In this work, we introduce a novel approach for the selective assembly of heterometallic complexes by unprecedented coordination of coinage metal cations to strained single ruthenium–boron bonds on a surface of icosahedral boron clusters. M( i ) cations (M = Cu, Ag, and Au) insert into B–Ru bonds of the (BB)–carboryne complex of ruthenium with the formation of four-membered B–M–Ru–B metalacycles. Results of theoretical calculations suggest that bonding within these metalacycles can be best described as unusual three-center-two-electron B–M⋯Ru interactions that are isolobal to B–H⋯Ru borane coordination for M = Cu and Ag, or the pairs of two-center-two electron B–Au and Au–Ru interactions for M = Au. These transformations comprise the first synthetic route to exohedral coinage metal boryl complexes of icosahedral closo -{C 2 B 10 } clusters, which feature short Cu–B (2.029(2) Å) and Ag–B (2.182(3) Å) bonds and the shortest Au–B bond (2.027(2) Å) reported to date. The reported heterometallic complexes contain Cu( i ) and Au( i ) centers in uncharacteristic square-planar coordination environments. These findings pave the way to rational construction of a broader class of multimetallic architectures featuring M–B bonds.
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Silver halide complexes of a borane/bis(phosphine) ligand
Silver halide complexes of a borane/bis(phosphine) ligand have been prepared and characterized. With AgF, the borane abstracts fluoride, resulting in a zwitterionic complex. With AgCl, AgBr, and AgI, the halide stays coordinated to Ag, with little to no Ag–B interaction.
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- Award ID(s):
- 1565923
- NSF-PAR ID:
- 10157326
- Date Published:
- Journal Name:
- Dalton Transactions
- Volume:
- 48
- Issue:
- 27
- ISSN:
- 1477-9226
- Page Range / eLocation ID:
- 9959 to 9961
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Recently, CuI‐ and AgI‐based halide double perovskites have been proposed as promising candidates for overcoming the toxicity and instability issues inherent within the emerging Pb‐based halide perovskite absorbers. However, up to date, only AgI‐based halide double perovskites have been experimentally synthesized; there are no reports on successful synthesis of CuI‐based analogues. Here we show that, owing to the much higher energy level for the Cu 3d10orbitals than for the Ag 4d10orbitals, CuIatoms energetically favor 4‐fold coordination, forming [CuX4] tetrahedra (X=halogen), but not 6‐fold coordination as required for [CuX6] octahedra. In contrast, AgIatoms can have both 6‐ and 4‐fold coordinations. Our density functional theory calculations reveal that the synthesis of CuIhalide double perovskites may instead lead to non‐perovskites containing [CuX4] tetrahedra, as confirmed by our material synthesis efforts.
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Abstract Recently, CuI‐ and AgI‐based halide double perovskites have been proposed as promising candidates for overcoming the toxicity and instability issues inherent within the emerging Pb‐based halide perovskite absorbers. However, up to date, only AgI‐based halide double perovskites have been experimentally synthesized; there are no reports on successful synthesis of CuI‐based analogues. Here we show that, owing to the much higher energy level for the Cu 3d10orbitals than for the Ag 4d10orbitals, CuIatoms energetically favor 4‐fold coordination, forming [CuX4] tetrahedra (X=halogen), but not 6‐fold coordination as required for [CuX6] octahedra. In contrast, AgIatoms can have both 6‐ and 4‐fold coordinations. Our density functional theory calculations reveal that the synthesis of CuIhalide double perovskites may instead lead to non‐perovskites containing [CuX4] tetrahedra, as confirmed by our material synthesis efforts.
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Abstract Two critical limitations of organic–inorganic lead halide perovskite materials for solar cells are their poor stability in humid environments and inclusion of toxic lead. In this study, high‐throughput density functional theory (DFT) methods are used to computationally model and screen 1845 halide perovskites in search of new materials without these limitations that are promising for solar cell applications. This study focuses on finding materials that are comprised of nontoxic elements, stable in a humid operating environment, and have an optimal bandgap for one of single junction, tandem Si‐perovskite, or quantum dot–based solar cells. Single junction materials are also screened on predicted single junction photovoltaic (PV) efficiencies exceeding 22.7%, which is the current highest reported PV efficiency for halide perovskites. Generally, these methods qualitatively reproduce the properties of known promising nontoxic halide perovskites that are either experimentally evaluated or predicted from theory. From a set of 1845 materials, 15 materials pass all screening criteria for single junction cell applications, 13 of which are not previously investigated, such as (CH3NH3)0.75Cs0.25SnI3, ((NH2)2CH)Ag0.5Sb0.5Br3, CsMn0.875Fe0.125I3, ((CH3)2NH2)Ag0.5Bi0.5I3, and ((NH2)2CH)0.5Rb0.5SnI3. These materials, together with others predicted in this study, may be promising candidate materials for stable, highly efficient, and nontoxic perovskite‐based solar cells.
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Facile and large-scale synthesis of well-defined, thermally stable silver nanoparticles protected by polymer brushes for use in practical applications is still a challenge. Recent work has reported a nanoreactor approach that can be used to synthesize these silver nanoparticles. This approach uses amphiphilic star-block copolymers, which have a hydrophilic core surrounded by a hydrophobic exterior. These polymers thus can serve as the nanoreactors. In this study, we hypothesize that the local high concentration of silver ions in the inner hydrophilic cores of these star-block copolymers facilitates the nucleation and subsequent growth of silver nanoparticles. When all silver nanoparticles nucleate from the cores of the star-block copolymers in solution, the particle size can be controlled by the core size of the polymer. To test this hypothesis, a polyisoprene-b-poly(p-tert-butylstyrene) (PI-b-PtBS) star-block copolymer was functionalized with carboxylic acid groups using a high-efficiency, photo-initiated thiol-ene click reaction. We characterized this modified polymer using proton nuclear magnetic resonance spectroscopy, and the results indicated that ~60% of the double bonds in the polyisoprene block were successfully functionalized with carboxylic acid groups. When silver ions were added to a solution of these functionalized star-block copolymers, the negatively charged carboxylic acid groups would attract the positively charged silver ions. Subsequent reduction of these Ag+ by a tert-butylamine-borane complex at room temperature produced nanosized silver particles. However, transmission electron microscopy images showed that a significant amount of relatively large silver nanoparticles grew outside the star-block copolymer nanoreactors.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/c9dt02100k
