All-Calixarene-Protected Silver Nanocluster with All Silver Atoms in a Face-Centered Cubic Arrangement.

Tailoring the surface ligands of metal nanoclusters is important for engineering unique configurations of metal nanoclusters. Thiacalix[4]arene has found extensive applications in the construction of metal nanoclusters. In this investigation, we present the synthesis and characterization of the first all-calixarene-protected silver nanoclusters, [Ag(CH 3 CN) 4 ] 2 [Ag 44 (BTCA) 6 ] ( Ag 44 , H 4 BTCA = p-tert -butylthiacalix[4]arene). Single-crystal X-ray structural analysis reveals that all silver atoms are in a face-centered cubic ( fcc ) arrangement. The formation of such an fcc structure is attributed to the selectively passivation on {100} facets by BTCA 4- . Thiacalixarene substantially facilitates the stability of Ag 44 due to its multiple coordination sites and bulkiness. Mass spectrometry and theoretical calculations reveal that Ag 44 is a superatomic silver nanocluster with 22 free electrons in the following configuration: 1S 2 1P 6 1D 6 1F 2 2S 2 1D 4 . This work not only elucidates the impact of macrocyclic ligands on the stabilization of silver clusters but also furnishes an approach for assembling atomically precise fcc nanoclusters.