meso- and <scp>D</scp>,<scp>L</scp>-D
 3-trishomocubylidene-D
 3-trishomocubane oxides and <scp>D</scp>,<scp>L</scp>-bi-D
 3-trishomocubyl

Watson, William H.; Kashyap, R. P.; Krawiec, Mariusz; Marchand, A. P.; Reddy, C. Malla; Gadgil, V. R.

doi:10.1107/s0108768192004178

Cited by 11 publications

(5 citation statements)

References 3 publications

(6 reference statements)

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“…The largest deviations are associated with the junction at C3. These data agree well with those reported for similar compounds (Watson et al, 1992). The ideal PCU moiety has mirror (Cs) symmetry.…”

Section: Commentsupporting

confidence: 91%

“…Ignoting the three bonds associated with C3, which joins the two cage moieties, the three classes of bonds in (1) average 1.564 (5), 1.528 (2) and 1.516 (2) A, respectively. These data agree well with the X-ray data on three similar compounds [averaged values 1.567 (5), 1.526 (8) and 1.518 (5) A] and with literature data (Watson et al, 1992). MM3 molecular-mechanics distances, rg, are parameterized to fit electron diffraction data and are approx- (1) with thermal ellipsoids at the 35% probability level and H atoms drawn as spheres of arbitrary size.…”

Section: Commentsupporting

confidence: 86%

“…The bonds C 1--C8, C5--C6 and C3--C10 are 1.545 ,& with the remainder being 1.527,4,. The ab initio (1.582, 1.543 and 1.534 ,~,) and AM1 (1.578, 1.565 and 1.532 ,~,) values have been reported previously (Watson, Kashyap, Krawiec, Marchand, Madhusudhan Reddy & Gadgil, 1992). The parameters in the latest MM3 (Technical Utilization Corporation, 1992) program lead to longer bond distances which agree more closely with the ab initio values.…”

Section: Commentsupporting

confidence: 78%

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8-Pentacyclo[6.3.0.02,6.03,10.05,9]undec-3'-yl-exo-pentacyclo[5.4.0.02,6.03,10.05,9]undecane

Watson¹,

Kashyap²,

Marchand³

et al. 1993

Acta Crystallogr C

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Section: Commentsupporting

confidence: 91%

Section: Commentsupporting

confidence: 86%

Section: Commentsupporting

confidence: 78%

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8-Pentacyclo[6.3.0.02,6.03,10.05,9]undec-3'-yl-exo-pentacyclo[5.4.0.02,6.03,10.05,9]undecane

Watson¹,

Kashyap²,

Marchand³

et al. 1993

Acta Crystallogr C

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“…Several competing scenarios have been proposed to explain rapid, either low-or highamplitude variability in blazar sources. Some include extrinsic causes, such as gravitational microlensing (Watson et al 1999;Webb et al 2000); others involve intrinsic origin, including purely geometrical effects (e.g., the 'light house effect', Camenzind & Krockenberger 1992), or various plasma instabilities leading to the formation of shocks, magnetic reconnection sites, and turbulence (see the recent discussion in, e.g., Narayan & Piran 2012;Subramanian et al 2012;Marscher 2014;Sironi et al 2015;Saito et al 2015). Since the radio-to-optical emission continuum of blazars (and BL Lacertae objects in particular) is known to be due to the synchrotron radiation by ultrarelativistic jet electrons, the temporal behavior of the optical polarization can be used as a powerful tool for diagnosing the structure of the blazar emission zone and the source of their variability.…”

Section: Introductionmentioning

confidence: 99%

Discovery of a Highly Polarized Optical Microflare in Blazar S5 0716+714 During the 2014 Webt Campaign

Bhatta¹,

Goyal²,

Ostrowski³

et al. 2015

ApJ

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The occurrence of low-amplitude flux variations in blazars on hourly timescales, commonly known as microvariability, is still a widely debated subject in high-energy astrophysics. Several competing scenarios have been proposed to explain such occurrences, including various jet plasma instabilities leading to the formation of shocks, magnetic reconnection sites, and turbulence. In this letter we present the results of our detailed investigation of a prominent, five-hour-long optical microflare detected during recent WEBT campaign in 2014, March 2-6 targeting the blazar 0716+714. After separating the flaring component from the underlying base emission continuum of the blazar, we find that the microflare is highly polarized, with the polarization degree ∼ (40−60)% ±(2−10)%, and the electric vector position angle ∼ (10−20) deg ±(1−8) deg slightly misaligned with respect to the position angle of the radio jet. The microflare evolution in the (Q, U ) Stokes parameter space exhibits a looping behavior with a counter-clockwise rotation, meaning polarization degree decreasing with the flux (but higher in the flux decaying phase), and approximately stable polarization angle. The overall very high polarization degree of the flare, its symmetric flux rise and decay profiles, and also its structured evolution in the Q − U plane, all imply that the observed flux variation corresponds to a single emission region characterized by a highly ordered magnetic field. As discussed in the paper, a small-scale but strong shock propagating within the outflow, and compressing a disordered magnetic field component, provides a natural, though not unique, interpretation of our findings.

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“…13 C NMR spectrum of compound IV (registered with the decoupling from protons and using the APT-sequence) contained 22 separate signals among which two pairs of signals belonged to the secondary carbon atoms at 33 ppm corresponding to the bridging atoms and indicating that this compound was 4,4'-bi-D 3 -trishomocubyl. Formerly on compound IV only an XRD study was published without a description of the synthesis and properties of the compound [3].…”

mentioning

confidence: 99%

Synthesis of new derivatives of D 3-trishomocubane

et al. 2010

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The only published procedure of preparation of D 3 -trishomocubane-4-carboxylic acid (I) [1] consists in the radical substitution in the hydrocarbon under the action of oxalyl chloride initiated by benzoyl peroxide. Therewith the chlorocarbonylation provided a certain admixture of isomers β (~3%) [1].Aiming at the preparation of D 3 -trishomocubane-4-carboxylic acid (I) we synthesized D 3 -trishomocubyl 4-iodide (II) in ~60% yield by treating with hydroiodic acid corresponding alcohol III obtained from Cookson's diketone by the known procedure [2]. It should be mentioned that the conversion should be kept below 80-85%, for at higher temperature or at prolonged heating diiodides formed, products of trishomocubane framework fragmentation.In order to obtain acid I the Grignard reagent prepared from iodide II was treated with CO 2 . However instead of the expected reaction product compound IV was obtained, m/z 290. 13 C NMR spectrum of compound IV (registered with the decoupling from protons and using the APT-sequence) contained 22 separate signals among which two pairs of signals belonged to the secondary carbon atoms R H H IV I _ III, V, VI R = COOH (I), I (II), OH (III), CN (V), CONH 2 (VI).at 33 ppm corresponding to the bridging atoms and indicating that this compound was 4,4'-bi-D 3 -trishomocubyl. Formerly on compound IV only an XRD study was published without a description of the synthesis and properties of the compound [3].We obtained from iodide II D 3 -trishomocubane-4-carboxylic acid nitrile (V). As expected, the reaction with potassium cyanide in aqueous-alcoholic solution did not proceed with the secondary halides. As an alternative we used DMF as high-boiling strongly polar solvent, but at 150°C after 20 h the yield of nitrile V attained only 5%. Proceeding from published date [4] we carried out the reaction of trishomocubyl iodide II with potassium cyanide in DMSO at 150°C. As a result we isolated a mixture containing 78% of trishomocubane-4-carbonitrile (V) and 22% of alcohol III. The mixture was separated on a column packed with aluminum oxide, eluent hexane-ethyl acetate, 8: 1.The hydrolysis of nitrile V with aqueous alkali was carried out for 50 h, and here predominantly formed D 3 -trishomocubane-4-carboxamide (VI); no more than 20% of nitrile was converted in acid I.Nitrile V was utilized in the synthesis of a series of D 3 -trishomocubane amino derivatives. Amine VII was obtained by nitrile V reduction with LiAlH 4 . At boiling nitrile V with Grignard reagents in benzene followed by treating the formed complexes with methanol and then reduction of the arising imines with sodium borohydride we obtained compounds VIII and IX (see the scheme). 4-Iodo-D 3 -trishomocubane (II).To 10 g of D 3 -trishomocuban-4-ol was added 60 ml of freshly distilled hydroiodic acid , the mixture was heated over 3 h at 100°C

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meso- and D,L-D ₃-trishomocubylidene-D ₃-trishomocubane oxides and D,L-bi-D ₃-trishomocubyl

Cited by 11 publications

References 3 publications

8-Pentacyclo[6.3.0.02,6.03,10.05,9]undec-3'-yl-exo-pentacyclo[5.4.0.02,6.03,10.05,9]undecane

8-Pentacyclo[6.3.0.02,6.03,10.05,9]undec-3'-yl-exo-pentacyclo[5.4.0.02,6.03,10.05,9]undecane

Discovery of a Highly Polarized Optical Microflare in Blazar S5 0716+714 During the 2014 Webt Campaign

Synthesis of new derivatives of D 3-trishomocubane

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meso- and D,L-D 3-trishomocubylidene-D 3-trishomocubane oxides and D,L-bi-D 3-trishomocubyl

Cited by 11 publications

References 3 publications

8-Pentacyclo[6.3.0.02,6.03,10.05,9]undec-3'-yl-exo-pentacyclo[5.4.0.02,6.03,10.05,9]undecane

8-Pentacyclo[6.3.0.02,6.03,10.05,9]undec-3'-yl-exo-pentacyclo[5.4.0.02,6.03,10.05,9]undecane

Discovery of a Highly Polarized Optical Microflare in Blazar S5 0716+714 During the 2014 Webt Campaign

Synthesis of new derivatives of D 3-trishomocubane

Contact Info

Product

Resources

About

meso- and D,L-D ₃-trishomocubylidene-D ₃-trishomocubane oxides and D,L-bi-D ₃-trishomocubyl