Synthesis of Gold-Silver Luminescent Honeycomb Aggregates by Both Solvent-Based and Solvent-Free Methods

A Photoluminescent Ag10 Cu6 Cluster Stablized by a PNNP Ligand and Phenylacetylides Selectively and Reversibly Senses Ammonia in Air and Water

A photoluminescent bimetallic cluster [Ag₁₀ Cu₆ (bdppthi)₂ (C≡CPh)₁₂ (MeOH)₂ (H₂ O)](ClO₄ )₄ (1, bdppthi=N,N'-bis(diphenylphosphanylmethyl)-tetrahydroimidazole} was synthesized from the PNNP type ligand bdppthi generated in-situ. Upon excitation at 365 nm, 1 exhibited strong phosphorescent emission at 630 nm, which was selectively quenched by NH₃ in air or water. The sensing of NH₃ was rapid and recoverable, with detection limits of 53 ppm (v/v) in N₂ and 21 μmol/L (0.36 ppm, w/w) for NH₃  ⋅ H₂ O in water. Cluster 1 could potentially serve as a bifunctional chemical sensor for the efficient detection of ammonia in waste-gas and waste-water.

Small Gold(I) and Gold(I)-Silver(I) Clusters by C-Si Auration

Auration of o-trimethylsilyl arylphosphines leads to the formation of gold and gold-silver clusters with ortho-metalated phosphines displaying 3c-2e Au-C-M bonds (M=Au/Ag). Hexagold clusters [Au6 L4 ](X)2 are obtained by reaction of (L-TMS)AuCl with AgX, whereas reaction with AgX and Ag2 O leads to gold-silver clusters [Au4 Ag2 L4 ](X)2 . Oxo-trigold(I) species [Au3 O]+ were identified as the intermediates in the formation of the silver-doped clusters. Other [Au5 ], [Au4 Ag], and [Au12 Ag4 ] clusters were also obtained. Clusters containing PAu-Au-AuP structural motif display good catalytic activity in the activation of alkynes under homogeneous conditions.

Linear Copper Complex Arrays as Versatile Molecular Strings: Syntheses, Structures, Luminescence, and Magnetism

The defined linear arrangement of metal atoms in discrete coordination complexes or polymers is still one of the most intriguing challenges in synthetic chemistry. These chain arrangements are of fundamental importance, because of their potential applications as molecular wires and single molecule magnets (SMM) in microelectronic devices on a molecular scale. Oligonuclear Group 11 metal complexes with suitable bridging ligands, specifically those that are based on copper as the first choice of a cheap precursor coinage metal, are of particular interest in this regard. This is due to the superior luminescence properties of these linear clusters that often show d¹⁰ ⋅⋅⋅d¹⁰ interactions in their molecular structures. The combination of Cu^I with heavier coinage metal ions results in tunable emissive arrays that are also stimuli-responsive. Thus, both linear multinuclear Cu^I and linear heteropolymetallic Cu^I /Ag^I as well as Cu^I /Au^I clusters are excellent candidates for applications in molecular/organic light-emitting devices (OLEDs). Alternatively, paramagnetic multinuclear cupric arrays are prominent as potential molecular wires with enhanced magnetic properties through multiple coupled d⁹ centers. This Review covers the whole range of linear multinuclear assemblies of cuprous and cupric ions in complexes and coordination polymers, their syntheses, photophysical behavior, and magnetic properties. Moreover, recent advances in the rapidly progressing field of hetero-Cu^I /Ag^I and Cu^I /Au^I molecular strings are also discussed.