A 195Pt NMR study on zero-magnetic-field splitting and the phosphorescence properties in the excited triplet states of cyclometalated platinum(II) complexes
A 195Pt NMR study on zero-magnetic-field splitting and the phosphorescence properties in the excited triplet states of cyclometalated platinum(II) complexes
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DOI：
10.1039/d0dt00532k
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发表时间：
2020-05-21
影响因子：
4
通讯作者：
Kitamura, Noboru
中科院分区：
文献类型：
--
作者：
Akagi, Soichiro;Fujii, Sho;Kitamura, Noboru
研究了环合铂（II）配合物最低电子激发三重态（T-1）零磁场分裂（zfs）的影响因素，其zfs能量介于T-1态的最低（phi（1））和最高自旋子能级（phi（3））之间（Delta E-zfs）已知：[Pt（bhq）（dpm）]（1 Pt）、[Pt（thpy）（acac）]（2 Pt）、[Pt（ppy）（acac）]（3 Pt）、顺式-[Pt（thpy）（2）（4Pt）和顺式-（Pt（ppy）（2）]（5 Pt），其中bhq、dpm、thpy、acac，PPy和PPy分别是苯并[H]喹啉、二新戊酰基甲烷、2-（2-噻吩基）吡啶、乙酰丙酮和2-苯基吡啶。作为重要的发现之一，我们显示了五个Pt（II）配合物的Δ E-zfs和Pt-195 NMR化学位移之间的关系。还讨论了在293 K下的Delta E-zfs值对Pt（II）络合物在乙腈中的发射性质的影响。特别是，我们证明了Pt（II）配合物的辐射速率常数与Δ E-zfs和Pt-195 NMR化学位移相关。
We report the factors governing zero-magnetic-field splitting (zfs) in the lowest-energy electronically excited triplet (T-1) states of cyclometalated platinum(II) complexes, whose zfs energies between the lowest- (phi(1)) and highest-energy spin-sublevels (phi(3)) in the T-1 states (Delta E-zfs) are already known: [Pt(bhq) (dpm)] (1Pt), [Pt(thpy)(acac)] (2Pt), [Pt(ppy)(acac)] (3Pt), cis-[Pt(thpy)(2) (4Pt), and cis-(Pt(ppy)(2)] ( 5Pt), where bhq, dpm, thpy, acac, and ppy are benzo[h]quinoline, dipivaloylmethane, 2-(2-thienyl)pyridine, acetylacetone, and 2-phenylpyridine, respectively. As one of the important findings, we show the relationship between the Delta E-zfs and Pt-195 NMR chemical shifts of the five Pt(II) complexes. The implications of the Delta E-zfs values on the emission properties of the Pt(II) complexes in acetonitrile at 293 K are also discussed. In particular, we demonstrate that the radiative rate constants of the Pt(II) complexes correlate with both Delta E-zfs and Pt-195 NMR chemical shifts.