantioselective hydrogenation of prochiral olefins and ketones under mild reaction conditions as discussed by the authors.
34 citations
TL;DR: This experiment affords a method of determining the configuration of rhodium enamide complexes in asymmetric hydrogenation (assuming structural homology between Rh and Ir).
33 citations
TL;DR: The first synthesis of 1,4-bishomohexaprismane 6, the true, face-to-face, heptacyclic dimer of norbornadiene ia delineated as mentioned in this paper.
Patent•
04 Sep 1991TL;DR: In this article, a method for making an epoxy functional organosilicon compound is provided, comprising the step of reacting at a temperature of from about 25° to about 100° C.
Abstract: A method for making an epoxyfunctional organosilicon compound is provided, comprising the step of reacting at a temperature of from about 25° to about 100° C. a mixture comprising (A) an ethylenically unsaturated epoxide; (B) an organohydrogenpolysiloxane or organohydrogensilane; and (C) a rhodium complex catalyst selected from the group consisting of: (i) RhX 3 (SR 2 ) 3 ; (ii) RhX 3 ·xH 2 O; (iii) [RhX(norbornadiene)] 2 ; (iv) RhX(CO)(R 3 P) 3 ; (v) RhX(R 3 P) 3 ; and (vi) [RhCl(cyclooctadiene)] 2 ; wherein X is a halogen atom, x is a number equal to 3 or 4, and R is an alkyl radical having from 1 to 8 inclusive carbon atoms, aryl, aralkyl, or alkaryl radical or the R 3 1 SiQ-- group in which Q represents a divalent aliphatic hydrocarbon radical having from 1 to 6 inclusive carbon atoms and R 1 represents an alkyl radical having from 1 to 8 inclusive carbon atoms, aryl, aralkyl, or alkaryl radical or a (CH 3 ) 3 Si-- radical.
TL;DR: In this article, a series of new and known Rh(I) complexes [Rh(R2P(CH2)nPR2)2]Y and [Rh (diene) nPR2)]Y were prepared and their 103Rh NMR spectra were recorded on a 100-MHz spectrometer by using inverse two-dimensional 31P, 103Rh{1H} NMR.
Abstract: A series of new and known Rh(I) complexes [Rh(R2P(CH2)nPR2)2]Y and [Rh(diene)(R2P(CH2)nPR2)]Y (R = Me, Et, Ph, C6F5, C6H4CF3; Y = Cl, ClO4, PF4, BF4, OSO2CF3; diene = norbornadiene, cyclooctadiene) were prepared and their 103Rh NMR spectra were recorded on a 100-MHz spectrometer by using inverse two-dimensional 31P, 103Rh{1H} NMR. This technique provides quick access to 103Rh NMR data (2–8 h for ca. 0.1 M samples) when dealing with Rh-phosphine complexes. The 103Rh NMR data are discussed. All δ(103Rh) of the cationic Rh(I) complexes appear at the lower frequency end of the Rh(I) range, i.e. between −1350 and + 200 ppm, which is in agreement with the fact that the Rh shift is determined by σp and with a large ΔE in square-planar d8 complexes. The relative change in ΔE between complexes is not large and the changes in paramagnetic shift for these complexes are essentially determined by their relative σ-donor capacities. δ(103Rh) shows an inverse correlation with δ(31P), which was rationalized by invoking the chelate ring size containing the Rh centre and the bidentate phosphine ligands.
TL;DR: The homo-Diels-Alder cycloadditions of norbornadiene with various alkynes including terminal and internal acetylenes and methyl prop-2-ynyl ether to give the corresponding deltacyclenes in good to excellent yields.
Abstract: [Col2(PPh3)n]–zinc systems (n=1 or 2) exhibit high catalytic activity for the homo-Diels–Alder [2 + 2 + 2] cycloadditions of norbornadiene with various alkynes including terminal and internal acetylenes and methyl prop-2-ynyl ether to give the corresponding deltacyclenes in good to excellent yields.
TL;DR: Oligonuclear ferrocene derivatives containing either sulfur or disulfur bridges were obtained by three methods as mentioned in this paper : 1) The reaction of 1,1′-dilithioferrocene, fcLi 2, with diferrocenyldisulfane, Fc-SS-Fc (1a), FcS-fc-ss-SSFc(S 3 ), fcS 3 ) and FcSH 2 with norbornadiene (1:1) gave yellow products the majority of which are insoluble in organic
TL;DR: In this article, the X-ray structure analysis of 1,5-Di-tert-butyl-2,4-dimethyl-1.5-diphenyl, 2.4-diaza-1,5diphosphapentan-3-one skeleton is presented.
Abstract: Compounds with the 2,4-Dimethyl-2,4-diaza-1,5-diphosphapentan-3-one Skeleton; Synthesis, Structure, and Properties of 1,5-Di-tert-butyl-2,4-dimethyl-1,5-diphenyl-2,4-diaza-1,5-diphosphapentan-3-one and Its Derivatives
N,N′-Dimethyl-N-N′-bis(trimethylsilyl)urea (1) reacts with tert-butylchlorophenylphosphane (2) to form the monophosphino/ trimethylsilyl-substituted urea 3. Under more vigorous conditions the bisphosphino-substituted derivative 4 was also obtained. The reaction of 4 with the tetracarbonyl norbornadiene derivatives of Cr, Mo, and W furnished the unusual chelate complexes 5–7, in which the ligand 4 is coordinated to the metal through one of the two phosphorus atoms and the oxygen atom of the carbonyl group. The free ligand 4 and the isostructural complexes 5 and 6 were subjected to X-ray structure analyses. The approximate twofold symmetry of 4 is lost as a result of a major conformational change on complex formation. In contrast, 4 reacts with Fe2(CO)9 and with (COD)-PtCl2 (COD=1,5-cyclooctadiene) to give the complexes 8 and 9. In both 8 and 9 the ligand 4 is coordinated by both phosphorus atoms. Reaction of 4 with sulfur and selenium led to the disulfide 10 and diselenide 11, whereas with tellurium no reaction was observed.
TL;DR: In this paper, a polymer bearing pendant norbornadiene (NBD) moieties and a low molecular weight model compound were synthesized by substitution reaction of poly(p-chloromethylstyrene) and benzyl chloride, respectively, with the potassium salt of 3-phenyl-2,5-norbornadienes-2-carboxylic acid.
Abstract: A polymer bearing pendant norbornadiene (NBD) moieties and a low molecular weight model compound ([2-carbobenzyloxy-3-phenyl-2,5-norbornadiene CBPNB)], were synthesized by substitution reaction of poly(p-chloromethylstyrene) and benzyl chloride, respectively, with the potassium salt of 3-phenyl-2,5-norbornadiene-2-carboxylic acid. Photochemical valence isomerization and storage stabilities of the resulting polymer having corresponding pendant quadricyclane (QC) groups and the low molecular weight QC compound were investigated in dichloromethane solution. It was found that the rate of photochemical valence isomerization of the pendant NBD moiety in the polymer was the same as or slightly higher than that of CBPNB, and the storage stability of the QC group in the polymer was higher than that of the QC compound resulting from CBPNB in the solution. The photochemical reaction of the pendant NBD moiety within the polymer without catalyst proceeded quantitatively in the film state. However, the photochemical reaction of the polymer films blended with 5,10,15,20-tetraphenyl-21H,23H-porphine cobalt (II) catalyst (Co-TPP) did not proceed quantitatively, and the degree of conversion of the pendant NBD moiety in the polymer decreased with increasing amounts of Co-TPP in the film. The QC group produced in the polymer by photo-irradiation had excellent storage stability in the film state without Co-TPP. On the other hand, the QC group in the polymer films blended with Co-TPP Catalyst reverted gradually to the NBD group at room temperature.
TL;DR: In this paper, photo-induced electron transfer isomerization of binary norbornadiene derivatives was investigated using phenanthrene, anthracene, pyrene or N -methyl carbazole as sensitizers.
Abstract: Some norbornadiene derivatives and novel covalently bonded electron donor (carbazole)—electron acceptor (norbornadiene) binary systems with different chain lengths were synthesized for the study of solar energy storage. Using phenanthrene, anthracene, pyrene or N -methylcarbazole as sensitizers, photo-induced electron transfer isomerization of norbornadiene derivatives was investigated. The results of photochemical and photophysical studies, especially the chemically induced dynamic nuclear polarization and flash photolysis, have provided direct evidence of the existence of radical-ion pair intermediates, which is in accord with an electron transfer mechanism. The intramolecular electron transfer isomerization of binary norbornadiene compounds to their isomeric quadricyclanes was achieved and the relationship between the chain length and conformation of binary compounds was discussed.
TL;DR: Dibenzoylmethanatoboron difluoride (DBMBF2) and allied BF2 complexes interact from their singlet excited state with trans-anethole (t-A), quadricyclene (QC), and norbornadiene (NBD) by electron tra...
Abstract: Dibenzoylmethanatoboron difluoride (DBMBF2) and allied BF2 complexes interact from their singlet excited state with trans-anethole (t-A), quadricyclene (QC), and norbornadiene (NBD) by electron tra...
TL;DR: In this article, a tetrameric structure was observed for a dicarbonyl-rhodium-Rhodium (DRI) complex, which exhibits N3, N9 coordination of bridging adeninate ligands.
TL;DR: In this article, it was shown that surface olefin complexes and not the metal atoms per se are directly involved in activating molecular hydrogen, which helps to explain why metals with low or negligible capacity for hydrogen chemisorption, e.g. Pt/TiO 2 after high temperature reduction, are still very effective hydrogenation catalysts.
TL;DR: In this article, it was shown that under matrix-isolation conditions of especially high dilution, ionization of quadricyclane leads to the bicyclo[3.2.0]hepta-2,6-diene radical cation, which is also shown to represent an important new intermediate on this much-studied C 7 H 8.+ potential energy surface.
Abstract: We report that under matrix-isolation conditions of especially high dilution, ionization of quadricyclane leads to the bicyclo[3.2.0]hepta-2,6-diene radical cation, which is also shown to represent an important new intermediate on this much-studied C 7 H 8 .+ potential energy surface.
TL;DR: In this article, the synthesis of functionalized norbornadiene dimers is described and a comparison is made between systems 1 and the geometrically similar adamantanes 2, on the one hand, and the attractive but still unknown derivatives of garudane 3 on the other hand.
Abstract: The syntheses of functionalized norbornadiene dimers 1 are described. These cage compounds feature remarkably high D2d symmetry as regards the dimethylene and dioxo derivatives 1d and 1e. On the other hand, the mixed enone compound 11 behaves differently: πcc and lone-pair nco orbitals mix strongly with each other, albeit only by means of the intervening five-bond σ system. All theoretical conclusions have been verified by using PE spectroscopy. A comparison is made between systems 1 and the geometrically similar adamantanes 2, on the one hand, and the attractive but still unknown derivatives of garudane 3 on the other hand. The latter exhibit the interesting parallel topology of suitable chromophores, thus making these polycycles 3 desirable candidates for transmission studies.
TL;DR: Ferrocenethiol and ferrocene-1,1′-dithiol, Fe(C5H5), C5H4SH, and Fe(c5h4SH)2 respectively, can be added to both norbornadiene and norbornene in a radical-induced process as mentioned in this paper.
TL;DR: In this article, a 10-step sequence is described for the conversion of 4methyl-exo-tricyclo [5.1.0 2,6 ] deca-4,8-dien-one (the Pauson-Khand cycloaddition product of norbornadiene with propyne) into 3,3dimethyl-2-[(2-methoxyethoxy) methoxy]-8-(1-methyl-2-oxopropyl) bicyclo [3.3.0] octan-6-
Abstract: A 10-step sequence is described for the conversion of 4-methyl-exo-tricyclo [5.2.1.0 2,6 ] deca-4,8-dien-one (the Pauson-Khand cycloaddition product of norbornadiene with propyne) into 3,3-dimethyl-2-[(2-methoxyethoxy) methoxy]-8-(1-methyl-2-oxopropyl) bicyclo [3.3.0] octan-6-ol. The latter diquinane, formed with complete stereocontrol and well-differentiated functionality, is appropriately substituted to serve as an entry to highly functionalized linearly fused triquinanes, although attempts to close a third five-membered ring via an enolate-epoxide ring-opening proces were unsucessful
TL;DR: In this paper, the authors describe a (1R)-(+)-camphor with 1,1-dimethylhydrazine 3a which with LiBu, followed by PPh2Cl, gives the corresponding compound 3c which has the Ph2P group in 3-exo position and the CN-NMe2 group in the Z configuration.
Abstract: Prolonged treatment of (1R)-(+)-camphor with 1,1-dimethylhydrazine gives (1R)-(+)-camphor dimethylhydrazone 3a which with LiBu, followed by PPh2Cl, gives the corresponding compound 3c which has the Ph2P group in 3-exo position and the CN–NMe2 group in the Z configuration. This new phosphine was quaternized with Mel to give a phosphonium salt and converted into the corresponding sulphide and oxide. Treatment of [M(CO)4(nbd)](M = Cr, Mo or W; nbd = norbornadiene) with 3c gives [[graphic omitted]NMe2)]4 in which the phosphine is chelated to the metal in a six-membered ring. However, when [Mo(CO)6] was heated with 3c in decane, isomerization around the CN bond occurred and the isomeric complex [[graphic omitted]NMe2)]5 was formed. When 4a was heated in diglyme it isomerized to 5. Proton and 31P-{1H} NMR and infrared data are given. Crystals of compound 3c are orthorhombic, space group P212121 with a= 1119.9(2), b= 1166.3(2), c= 1690.7(2) pm and Z= 4; final R factor 0.0443 for 3910 observed reflections. Crystals of complex 5 are orthorhombic, space group P212121, with a= 974.8(2), b= 1658.9(4), c= 1982.0(4) pm and Z= 4; R 0.0425 for 2991 observed reflections. The structure shows that the co-ordinated PPh2 group is in the 3-exo position whilst the CNNMe2 moiety is co-ordinated through the CN nitrogen, giving a five-membered co-ordinated ring and an unco-ordinated NMe2 group. The arrangement around the CN is E, i.e. the opposite to that in 3c.
TL;DR: The microstructures of both the toluene soluble and o-dichlorobenzene insoluble fractions were characterized by high resolution 13C nuclear magnetic resonance spectroscopy in solution and/or in the solid state and by differential scanning calorimetry as mentioned in this paper.
TL;DR: The strength and symmetry of the nuclear quadrupole interaction of the following 199mHg mercaptides were measured at room temperature byγ-γ-perturbed angular correlations: dithiotreitol (DTT), benzylmercaptan (BEM), 1,3-dimercaptobenzene (DMB), glycoldimercaptoacetate (GDMA) as mentioned in this paper.
TL;DR: In this article, it has been demonstrated that polymer-analogous reactions are an attractive alternative to prepare polymers with pendent ferrocene units in the main chain, which can be obtained from interfacial condensation reaction between Ferrocene-1, 1, 1′-dicarbonic acid dichloride with α, ω-diamines.
Abstract: Polymers with pendent ferrocene units are synthesized by radical and anionic methods. It has been demonstrated that polymer-analogous reactions are an attractive alternative to prepare those polymers. Polymers with ferrocene units in the main chain are available from interfacial condensation reaction between ferrocene-1,1′-dicarbonic acid dichloride with α, ω-diamines. Addition of ferrocene-1,1′-dithiol onto norbornadiene yields a polymer with repeating units from ferrocene disulfide and norbornene and nortricyclane end-groups. End-capping reactions of α, ω-dimercapto-telechelics with vinylferrocene yield polymers with ferrocene end-groups.