7 research outputs found
A new general route to 1,2-diarylethylenes, 1,4-diarylbutadienes and 1,6-diarylhexatrienes through cycloaromatization of β-oxodithioacetals
A new general route for the title olefins 5a-e, 12, 13, 8a-e and 11a-e has been developed through nucleophilic addition of respective Grignard reagents i.e. allyl-, benzyl-, 1-(naphthylmethyl) magnesium halides to 5-aryl- 1,1-bis(methylthio)pent-4-en-3-ones, 7-aryl-1,1-bis(methylthio)hepta-4,6-dien-3-ones and 9-phenyl-1, 1-bis(methylthio)nona-4,6,8-trien-3-one followed by cycloaromatization of the resulting 3-substituted 1,1-bis(methylthio)alken-3-ols in the presence of boron trifluoride-diethyl ether complex
Facile synthesis of enantiopure chiral molecular rectangles exhibiting induced circular dichroism
The facile syntheses of enantiopure molecular rectangles using 1,8-bis(trans-Pt(Pet<sub>3</sub>)<sub>2</sub>(NO<sub>3</sub>))anthracene and optically pure D- or L-tartrate are reported in high yields. These self-assembled macrocycles are unique examples where the phenomenon of Induced Chiral Dichroism (ICD) has been observed in chiral metallosupramolecular assemblies
Enhanced Thermoelectric Properties of Selenium-Deficient Layered TiSe<sub>2–<i>x</i></sub>: A Charge-Density-Wave Material
In the present work, we report on
the investigation of low-temperature
(300–5 K) thermoelectric properties of hot-pressed TiSe<sub>2</sub>, a charge-density-wave (CDW) material. We demonstrate that,
with increasing hot-pressing temperature, the density of TiSe<sub>2</sub> increases and becomes nonstoichiometric owing to the loss
of selenium. X-ray diffraction, scanning electron microscopy, and
transimission electron microscopy results show that the material consists
of a layered microstructure with several defects. Increasing the hot-press
temperature in nonstoichiometric TiSe<sub>2</sub> leads to a reduction
of the resistivity and enhancement of the Seebeck coefficient in concomitent
with suppression of CDW. Samples hot-pressed at 850 °C exhibited
a minimum thermal conductivity (κ) of 1.5 W/m·K at 300
K that, in turn, resulted in a figure-of-merit (<i>ZT</i>) value of 0.14. This value is higher by 6 orders of magnitude compared
to 1.49 × 10<sup>–7</sup> obtained for cold-pressed samples
annealed at 850 °C. The enhancement of <i>ZT</i> in
hot-pressed samples is attributed to (i) a reduced thermal conductivity
owing to enhanced phonon scattering and (ii) improved power factor
(α<sup>2</sup>σ)