We present the first example of polymorphism (cubic & trigonal) in single crystals of an atomically precise monolayer protected cluster, Ag29(BDT)12(TPP)43-. We demonstrate that C-Hπ interactions of the secondary ligands (TPP) are dominant in a cubic lattice compared to a trigonal lattice, resulting in a greater rigidity of the structure, which in turn, results in a higher luminescence efficiency in it.

We introduce a cluster coprotected by thiol and diphosphine ligands, [Ag22(dppe)4(2,5-DMBT)12Cl4]2+ (dppe = 1,2-bis­(diphenylphosphino)­ethane; 2,5-DMBT= 2,5-dimethylbenzenethiol), which has an Ag10 core encapsulated by an Ag12(dppe)4(2,5-DMBT)12Cl4 shell. The Ag10 core comprises two Ag5 distorted trigonal bipyramidal units and is uncommon in Au and Ag nanoclusters. The electrospray ionization mass spectrum reveals that the cluster is divalent and contains four free electrons. An uncommon crystallization-induced enhancement of emission is observed in the cluster. The emission is weak in the solution and amorphous states. However, it is enhanced 12 times in the crystalline state compared to the amorphous state. A detailed investigation of the crystal structure suggests that well-arranged C–H···π and π···π interactions between the ligands are the major factors for this enhanced emission. Further, in-depth structural elucidation and density functional theory calculations suggest that the cluster is a superatom with four magic electrons.

Reactions between atomically precise noble metal nanoclusters (NCs) have been studied widely in the recent past, but such processes between NCs and plasmonic nanoparticles (NPs) have not been explored earlier....

We report the crystal structure of a supramolecular coassembly of a red luminescent silver cluster, [Ag29(BDT)12(TPP)4]3– (referred to as Ag29) (BDT, 1,3-benzene dithiol; TPP, triphenyl phosphine), with dibenzo-18-crown-6 (DB18C6). The structure may be viewed as crystallization-induced self-organization of DB18C6 molecules into cage-like hexamers in the interstitial spaces of the lattice of trigonal Ag29 (Ag29T) clusters, which resulted in an anisotropic expansion of the Ag29T lattice along its z-axis. This structure corresponds to a new family of “lattice inclusion” compounds in nanoclusters. Supramolecular forces guide the assembly of the clusters and the crown ethers, which pack into complex hierarchical patterns in their crystal lattice. We identified the effect of such a coassembly on the solid-state luminescence of the cluster. The crystals containing the coassembly were ∼3.5-fold more luminescent than the parent Ag29T crystals. We also used high-resolution electrospray ionization mass spectrometry to get further insights into the nature of the complexation between Ag29 cluster and DB18C6. This study provides a new strategy for designing cluster-assembled functional materials with enhanced properties.

Arsenicosis was recognized over 104 years ago. Elevated arsenic (As) concentrations in water is faced by about 200 million people worldwide and has become one of the biggest challenges in the context of water purification. Providing sustainable and affordable solutions to tackle this menace is a need of the hour. Adsorption on advanced materials is increasingly being recognized as a potential solution. Here, we report various functionalized microcellulose-reinforced 2-line ferrihydrite composites which show outstanding As­(III) and As­(V) adsorption capacities. Green synthesis of the composite yields granular media with high mechanical strength which show faster adsorption kinetics in a wide pH range, irrespective of the presence of other interfering ions in water. The composites and their interaction with As­(III) and As­(V) were studied by XRD, HRTEM, SEM, XPS, Raman, TG, and IR spectroscopy. Performance of the media in the form of cartridge reaffirms its utility for point-of-use water purification. We show that cellulose microstructures are more efficient than corresponding nanostructures for the purpose of arsenic remediation. We have also performed an evaluation of several sustainability metrics to understand the “greenness” of the composite and its manufacturing process.