Competing Roles of Crystallization and Degradation of a Metal–Organic Chalcogenolate Assembly under Biphasic Solvothermal Conditions

Abstract

Metal−organic chalcogenolate assemblies have attracted recent interest as ensemble nanomaterials that contain one-or two-dimensional inorganic nanostructures in a periodic array with supramolecular isolation provided by an associated organic ligand lattice. Biphasic immiscible synthesis at liquid−liquid interfaces is a convenient way to grow crystalline d 10 metal−organic chalcogenolate assemblies. However, there has been little systematic study of the role of temperature on the nucleation, growth, and stability of hybrid chalcogenolates during biphasic synthesis. Silver benzeneselenolate, a robustly blue-luminescent, lamellar metal−organic chalcogenolate assembly, was crystallized at biphasic immiscible liquid−liquid interfaces under solvothermal conditions. A positive correlation between temperature and nucleation density was observed, and the luminescence was conserved in all examples of the crystalline phase. Applying solvothermal conditions to the biphasic synthesis generally increased the lateral dimensions of the crystals and strongly favored the crystalline phase of the compound. Although thin, well-formed crystals were observed within 1 h for interfacial reactions performed at high temperatures, degradation was observed in long duration growths resulting in aggregated silver metal. A study of the thermal stability of the material via thermogravimetric analysis revealed that the decomposition is likely a redox reaction reverting the compound to silver metal and diphenyl diselenide. In situ analysis of this degradation was performed by grazingincidence wide-angle X-ray scattering, which confirmed that the decomposition occurs in a single step with no preceding changes to the structure of the material. This work demonstrates that biphasic solvothermal methods are amenable to the synthesis of hybrid metal−organic chalcogenolate assemblies and that temperature can be used to control product morphology and lateral crystal growth at the immiscible interface.

Size and Quality Enhancement of 2D Semiconducting Metal–Organic Chalcogenolates by Amine Addition

“…Of the 2D MOCs reported so far, silver phenyl­selenolate (AgSePh) ,− has received the most attention because of its blue luminescence (Figure a) and in-plane anisotropy, which are attractive features for light-emitting applications and light–matter coupling. AgSePh naturally adopts a multi-quantum-well structure consisting of slabs of silver selenide separated by layers of phenyl rings (Figure b), leading to a high exciton binding energy of ∼400 meV , and a picosecond photoluminescence (PL) lifetime .…”

Sterically Invariant Carborane-Based Ligands for the Morphological and Electronic Control of Metal-Organic Chalcogenolate Assemblies

“…The formed structures, more recently referred to as metal-organic chalcogenolate assemblies (MOCHAs, Figure 1a), have shown great promise in the preparation of low-dimensional metal-chalcogenide materials. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] More specifically, some MOCHAs have been synthesized using a biphasic approach from aqueous metal cations (e.g. copper(I) 20 , silver(I) 24 ) layered with chalcogenols (e.g.…”

Investigation of Nucleation and Growth at a Liquid–Liquid Interface by Solvent Exchange and Synchrotron Small-Angle X-Ray Scattering

“…Biphasic synthesis can be used to grow large (>3 µm) rhombic single crystals, providing a useful way to access complex materials via a straightforward synthetic approach. In our earlier studies, we examined the role of reagent concentration and temperature on its interfacial crystallization ( Schriber et al, 2018 ; Forster et al, 2002 ) and their role in the assembly of both the target crystals and an amorphous byproduct ( Schriber et al, 2018 ; Popple et al, 2018 ). These studies focused on modifying external components to the interfacial synthesis, as opposed to affecting the interface itself.…”