Neutral radical bis(dithiolene) gold complexes [Au(dt)₂]˙ are known to exhibit a strong absorption in the 1400–2000 nm NIR absorption range. Here, we demonstrate that the NIR signature of mixed-ligand bis(dithiolene) gold complexes [Au(dt_A)(dt_D)]˙ associating two different dithiolene, dt_A and dt_D, is found at higher energy, out of the range of the homoleptic analogs [Au(dt_A)₂]˙ and [Au(dt_D)₂]˙, in the looked-after NIR-II 1000–1400 nm absorption range. An efficient synthetic approach towards precursor mixed-ligand monoanionic gold bis(dithiolene) complexes [Au(dt_A)(dt_D)]⁻¹ is reported. Using this strategy, no symmetrical complexes are formed and, upon electrocrystallization, no scrambling was observed in solution, allowing for the isolation of radical gold bis(dithiolene) complex such as [Au(bdt)(Et-thiazdt)]˙ (bdt: benzene-1,2-dithiolate; Et-thiazdt: N-ethyl-thiazoline-2-thione-3,4-dithiolate), which behaves as a single-component conductor. It is shown from theoretical calculations that the spin polarization induced by electron repulsions leads to a strong localization of the spin–orbitals, and provides a sound basis to understand, (i) the different ligand-based oxidation potentials, (ii) the NIR optical absorption at notably higher energies and (iii) the larger potential difference of the two redox processes than in the parent symmetric complexes. The solid-state properties of the radical complex [Au(bdt)(Et-thiazdt)]˙ are the consequence of a strongly 1D electronic structure with weakly dimerized chains and electronic localization favoring a semiconducting behavior, stable under pressures up to 18.2 GPa. Altogether, the versatility of the preparation method of [Au(dt_A)(dt_D)]⁻¹ salts opens the route for a wide library of different mixed-ligand radical complexes [Au(dt_A)(dt_D)]˙ with simultaneously an adaptable absorption in the NIR-II range and the rich structural chemistry of single-component conductors.

中文翻译：

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混合配体、自由基、金双（二硫醇）配合物：从单组分导体到可控 NIR-II 吸收剂


已知中性自由基双（二硫烯）金络合物 [Au(dt) ₂ ]˙ 在 1400–2000 nm NIR 吸收范围内表现出强吸收。在这里，我们证明了混合配体双（二硫醇）金配合物 [Au(dt _A )(dt _D )]˙ 关联两种不同的二硫醇 dt _A 和 dt _D ，被发现处于较高能量，超出同配类似物的范围 [Au(dt _A ) ₂ ]˙和 [Au(dt _D ) ₂ ]˙，在 NIR-II 1000–1400 nm 吸收范围内。报道了一种前体混合配体单阴离子金双(二硫醇烯)配合物[Au(dt _A )(dt _D )] ⁻¹ 的有效合成方法。使用这种策略，不会形成对称配合物，并且在电结晶时，在溶液中没有观察到扰乱，从而可以分离自由基金双（二硫烯）配合物，例如 [Au(bdt)(Et-thiazdt)]˙ (bdt:苯-1,2-二硫醇盐；Et-thiazdt：N-乙基-噻唑啉-2-硫酮-3,4-二硫醇盐），其表现为单组分导体。理论计算表明，电子排斥引起的自旋极化导致自旋轨道的强烈局域化，并为理解以下内容提供了良好的基础：(i) 不同的基于配体的氧化电位，(ii) 近红外光学在明显更高的能量下吸收，并且（iii）两个氧化还原过程的电势差比母体对称配合物更大。自由基配合物 [Au(bdt)(Et-thiazdt)]˙ 的固态特性是强一维电子结构的结果，具有弱二聚链和有利于半导体行为的电子局域化，在高达 18.2 GPa 的压力下保持稳定。 总而言之，[Au(dt _A )(dt _D )] ⁻¹ 盐制备方法的多功能性为广泛的不同混合库开辟了道路。 -配体自由基配合物 [Au(dt _A )(dt _D )]˙ 同时具有 NIR-II 范围内的适应性吸收和单组分导体的丰富结构化学。