An overview of selected current approaches to the characterization of aqueous inorganic clusters

Jackson, Milton N.; Kamunde-Devonish, Maisha K.; Hammann, Blake A.; Wills, Lindsay A.; Fullmer, Lauren B.; Hayes, Sophia E.; Cheong, Paul Ha‐Yeon; Casey, William H.; Nyman, May; Johnson, Darren W.

doi:10.1039/c5dt01268f

Cited by 44 publications

(68 citation statements)

References 129 publications

(206 reference statements)

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“…Despite its utility for species characterization, X-ray scattering has been applied infrequently to identify clusters in solution. [17][18][19][20] It uniquely complements the molecular-scale structural information derived from NMR. Figure S3 shows scattering data for the 1 m Al reaction solution and asimulated curve for Al 8 .T he plateau in the experimental curve for q < 0.7 indicates that the solution contains nearly monodisperse, spherical species.Inthe Guinier region (q = 0.06-0.5 À1 ), the drop in the solution scattering intensity relative to the Data are normalized to the strongest peak in each spectrum over the selected range.…”

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confidence: 99%

Synthesis of an Aluminum Hydroxide Octamer through a Simple Dissolution Method

et al. 2017

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Multimeric oxo-hydroxo Al clusters function as models for common mineral structures and reactions. Cluster research, however, is often slowed by a lack of methods to prepare clusters in pure form and in large amounts. Herein, we report a facile synthesis of the little known cluster Al (OH) (H O) (SO ) (Al ) through a simple dissolution method. We confirm its structure by single-crystal X-ray diffraction and show by Al NMR spectroscopy, electrospray-ionization mass spectrometry, and small- and wide-angle X-ray scattering that it also exists in solution. We speculate that Al may form in natural water systems through the dissolution of aluminum-containing minerals in acidic sulfate solutions, such as those that could result from acid rain or mine drainage. Additionally, the dissolution method produces a discrete Al cluster on a scale suitable for studies and applications in materials science.

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Section: àmentioning

confidence: 99%

Synthesis of an Aluminum Hydroxide Octamer through a Simple Dissolution Method

et al. 2017

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“…Despite its utility for species characterization, X‐ray scattering has been applied infrequently to identify clusters in solution . It uniquely complements the molecular‐scale structural information derived from NMR.…”

Section: Figurementioning

confidence: 99%

Synthesis of an Aluminum Hydroxide Octamer through a Simple Dissolution Method

et al. 2017

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Multimeric oxo-hydroxo Al clusters function as models for common mineral structures and reactions.C luster research, however,i so ften slowed by al acko fm ethods to prepare clusters in pure form and in large amounts.Herein, we report af acile synthesis of the little knownc luster Al 8 (OH) 14 -(H 2 O) 18 (SO 4 ) 5 (Al 8 )through asimple dissolution method. We confirm its structure by single-crystal X-rayd iffraction and show by 27 Al NMR spectroscopy, electrospray-ionization mass spectrometry,and small-and wide-angle X-ray scattering that it also exists in solution. We speculate that Al 8 may form in natural water systems through the dissolution of aluminumcontaining minerals in acidic sulfate solutions,s uch as those that could result from acid rain or mine drainage.Additionally, the dissolution method produces adiscrete Al cluster on ascale suitable for studies and applications in materials science.

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“…This dissolution, coupled with stability of a similar peroxo‐phosphato‐niobium cluster observed in both basic and acidic solutions has led us to propose the concept of amphoteric clusters , wherein simple ligand sets stabilize a single cluster or similar clusters at the extreme ends of the pH scale. This concept broadens the approach to cluster synthesis and study, as most common cluster types exist across limited pH ranges . For example, Group 13 polycations are currently known to exist in the narrow range pH 3–4; V, Mo, and W polyoxometalates (POMs), pH≈1–7; and Nb and Ta POMs, pH>10 …”

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confidence: 99%

Amphoteric Aqueous Hafnium Cluster Chemistry

et al. 2016

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Selective dissolution of hafnium-peroxo-sulfate films in aqueous tetramethylammonium hydroxidee nables extreme UV lithographic patterning of sub-10 nm HfO 2 structures.H afnium speciation under these basic conditions (pH > 10), however,i su nknown, as studies of hafnium aqueous chemistry have been limited to acid. Here,w er eport synthesis,crystal growth, and structural characterization of the first polynuclear hydroxo hafnium cluster isolated from base, [TMA] 6 [Hf 6 (m-O 2 ) 6 (m-OH) 6 (OH) 12 ]·38 H 2 O. The solution behavior of the cluster,i ncluding supramolecular assembly via hydrogen bonding is detailed via small-angle X-ray scattering (SAXS) and electrospray ionization mass spectrometry (ESI-MS). The study opens anew chapter in the aqueous chemistry of hafnium, exemplifying the concept of amphoteric clusters and informing ac ritical process in single-digit-nm lithography.Water-soluble molecular oxo-hydroxo metal clusters are recognized building blocks for deposition of functional thinfilm coatings,offering low energy and "green" processing. [1][2][3] Additionally,s elected hafnium-peroxo-sulfate clusters provide unprecedented dimensional control in nanolithography. [4,5] In this lithography,u nexposed oxo-hydroxo Hf regions dissolve in base,m eaning soluble hafnium species exist at high pH.Up to now,h owever,t he aqueous chemistry of hafnium has been documented only for strongly acidic conditions.I n mildly acidic conditions (pH ! 3), gels and precipitates result from rapid hydrolysis and condensation. [6,7] At low pH, oxohydroxo hafnium clusters are commonly stabilized and isolated with capping sulfate ligands,s ometimes linking clusters into 1, 2o r3 -dimensional networks.[ [12,13] Our interest in oxo-hydroxo hafnium speciation in base arises from the development step in lithographic patterning with the water-processed hafnium material known as HafSO x , formulated Hf 4 (OH) 6.4 (O 2 ) 2 (SO 4 ) 2.8 . [4,5,14] Nanolithography allows bulk semiconductors and metals to be shaped into computing devices with sub-10 nm features.[15] New inorganic resists,such as HafSO x ,offer ultra-high-resolution patterns. [6] There are two major steps in the patterning process with HafSOx:1)exposure,which causes dissociation of the peroxo ligand and induces condensation;and 2) development, where unexposed material is selectively dissolved in concentrated aqueous tetramethylammonium hydroxide (TMAH). The nature of the species produced in these basic solutions is unknown. This dissolution, coupled with stability of asimilar peroxo-phosphato-niobium cluster observed in both basic and acidic solutions [16] has led us to propose the concept of amphoteric clusters,w herein simple ligand sets stabilize as ingle cluster or similar clusters at the extreme ends of the pH scale.T his concept broadens the approach to cluster synthesis and study,asmost common cluster types exist across limited pH ranges.[17] Forexample,Group 13 polycations are currently known to exist in the narrow range pH 3-4; [18,19] V, Mo,and Wpolyoxom...

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An overview of selected current approaches to the characterization of aqueous inorganic clusters

Cited by 44 publications

References 129 publications

Synthesis of an Aluminum Hydroxide Octamer through a Simple Dissolution Method

Synthesis of an Aluminum Hydroxide Octamer through a Simple Dissolution Method

Synthesis of an Aluminum Hydroxide Octamer through a Simple Dissolution Method

Amphoteric Aqueous Hafnium Cluster Chemistry

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