Halide‐Directed Assembly of Multicomponent Systems: Highly Ordered Au^I–Ag^I Molecular Aggregates

Abstract

A great deal of research in inorganic and organometallic chemistry is devoted to investigation of self-assembly processes, which spontaneously lead to formation of complex multimetallic supramolecular entities from relatively simple building blocks under mild conditions. The resulting wellordered species are of significant interest due to their fascinating structural characteristics and promising optical, electronic, or catalytic properties. [1,2] In most cases these species are prepared by a metal-ligand coordination-based strategy. However, group 11 metal ions tend to exhibit effective noncovalent metal-metal interactions, which often complicate the assembly processes and may result in formation of polymers or networks, catenanes, and polymetallic clusters. [2, 3] Hence, it is difficult to predict the structural topology of coinage metal aggregates, and controlling the system organization at the molecular or nanoscale level is a major synthetic challenge.One of the approaches to high-nuclearity coinage metal clusters is an elegant anion-templated synthesis of homometallic silver alkynyl cage compounds, which were shown to incorporate halides, [4] carbonate, [5] chromate, [6] and even polyoxometalates. [7] However, this approach is very little studied and the assembly processes of the d 10 heterometallic compounds in the presence of coordinating anions have never been investigated.In the course of our studies on coinage metal clusters [8][9][10] we . [9] This preparative route, which eventually involves cleavage of C À Cl bonds of CH 2 Cl 2 molecules as a source of chloride, was quite ineffective (yield of < 20 %). Alternatively, it was found that treatment of a stoichiometric reaction mixture with Ag + and Cl À ions results in rather fast and nearly quantitative formation of 1 (Scheme 1).The bromide-and iodide-containing congeners (2 and 3) were obtained analogously, though some addition of CHBr 3 and MeI, respectively, was necessary to decrease possible halide exchange with solvent (CH 2 Cl 2 ). Complexes 1-3 were characterized by 1 H and 31 P NMR spectroscopy. An X-ray diffraction study on 3 revealed its structure in the solid state (Figure 1). [11] The molecule consists of the heterometallic cluster [Au 9 Ag 12 (C 2 Ph) 18 I 3 ] surrounded by a cationic "belt" [Au 3 (P 3 P) 3 ] 3+ . Even though the general structural motif-a bimetallic cluster [Autriangle-has been described before, [12,13] the peculiarity of 3 resides in the central "axis" of three I À ions, which effectively directed the framework aggregation process and stabilized the resulting metal core. The IÀAg distances of 2.8330(14)-3.0173(13) suggest a significant contribution of a conventional bonding between the halide and metal ions. The AuÀ Ag contacts vary significantly from 2.7844(11) to 3.3472(11) , the longest of which involve silver ions bound to iodide ions. The average Au-Ag distance (3.02 ) and the AuÀAu bonds between the central cluster and the external "belt" (2.8813(6)-2.9055(6) ) are not exceptional and agree with the previously re...

Role of Anions Associated with the Formation and Properties of Silver Clusters

“…The effort to assemble intercluster compounds from well-defined inorganic clusters aims to discover new properties due to cooperative effects. Wang and Xiao chose silver thiolate cluster cations and POM anions as basic units for the assembly of intercluster compounds, 36 Figure 15a, the centrosymmetric Ag62 cluster is situated at the origin of the unit cell), and two Mo 6 O 19 2− ions are presented inside the unit cell. The crystal structure is stabilized by electrostatic attractions as well as C−H···O contacts between terminal oxygen atoms of Mo 6 O 19 2− and carbon atoms of the tert-butyl groups.…”

“…Wang and Xiao chose silver thiolate cluster cations and POM anions as basic units for the assembly of intercluster compounds, 36 Figure 15a, the centrosymmetric Ag62 cluster is situated at the origin of the unit cell), and two Mo 6 O 19 2− ions are presented inside the unit cell. The crystal structure is stabilized by electrostatic attractions as well as C−H···O contacts between terminal oxygen atoms of Mo 6 O 19 2− and carbon atoms of the tert-butyl groups. The shortest distance from the methyl carbon of the tert-butyl group to the surface oxygen of Mo 6 , it can interact with Ag62 to form a charge transfer salt.…”

Synthesis, characterization and photophysical properties of gold(I)–copper(I) alkynyl clusters with 1,4-bis(diphenylphosphino)butane, effect of the diphosphine ligand on luminescence characteristics

“…Additionally, accessible modification of these ligands provides an opportunity for fine tuning of the physicochemical properties of the resulting organometallic aggregates. Recently we have described a family of the polynuclear AueCu and AueAg complexes, which contain a central core composed of gold(bis-alkynyl) "rods" and copper or silver ions stabilized by the {Auediphosphine} 3 "belt" (diphosphines: Ph 2 Pe(C 6 H 4 ) n ePPh 2 , n ¼ 1e5, Ph 2 PeC^Ce(C 6 H 4 ) n eC^CePPh 2 , n ¼ 0e2) [17,24,25]. Particular attention was paid to the photophysical studies of these compounds, which demonstrate extremely high quantum yields of phosphorescence, negligible quenching of emission with molecular oxygen and intriguing non-linear properties.…”

Laser-induced synthesis of metallic silver-gold nanoparticles encapsulated in carbon nanospheres for surface-enhanced Raman spectroscopy and toxins detection

“…The choice of He-Cd laser was determined by the position of an intense absorption band of the complex at 328 nm, which was assigned to metal-to-ligand charge transfer. 32 The unfocused laser beam irradiated the substrate-solution interface from the substrate side; the diameter of laser spot was 3 mm and exposure time varied from 1 to 15 min. As a result of the laser irradiation, nanostructured spots with diameter of 3 mm consisted of C-AgAu NPs have been formed.…”

“…The used supramolecular complex consists of central bimetallic (Au-Ag) core with 12 Au and 12 Ag atoms stabilized by the alkynyl and phosphine ligands. 32 Nanoparticles were deposited from dichloroethane solution of the supramolecular complex onto the surface of silica-based (microscope-cover) glass. The deposition of the nanoparticles on the surface of the substrate was carried out with He-Cd laser (continuous wave, k ¼ 325 nm, P ¼ 0.1 W/cm 2 ).…”