35 research outputs found
Conjugated poly-ynes and poly(metalla-ynes) incorporating thiophene-based spacers for solar cell (SC) applications
Solar cells (SCs) are of considerable current research interest because of their potential as a clean alternative to fossil fuels. Researchers across the globe are developing novel polymeric materials with enhanced power conversion efficiency (PCE). Conjugated poly-ynes and poly(metalla-ynes) incorporating late transition metals and thiophene-based spacers have played a very important role in this strategic area of materials research. The performance of the SCs can be optimized by varying the conjugated spacers and/or the metal ions along the polymer backbone. Therefore, an analysis of structure-photovoltaic property relationships in poly-ynes and poly(metalla-ynes) is desirable as a guide for the development of new functional materials for use in SCs. Keeping the importance of this strategic topic in mind, herein we present a brief review on conjugated poly-ynes and poly(metalla-ynes) incorporating thiophene-based spacers that have potential SC applications. Attempts have been made to correlate the photovoltaic performance of the SCs to the chemical structure of thiophene-incorporated poly-ynes and poly(metalla-ynes). The performance of SCs is also strongly influenced by other factors such as morphology and device structure.</p
Synthesis, optical spectroscopy, structural, and DFT studies on dimeric iodo-bridged Copper(I)complexes
Three new iodo-bridged copper(I)complexes of the type [CuI(PPh 3 )L] 2 , where L = Ar–≡–C 5 H 4 N, Ar = phenyl (C 1 ), biphenyl (C 2 )and flourenyl (C 3 )have been synthesized via coordination-driven self-assembly processes. Two of Cu(I)complexes, C 2 and C 3 , have been characterized by single-crystal X-ray diffraction studies. The complexes have two molecules of the P-donor ligand and two molecules of the N-donor ligand in trans configurations, supporting the central Cu 2 I 2 unit. Absorption properties of the complexes have been investigated. Extensive DFT calculation has been carried out to delineate the influence of aromatic spacers on the optical properties and the nature of excited states. The ease of synthesis of these Cu(I)dimers and the wide range of ethynylpyridine supporting ligands that can be incorporated highlights the potential for these materials to form polymers by linking through the ethylylpyridine ligands. </p
Conjugated poly-ynes and poly(metalla-ynes) incorporating thiophene-based spacers for solar cell (SC) applications
Solar cells (SCs) are of considerable current research interest because of their potential as a clean alternative to fossil fuels. Researchers across the globe are developing novel polymeric materials with enhanced power conversion efficiency (PCE). Conjugated poly-ynes and poly(metalla-ynes) incorporating late transition metals and thiophene-based spacers have played a very important role in this strategic area of materials research. The performance of the SCs can be optimized by varying the conjugated spacers and/or the metal ions along the polymer backbone. Therefore, an analysis of structure-photovoltaic property relationships in poly-ynes and poly(metalla-ynes) is desirable as a guide for the development of new functional materials for use in SCs. Keeping the importance of this strategic topic in mind, herein we present a brief review on conjugated poly-ynes and poly(metalla-ynes) incorporating thiophene-based spacers that have potential SC applications. Attempts have been made to correlate the photovoltaic performance of the SCs to the chemical structure of thiophene-incorporated poly-ynes and poly(metalla-ynes). The performance of SCs is also strongly influenced by other factors such as morphology and device structure.</p
The impact of the alkyne substitution pattern and metalation on the photo-isomerization of azobenzene-based platinum(II) diynes and polyynes
Trimethylsilyl-protected
dialkynes incorporating azobenzene linker groups, Me<sub>3</sub>SiCCRCCSiMe<sub>3</sub> (R = azobenzene-3,3′-diyl, azobenzene-4,4′-diyl,
2,5-dioctylazobenzene-4,4′-diyl), and the corresponding terminal
dialkynes, HCCRCCH, have been synthesized and characterized.
The CuI-catalyzed dehydrohalogenation reaction between <i>trans</i>-[Ph(Et<sub>3</sub>P)<sub>2</sub>PtCl] and the deprotected dialkynes
in a 2:1 ratio in <sup>i</sup>Pr<sub>2</sub>NH/CH<sub>2</sub>Cl<sub>2</sub> gives the platinum(II) diynes <i>trans</i>-[Ph(Et<sub>3</sub>P)<sub>2</sub>PtCCRCCPt(PEt<sub>3</sub>)<sub>2</sub>Ph], while the dehydrohalogenation polycondensation reaction
between <i>trans</i>-[(<sup>n</sup>Bu<sub>3</sub>P)<sub>2</sub>PtCl<sub>2</sub>] and the dialkynes in a 1:1 molar ratio under
similar reaction conditions affords the platinum(II) polyynes, [−Pt(P<sup>n</sup>Bu<sub>3</sub>)<sub>2</sub>–CCRCC−]<sub><i>n</i></sub>. The materials have been characterized spectroscopically,
with the diynes also studied using single-crystal X-ray diffraction.
The platinum(II) diynes and polyynes are all soluble in common organic
solvents. Optical-absorption measurements show that the compounds
incorporating the <i>para</i>-alkynylazobenzene spacers
have a higher degree of electronic delocalisation than their <i>meta</i>-alkynylazobenzene counterparts. Reversible photoisomerization
in solution was observed spectroscopically for the alkynyl-functionalized
azobenzene ligands and, to a lesser extent, for the platinum(II) complexes.
Complementary quantum-chemical modeling was also used to analyze the
optical properties and isomerization energetics
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Chloridobis(ethane-1,2-diamine-κ2N,N′)(3-methylpyridine-κN)cobalt(III) dichloride monohydrate
In the title hydrated salt, [CoCl(C6H7N)(C2H8N2)2]Cl2·H2O, the CoIII ion exhibits a distorted octahedral coordination envirnoment defined by four N atoms of two ethane-1,2-diamine ligands, another N atom of the pyridine ligand and a Cl− ligand. The pyridine N atom and the Cl− ligand are in cis positions relative to each other. The crystal packing is dominated by intermolecular N—H...Cl, O—H...Cl and O—H...H hydrogen-bonding interactions involving the amino groups of the complex cation, the lattice water molecule and the non-coordinating Cl− anions. Weak C—H...Cl interactions consolidate the three-dimensional hydrogen-bonded network structure
Synthesis, optical spectroscopy, structural, and DFT studies on dimeric iodo-bridged Copper(I)complexes
Three new iodo-bridged copper(I)complexes of the type [CuI(PPh 3 )L] 2 , where L = Ar–≡–C 5 H 4 N, Ar = phenyl (C 1 ), biphenyl (C 2 )and flourenyl (C 3 )have been synthesized via coordination-driven self-assembly processes. Two of Cu(I)complexes, C 2 and C 3 , have been characterized by single-crystal X-ray diffraction studies. The complexes have two molecules of the P-donor ligand and two molecules of the N-donor ligand in trans configurations, supporting the central Cu 2 I 2 unit. Absorption properties of the complexes have been investigated. Extensive DFT calculation has been carried out to delineate the influence of aromatic spacers on the optical properties and the nature of excited states. The ease of synthesis of these Cu(I)dimers and the wide range of ethynylpyridine supporting ligands that can be incorporated highlights the potential for these materials to form polymers by linking through the ethylylpyridine ligands. </p