Crystal structure of fac-Ir(ppy)3 and emission properties under ambient conditions and at high pressure
Crystal structure of fac-Ir(ppy)3 and emission properties under ambient conditions and at high pressure
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DOI：
10.1021/cm0486767
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发表时间：
2005-04-05
影响因子：
8.6
通讯作者：
Yersin, H
中科院分区：
文献类型：
--
作者：
Breu, J;Stössel, P;Yersin, H
FeC-Ir(Ppy)(3)的晶体结构的溶解和细化受到系统孪晶和伪对称性的严重阻碍，从单晶结构的细化和对fac-Ir(Ppy)(3)粉末的二次谐波(SHG)的研究中得出，fac-Ir(Ppy)(3)的晶体是在棒上的中心对称空间群P(3)中结晶的。Fac-Ir(Ppy)(3)的分子堆积拓扑与[Ru(Bpy)(3)](0)的堆积相同，但所有Ir(Ppy)(3)分子的格位对称性必然从D-3降低到C-3。实现了分子间“pi-pi相互作用”的T形和“移位pi堆积”构型。系统的孪生导致了晶区的出现，晶区内的大部分磁区具有严格交替的手性，但在磁区界面具有同手性的fac-ir(Ppy)(3)接触。这些不同的堆积基序表现在发射光谱和高压诱导的发射位移中。对于p<；25kbar和T=295K的Delta nu/Delta分别在18350 cm(-1)(545 Nm)和19 700 cm-1(507 Nm)处经历了发射极大值，p=-(12+/-2)cm(-1)/kbar和-(22+/-4)cm(-1)/kbar。
Solution and refinement of the crystal structure of fac-Ir(ppy)(3) is severely hampered by systematic twinning and pseudo-symmetry.fac-Ir(ppy)(3) Crystallizes in the centrosymmetric space group P (3) over bar as has been deduced from single-crystal structure refinement and investigations of the second harmonic generation (SHG) of fac-Ir(ppy)(3) powder as compared to two standard materials. The topology of the molecular packing of fac-Ir(ppy)(3) is identical to the packing observed for [Ru(bpy)(3)](0), however, the site symmetry of all Ir(ppy)(3) molecules is necessarily lowered from D-3 to C-3. Packing motifs with intermolecular "pi-pi interactions" of T-shaped and "shifted pi stack" geometry are realized. The systematic twinning leads to the occurrence of crystalline domains with rigorously alternating chirality within the bulk of the domains but with homochiral fac-Ir(ppy)(3) contacts at the domain interfaces. These differences in packing motifs are displayed in the emission spectra and in the high-pressure-induced shifts of the emission. The emission maximum of the bulk material at 18 350 cm(-1) (545 nm) and of the domain interfaces at 19 700 cm-1 (507 nm) experience for p < 25 kbar and T = 295 K red shifts of Delta nu/Delta p = -(12 +/- 2) cm(-1)/kbar, and -(22 +/- 4) cm(-1)/kbar, respectively.