The Crystallization of Extended Niobium-Cluster Framework Compounds: A Novel Approach Using Ionic Liquids

Pigorsch, Arne; Köckerling, Martin

doi:10.1021/acs.cgd.6b00225

Cited by 15 publications

(6 citation statements)

References 52 publications

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“…Among those systems, the edge-bridged cluster units of formula [{M 6 X i 12 }X a 6 ] are known to be redox agents and UV-absorbents . They have been used as precursors for the syntheses of a wide range of hybrid compounds exhibiting unusual structural arrangements − as well as for the syntheses of some composites presenting catalytic or energy-saving abilities. ,, Their true nanosized, strong molecular character and their very good solubility in water and in several organic solvents makes them very easy to be processed as nanocomposites. This gives them significant advantages over the most common solar control IR absorbers since solutions are often involved in low-cost synthetic processes to fabricate the final materials.…”

Section: Introductionmentioning

confidence: 99%

Nanoarchitectonics of Glass Coatings for Near-Infrared Shielding: From Solid-State Cluster-Based Niobium Chlorides to the Shaping of Nanocomposite Films

Lebastard

Wilmet

Cordier

et al. 2022

ACS Appl. Mater. Interfaces

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The high potential of [{Nb 6 Cl i 12 }L a 6 ] cluster-based building blocks as near-infrared radiation blockers for energy saving applications is exposed in the present paper (i = inner edge-bridging ligand, a = apical ligand of the Nb 6 ; L = H 2 O and/or Cl). To do so, a combined experimental and theoretical investigation of edge-bridged [{Nb 6 Cl i 12 }Cl a 6−x (H 2 O) x ] m+/0/n− cluster unit series (x = 0, 4, 6; m = 2, 3, 4; n = 2, 3, 4) has been carried out. By using the K 4 [{Nb 6 Cl i 12 }Cl a 6 ] starting solid-state precursor, we explored the behavior of the [{Nb 6 Cl i 12 }Cl a 6 ] 4− cluster unit during the different steps of its integration as a building block into a polyvinylpyrrolidone (PVP) matrix to form a glass coating composite denoted {Nb 6 Cl i 12 } m+ @PVP (m = 2 or 3). The optical, vibrational and redox properties [{Nb 6 Cl i 12 }Cl a 6−x (H 2 O) x ] m+/0/n− building blocks have been interpreted with the support of electronic structure calculations and simulation of properties. The chemical modifications and oxidation properties have been identified and studied thanks to various techniques in solution. Combining Raman and ultraviolet−visible spectroscopies, electrochemistry, and quantum chemical simulations, we bring new knowledge to the understanding of the evolution of the properties of the [{Nb 6 Cl i 12 }Cl a 6−x (H 2 O) x ] m+/0/n− cluster units as a function of the number of valence electron per cluster (VEC) and the nature of terminal ligands (x = 0, n = 4; x = 4, charge = 0; x = 6, m = 4). The fine understanding of the physical properties and vibrational fingerprints depending on the VEC and chemical modifications in solution are mandatory to master the processing of cluster-based building blocks for the controlled design and shaping of glass coating nanocomposites. On the basis of this acquired knowledge, [{Nb 6 Cl i 12 }Cl a 6−x (H 2 O) x ] m+/0/n− building blocks were embedded in a PVP matrix. The resulting {Nb 6 Cl i 12 } 2+ @PVP nanocomposite film shows excellent ultraviolet (UV, 280−380 nm) and near-infrared (NIR, 780−1080 nm) blocking ability (>90%) and a highly visible light transmittance thanks to the controlled integration of the {Nb 6 Cl i 12 } 2+ cluster core. The figures of merit (FOM) value of T vis /T sol (T vis = visible transmittance and T sol = solar transmittance) as well as the haze, clarity, and the NIR shielding values (S NIR ) were measured. After optimization of the integration process, a {Nb 6 Cl i 12 } 2+ @PVP nanocomposite on glass substrate has been obtained with a high FOM equal to 1.29. This high value places the transparent green olive {Nb 6 Cl i 12 } 2+ @PVP nanocomposites at the top system in the benchmark in the field of glass coating composites for energy-saving applications.

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Section: Introductionmentioning

confidence: 99%

Nanoarchitectonics of Glass Coatings for Near-Infrared Shielding: From Solid-State Cluster-Based Niobium Chlorides to the Shaping of Nanocomposite Films

Lebastard

Wilmet

Cordier

et al. 2022

ACS Appl. Mater. Interfaces

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“…This led us to the hypothesis that niobium-chlorine Nb 6 Cl 12 clusters could be a good choice, because they have been widely employed to produce various crystals. [4,[88][89][90][91] In the niobium clusters, 6 Nb atoms form an octahedron, and the 12 chlorine atoms (Cl bridge ) are positioned at the edges of the octahedron. This has the perfect geometry for our purpose, and it has a 2 þ oxidation state.…”

Section: Materials Design Principles and Perspectivesmentioning

confidence: 99%

An Ab Initio Study of Clusters as Building Blocks for Crystals: From Prussian Blue Analogs to Hybrid Perovskites

Seriani

2022

Physica Status Solidi (b)

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Cluster‐based crystals containing the (Nb6Cl12)2+ or (Ta6Cl12)2+ clusters, including the well‐known Nb6Cl14, K4Nb6Cl18, and the Prussian blue analog (Me4N)2 [MnNb6Cl12(CN)6], have been investigated by density functional theory. The electronic structure of the cluster is the same for all compounds, with a semiconducting gap of around 1 eV between occupied and empty states, in the range of interest for solar energy applications. Calculations suggest that these clusters could be used as cations in hybrid organic–inorganic perovskites, as a substitute for toxic Pb2+. Moreover, bandgaps, band alignment, and hydrogen adsorption calculations show that the designed cluster‐based hybrid perovskites have potential as intermediate band materials for photovoltaics, and as photocatalysts for the hydrogen evolution reaction.

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“…P- 1 for comparison ( Figure S9, Figure S10). The stereochemical purity of (S,R mp )-4 was ultimately confirmed by analysis of its derivative, (R mp )-5 ( Figure S32), due to better HPLC peak separation, although it should be noted that direct HPLC analysis of (S,R mp )-4 ( Figure S11) is consistent with this value.…”

Section: S4mentioning

confidence: 99%

A Mechanically Planar Chiral Rotaxane Ligand for Enantioselective Catalysis

Heard¹,

Goldup²

2019

Preprint

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<p> <b>Rotaxanes are interlocked molecules in which a molecular ring is trapped on a dumbbell-shaped axle due to its inability to escape over the bulky end groups, resulting in a so-called mechanical bond. Interlocked molecules have mainly been studied as components of molecular machines, but the crowded, flexible environment created by threading one molecule through another, reminiscent of the active site of an enzyme, has also been explored in catalysis and sensing. However, so far the applications of one of the most intriguing properties of interlocked molecules, their ability to display stereogenic units that do not rely on the stereochemistry of their covalent subunits, termed "mechanical chirality", have yet to be properly explored and prototypical demonstration of the applications of mechanically chiral rotaxanes remain scarce. Here we describe a mechanically planar chiral rotaxane-based Au complex that mediates a cyclopropanation reaction with stereoselectivities that are comparable with conventional covalent catalyst reported for this reaction.</b></p>

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The Crystallization of Extended Niobium-Cluster Framework Compounds: A Novel Approach Using Ionic Liquids

Cited by 15 publications

References 52 publications

Nanoarchitectonics of Glass Coatings for Near-Infrared Shielding: From Solid-State Cluster-Based Niobium Chlorides to the Shaping of Nanocomposite Films

Nanoarchitectonics of Glass Coatings for Near-Infrared Shielding: From Solid-State Cluster-Based Niobium Chlorides to the Shaping of Nanocomposite Films

An Ab Initio Study of Clusters as Building Blocks for Crystals: From Prussian Blue Analogs to Hybrid Perovskites

A Mechanically Planar Chiral Rotaxane Ligand for Enantioselective Catalysis

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