We present the first example of polymorphism (cubic &amp; trigonal) in single crystals of an atomically precise monolayer protected cluster, Ag29(BDT)12(TPP)43-. We demonstrate that C-H⋯π 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. © 2018 The Royal Society of Chemistry.

Pradeep Thalappil

Department Of Chemistry

Abhijit Nag

Papri Chakraborty

Mohammad Bodiuzzaman

Tripti Ahuja

Sudhadevi Antharjanam

Luminescence

Single crystals

CUBIC LATTICE

Luminescence efficiencies

MONOLAYER PROTECTED CLUSTERS

Pi interactions

SECONDARY LIGANDS

Ligands

article

genetic association

Rigidity

solid state

Fulltext

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It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Nanoscale

Rapid solution-state exchange dynamics in nanoscale pieces of matter is revealed, taking isotopically pure atomically precise clusters as examples. As two isotopically pure silver clusters made of 107 Ag and 109 Ag are mixed, an isotopically mixed cluster of the same entity results, similar to the formation of HDO, from H 2 O and D 2 O. This spontaneous process is driven by the entropy of mixing and involves events at multiple time scales. Copyright © 2019 The Authors.

Science Advances

Rapid isotopic exchange in nanoparticles

ConspectusSupramolecular chemistry is a major area of chemistry that utilizes weaker non-covalent interactions between molecules, including hydrogen bonding, van der Waals, electrostatic, π···π, and C-H···π interactions. Such forces have been the basis of several molecular self-assemblies and host-guest complexes in organic, inorganic, and biological systems. Atomically precise nanoclusters (NCs) are materials of growing interest that display interesting structure-property correlations. The evolving science of such systems reaffirms their molecular behavior. This gives a possibility of exploring their supramolecular chemistry, leading to assemblies with similar or dissimilar cluster molecules. Such assemblies with compositional, structural, and conformational precision may ultimately result in cluster-assembled hybrid materials. In this Account, we present recent advancements on different possibilities of supramolecular interactions in atomically precise cluster systems that can occur at different length scales. We first present a brief discussion of the aspicule model of clusters, considering Au 25 (SR) 18 as an example, that can explain various aspects of its atomic precision and distinguish the similar or dissimilar interacting sites in their structures. The supramolecular interaction of 4-tert-butylbenzyl mercaptan (BBSH)-protected [Au 25 (SBB) 18 ] - NCs with cyclodextrins (CD) to form Au 25 SBB 18 ∩CD n (n = 1-4) and that of [Ag 29 (BDT) 12 ] 3- with fullerenes to form [Ag 29 (BDT) 12 (C 60 ) n ] 3- (n = 1-9) (BDT = 1,3-benzenedithiolate) are discussed subsequently. The formation of these adducts was studied by electrospray ionization mass spectrometry (ESI MS), optical absorption and NMR spectroscopy. In the subsequent sections, we discuss how variation in intercluster interactions can lead to polymorphic crystals, which are observable in single-crystal X-ray diffraction. Taking [Ag 29 (BDT) 12 (TPP) 4 ] 3- (TPP = triphenylphosphine) clusters as an example, we discuss how the different patterns of C-H···π and π···π interactions between the secondary ligands can alter the packing of the NCs into cubic and trigonal lattices. Finally, we discuss how the supramolecular interactions of atomically precise clusters can result in their hybrid assemblies with plasmonic nanostructures. The interaction of p-mercaptobenzoic acid (p-MBA)-protected Ag 44 (p-MBA) 30 NCs with tellurium nanowires (Te NWs) can form crossed-bilayer precision assemblies with a woven-fabric-like structure with an angle of 81° between the layers. Similar crossed-bilayer assemblies show an angle of 77° when Au 102 (p-MBA) 44 clusters are used to form the structure. Such assemblies were studied by transmission electron microscopy (TEM). Precision in these hybrid assemblies of Te NWs was highly controlled by the geometry of the ligands on the NC surface. Moreover, we also present how Ag 44 (p-MBA) 30 clusters can encapsulate gold nanorods to form cage-like nanostructures. Such studies involved TEM, scanning transmission electron microscopy (STEM), and three-dimensional tomographic reconstructions of the nanostructures. The hydrogen bonding interactions of the -COOH groups of the p-MBA ligands were the major driving force in both of these cases. An important aspect that is central to the advancement of the area is the close interplay of molecular tools such as MS with structural tools such as TEM along with detailed computational modeling. We finally conclude this Account with a future perspective on the supramolecular chemistry of clusters. Advancements in this field will help in developing new materials with potential optical, electrical, and mechanical properties. © Copyright © 2018 American Chemical Society.

Accounts of Chemical Research

Approaching Materials with Atomic Precision Using Supramolecular Cluster Assemblies

Polymorphism of Ag29(BDT)12(TPP)43- cluster: Interactions of secondary ligands and their effect on solid state luminescence

Journal	Data powered by TypesetNanoscale
Publisher	Data powered by TypesetRoyal Society of Chemistry
ISSN	20403364
Open Access	No