Controlling the Ring Curvature, Solution Assembly, and Reactivity of Gigantic Molybdenum Blue Wheels

Xuan, Weimin; Surman, Andrew J.; Miras, Haralampos N.; Long, De Liang; Cronin, Leroy

doi:10.1021/ja5062483

Cited by 82 publications

(80 citation statements)

References 54 publications

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“…Deconvolution analysis was carried out in the region 400-800 nm by means of Gaussian peaks [17]. The spectra were normalized to 1 unit of absorbance for comparison 5 purposes. The fitting of the spectra and their deconvolution was carried out using two procedures in order to provide a statistically univocal deconvolution set.…”

Section: Diffuse Reflectance Spectroscopymentioning

confidence: 99%

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Insights into the Reaction Mechanism of Cyclohexane Oxidation Catalysed by Molybdenum Blue Nanorings

et al. 2015

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Molybdenum blue (MB), is a polyoxometalate with a nanoring structure comprising Mo 5+ -OMo 6+ bridges, which is active for the catalytic oxidation of cyclohexane to cyclohexanol and cyclohexanone. However, little is known about the mechanistic features responsible of this catalytic activity. In the present work, the Mo 5+ -O-Mo 6+ moieties embedded in the MB nanoring structure were characterized using diffuse reflectance-UV-Visible spectroscopy and solid state EPR spectroscopy. The amount of Mo 5+ centres was then varied by thermal treatment of the polyoxometalate in the absence of oxygen, and the resultant effect on the catalytic activity was investigated. It was observed that, an increased amount of Mo 5+ centres preserved the conversion of cyclohexane (ca. 6%) but led to a loss of selectivity to cyclohexanol giving cyclohexanone as the major product, and the simultaneous formation of adipic acid. To rationalise these results the catalysts were studied using EPR spin trapping to investigate the decomposition of cyclohexyl hydroperoxide (CHHP), a key intermediate in the oxidation process of cyclohexane. This analysis showed that CHHP has to be bound to the MB surface in order to explain its catalytic activity and product distribution.

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Section: Diffuse Reflectance Spectroscopymentioning

confidence: 99%

“…2 nm of internal diameter. This material gathered considerable attention in recent years as a model system for self-assembling inorganic structures [5,6]. In fact, regular nanorings or clusters comprising 150 or 36 Mo units can be obtained from Na 2 MoO 4 precursors [7].…”

Section: Introductionmentioning

confidence: 99%

Insights into the Reaction Mechanism of Cyclohexane Oxidation Catalysed by Molybdenum Blue Nanorings

et al. 2015

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“…We have been developing electrospray ionization ion mobility mass spectrometry (ESI‐IMS‐MS) as a tool for cluster discovery, characterization, and structural assignment 13, 14, 15. This technique is valuable as it gives information on size and shape—as collision cross‐section (CCS He )—as well as composition, m / z .…”

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confidence: 99%

Overcoming the Crystallization Bottleneck: A Family of Gigantic Inorganic {Pd_x}^L (x=84, 72) Palladium Macrocycles Discovered using Solution Techniques

et al. 2016

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The {Pd84}Ac wheel, initially discovered serendipitously, is the only reported giant palladium macrocycle—a unique structure that spontaneously assembles from small building blocks. Analogues of this structure are elusive. A new modular route to {Pd84}Ac is described, allowing incorporation of other ligands, and a new screening approach to cluster discovery. Structural assignments were made of new species from solution experiments, overcoming the need for crystallographic analysis. As a result, two new palladium macrocycles were discovered: a structural analogue of the existing {Pd84}Ac wheel with glycolate ligands, {Pd84}Gly, and the next in a magic number series for this cluster family—a new {Pd72}Prop wheel decorated with propionate ligands. These findings confirm predictions of a magic number rule for the family of {Pdx} macrocycles. Furthermore, structures with variable fractions of functional ligands were obtained. Together these discoveries establish palladium clusters as a new class of tunable nanostructures. In facilitating the discovery of species that would not have been discovered by orthodox crystallization approaches, this work also demonstrates the value of solution‐based screening and characterization in cluster chemistry, as a means to decouple cluster formation, discovery, and isolation.

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“…[15][16][17][18][19][20][21] Compound 1 is isostructural to the reported [22] Na 6 Thesingle-crystal X-ray structure analysis reveals four of the dodecameric ring-shaped clusters 1 in the unit cell, packed parallel to the crystallographic bc plane giving rise to 1D channels occupied by guest water molecules ( Figure S3 in the Supporting Information). Thef ramework of 1 consists of 12 sets of basic building blocks {Mo 8 }, {Mo 2 }and {Mo 1 }units, which are well-defined in Mo Blue clusters such as the archetypal {Mo 154 }, [22] {Mo 176 }, [23] and {Mo 368 }, [24] with 6{Mo 2 } units substituted by 6Ce III ions.O nt he whole,t he architecture of 1 is constructed from 12 {Mo 8 }u nits,6{Mo 2 }u nits, 12 {Mo 1 }u nits and 6{Ce(H 2 O) 5 }u nits ( Figure 1).…”

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confidence: 86%

Human versus Robots in the Discovery and Crystallization of Gigantic Polyoxometalates

et al. 2017

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The discovery of new gigantic molecules formed by self-assembly and crystal growth is challenging as it combines two contingent events;first is the formation of anew molecule, and second its crystallization. Herein, we construct aworkflow that can be followed manually or by ar obot to probe the envelope of both events and employ it for an ew polyoxometalate cluster,N a 6 [Mo 120 Ce 6 O 366 H 12 (H 2 O) 78 ]·200 H 2 O( 1) which has at rigonal-ring type architecture (yield 4.3 %b ased on Mo). Its synthesis and crystallization was probed using an active machine-learning algorithm developed by us to explore the crystallization space,t he algorithm results were compared with those obtained by human experimenters.T he algorithmbased search is able to cover ca. 9t imes more crystallization space than arandom search and ca. 6times more than humans and increases the crystallization prediction accuracy to 82.4 AE 0.7 %over 77.1 AE 0.9 %f rom human experimenters.

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Controlling the Ring Curvature, Solution Assembly, and Reactivity of Gigantic Molybdenum Blue Wheels

Cited by 82 publications

References 54 publications

Insights into the Reaction Mechanism of Cyclohexane Oxidation Catalysed by Molybdenum Blue Nanorings

Insights into the Reaction Mechanism of Cyclohexane Oxidation Catalysed by Molybdenum Blue Nanorings

Overcoming the Crystallization Bottleneck: A Family of Gigantic Inorganic {Pd_x}^L (x=84, 72) Palladium Macrocycles Discovered using Solution Techniques

Human versus Robots in the Discovery and Crystallization of Gigantic Polyoxometalates

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Controlling the Ring Curvature, Solution Assembly, and Reactivity of Gigantic Molybdenum Blue Wheels

Cited by 82 publications

References 54 publications

Insights into the Reaction Mechanism of Cyclohexane Oxidation Catalysed by Molybdenum Blue Nanorings

Insights into the Reaction Mechanism of Cyclohexane Oxidation Catalysed by Molybdenum Blue Nanorings

Overcoming the Crystallization Bottleneck: A Family of Gigantic Inorganic {Pdx}L (x=84, 72) Palladium Macrocycles Discovered using Solution Techniques

Human versus Robots in the Discovery and Crystallization of Gigantic Polyoxometalates

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Overcoming the Crystallization Bottleneck: A Family of Gigantic Inorganic {Pd_x}^L (x=84, 72) Palladium Macrocycles Discovered using Solution Techniques