Khatun Esma, Bodiuzzaman Mohammad, Sugi Korath Shivan, Chakraborty Papri, Paramasivam Ganesan, Dar Wakeel Ahmed, Ahuja Tripti, Antharjanam Sudhadevi, Pradeep Thalappil
Department of Chemistry, DST Unit of Nanoscience (DST UNS) and Thematic Unit of Excellence (TUE) , Indian Institute of Technology Madras , Chennai 600036 , India.
Sophisticated Analytical Instruments Facility , Indian Institute of Technology Madras , Chennai 600036 , India.
ACS Nano. 2019 May 28;13(5):5753-5759. doi: 10.1021/acsnano.9b01189. Epub 2019 May 1.
We introduce a cluster coprotected by thiol and diphosphine ligands, [Ag(dppe)(2,5-DMBT)Cl] (dppe = 1,2-bis(diphenylphosphino)ethane; 2,5-DMBT= 2,5-dimethylbenzenethiol), which has an Ag core encapsulated by an Ag(dppe)(2,5-DMBT)Cl shell. The Ag core comprises two Ag distorted trigonal bipyramidal units and is uncommon in Au and Ag nanoclusters. The electrospray ionization mass spectrum reveals that the cluster is divalent and contains four free electrons. An uncommon crystallization-induced enhancement of emission is observed in the cluster. The emission is weak in the solution and amorphous states. However, it is enhanced 12 times in the crystalline state compared to the amorphous state. A detailed investigation of the crystal structure suggests that well-arranged C-H···π and π···π interactions between the ligands are the major factors for this enhanced emission. Further, in-depth structural elucidation and density functional theory calculations suggest that the cluster is a superatom with four magic electrons.
我们介绍了一种由硫醇和二膦配体共同保护的簇合物，[Ag(dppe)(2,5-DMBT)Cl]（dppe = 1,2-双（二苯基膦基）乙烷；2,5-DMBT = 2,5-二甲基苯硫醇），其具有由Ag(dppe)(2,5-DMBT)Cl壳层包裹的Ag核。该Ag核由两个扭曲的三角双锥Ag单元组成，在金和银纳米簇中并不常见。电喷雾电离质谱表明该簇合物是二价的且包含四个自由电子。在该簇合物中观察到了一种罕见的结晶诱导发光增强现象。该发光在溶液态和非晶态时较弱。然而，与非晶态相比，其在结晶态时增强了12倍。对晶体结构的详细研究表明，配体之间排列良好的C-H···π和π···π相互作用是这种发光增强的主要因素。此外，深入的结构解析和密度泛函理论计算表明该簇合物是一个具有四个幻数电子的超原子。
