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691.
Sreehari Surendran Rajasree Jierui Yu Dr. H. Christopher Fry Ryther Anderson Dr. Wenqian Xu Riya Krishnan Jiaxin Duan Dr. Subhadip Goswami Prof. Dr. Diego A. Gómez-Gualdrón Prof. Dr. Pravas Deria 《Angewandte Chemie (International ed. in English)》2023,62(38):e202305323
High quantum yield triplets, populated by initially prepared excited singlets, are desired for various energy conversion schemes in solid working compositions like porous MOFs. However, a large disparity in the distribution of the excitonic center of mass, singlet-triplet intersystem crossing (ISC) in such assemblies is inhibited, so much so that a carboxy-coordinated zirconium heavy metal ion cannot effectively facilitate the ISC through spin-orbit coupling. Circumventing this sluggish ISC, singlet fission (SF) is explored as a viable route to generating triplets in solution-stable MOFs. Efficient SF is achieved through a high degree of interchromophoric coupling that facilitates electron super-exchange to generate triplet pairs. Here we show that a predesigned chromophoric linker with extremely poor ISC efficiency (kISC) but form triplets in MOF in contrast to the frameworks that are built from linkers with sizable kISC but . This work opens a new photophysical and photochemical avenue in MOF chemistry and utility in energy conversion schemes. 相似文献
692.
693.
Attar Singh Vivek K. Gupta Rajnikant K. N. Goswami 《Crystal Research and Technology》1995,30(7):991-996
The title compound, C16H14O5, a furanocoumarin crystallizes in the triclinic space group P1 . The unit cell parameters are a = 7.852(2), b = 8.485(1), c = 11.095(1) Å; α = 105.90(1), β = 103.18(2), γ = 95.07(1)°. The structure has been solved by direct methods. Final R = 0.048 for 1943 observed reflections. The furanocoumarin system is almost planar. The epoxide ring makes a dihedral angle with the fused ring system of 98.21(11)°. Molecules are held together by C—H… O hydrogen bonds. 相似文献
694.
A refined crystal structure of andrographolide has been obtained by X-ray anaysis using CuKα radiation. It crystallizes in the monoclinic crystal system with unique b-axis in space group P21. The unit cell parameters are a = 6.552(2) Å, b = 8.009(1) Å, c = 17.989(1) Å and interaxial angle β = 97.32(1)°. The structure has been solved by direct methods and was refined up to R = 0.041, ωR = 0.0464. Both the cyclohexane rings are in chair conformation with the furan ring in twist conformation. The crystal structure is stabilized by hydrogen bonding. 相似文献
695.
S. D. Sharma V. M. Padmanabhan K. N. Goswami Vivek K. Gupta 《Crystal Research and Technology》1993,28(7):945-951
The crystal structure of N-methyl crotananinium iodide has been determined by X-ray structure analysis. The compound crystallizes in the orthorhombic space group P212121 with cell parameters a = 19.37(2), b = 7.70(2), c = 13.38(2) Å. The structure has been solved by Patterson and successive Fourier methods and refined by full matrix least-squares methods to an R-index of 0.075. The structural features of the title compound are noted and are compared with those of similar others of such pyrrolizidine alkaloids. 相似文献
696.
Attar Singh Vivek K. Gupta Rajnikant K. N. Goswami 《Crystal Research and Technology》1995,30(8):1115-1120
The title compound, C16H18O5, a simple coumarin crystallizes in the monoclinic space group P21/c with unit cell parameters a = 7.321(3), b = 21.111(9), c = 11.649(3) Å; β = 123.14(2)°. The structure has been solved by direct methods. The coumarin ring system is planar. The methoxy groups at C5 and C7 are almost coplanar with the coumarin mean plane. The crystal structure is stabilized by C–H… O hydrogen bonds. 相似文献