Same Magic Number but Different Arrangement: Alkynyl‐Protected Au₂₅ with D₃ Symmetry

Abstract

Two homoleptic alkynyl‐protected gold clusters with compositions of Na[Au25(C≡CAr)18] and (Ph4P)[Au25(C≡CAr)18] (Na⋅1 and Ph4P⋅1, Ar=3,5‐bis(trifluoromethyl)phenyl) were synthesized via a direct reduction method. 1 is a magic cluster analogous to [Au25(SR)18]− in terms of electron counts and metal‐to‐ligand ratio. Single‐crystal structure analysis reveals that 1 has an identical Au13 kernel to [Au25(SR)18]−, but adopts a distinctly different arrangement of the six peripheral dimer staple motifs. The steric hindrance of alkynyl ligands is responsible for the D3 arrangement of Au25. The introduction of alkynyl also significantly changes the optical absorption features of the nanocluster as supported by DFT calculations. This magic cluster confirms that there is a similar but quite different parallel alkynyl‐protected metal cluster universe in comparison to the thiolated one.

Doping-mediated excited state dynamics of diphosphine-protected M@Au12 (M = Au, Ir) superatom nanoclusters

“…41 The aromatic character of these ligand-protected Au NCs originates from the [Au 11 ] 3+ , [Ir@Au 10 ] 1+ , [Au 13 ] 5+ , and [Ir@Au 12 ] 3+ cores, further revealing the enhanced stability of Au 13 -based NCs. 42 This multicenter –2e binding pattern is in accordance with previous experimentally systemized [Au 19 (Hdppa) 3 (CCPh) 9 ] 2+ , 43 [Au 25 (SR) 18 ] − , 44 Au 13 Cu 4 (PPh 2 Py) 3 (SePh) 9 , 45 and [Au 13 Cu 2 (PPh 3 ) 6 (SR) 6 ] + . 46…”

Halogen effects on the electronic and optical properties of Au13nanoclusters

“…To obtain novel gold clusters with different photophysical properties, organic ligands such as thiols, phosphines and alkynes have been widely exploited in the syntheses of gold nanoclusters (Au n ) such as Au 8 , 17,18 Au 9 , 19 Au 11 , 20,21 Au 13 , 22–27 Au 18 , 27,28 Au 20 , 29,30 Au 22 , 31,32 Au 23 , 33 Au 24 , 34 Au 25 , 35,36 Au 32 , 37 Au 37 , 38 Au 44 , 39 Au 52 , 40 Au 55 , 41 and Au 102 . 13 Among all of the gold nanoclusters that have been structurally characterized, icosahedral Au 13 nanoclusters have been more extensively studied due to their highly symmetrical structure and prominent photoluminescence properties.…”

Gas-Phase Structures of [Au21(SR)14]− and [Au17(SR)10]− with Eight Electrons: Can They Support an Icosahedral Au13 Core?

“…Ligand-protected gold clusters with well-defined structures have gained much attention because of their unique and tunable optical, magnetic, and catalytic properties. − Previous single-crystal X-ray diffraction (SCXRD) studies have witnessed that the icosahedral ( I h ) Au 13 core with eight valence electrons has been formed commonly regardless of the type of ligands, including thiolate (RS), − selenolate, alkynyl, phosphine, and N -heterocyclic carbene. , For example, the representative cluster [Au 25 (SR) 18 ] − (RS = 2-phenylethanethiolate , and 1-naphthalenethiolate) has an I h Au 13 core capped by six bidentate SR-Au-SR-Au-SR (Au 2 (SR) 3 ) units (Table ). The ubiquity of the I h Au 13 core originates from its intrinsic stability due to low surface energy and a closed electron configuration of (1S) 2 (1P) 6 , where the 1S and 1P orbitals are distributed over the Au 13 core and have an angular momentum quantum number of 0 and 1, respectively. , The I h Au 13 (8e) core can be viewed as an electronically closed-shell superatom corresponding to the rare gas atoms.…”

“…Ligand-protected gold clusters with well-defined structures have gained much attention because of their unique and tunable optical, magnetic, and catalytic properties. 1−8 Previous single-crystal X-ray diffraction (SCXRD) studies have witnessed that the icosahedral (I h ) Au 13 core with eight valence electrons has been formed commonly regardless of the type of ligands, including thiolate (RS), 9−11 selenolate, 12 alkynyl, 13 phosphine, 14 and N-heterocyclic carbene. 15,16 For example, the representative cluster [Au 25 (SR) 18 ] − (RS = 2phenylethanethiolate 9,10 and 1-naphthalenethiolate 11 ) has an I h Au 13 core capped by six bidentate SR-Au-SR-Au-SR (Au 2 (SR) 3 ) units (Table 1).…”