Homoleptic tris(6,6’-dimethyl-2,2’-bipyridine)rare earth metal complexes M(κ^(2)-dmbp)3(M=Y,Tb,Dy,Ho,Er;dmbp=6,6’-dimethyl-2,2’-bipyridine)were synthesized by in situ reduction of 3 equiv.of dmbp with excess KC8 ...Homoleptic tris(6,6’-dimethyl-2,2’-bipyridine)rare earth metal complexes M(κ^(2)-dmbp)3(M=Y,Tb,Dy,Ho,Er;dmbp=6,6’-dimethyl-2,2’-bipyridine)were synthesized by in situ reduction of 3 equiv.of dmbp with excess KC8 in the presence of 1 equiv.of rare earth metal trihalides.All compounds were characterized by X-ray crystallography,UV-Vis-NIR spectroscopy,infrared(IR)spectroscopy,elemental analysis,and magnetic measurements.While the structural parameters and spectroscopic data confirmed the existence of the trivalent rare earth metal cation and three dmbp radical anions,the electron paramagnetic resonance(EPR)spectrum and the measured magnetic moment of Y(κ^(2)-dmbp)3 indicated that two parallel dmbp radical anions were antiferromagnetically coupled.For paramagnetic rare earth metal ions,room temperature magnetic susceptibility values indicated a weak ferromagnetic interaction between the metal ion and the remaining dmbp radical.Density functional theory(DFT)calculations were performed on Y(κ^(2)-dmbp)3 to gain insight into the electronic structures of these homoleptic metal complexes.The computational results were consistent with the structural,spectroscopic,and magnetic data for a S=1/2 ground state and spin densities mostly residing on one dmbp radical anion,while the spins on the other two parallel dmbp radical anions being antiferromagnetically coupled.展开更多
In this report we present the structural and magnetic characterization of four distorted tetrahedral homoleptic Co(II)complexes bearing two 2-formiminopyrrolyl N,N’-chelating ligands.
Homoleptic Ir_((III))based carbene complexes are known to be the most promising emitters of future blue OLED devices.To provide the proof-of-concept,we designed a series of functional di-CF_(3)-functionalized benzo[d]...Homoleptic Ir_((III))based carbene complexes are known to be the most promising emitters of future blue OLED devices.To provide the proof-of-concept,we designed a series of functional di-CF_(3)-functionalized benzo[d]imidazol-3-ium pro-chelates,which could afford single product emitters after proper modification.For benzoimidazol-2-ylidene with an N-methyl substituent,selective formation of the product can be achieved by introduction of t-butylphenyl for the phenyl group,as shown by shifting the product from mixed m-Ir(dfp)_(3)and f-Ir(dfp)_(3)to the single isomer f-Ir(dfpb)_(3).Alternatively,for di-N-aryl substituted carbene chelates,the steric encumbrance imposed between the ortho-CF_(3)group and the adjacent N-aryl substituent redirects the cyclometalation to the other N-aryl substituent,leading to the formation of one single product,e.g.,f-Ir(tBpp)_(3)and f-Ir(ptBp)_(3).Moreover,the doped OLED based on f-Ir(tBpp)_(3)delivered true-blue emission centered at 457 nm and a maximum EQE of 15.6%.Furthermore,upon addition of terminal emittersν-DABNA and t-DABNA,the respective hyper^(-)OLEDs exhibited narrowband blue emission with a maximum EQE of 18.9%at 474 nm and 18.1%at 462 nm,respectively.These highlighted the potential of these Ir_((III))emitters in the fabrication of blue OLEDs.展开更多
Emitters with suppressed intermolecular interactions are desired for high efficiency OLEDs.Herein,five phosphorescent homoleptic Ir(Ⅲ)complexes with a triptycene skeleton were successfully synthesized.Benefitting fro...Emitters with suppressed intermolecular interactions are desired for high efficiency OLEDs.Herein,five phosphorescent homoleptic Ir(Ⅲ)complexes with a triptycene skeleton were successfully synthesized.Benefitting from the unique rigid and bulky triptycene skeleton,these complexes exhibit excellent thermal and photophysical properties.Their crystal structures indicated that the π-π stacking interactions can be completely eliminated by reasonable combination of the triptycene skeleton and steric hindrance groups.These complexes show significantly good to excellent quantum yields(73.7%-88.9%)and thermal stability(Td=364-451℃).A highly efficient OLED with an external quantum efficiency of up to 27.5% is developed with very low efficiency roll-off and is the most efficient OLED based on phthalazine iridium complexes.展开更多
Two new iridium complexes with C^N=N type ligand(i.e.,Ir(BFPPya)3{tris[3,6-bis(4-fluorophenyl)pyridazine]iridium(III)}and Ir(BDFPPya)3{tris[3,6-bis(2,4-di-fluorophenyl)pyridazine]iridium(III)})attaching with fluorine ...Two new iridium complexes with C^N=N type ligand(i.e.,Ir(BFPPya)3{tris[3,6-bis(4-fluorophenyl)pyridazine]iridium(III)}and Ir(BDFPPya)3{tris[3,6-bis(2,4-di-fluorophenyl)pyridazine]iridium(III)})attaching with fluorine atoms,were synthesized and the effects of fluorination on the material properties and device performance were investigated.Compared with our previously reported fluorine-free analogue material,that is Ir(BPPya)3{tris[3,6-bis(phenyl)pyridazine]iridium(III)},blue shifts in the emission spectra as well as in the long wavelength region of the absorptions were observed.The photoluminescence quantum yield(PLQY)(0.44 and 0.84 vs.0.29),phosphoresces lifetime(0.88 and 1.31 vs.0.66 gs),and oxidation potential(1.10 and 1.37 vs.0.95 V)increased obviously after fluorinating the ligand.In contrast,the thermal stability of the iridium complexes decreased slightly(Td:435 and 402 vs.440℃).In the density functional theory(DFT)calculations,by comparing the steric shape of the three ligands within one optimized molecule,orientational differences among the complexes were observed.In OLED device studies,bluish green electroluminescence with peak emission of 500 nm,using the electron-transporting host of TPBI[2,2',2"-(1,3,5-benzenetriyl)tris(1-phenyl-lH-benzimidazole)]and the most fluorinated dopant of Ir(BDFPPya)3,was achieved with maximum efficiency of 20.3 cd/A.On one hand this efficiency is not satisfactory considering a high PLQY of 0.84.On the other hand with the similar device structure,that the(HOMO-LUMO)s of all the dopants are wrapped within that of the host TPBI,and all the triplet energies of the dopants are smaller than that of the host TPBI,it is abnormal that the ordering of device efficiencies is contradictory to that of PLQY.Assisting with the phosphorescent spectrum of TPBI and the absorption spectra of the dopant,the contradiction was interpreted reasonably.展开更多
The study of various oxidation states of chromium with Sargassum <i>sp</i>. is of particular interest since hexavalent chromium </span><span style="font-size:10.0pt;font-family:""&g...The study of various oxidation states of chromium with Sargassum <i>sp</i>. is of particular interest since hexavalent chromium </span><span style="font-size:10.0pt;font-family:"">is </span><span style="font-size:10.0pt;font-family:"">reduced to trivalent chromium in </span><span style="font-size:10.0pt;font-family:"">an </span><span style="font-size:10.0pt;font-family:"">aqueous solution. In this study, a systematic density functional theory (DFT) calculations were performed to study the interactions of transition metal chromium ion with different oxidation states and spin states with the <i>Sar</i></span><i><span style="font-size:10.0pt;font-family:"">gassum sp</span></i><span style="font-size:10.0pt;font-family:"">. decorated with carboxylate</span><span style="font-size:10.0pt;font-family:""> </span><span style="font-size:10.0pt;font-family:"">(acetate) at the wB97XD/6-311++</span><span style="font-size:10.0pt;font-family:""> </span><span style="font-size:10.0pt;font-family:"">G(d,p)</span><span style="font-size:10.0pt;font-family:""> </span><span style="font-size:10.0pt;font-family:"">level of theory. The structures and binding energies of chromium met<span>al</span></span><span style="font-size:10.0pt;font-family:"">-</span><span style="font-size:10.0pt;font-family:"">carboxylate complexes at various oxidation states and spin states in gas</span><span style="font-size:10.0pt;font-family:""> phase were examined. The coordination strength of Cr(VI) with the acetate <span>ligand was predominantly the strongest compare</span></span><span style="font-size:10.0pt;font-family:"">d</span><span style="font-size:10.0pt;font-family:""> to the other oxidation</span><span style="font-size:10.0pt;font-family:""> states. <span>Vibrational frequency analysis, for the homoleptic monomers of tris</span> <span>[</span><span>Cr<sup>III</sup>(AC)<sub>3</sub>]<sup>0</sup> and </span>[Cr<sup>VI</sup>(AC)<sub>3</sub>]<sup>3+</sup> complexes, illustrate good harmony with the experimental and<span> theoretical calculated frequencies. Using the time</span></span><span style="font-size:10.0pt;font-family:"">-</span><span style="font-size:10.0pt;font-family:"">dependent DFT</span><span style="font-size:10.0pt;font-family:""> (TD-DFT) at the level of CAM-B3LYP/6-311++G(d,p), the vertical excitation energies were obtained. The stabilization energies derived using the second order perturbation </span><span style="font-size:10.0pt;font-family:"">theory, <i>E</i><sub>ij</sub><sup>(2)</sup>, of NBO analysis confirmed the greater charge transfer for the</span><span style="font-size:10.0pt;font-family:""> observed trends in the metal binding. The calculated binding </span><span style="font-size:10.0pt;font-family:"">energies</span><span style="font-size:10.0pt;font-family:""> </span><span style="font-size:10.0pt;font-family:"">(ΔE) and interactions energies </span><span style="font-size:10.0pt;font-family:Symbol;">S</span><i><span style="font-size:10.0pt;font-family:"">E</span></i><sub><span style="font-size:10.0pt;font-family:"">ij</span></sub><sup><span style="font-size:10.0pt;font-family:"">(2)</span></sup><span style="font-size:10.0pt;font-family:""> favor</span><span style="font-size:10.0pt;font-family:""> </span><span style="font-size:10.0pt;font-family:"">the formation of</span><span style="font-size:10.0pt;font-family:""> [Cr<sup>VI</sup>(AC)<sub>3</sub>]<sup>3+</sup> complexes. The findings of this study identify efficient electronic factors as major contributors to the metal binding affinities, with promising possibilities for the design of metal-ligand complexes and sensing of the metal ions.展开更多
Herein we report the synthesis,characterization,and initial reactivity of homoleptic yttrium and lanthanum complexes of bis(phosphine-oxide)methanides,H^(R)L-(R=Me,Ph;RE(HPhL)3 and RE2(HMeL)6).Our combined experimenta...Herein we report the synthesis,characterization,and initial reactivity of homoleptic yttrium and lanthanum complexes of bis(phosphine-oxide)methanides,H^(R)L-(R=Me,Ph;RE(HPhL)3 and RE2(HMeL)6).Our combined experimental and computational studies reveal rich structural diversity dictated by R-group and rare-earth,and the complexes are highly fluxional in solution,even at-80℃.Computational studies provide quantitative insight into the extensive negative hyperconjugation between the methanide lonepair and theσ*(P-R)andσ*(P-O).These interactions provide substantial stabilization of coordinated H^(R)L-,yet leave significant charge density at the methanide carbon.The stabilization energies are insenstive to ligand conformation,which contributes to the range of accessible binding modes,structures,and dynamic solution behavior.The largely localized anionic charge leads to strongly nucleophilic and Brønsted-basic reactivity of the methanide.This is demonstrated by the first report of a rare-earth promoted Horner-Wittig reaction and rapid reactivity of Y(H^(Ph)L)_(3) and Y_(2)(H^(Me)L)_(6) with MeOH/MeOD.The rapid acid-base reactivity of Y(H^(Ph)L)_(3) with MeOH supports a lowering of the effective pKa of a protic Lewis base by>6 orders of magnitude upon binding to Y(H^(Ph)L)_(3),and implies that multifunctional reactivity(Lewis-acid/Brønsted-base)may be possible.Our studies suggest that a rich set of stoichiometric and catalytic reactivity might be realized with these otherwise overlooked fragments.展开更多
A homoleptic four-coordinate dysprosium complex[K(THF)_(6)][Dy{(NAr)_(2)SiPh_(2)}_(2)](Ar=2,6-iPr_(2)C_(6)H_(3))bearing two bulky chelating silyldiamide ligands was synthesized and structurally characterized.The coord...A homoleptic four-coordinate dysprosium complex[K(THF)_(6)][Dy{(NAr)_(2)SiPh_(2)}_(2)](Ar=2,6-iPr_(2)C_(6)H_(3))bearing two bulky chelating silyldiamide ligands was synthesized and structurally characterized.The coordination geometry between square and seesaw enables slow magnetic relaxation up to 42 K,making it the first silyldiamido dysprosium single-molecule magnet.展开更多
基金Peking University and Beijing National Laboratory for Molecular Sciences for funding.
文摘Homoleptic tris(6,6’-dimethyl-2,2’-bipyridine)rare earth metal complexes M(κ^(2)-dmbp)3(M=Y,Tb,Dy,Ho,Er;dmbp=6,6’-dimethyl-2,2’-bipyridine)were synthesized by in situ reduction of 3 equiv.of dmbp with excess KC8 in the presence of 1 equiv.of rare earth metal trihalides.All compounds were characterized by X-ray crystallography,UV-Vis-NIR spectroscopy,infrared(IR)spectroscopy,elemental analysis,and magnetic measurements.While the structural parameters and spectroscopic data confirmed the existence of the trivalent rare earth metal cation and three dmbp radical anions,the electron paramagnetic resonance(EPR)spectrum and the measured magnetic moment of Y(κ^(2)-dmbp)3 indicated that two parallel dmbp radical anions were antiferromagnetically coupled.For paramagnetic rare earth metal ions,room temperature magnetic susceptibility values indicated a weak ferromagnetic interaction between the metal ion and the remaining dmbp radical.Density functional theory(DFT)calculations were performed on Y(κ^(2)-dmbp)3 to gain insight into the electronic structures of these homoleptic metal complexes.The computational results were consistent with the structural,spectroscopic,and magnetic data for a S=1/2 ground state and spin densities mostly residing on one dmbp radical anion,while the spins on the other two parallel dmbp radical anions being antiferromagnetically coupled.
基金Dr Auguste Fernandes and Prof.M.Teresa Duarte for performing the powder X-ray diffraction analysis.We thank the Fundação para a Ciência e a Tecnologia for financial support(Projects PTDC/QUI-QIN/31585/2017 and PTDC/QUI-QFI/29236/2017)for a fellowship to P.S.F.(PD/BD/135530/2018–ChemMat PhD Program)+1 种基金Centro de Química Estrutural(CQE)and Institute of Molecular Sciences(IMS),Centro de Ciências e Tecnologias Nucleares(C2TN)and BioISI–Biosystems&Integrative Sciences Institute acknowledge the financial support of Fundação para a Ciência e Tecnologia(respectively:Projects UIDB/00100/2020,UIDP/00100/2020 and LA/P/0056/2020,UIDB/04349/2020,UIDP/04349/2020 and LISBOA-01-0145-FEDER-022096,and UIDB/04046/2020 and UIDP/04046/2020)J.v.S.,and D.H.thank the Landesgraduiertenförderung Baden-Württemberg and the German Science Foundation DFG(SL104/10).
文摘In this report we present the structural and magnetic characterization of four distorted tetrahedral homoleptic Co(II)complexes bearing two 2-formiminopyrrolyl N,N’-chelating ligands.
基金supported by funding from the Research Grant Council(CityU 11304221 and CityU 11312722)the City University of Hong Kong,Hong Kong SAR。
文摘Homoleptic Ir_((III))based carbene complexes are known to be the most promising emitters of future blue OLED devices.To provide the proof-of-concept,we designed a series of functional di-CF_(3)-functionalized benzo[d]imidazol-3-ium pro-chelates,which could afford single product emitters after proper modification.For benzoimidazol-2-ylidene with an N-methyl substituent,selective formation of the product can be achieved by introduction of t-butylphenyl for the phenyl group,as shown by shifting the product from mixed m-Ir(dfp)_(3)and f-Ir(dfp)_(3)to the single isomer f-Ir(dfpb)_(3).Alternatively,for di-N-aryl substituted carbene chelates,the steric encumbrance imposed between the ortho-CF_(3)group and the adjacent N-aryl substituent redirects the cyclometalation to the other N-aryl substituent,leading to the formation of one single product,e.g.,f-Ir(tBpp)_(3)and f-Ir(ptBp)_(3).Moreover,the doped OLED based on f-Ir(tBpp)_(3)delivered true-blue emission centered at 457 nm and a maximum EQE of 15.6%.Furthermore,upon addition of terminal emittersν-DABNA and t-DABNA,the respective hyper^(-)OLEDs exhibited narrowband blue emission with a maximum EQE of 18.9%at 474 nm and 18.1%at 462 nm,respectively.These highlighted the potential of these Ir_((III))emitters in the fabrication of blue OLEDs.
基金supported by the National Natural Science Foundation of China(21572001 and 61875144)the Scientific Research Project of Anhui Provincial Department of Education(YJS20210332)+6 种基金the Distinguished Professor of the Wanjiang Scholars Projectthe Scientific Research Project of Anhui Provincial Department of Education(YJS20210332)the Anhui special support plan(T000609)the Suzhou Key Laboratory of Functional Nano&Soft Materialsthe Collaborative Innovation Center of Suzhou Nano Science and Technology(NANO-CIC)the 111 Projectthe Joint International Research Laboratory of Carbon-Based Functional Materials and Devices.
文摘Emitters with suppressed intermolecular interactions are desired for high efficiency OLEDs.Herein,five phosphorescent homoleptic Ir(Ⅲ)complexes with a triptycene skeleton were successfully synthesized.Benefitting from the unique rigid and bulky triptycene skeleton,these complexes exhibit excellent thermal and photophysical properties.Their crystal structures indicated that the π-π stacking interactions can be completely eliminated by reasonable combination of the triptycene skeleton and steric hindrance groups.These complexes show significantly good to excellent quantum yields(73.7%-88.9%)and thermal stability(Td=364-451℃).A highly efficient OLED with an external quantum efficiency of up to 27.5% is developed with very low efficiency roll-off and is the most efficient OLED based on phthalazine iridium complexes.
基金financially supported by the National Natural Science Foundation of China(61077021,61076016)the Nanjing University of Posts and Telecommunications(NY212076,NY212050)
文摘Two new iridium complexes with C^N=N type ligand(i.e.,Ir(BFPPya)3{tris[3,6-bis(4-fluorophenyl)pyridazine]iridium(III)}and Ir(BDFPPya)3{tris[3,6-bis(2,4-di-fluorophenyl)pyridazine]iridium(III)})attaching with fluorine atoms,were synthesized and the effects of fluorination on the material properties and device performance were investigated.Compared with our previously reported fluorine-free analogue material,that is Ir(BPPya)3{tris[3,6-bis(phenyl)pyridazine]iridium(III)},blue shifts in the emission spectra as well as in the long wavelength region of the absorptions were observed.The photoluminescence quantum yield(PLQY)(0.44 and 0.84 vs.0.29),phosphoresces lifetime(0.88 and 1.31 vs.0.66 gs),and oxidation potential(1.10 and 1.37 vs.0.95 V)increased obviously after fluorinating the ligand.In contrast,the thermal stability of the iridium complexes decreased slightly(Td:435 and 402 vs.440℃).In the density functional theory(DFT)calculations,by comparing the steric shape of the three ligands within one optimized molecule,orientational differences among the complexes were observed.In OLED device studies,bluish green electroluminescence with peak emission of 500 nm,using the electron-transporting host of TPBI[2,2',2"-(1,3,5-benzenetriyl)tris(1-phenyl-lH-benzimidazole)]and the most fluorinated dopant of Ir(BDFPPya)3,was achieved with maximum efficiency of 20.3 cd/A.On one hand this efficiency is not satisfactory considering a high PLQY of 0.84.On the other hand with the similar device structure,that the(HOMO-LUMO)s of all the dopants are wrapped within that of the host TPBI,and all the triplet energies of the dopants are smaller than that of the host TPBI,it is abnormal that the ordering of device efficiencies is contradictory to that of PLQY.Assisting with the phosphorescent spectrum of TPBI and the absorption spectra of the dopant,the contradiction was interpreted reasonably.
文摘The study of various oxidation states of chromium with Sargassum <i>sp</i>. is of particular interest since hexavalent chromium </span><span style="font-size:10.0pt;font-family:"">is </span><span style="font-size:10.0pt;font-family:"">reduced to trivalent chromium in </span><span style="font-size:10.0pt;font-family:"">an </span><span style="font-size:10.0pt;font-family:"">aqueous solution. In this study, a systematic density functional theory (DFT) calculations were performed to study the interactions of transition metal chromium ion with different oxidation states and spin states with the <i>Sar</i></span><i><span style="font-size:10.0pt;font-family:"">gassum sp</span></i><span style="font-size:10.0pt;font-family:"">. decorated with carboxylate</span><span style="font-size:10.0pt;font-family:""> </span><span style="font-size:10.0pt;font-family:"">(acetate) at the wB97XD/6-311++</span><span style="font-size:10.0pt;font-family:""> </span><span style="font-size:10.0pt;font-family:"">G(d,p)</span><span style="font-size:10.0pt;font-family:""> </span><span style="font-size:10.0pt;font-family:"">level of theory. The structures and binding energies of chromium met<span>al</span></span><span style="font-size:10.0pt;font-family:"">-</span><span style="font-size:10.0pt;font-family:"">carboxylate complexes at various oxidation states and spin states in gas</span><span style="font-size:10.0pt;font-family:""> phase were examined. The coordination strength of Cr(VI) with the acetate <span>ligand was predominantly the strongest compare</span></span><span style="font-size:10.0pt;font-family:"">d</span><span style="font-size:10.0pt;font-family:""> to the other oxidation</span><span style="font-size:10.0pt;font-family:""> states. <span>Vibrational frequency analysis, for the homoleptic monomers of tris</span> <span>[</span><span>Cr<sup>III</sup>(AC)<sub>3</sub>]<sup>0</sup> and </span>[Cr<sup>VI</sup>(AC)<sub>3</sub>]<sup>3+</sup> complexes, illustrate good harmony with the experimental and<span> theoretical calculated frequencies. Using the time</span></span><span style="font-size:10.0pt;font-family:"">-</span><span style="font-size:10.0pt;font-family:"">dependent DFT</span><span style="font-size:10.0pt;font-family:""> (TD-DFT) at the level of CAM-B3LYP/6-311++G(d,p), the vertical excitation energies were obtained. The stabilization energies derived using the second order perturbation </span><span style="font-size:10.0pt;font-family:"">theory, <i>E</i><sub>ij</sub><sup>(2)</sup>, of NBO analysis confirmed the greater charge transfer for the</span><span style="font-size:10.0pt;font-family:""> observed trends in the metal binding. The calculated binding </span><span style="font-size:10.0pt;font-family:"">energies</span><span style="font-size:10.0pt;font-family:""> </span><span style="font-size:10.0pt;font-family:"">(ΔE) and interactions energies </span><span style="font-size:10.0pt;font-family:Symbol;">S</span><i><span style="font-size:10.0pt;font-family:"">E</span></i><sub><span style="font-size:10.0pt;font-family:"">ij</span></sub><sup><span style="font-size:10.0pt;font-family:"">(2)</span></sup><span style="font-size:10.0pt;font-family:""> favor</span><span style="font-size:10.0pt;font-family:""> </span><span style="font-size:10.0pt;font-family:"">the formation of</span><span style="font-size:10.0pt;font-family:""> [Cr<sup>VI</sup>(AC)<sub>3</sub>]<sup>3+</sup> complexes. The findings of this study identify efficient electronic factors as major contributors to the metal binding affinities, with promising possibilities for the design of metal-ligand complexes and sensing of the metal ions.
基金JRR acknowledges Brown University for financial support of this work.KCC thanks Matthew Lueckheide for samples of decamethylferroceneXiang Dong for helpful discussions related to the DOSY studiesJRR and AMB thank Dr Mehmed Z.Ertem for helpful discussions related to the computational studies.
文摘Herein we report the synthesis,characterization,and initial reactivity of homoleptic yttrium and lanthanum complexes of bis(phosphine-oxide)methanides,H^(R)L-(R=Me,Ph;RE(HPhL)3 and RE2(HMeL)6).Our combined experimental and computational studies reveal rich structural diversity dictated by R-group and rare-earth,and the complexes are highly fluxional in solution,even at-80℃.Computational studies provide quantitative insight into the extensive negative hyperconjugation between the methanide lonepair and theσ*(P-R)andσ*(P-O).These interactions provide substantial stabilization of coordinated H^(R)L-,yet leave significant charge density at the methanide carbon.The stabilization energies are insenstive to ligand conformation,which contributes to the range of accessible binding modes,structures,and dynamic solution behavior.The largely localized anionic charge leads to strongly nucleophilic and Brønsted-basic reactivity of the methanide.This is demonstrated by the first report of a rare-earth promoted Horner-Wittig reaction and rapid reactivity of Y(H^(Ph)L)_(3) and Y_(2)(H^(Me)L)_(6) with MeOH/MeOD.The rapid acid-base reactivity of Y(H^(Ph)L)_(3) with MeOH supports a lowering of the effective pKa of a protic Lewis base by>6 orders of magnitude upon binding to Y(H^(Ph)L)_(3),and implies that multifunctional reactivity(Lewis-acid/Brønsted-base)may be possible.Our studies suggest that a rich set of stoichiometric and catalytic reactivity might be realized with these otherwise overlooked fragments.
基金the National Natural Science Foundation of China(22271228 and 22101116)for funding。
文摘A homoleptic four-coordinate dysprosium complex[K(THF)_(6)][Dy{(NAr)_(2)SiPh_(2)}_(2)](Ar=2,6-iPr_(2)C_(6)H_(3))bearing two bulky chelating silyldiamide ligands was synthesized and structurally characterized.The coordination geometry between square and seesaw enables slow magnetic relaxation up to 42 K,making it the first silyldiamido dysprosium single-molecule magnet.
