Exploiting exciton coupling of ligand radical intervalence charge transfer transitions to tune NIR absorption.
Exploiting exciton coupling of ligand radical intervalence charge transfer transitions to tune NIR absorption.
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DOI：
10.1039/c7sc04537a
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发表时间：
2018-02-14
期刊：
影响因子：
8.4
通讯作者：
Storr T
中科院分区：
文献类型：
--
作者：
Clarke RM;Jeen T;Rigo S;Thompson JR;Kaake LG;Thomas F;Storr T
我们详细介绍了一系列的双配体自由基镍salen配合物的合理设计，其中配体自由基发色团的相对取向提供了一种机制，以调整在近红外（NIR）区域的强烈的价间电荷转移（IVCT）带的能量。我们详细介绍了一系列的双配体自由基镍salen配合物的合理设计，其中配体自由基发色团的相对取向提供了一种机制，以调整在近红外（NIR）区域的强烈的价间电荷转移（IVCT）带的能量。通过一套实验（电化学，电子顺磁共振光谱，紫外-可见-近红外光谱）和理论（密度泛函理论）技术，我们证明，Ni-Salen配合物形成双配体自由基后，两个电子的氧化，其近红外吸收能量依赖于施加在双配体自由基复合物的几何形状。相对于氧化单体[1 tec]+（E = 4500 cm-1，ε = 27 700 M-1 cm-1），共面约束类似物2氧化为[2 stecstec]2+导致近红外光谱带蓝移（E = 4830 cm-1，ε = 42 900 M-1 cm-1），而5氧化为[5 stecstec]2+，发色团平行排列，导致近红外光谱带红移（E = 4150 cm-1，ε = 46 600 M-1 cm-1）;与单体相比，NIR谱带显示出两倍的强度。中间取向的氧化导致[3 stecstec]2+的能带分裂（E = 4890和4200 cm-1; ε = 26 500和21 100 M-1 cm-1），以及[4 stecstec]2+分别使用邻亚苯基和间亚苯基连接基的红移。这项研究首次证明了激子耦合对近红外区域吸收的配体自由基系统的适用性，并表明通过简单的几何形状变化，可以将强烈的低能量吸收的能量调节近400 nm。
We detail the rational design of a series of bimetallic bis-ligand radical Ni salen complexes in which the relative orientation of the ligand radical chromophores provides a mechanism to tune the energy of intense intervalence charge transfer (IVCT) bands in the near infrared (NIR) region. We detail the rational design of a series of bimetallic bis-ligand radical Ni salen complexes in which the relative orientation of the ligand radical chromophores provides a mechanism to tune the energy of intense intervalence charge transfer (IVCT) bands in the near infrared (NIR) region. Through a suite of experimental (electrochemistry, electron paramagnetic resonance spectroscopy, UV-vis-NIR spectroscopy) and theoretical (density functional theory) techniques, we demonstrate that bimetallic Ni salen complexes form bis-ligand radicals upon two-electron oxidation, whose NIR absorption energies depend on the geometry imposed in the bis-ligand radical complex. Relative to the oxidized monomer [1˙]+ (E = 4500 cm–1, ε = 27 700 M–1 cm–1), oxidation of the cofacially constrained analogue 2 to [2˙˙]2+ results in a blue-shifted NIR band (E = 4830 cm–1, ε = 42 900 M–1 cm–1), while oxidation of 5 to [5˙˙]2+, with parallel arrangement of chromophores, results in a red-shifted NIR band (E = 4150 cm–1, ε = 46 600 M–1 cm–1); the NIR bands exhibit double the intensity in comparison to the monomer. Oxidation of the intermediate orientations results in band splitting for [3˙˙]2+ (E = 4890 and 4200 cm–1; ε = 26 500 and 21 100 M–1 cm–1), and a red-shift for [4˙˙]2+ using ortho- and meta-phenylene linkers, respectively. This study demonstrates for the first time, the applicability of exciton coupling to ligand radical systems absorbing in the NIR region and shows that by simple geometry changes, it is possible to tune the energy of intense low energy absorption by nearly 400 nm.
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DOI：
10.1016/s0005-2728(89)80081-7
发表时间：
1989-12-07
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
--
作者：
BIXON, M;JORTNER, J;OGRODNIK, A
通讯作者：
OGRODNIK, A
影响因子：
4.9
作者：
Askarizadeh, Elham;Yaghoob, Sahar Bani;Love, Jason B.
通讯作者：
Love, Jason B.
影响因子：
15
作者：
Cui, Bin-Bin;Zhong, Yu-Wu;Yao, Jiannian
通讯作者：
Yao, Jiannian
影响因子：
4.6
作者：
Clarke, Ryan M.;Hazin, Khatera;Storr, Tim
通讯作者：
Storr, Tim
影响因子：
2.8
作者：
Cohen, SM;Halper, SR
通讯作者：
Halper, SR