A series of isomeric sandwich-type dysprosiacarboranyl complexes,including[Na(THF)_(5)][3.2'-(THF)_(2)-3.2-Dy(1,2-C_(2)B_(9)H_(11))_(x)(1'7'-C_(2)B_(9)H_(11))_(2-x))(o/m-Dy)and[Na(THF)_(5)][2.2'-(THF)_...A series of isomeric sandwich-type dysprosiacarboranyl complexes,including[Na(THF)_(5)][3.2'-(THF)_(2)-3.2-Dy(1,2-C_(2)B_(9)H_(11))_(x)(1'7'-C_(2)B_(9)H_(11))_(2-x))(o/m-Dy)and[Na(THF)_(5)][2.2'-(THF)_(2)-2.2'-Dy(1,7-C_(2)B_(9)H_(11))2](m-Dy)were synthesized by using the isomeric dicarbollide ligands,namely[nido-7,8-C2BgH_(11)]^(2-)and[nido-7,9-C_(2)B_(9)H_(11)]^(2-).The structural details of o/m-Dy and m-Dy and magnetic dynamics of m-Dy were investigated to compare with the previous study on[Na(THF)_(5)][2.2'-(THF)_(2)-2.2'-Dy(1,2-C_(2)B_(9)H_(11))_(2)]o-Dy.The bending angles of sandwiched dysprosiacarboranes are straightened so as to improve energy bar-riers(U_(eff))from 430(5)to 591(0)K.Magneto-structural correlations show that the introduction of meta-C sites within the π-electron delocalized heterocyclic ring can effectively shorten the Dy-C_(2)B_(3)centroid distance and increase the C_(2)B_(3)centroid...Dy...C_(2)B_(3)centroid bending angle which is attributed to the dif-ferences in electronegativity between C and B atoms on the ring of C_(2)B_(3)^(2-).Therefore,to further enhance the performance of single-molecule magnets(SMMs)on this basis,future endeavors should focus on diminishing the equatorial solvent molecules to make a wider C2B3...Dy...C_(2)B_(3)bending angle.展开更多
Two o-carboranyl compounds containing 1,2,4-triazole groups,each appended with an N-aryl ring(either N-phenyl or N-diisopropylphenyl),were strategically designed and prepared to elucidate the relationship between thei...Two o-carboranyl compounds containing 1,2,4-triazole groups,each appended with an N-aryl ring(either N-phenyl or N-diisopropylphenyl),were strategically designed and prepared to elucidate the relationship between their structural orientation(planarity)and intramolecular charge transfer(ICT)-based radiative decay.The photophysical analysis of both compounds shows that the N-phenyl appended com-pound shows a much higher quantum yield and larger radiative decay constant for ICT-based emission in the rigid state(solution at 77 K and film)than those of the N-diisopropylphenyl appended compound,even exhibiting an additional ICT-based emission in solution at 298 K.Theoretical calculations on their ground and excited states indicate that the planarity of the N-aryl appended triazole moiety affects the efficiency of radiative decay for the ICT transition.These findings firmly establish a strong relationship between the planarity of the appended aryl groups relative to the triazole ring and ICT-based radiative decay in these o-carboranyl luminophores.展开更多
Herein,we compared the optical properties of four compounds with an o-carborane cage linked to 1H-phenanthro[9,10-d]imidazole at the ortho-(oPC),meta-(mPC),or para-position(pPC)of the 2-phenyl ring or at the C2-positi...Herein,we compared the optical properties of four compounds with an o-carborane cage linked to 1H-phenanthro[9,10-d]imidazole at the ortho-(oPC),meta-(mPC),or para-position(pPC)of the 2-phenyl ring or at the C2-position(PC)of the phenanthroimidazole moiety.In the solid state,pPC and PC exhibited intense intramolecular charge transfer(ICT)-based emission centred at∼560 nm,while oPC and mPC exhibited dual emission in high-energy(λ_(em)≈385 nm)and low-energy(λ_(em)≈580 nm)regions due to a locally excited transition and ICT-based emission,respectively.Thus,the quantum efficiency and radiative decay constant of ICT-based emission in the film state were much higher for pPC and PC than for oPC and mPC.Analysis of solid-state molecular structure revealed a notable geometric difference between these two pairs,showing that the C-C bond axis of the o-carborane was orthogonal to the plane of the appended aromatic group for pPC and PC but not for oPC and mPC.Theoretical modelling of the low-energy transition in the first excited states of pPC and PC upon the rotation of the o-carborane cage verified that the above orthogonality plays an important role in the maximisation of ICT-based luminescence.Our findings suggest that the molecular geometry around the o-carborane cage is a major factor determining the efficiency of ICT-based radiative decay in o-carboranyl-substitutedπ-conjugated fluorophores.展开更多
基金the National Natural Science Foundation of China(22375157)the Programme of Introducing Talents of Discipline to Universities(B23025)+4 种基金State Key Laboratory of Electrical Insulation and Power Equipment(EIPE23402,EIPE23405)SpecialSupportPlanof ShaanxiProvincefor Young Top-notch Talent,the Fundamental Research Funds for Central Universities(xtr052023002,xzy012023024)the China Postdoctoral Science Foundation(2023M742783)Shaanxi Postdoctoral Science Foundation(2023BSHYDZZ12)the"Scientists+engineers"Team Building Project of Qin Chuang Yuan(2022KXJ-088).
文摘A series of isomeric sandwich-type dysprosiacarboranyl complexes,including[Na(THF)_(5)][3.2'-(THF)_(2)-3.2-Dy(1,2-C_(2)B_(9)H_(11))_(x)(1'7'-C_(2)B_(9)H_(11))_(2-x))(o/m-Dy)and[Na(THF)_(5)][2.2'-(THF)_(2)-2.2'-Dy(1,7-C_(2)B_(9)H_(11))2](m-Dy)were synthesized by using the isomeric dicarbollide ligands,namely[nido-7,8-C2BgH_(11)]^(2-)and[nido-7,9-C_(2)B_(9)H_(11)]^(2-).The structural details of o/m-Dy and m-Dy and magnetic dynamics of m-Dy were investigated to compare with the previous study on[Na(THF)_(5)][2.2'-(THF)_(2)-2.2'-Dy(1,2-C_(2)B_(9)H_(11))_(2)]o-Dy.The bending angles of sandwiched dysprosiacarboranes are straightened so as to improve energy bar-riers(U_(eff))from 430(5)to 591(0)K.Magneto-structural correlations show that the introduction of meta-C sites within the π-electron delocalized heterocyclic ring can effectively shorten the Dy-C_(2)B_(3)centroid distance and increase the C_(2)B_(3)centroid...Dy...C_(2)B_(3)centroid bending angle which is attributed to the dif-ferences in electronegativity between C and B atoms on the ring of C_(2)B_(3)^(2-).Therefore,to further enhance the performance of single-molecule magnets(SMMs)on this basis,future endeavors should focus on diminishing the equatorial solvent molecules to make a wider C2B3...Dy...C_(2)B_(3)bending angle.
基金supported by the National Research Foundation of Korea(NRF)grant(NRF-2020R1A2C1006400 and NRF-2016M3A7B4909246 for K.M.Lee and 2020R1I1A1A01073381 for J.H.Lee)funded by the Ministry of Science and ICT and the Ministry of Education.
文摘Two o-carboranyl compounds containing 1,2,4-triazole groups,each appended with an N-aryl ring(either N-phenyl or N-diisopropylphenyl),were strategically designed and prepared to elucidate the relationship between their structural orientation(planarity)and intramolecular charge transfer(ICT)-based radiative decay.The photophysical analysis of both compounds shows that the N-phenyl appended com-pound shows a much higher quantum yield and larger radiative decay constant for ICT-based emission in the rigid state(solution at 77 K and film)than those of the N-diisopropylphenyl appended compound,even exhibiting an additional ICT-based emission in solution at 298 K.Theoretical calculations on their ground and excited states indicate that the planarity of the N-aryl appended triazole moiety affects the efficiency of radiative decay for the ICT transition.These findings firmly establish a strong relationship between the planarity of the appended aryl groups relative to the triazole ring and ICT-based radiative decay in these o-carboranyl luminophores.
基金supported by the National Research Foundation of Korea(NRF)grant(NRF-2020R1A2C1006400 and NRF-2021M3H4A1A02055684 for K.M.Lee)funded by the Ministry of Science and ICT.
文摘Herein,we compared the optical properties of four compounds with an o-carborane cage linked to 1H-phenanthro[9,10-d]imidazole at the ortho-(oPC),meta-(mPC),or para-position(pPC)of the 2-phenyl ring or at the C2-position(PC)of the phenanthroimidazole moiety.In the solid state,pPC and PC exhibited intense intramolecular charge transfer(ICT)-based emission centred at∼560 nm,while oPC and mPC exhibited dual emission in high-energy(λ_(em)≈385 nm)and low-energy(λ_(em)≈580 nm)regions due to a locally excited transition and ICT-based emission,respectively.Thus,the quantum efficiency and radiative decay constant of ICT-based emission in the film state were much higher for pPC and PC than for oPC and mPC.Analysis of solid-state molecular structure revealed a notable geometric difference between these two pairs,showing that the C-C bond axis of the o-carborane was orthogonal to the plane of the appended aromatic group for pPC and PC but not for oPC and mPC.Theoretical modelling of the low-energy transition in the first excited states of pPC and PC upon the rotation of the o-carborane cage verified that the above orthogonality plays an important role in the maximisation of ICT-based luminescence.Our findings suggest that the molecular geometry around the o-carborane cage is a major factor determining the efficiency of ICT-based radiative decay in o-carboranyl-substitutedπ-conjugated fluorophores.
