Griffin Paul J, Olshansky Lisa
Department of Chemistry, Center for Biophysics and Quantitative Biology, and Materials Research Laboratory, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States.
J Am Chem Soc. 2023 Sep 20;145(37):20158-20162. doi: 10.1021/jacs.3c05935. Epub 2023 Sep 8.
We report the electron transfer (ET) self-exchange rate constants () for a pair of Cu complexes utilizing dpa (dpa = dipicolylaniline, R = OMe, SMe) ligands assessed by NMR line broadening experiments. These ligands afford copper complexes that are conformationally dynamic in one oxidation state. With R = OMe, the Cu complex is dynamic, while with R = SMe, the Cu complex is dynamic. Both complexes exhibit unexpectedly large values of 2.48(6) × 10 and 2.21(9) × 10 M s for [CuCl(dpa)] and [CuCl(dpa)], respectively. Among the fastest reported molecular copper coordination complexes to date, that of [CuCl(dpa)] exceeds all others by an order of magnitude and compares only with those observed in type 1 blue copper proteins. The dynamicity of these complexes establishes pre-steady-state conformational equilibria that minimize the inner-sphere reorganization energies to 0.71 and 0.62 eV for R = OMe and SMe, respectively. In contrast to the emphasis on rigidity in the formulation of entatic states applied to blue copper proteins, the success of these two systems highlights the relevance of conformational dynamicity in mediating rapid ET.
我们报道了通过核磁共振线宽实验评估的一对使用dpa（dpa = 二吡啶基苯胺，R = OMe、SMe）配体的铜配合物的电子转移（ET）自交换速率常数（）。这些配体提供了在一种氧化态下构象动态的铜配合物。当R = OMe时，铜配合物是动态的，而当R = SMe时，铜配合物也是动态的。对于[CuCl(dpa)]和[CuCl(dpa)]，这两种配合物分别表现出出乎意料的大值，即2.48(6)×10和2.21(9)×10 M⁻¹ s⁻¹。在迄今为止报道的最快的分子铜配位配合物中，[CuCl(dpa)]的速率超过其他所有配合物一个数量级，仅与在1型蓝铜蛋白中观察到的速率相当。这些配合物的动态性建立了预稳态构象平衡，对于R = OMe和SMe，分别将内球体重组能最小化至0.71和0.62 eV。与应用于蓝铜蛋白的内禀态表述中对刚性的强调相反，这两个体系的成功突出了构象动态性在介导快速电子转移中的相关性。
