Six aryl-and pyridine-substituted nitronyl-nitroxide radicals were synthesized and characterized to investigate their optical anisotropic properties.Single-crystal X-ray diffraction analysis revealed molecular packing...Six aryl-and pyridine-substituted nitronyl-nitroxide radicals were synthesized and characterized to investigate their optical anisotropic properties.Single-crystal X-ray diffraction analysis revealed molecular packing organized by either halogen and hydrogen bonding or hydrogen bonding alone.Single-crystal electronic absorption spectra in the visible region of three studied radicals exhibit pronounced linear dichroism,while single crystals of other radicals do not demonstrate this property.Time-dependent DFT and ab initio calculations were employed to determine the transition dipole moment(TDM)vectors corresponding to the long-wavelength absorption bands.For all radicals,these vectors are found to be practically parallel to the O⋯O direction of the nitronyl-nitroxide chromophore.Correlation between the dichroic properties and crystal structure was established through comprehensive analysis of TDM vector orientations relative to the crystal surface.The strongest dichroic effect was observed in crystals where all projections of the TDM vectors onto the illuminated face are parallel to each other,while weaker or absent effects correspond to non-parallel arrangements.This study constitutes the first systematic investigation of linear dichroism in paramagnetic organic crystals,thereby establishing new avenues for developing multifunctional materials that respond to both optical and magnetic stimuli.展开更多
Chemical hydrogen storage technology is crucial for the widespread use of hydrogen,with significant research progress being made in hydrazine hydrate(N_(2)H_(4)·H_(2)O).However,the efficient decomposition of N_(2...Chemical hydrogen storage technology is crucial for the widespread use of hydrogen,with significant research progress being made in hydrazine hydrate(N_(2)H_(4)·H_(2)O).However,the efficient decomposition of N_(2)H_(4)·H_(2)O remains a major challenge,hindered by dynamic constraints.To address this,we prepared NiPt nanoparticles deposited onto urchin-like TiO_(2)(u-TiO_(2))using the impregnation-reduction method,resulting in the NiPt/u-TiO_(2)catalyst.Remarkably,the Ni0.5Pt0.5/u-TiO_(2)catalyst demonstrated 100%H_(2)selectivity,ultrahigh catalytic activity and remarkable durability for N_(2)H_(4)·H_(2)O dehydrogenation,with a turnover frequency(TOF)of115.8 min^(-1),surpassing that of the corresponding NiPt/commercial TiO_(2)(c-TiO_(2)).Characterization and experimental findings suggest that the remarkable activity may originate from the unique urchin-like structure of the catalyst,along with the synergistic interaction between NiPt metals and the support.This research opens new avenues for designing nanomaterials with morphology advantages for hydrogen evolution reaction.展开更多
Controllable hydrogen production via the catalytic decomposition of hydrous hydrazine(N_(2)H_(4)·H_(2)O)holds significant promise for mobile and portable applications.However,current catalysts suffer from unsatis...Controllable hydrogen production via the catalytic decomposition of hydrous hydrazine(N_(2)H_(4)·H_(2)O)holds significant promise for mobile and portable applications.However,current catalysts suffer from unsatisfactory reaction activity and hydrogen(H2)selectivity.Based on the unique redox properties of CeO_(2),this article aims to enhance the thermal catalytic performance for the decomposition of N_(2)H_(4)·H_(2)O by improving metal-support interactions between the TiCeO_(2)and NiPt active components.Meanwhile,the sea urchin-like TiCeO_(2)support,which is more conducive to the dispersion of the NiPt nanoparticles and provides more reactive sites for the reaction,was used to immobilize Ni-Pt into the NixPt1-x/TiCeO_(2)sample using the impregnation-reduction method.By modulating Ce doping and the Ni-Pt molar ratio,samples with different Ni-Pt compositions were synthesized.The optimal Ni0.5Pt0.5/TiCeO_(2)(nNi:nPt=1)shows the highest catalytic performance compared with the other samples,with a TOF(turnover frequency)of 212.58 min-1and 100%hydrogen selectivity at 323 K.Furthermore,the hydrogen selectivity remains 100%after six cycles.This remarkable activity and stability provide valuable insights and encouragement for accelerating the practical application of N_(2)H_(4)·H_(2)O as a viable hydrogen carrier.展开更多
基金supported by the Russian Science Foundation(No.24-73-10026)https://rscf.ru/en/project/24-73-10026/Investigation of dichroic properties was supported by Ministry of Science and Higher Education of the Russian Federation(No.075-03-2024-118/1)+2 种基金The computational part of this work was supported by the Ministry of Science and Higher Education of the Russian Federation(No.AAAA-A21-121011390040-4)SCXRD experiments were supported by the Ministry of Science and Higher Education of the Russian Federation(No.125021302132-4)The measurement of the solid state electronic absorption spectra was supported by the Ministry of Science and Higher Education of the Russian Federation(No.AAAAA-A21-1210112290043-3).
文摘Six aryl-and pyridine-substituted nitronyl-nitroxide radicals were synthesized and characterized to investigate their optical anisotropic properties.Single-crystal X-ray diffraction analysis revealed molecular packing organized by either halogen and hydrogen bonding or hydrogen bonding alone.Single-crystal electronic absorption spectra in the visible region of three studied radicals exhibit pronounced linear dichroism,while single crystals of other radicals do not demonstrate this property.Time-dependent DFT and ab initio calculations were employed to determine the transition dipole moment(TDM)vectors corresponding to the long-wavelength absorption bands.For all radicals,these vectors are found to be practically parallel to the O⋯O direction of the nitronyl-nitroxide chromophore.Correlation between the dichroic properties and crystal structure was established through comprehensive analysis of TDM vector orientations relative to the crystal surface.The strongest dichroic effect was observed in crystals where all projections of the TDM vectors onto the illuminated face are parallel to each other,while weaker or absent effects correspond to non-parallel arrangements.This study constitutes the first systematic investigation of linear dichroism in paramagnetic organic crystals,thereby establishing new avenues for developing multifunctional materials that respond to both optical and magnetic stimuli.
基金financially supported by the National Natural Science Foundation of China(Nos.22478001,U22A20408 and 22108238)the Excellent Young Scholars Program of Natural Science Foundation Anhui Province(No.2408085Y005)+3 种基金the Excellent Youth Scholars Program of Higher Education Institutions of Anhui Province(No.2024AH030008)the Open Fund of Shanghai Jiao Tong University Shaoxing Research Institute(No.JDSX2023014)the State Key Laboratory of Clean Energy Utilization(No.ZJUCEU2024017)the Outstanding Scientific Research and Innovation Team Program of Higher Education Institutions of Anhui Province(No.2023AH010015)
文摘Chemical hydrogen storage technology is crucial for the widespread use of hydrogen,with significant research progress being made in hydrazine hydrate(N_(2)H_(4)·H_(2)O).However,the efficient decomposition of N_(2)H_(4)·H_(2)O remains a major challenge,hindered by dynamic constraints.To address this,we prepared NiPt nanoparticles deposited onto urchin-like TiO_(2)(u-TiO_(2))using the impregnation-reduction method,resulting in the NiPt/u-TiO_(2)catalyst.Remarkably,the Ni0.5Pt0.5/u-TiO_(2)catalyst demonstrated 100%H_(2)selectivity,ultrahigh catalytic activity and remarkable durability for N_(2)H_(4)·H_(2)O dehydrogenation,with a turnover frequency(TOF)of115.8 min^(-1),surpassing that of the corresponding NiPt/commercial TiO_(2)(c-TiO_(2)).Characterization and experimental findings suggest that the remarkable activity may originate from the unique urchin-like structure of the catalyst,along with the synergistic interaction between NiPt metals and the support.This research opens new avenues for designing nanomaterials with morphology advantages for hydrogen evolution reaction.
基金Project supported by the National Natural Science Foundation of China(22478001,22108238,22108002,U22A20408)Excellent Young Scholars Program of Natural Science Foundation Anhui Province(2408085Y005)+2 种基金Excellent Youth Scholars Program of Higher Education Institutions of Anhui Province(2024AH030008)the Open Fund of Shanghai Jiao Tong University Shaoxing Research Institute(JDSX2023014)the Outstanding Scientific Research and Innovation Team Program of Higher Education Institutions of Anhui Province(2023AH010015)。
文摘Controllable hydrogen production via the catalytic decomposition of hydrous hydrazine(N_(2)H_(4)·H_(2)O)holds significant promise for mobile and portable applications.However,current catalysts suffer from unsatisfactory reaction activity and hydrogen(H2)selectivity.Based on the unique redox properties of CeO_(2),this article aims to enhance the thermal catalytic performance for the decomposition of N_(2)H_(4)·H_(2)O by improving metal-support interactions between the TiCeO_(2)and NiPt active components.Meanwhile,the sea urchin-like TiCeO_(2)support,which is more conducive to the dispersion of the NiPt nanoparticles and provides more reactive sites for the reaction,was used to immobilize Ni-Pt into the NixPt1-x/TiCeO_(2)sample using the impregnation-reduction method.By modulating Ce doping and the Ni-Pt molar ratio,samples with different Ni-Pt compositions were synthesized.The optimal Ni0.5Pt0.5/TiCeO_(2)(nNi:nPt=1)shows the highest catalytic performance compared with the other samples,with a TOF(turnover frequency)of 212.58 min-1and 100%hydrogen selectivity at 323 K.Furthermore,the hydrogen selectivity remains 100%after six cycles.This remarkable activity and stability provide valuable insights and encouragement for accelerating the practical application of N_(2)H_(4)·H_(2)O as a viable hydrogen carrier.
