Towards panchromatic Fe( ii ) NHC sensitizers via HOMO inversion
Towards panchromatic Fe( ii ) NHC sensitizers via HOMO inversion
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通过HOMO反转研究全色Fe(ii)NHC敏化剂
DOI：
10.1039/d2qi01903e
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发表时间：
2023
影响因子：
7
通讯作者：
Marri A
中科院分区：
文献类型：
--
作者：
Marri A
结合实验和理论研究的铁（II）配合物与吡啶基N-杂环卡宾配体，与一个新的重点扩展的配体与噻吩的可变数量的效果。与Jakubikova小组最近的理论预测一致，这些配体诱导了占据的t2 g和π HOMO轨道的实质性混合，如通过1 MLCT跃迁的近80 nm红移和摩尔消光系数的2-3倍增加所表现的。噻吩部分允许MLCT状态在配体上的离域，这导致激发态寿命在13-18 ps范围内，几乎是缺乏噻吩基取代基的参比化合物的两倍。弛豫成3 MC状态仍然是主要的3 MLCT猝灭机制，并且噻吩的数量在延长3 MLCT寿命方面的效果在定性上与3 MLCT-3 MC能隙的减小一致。
A combined experimental and theoretical study of iron(II) complexes with pyridyl N-heterocyclic carbene ligands is presented, with a new focus on the effect of extending the ligands with thiophenes of variable number. In agreement with recent theoretical predictions by the Jakubikova group, these ligands induce a substantial mixture of the occupied t2g and π HOMO orbitals, as manifested by a near 80 nm red-shift of the 1MLCT transition and a 2–3 fold increase of the molar extinction coefficient. The thiophene moieties permit delocalisation of the MLCT state on the ligands, which results in excited state lifetimes in the 13–18 ps range, almost twice as much as for the reference compound lacking the thienyl substituents. Relaxation into 3MC states remains the main 3MLCT quenching mechanism, and the effect of the number of thiophenes in lengthening the 3MLCT lifetime is qualitatively consistent with a reduction in the 3MLCT–3MC energy gap.