当前位置: X-MOL 学术J. Phys. Chem. A › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Site-Dependent Spin Delocalization and Evidence of Ferrimagnetism in Atomically Precise Au25(SR)180 Clusters as Seen by Solution 13C NMR Spectroscopy.
The Journal of Physical Chemistry A ( IF 2.7 ) Pub Date : 2020-08-20 , DOI: 10.1021/acs.jpca.0c02915
Rongfeng Zheng 1 , Gianna M Bevacqua 1 , Nicholas R Young 1 , Thomas C Allison 2 , YuYe J Tong 1
Affiliation  

We report a simple but detailed solution 13C nuclear magnetic resonance spectroscopic study of atomically precise neutral Au25(SR)180 (SR = alkyl thiolate) clusters. The paramagnetic 13C Knight shift of alkyl chain carbons, which is proportional to the local electron spin density, exhibits an electron spin delocalization that exponentially decays along the alkyl chain. The magnitude and decay constant of the observed electron spin delocalization, although largely independent of alkyl chain length, depend on where, that is, “in” versus “out” (vide infra) position, the alkyl chain is bound, in agreement with density functional theory calculations. Notably, the determined position-dependent decay constants, 1.70/Å and 0.41/Å for “in” and “out” ligands, respectively, not only could have important ramifications in molecular spintronics but are also comparable to measured decay constants in molecular electrical conductance of alkyl chains, potentially offering an alternative, simple method for estimating the latter. Moreover, the negative intercept temperatures of linear fits of reciprocal 13C (as well its bound 1H) Knight shift versus temperature strongly suggest the existence of local ferrimagnetism in individual Au25(SR)180 clusters.

中文翻译:

通过溶液13C NMR光谱观察到,原子精确的Au25(SR)180簇中的位点自旋离域和铁磁性的证据。

我们报告了一个简单但详细的解决方案,对原子精确的中性Au 25(SR)18 0(SR =烷基硫醇盐)团簇进行13 C核磁共振波谱研究。烷基链碳的顺磁性13 C Knight位移与局部电子自旋密度成正比,显示出电子自旋离域,其沿着烷基链呈指数衰减。尽管很大程度上不依赖于烷基链长,但观察到的电子自旋离域的大小和衰减常数取决于“进”“出”的位置(见下文))位置,烷基链被键合,符合密度泛函理论计算。值得注意的是,所确定的与位置有关的衰减常数,分别针对“内”和“外”配体分别为1.70 /Å和0.41 /Å,不仅在分子自旋电子学中可能会产生重要的影响,而且与分子电导中测得的衰减常数相当烷基链的数目,可能提供估计后者的另一种简单方法。此外,倒数13 C(及其边界1 H)的线性拟合的负截距温度相对于温度的奈特位移强烈表明在各个Au 25(SR)18 0团簇中存在局部亚铁磁性。
更新日期:2020-09-18
down
wechat
bug