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
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.
