【摘 要】
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Two diphosphine-protected superatom gold selenido nanoclusters,[Au8Se2(dppm)4]2+ (SD/Au8a,dppm =Ph2PCH2PPh2) and[Au8Se2(dppe)4]2+ (SD/Au8b,dppe =Ph2P(CH2)2PPh2),were obtained by the reduction of[Au(SMe2)Cl]in the presence of Ph3PSe as the selenium ion rel
【机 构】
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School of Chemistry and Chemical Engineering,State Key Laboratory of Crystal Materials,Shandong Univ
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Two diphosphine-protected superatom gold selenido nanoclusters,[Au8Se2(dppm)4]2+ (SD/Au8a,dppm =Ph2PCH2PPh2) and[Au8Se2(dppe)4]2+ (SD/Au8b,dppe =Ph2P(CH2)2PPh2),were obtained by the reduction of[Au(SMe2)Cl]in the presence of Ph3PSe as the selenium ion releasing agents.Both can be regarded as “superatoms” with 1S2 configuration based on the spherical Jellium model.Despite the same metal-ligand binding motifs on the surface and the intrinsic C2 molecular symmetry,the configurations of Au8Se2 kernels in them are different in terms of Au-Au bonded metallic frameworks.SD/Au8a displays a heart-shaped[core + exo]type structure (Au4 tetrahedron core + two exo Au2Se units),whereas the two exo Au2Se counterparts in SD/Au8b are additionally locked by an obvious Au-Au bond,forming a distorted hexagonal Au6 ring with two capping AuSe units appended above and below it.Consequently,they showed different photophysical properties as reflected by their electronic absorption and emission spectra.Especially,both SD/Au8a and SD/Au8b exhibit blue-shifted thermochromic luminescence upon cooling from 293 to 83 K but the latter exhibits anomalous emission intensity evolution trends due to the occurrence of temperature-induced phase transition as revealed by varied-temperature crystallographic analyses.This work not only clearly illustrates the significance of ligands on tuning the kernel structure but also provides two rarely comparable examples for better understanding of the structure-property relationship of gold nanoclusters.
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