Synthesis and crystal structure of an Ag20 cluster incorporating in situ generated bipodal [ArP(OEt)S2]− and tripodal [ArPOS2]2− ligands (Ar=4-methoxyphenyl)

Ferrocenyl Dithiophosphonate Ag(I) Complexes: Synthesis, Structures, Luminescence, and Electrocatalytic Water Splitting Tuned by Nuclearity and Ligands

The heterometallic [Ag(I)/Fe(II)] molecular electrocatalysts for hydrogen production were introduced here to recognize the mutual role of metallic nuclearity and ligand engineering. A series of ferrocenyl dithiophosphonate stabilized mononuclear [Ag(PPh3)2{S2PFc(OR)}] {where R=Me (1), Et (2), nPr (3), iPr (4), iAmyl (5); Fc=Fe (ɳ5-C5H4) (ɳ5-C5H5)} and dinuclear [Ag(PPh3){S2PFc(OR}]2 {where R=Et (2 a), and nPr (3 a)} complexes were synthesized and characterized by SCXRD, NMR (31P and 1H), ESI-MS, UV-Vis, and FT-IR spectroscopy. The comparative electrocatalytic HER behavior of 1-5 and 2 a-3 a showed effective current density of 1 mA/cm2 with overpotentials ranging from 772 to 991 mV, demonstrating the influence of extended and branched carbon chains in dithiophosphonates and metallic (mono-/di-) nuclearity, which correlates with documented tetra-nuclear [Ag4(S2PFc(OnPr)4], 6. DFT study suggests the coordinated (μ1-S) site of ligands is the reactivity center and the adsorption energy of intermediate [H*-SM] varies with the engineering of ligand and nuclearity. A catalytic mechanism using mononuclear (1) and di-nuclear (2 a) was proposed with the assistance of DFT. Each complex, being the first example of Ag(I) dithiophosphonates, exhibits intense photoluminescence with high quantum yields ranging from 33 % to 67 %. These results link the lower nuclearity structures to their physical and catalytic properties.

Dithiophosphonate-Protected Eight-Electron Superatomic Ag21 Nanocluster: Synthesis, Isomerism, Luminescence, and Catalytic Activity

The structure-property relationship considering isomerism-tuned photoluminescence and efficient catalytic activity of silver nanoclusters (NCs) is exclusive. Asymmetrical dithiophosphonate NH4[S2P(OR)(p-C6H4OCH3)] ligated first atomically precise silver NCs [Ag21{S2P(OR)(p-C6H4OCH3)}12]PF6 {where, R = nPr (1), Et (2)} were established by single-crystal X-ray diffraction and characterized by electrospray ionization mass spectrometry, NMR (31P, 1H, 2H), X-ray photoelectron spectroscopy, UV-visible, energy-dispersive X-ray spectroscopy, Fourier transforms infrared, thermogravimetric analysis, etc. NCs 1 and 2 consist of eight silver atoms in a cubic framework and enclose an Ag@Ag12-centered icosahedron to constitute an Ag21 core of Th symmetry, which is concentrically inscribed within the S24 snub-cube, P12 cuboctahedron, and the O12 truncated tetrahedron formed by 12 dithiophosphonate ligands. These NCs facilitate to be an eight-electron superatom (1S21P6), in which eight capping Ag atoms exhibit structural isomerism with documented isoelectronic [Ag21{S2P(OiPr)2}12]PF6, 3. In contrast to 3, the stapling of dithiophosphonates in 1 and 2 triggered bluish emission within the 400 to 500 nm region at room temperature. The density functional theory study rationalized isomerization and optical properties of 1, 2, and 3. Both (1, and 2) clusters catalyzed a decarboxylative acylarylation reaction for rapid oxindole synthesis in 99% yield under ambient conditions and proposed a multistep reaction pathway. Ultimately, this study links nanostructures to their physical and catalytic properties.

Anion-templated nanosized silver clusters protected by mixed thiolate and diphosphine

S^2-, MoO₄^2-, and Mo₆O₂₂^8- were successfully employed as templates in the formation of six high-symmetry polynuclear silver clusters as exemplified in the single-crystal X-ray structures of [S@Ag₁₈(^tBuC₆H₄S)₁₆(dppp)₄]·DMF·5CH₃CN·3CH₃OH (1), [MoO₄@Ag₂₄(MeC₆H₄S)₁₂(dppm)₆(MoO₄)₄]·2BF₄·C₂H₅NO (2), [MoO₄@Ag₂₄(MeC₆H₄S)₁₂(dppm)₆(MoO₄)₄]·2CF₃SO₃ (3), [MoO₄@Ag₂₄(MeC₆H₄S)₁₂(dppf)₆(MoO₄)₄]·2CF₃SO₃ (4), [MoO₄@Ag₂₄(MeC₆H₄S)₁₂(dppb)₆(MoO₄)₄]·2CF₃SO₃ (5) and [Mo₆O₂₂@Ag₄₆(^tBuC₆H₄S)₃₂(dppm)₄(CH₃CN)₈]·6CF₃SO₃ (6) (dppp = 1,3-bis(diphenylphosphino)propane, dppm = bis(diphenylphosphino)methane, dppf = 1,1'-bis(diphenylphosphino)ferrocene and dppb = 1,4-bis(diphenylphosphino)butane). Cluster 1 is a S^2--centered octadecanuclear banana-shaped molecule. Clusters 2-5 have similar structures consisting of a tetrahedron of a MoO₄^2- core and four MoO₄^2- where three silver atoms cap each face and a pair sits on each edge, giving tetraicosanuclear ball-shaped molecules. Although different diphosphine ligands and silver salts were used in the syntheses, 2-5 contain a common building cluster unit with similar geometry and nuclearity. With (Bu₄N)₂Mo₆O₁₉ as a template, a giant 46-silver-atom cluster encapsulates an in situ modified Mo₆O₂₂^8- unit. The nuclearity and geometry depend on the size and shape of the templates. High-resolution electrospray mass spectrometry (HR-ESI-MS) analyses of 4 indicate its exceptionally high stability in acetonitrile. The solid-state luminescence of 1 as a function of the temperature exhibits thermochromism from red to yellow due to the different intensities of the two bands. This work established a new strategy for the construction of polynuclear silver clusters using an anionic template and mixed S- and P-donor ligands where a promising approach for building novel dual emissive materials is unraveled.

catena-Poly[[[μ-1,3-bis(diphenylphosphanyl)propane-κ2P:P'][O-ethyl (4-methoxyphenyl)phosphonodithioato-κ2S,S']silver(I)] chloroform monosolvate]

Reaction of a mixture of AgOAc, Lawesson's reagent [2,4-bis(4-methoxyphenyl)-1,3-dithiadiphosphetane-2,4-disulfide] and 1,3-bis(diphenylphosphanyl)propane (dppp) under ultrasonic treatment gave the title compound, {[Ag(C(9)H(12)O(2)PS(2))(C(27)H(26)P(2))]·CHCl(3)}(n), a novel one-dimensional chain based on the in situ-generated bipodal ligand [ArP(OEt)S(2)](-) (Ar = 4-methoxyphenyl). The compound consists of bidentate bridging 1,3-bis(diphenylphosphanyl)propane (dppp) and in situ-generated bidentate chelating [ArP(OEt)S(2)](-) ligands. The dppp ligand links the [Ag{ArP(OEt)S(2)}] subunit to form an achiral one-dimensional infinite chain. These achiral chains are packed into chiral crystals by virtue of van der Waals interactions. No π-π interactions are observed in the crystal structure.