CONSPECTUS:The chalcogenolato silver and copper superatoms are currently a topic of cutting edge research besides the extensively studied Au n (SR) m clusters. The crystal structural analysis is an indispensable tool to gain deep insights into the anatomy of these subnanometer clusters. The metal framework and spatial arrangement of the chalcogenolates around the metal core assist in unravelling the structure-property relationship and fundamental mechanistic involved in their fabrication. In this Account, we discuss our contribution towards the development of dichalcogenolato Ag and Cu cluster chemistry covering their fabrications and precise molecular structures. Briefly introducing the significance of the single crystal structures of the atomically precise clusters; the novel dichalcogenolated 2-electron superatomic copper and their alloy systems are presented first. The [Cu 13 {S 2 CNR} 6 {C≡CR'} 4 ] + is so far the first unique copper cluster having Cu 13 centred cuboctahedron, which is a miniature of bulk fcc. The galvanic exchange of the central Cu with Ag/Au results in a similar anatomy of formed bimetallic [Au/Ag@Cu 12 (S 2 CN n Bu 2 ) 6 (C≡CPh) 4 ][CuCl 2 ] species. This is unique in a sense that other contemporary M 13 cores in group 11 superatomic chemistry are compact icosahedra. The central doping of Ag or Au significantly affects the physiochemical properties of the bimetallic Cu rich clusters. It is manifested in the dramatic quantum 1 yield enhancement of the doped species [Au@Cu 12 (S 2 CN n Bu 2 ) 6 (C≡CPh) 4 ] + with a value of 0.59 at 77 K in 2-MeTHF. In the second part, the novel eight-electron dithiophosphate-and diselenophosphate-protected silver systems are presented. A completely different type of architecture was revealed for the first time from the successful structural determination of [Ag 21 {S 2 P(O i Pr) 2 } 12 ] + , [Ag 20 {S 2 P(O i Pr) 2 } 12 ] and [Au@Ag 19 {S 2 P(OPr) 2 } 12 ]. They exhibit a non-hollow M 13 (Ag or AuAg 12 ) icosahedron, capped by 8 and 7 Ag atoms in the former and latter two species, respectively. The overall metal core units are protected by 12 dithiophosphate ligands and the metal-ligand interface structure was found to be quite different from that of Au n (SR) m . Notably, the [Ag 20 {S 2 P(O i Pr)} 12 ] cluster provides the first structural evidence of silver superatom with a chiral metallic core. This chirality arises through the simple removal of one of capping Ag + cation of [Ag 21 {S 2 P(O i Pr) 2 } 12 ] + present on its C 3 axis. Further, the effects of the ligand exchange on the structures of [Ag 20 {Se 2 P(O i Pr) 2 } 12 ], [Ag 21 {Se 2 P(OEt) 2 } 12 ] + and [AuAg 20 {Se 2 P(OEt) 2 } 12 ] + are studied extensively. The structure of the former species is similar to its dithiophosphate counterpart (C 3 symmetry). The latter two (T symmetry) differ in the arrangement of 8 capping Ag atoms, as they form a cube engraving the Ag 13 (AuAg 12 ) icosahedron. The blue shifts in absorption spectra and photoluminescence further indicate the strong influence of ...
Highly reactive copper‐dihydride clusters, [Cu15(H)2(S2CNR2)6(C2Ph)6](PF6) {R = nBu (1H), nPr (2H), iBu (3H)}, are isolated during the reaction of [Cu28H15{S2CNnBu2}12](PF6) with ten equivalents of phenylacetylene. They are found to be intermediates in the formation of the earlier reported two‐electron superatom [Cu13(S2CNR2)6(C2Ph)4]+. Better yields are obtained by reacting dithiocarbamate sodium salts, [Cu(CH3CN)4](PF6), BH4− and phenylacetylene. The presence of two hydrides in the isolated clusters is confirmed by the synthesis and characterization of its deuteride analogue [Cu15(D)2(S2CNR2)6(C2Ph)6]+, and a single‐crystal neutron structure of 2H. Structural characterization of 1H reveals a new bicapped icosahedral copper(I) cage encapsulating a linear copper dihydride (CuH2)− unit. Reaction of 3H with Au(I) salts yields a highly luminescent [AuCu12(S2CNiBu2)6(C2Ph)4]+ cluster.
The first stable structure of silver(I) cluster cations [Ag(8)(mu(4)-H){Se(2)P(OR)(2)}(6)](+) [R = (i)Pr, 1; Et, 2] containing Ag(I)-hydride bridges (Ag-mu-H-Ag) in T symmetry was reported. The clusters having an interstitial hydride were composed of an octanuclear silver core in tetracapped tetrahedral geometry, which was inscribed within a Se(12) icosahedron represented by six dialkyl diselenophosphate ligands in a tetrametallic-tetraconnective (mu(2), mu(2)) bonding mode. The presence of hydride was unequivocally corroborated by both (1)H and (109)Ag NMR spectroscopies of which a nonet in the (1)H NMR spectrum for the hydride resonance coupled with a doublet peak observed in the (109)Ag NMR spectrum clearly suggests that eight silver nuclei are equivalent in the NMR time scale and a fast exchange of the positions between the vertex and capping silver atoms in solution must occur. The hypothesis was also supported by a density functional theory (DFT) investigation on a simplified model [Ag(8)(H)(Se(2)PH(2))(6)](+), which confirmed that the Ag(8)H cubic core of T(h) symmetry may not be formed as it is energetically highly unfavorable (0.67 eV less stable than the T structure).
Structurally precise palladium doped silver-nanoclusters [PdAg20] and [Pd6Ag14(S)] stabilized by twelve dithiophosphate ligands have been isolated. The latter is the first example where a hexa-palladium(0) core is embodied within a silver(i) cluster.
Structurally precise copper hydrides [Cu 11 H 2 {S 2 P(O i Pr) 2 } 6 (C≡CR) 3 ], (R= Ph (1), C 6 H 4 F (2) and C 6 H 4 OMe (3) were first synthesized from the polyhydrido copper cluster [Cu 20 H 11 {S 2 P(O i Pr) 2 } 9 ] with nine equiv. of terminal alkynes. Later their isolated yields were significantly improved by direct synthesis from [Cu(CH 3 CN) 4 ](PF 6), [NH 4 ][S 2 P(O i Pr) 2 ], NaBH 4 , and alkynes along with NEt 3 in THF. 1, 2, and 3 were fully characterized by single-crystal X-ray diffraction, ESI-MS and multinuclear NMR spectroscopy. All three clusters have eleven copper atoms adopting 3, 3, 4, 4, 4-pentaccaped trigonal prismatic geometry, with two hydrides inside the Cu 11 cage, the position of which being ascertained by a single-crystal neutron diffraction structure of cluster 1 co-crystallized with a [Cu 7 (H){S 2 P(O i Pr) 2 } 6 ], 4 cluster. Six dithiophosphate and three alkynyl ligands stabilize the Cu 11 H 2 core in which the two hydrides adopt a trigonal pyramidal coordination mode. This coordination mode is so far unprecedented for hydride. The 1 H NMR resonance frequency of the two hydrides appears at 4.8 ppm, a value further confirmed 1 A c c e p t e d m a n u s c r i p t by 2 H NMR spectroscopy for their deuteride derivatives [Cu 11 (D) 2 {S 2 P(O i Pr) 2 } 6 (C≡CR) 3 ]. A DFT investigation allows understanding the bonding within this new type of copper(I) hydrides.
The bimetallic M20 and M21 compounds, {[Cu3Ag17{S2P(O i Pr)2}12]0.5 [Cu4Ag16{S2P(O i Pr)2}12]0.5} ({[1a]0.5[1b]0.5}) and [Cu4Ag17{S2P(O i Pr)2}12](PF6) (2) have been structurally characterized, in which the Cu(I) ions are randomly distributed on the eight outer positions capping the 8-electron [Ag13] 5+ core. DFT calculations show that his statistical disorder results from the nearly neutral preference of copper to occupy any of the eight outer positions. Surprisingly, the UV-Vis absorption spectra of the M20 and M21 bimetallic nanoclusters display an almost identical absorption profile as that of their homometallic [Ag20{S2P(O i Pr)2}12] and [Ag21{S2P(O i Pr)2}12] + relatives. This is rationalized by TD-DFT calculations which show that the frontier orbitals of such 8-electron alloys are largely independent from the nature of the capping metal ions. A blue-shifted absorption is observed upon replacing by Au the central Ag atom in 2, forming the trimetallic compound [Cu4AuAg16{S2P(O i Pr)2}12](PF6) (3).
DFT calculations were carried out on a series of cluster cores, the framework of which being made of the condensation of several Pt@Ag12 centered icosahedra. Icosahedra condensations through vertex-sharing, face-sharing...
SummarySecondary phosphine oxides react with vinyl sulfides (both alkyl- and aryl-substituted sulfides) under aerobic and solvent-free conditions (80 °C, air, 7–30 h) to afford 1-hydroxy-2-(organosulfanyl)ethyl(diorganyl)phosphine oxides in 70–93% yields.
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