Rearrangement of {α-P2W15} to {PW6} moieties during the assembly of transition-metal-linked polyoxometalate clusters

We report the formation of two polyoxotungstates of the general formula [M6(PW6O26)(α-P2W15O56)2(H2O)2]23− (M = CoII or MnII), which contain {PW6} fragments generated from the [P2W15O56]12− precursor, which demonstrates for the first time the transformation of a Dawson lacunae into a Keggin lacunary building block. Solution analysis of the clusters has been conducted via electrospray ionisation mass spectrometry

Transition metal decorated soft nanomaterials through modular self-assembly of an asymmetric hybrid polyoxometalate

An asymmetrically functionalised Wells–Dawson organic–inorganic hybrid polyoxometalate has been post-functionalised by Pt2+ coordination, and demonstrates self-assembly into surface-decorated micellar nanostructures. This multifunctional hybrid material is found to be a redox-active soft nanomaterial and demonstrates a new molecular design strategy with potential for applications in photo- or electro-catalysis

Investigating the transformations of polyoxoanions using mass spectrometry and molecular dynamics

The reactions of [γ-SiW10O36]8– represent one of the most important synthetic gateways into a vast array of polyoxotungstate chemistry. Herein, we set about exploring the transformation of the lacunary polyoxoanion [β2-SiW11O39]8– into [γ-SiW10O36]8– using high-resolution electrospray mass spectrometry, density functional theory, and molecular dynamics. We show that the reaction proceeds through an unexpected {SiW9} precursor capable of undertaking a direct β → γ isomerization via a rotational transformation. The remarkably low-energy transition state of this transformation could be identified through theoretical calculations. Moreover, we explore the significant role of the countercations for the first time in such studies. This combination of experimental and the theoretical studies can now be used to understand the complex chemical transformations of oxoanions, leading to the design of reactivity by structural control

Point source generation of chiral fields:measures of near- and far-field optical helicity

To consider the relationship between different measures of chirality in an optical field, the simplest case is considered: direct spontaneous emission of circularly polarized light by a point source. In the electromagnetic fields radiated from a suitably chiral source, such as a low-symmetry chiral molecule undergoing radiative decay, optical helicity is exhibited in the extent of a difference in left- and right-handed circular polarization components. There are several practical measures for quantifying the emergence of ensuing optical helicity, exhibiting different forms of dependence on the properties of the emitter and the positioning of a detector. By casting each measure in terms of an irreducible helicity density, connections and distinctions can be drawn between results expressible in either classical or quantum form

Urban PDS Partnership: Preparing Teachers for Social Justice

We believe that for urban schools to meet their goals and mission — in the way the DECA is modeling — takes a partnership among many stakeholders. One such partnership that supports DECA, and might buttress other schools and students — and simultaneously help to enact a social justice ideal — is a school-university connection. DECA was founded as a Professional Development School (PDS), with the school and university developing a reciprocal relationship with a shared focus on the preparation of new teachers, the enhancement of high school students\u27 achievement, school and university faculty members\u27 professional development, and collaborative inquiries aimed at improving instructional practices for all of the educators involved. In this chapter, we will describe our Midwestern university\u27s response to two social justice issues: the lack of support for urban students to be ready for college; and the issue of teacher quality in urban schools. DECA explicitly endeavors to respond to the dearth of educational opportunities for city youth. As well, as a PDS, DECA serves the university and our profession as a site for preparing the next generation of urban teachers. Our partnership relies on a PDS framework and a social justice approach to impact students\u27 access to learning and to develop quality educators through learning communities. Using the lenses of the Marianist Catholic tradition and the PDS mission, here we will frame our social justice stance. We will specifically describe the revamping of two critical courses in the teacher education program with the goal of enacting social justice through developing effective teachers for urban settings

Shining a light on the photo-sensitisation of organic-inorganic hybrid polyoxometalates

Finding new ways of using visible light (or, more specifically, solar irradiation) to drive commercially significant and/or challenging chemical processes is an ongoing research goal. Polyoxometalates (POMs) are discrete, metal-oxide clusters which are cheap, robust and easily synthesized but can also act as versatile molecular building blocks, allowing for astonishing variety in their structures and properties. In particular, the rich redox chemistry and inherent photo-activity of POMs makes them attractive for use in a variety of photochemical applications however POMs characteristically only absorb strongly in the UV region. In this perspective, we discuss the various strategies which have been employed in order to sensitize POMs to visible light, with a particular focus on hybrid inorganic-organic POM species. We will discuss the two clear photo-activation mechanisms which have been developed to date and provide an outlook on some of the possible future directions of the field

A metamorphic inorganic framework that can be switched between eight single-crystalline states

The design of highly flexible framework materials requires organic linkers, whereas inorganic materials are more robust but inflexible. Here, by using linkable inorganic rings made up of tungsten oxide (P8W48O184) building blocks, we synthesized an inorganic single crystal material that can undergo at least eight different crystal-to-crystal transformations, with gigantic crystal volume contraction and expansion changes ranging from −2,170 to +1,720 Å3 with no reduction in crystallinity. Not only does this material undergo the largest single crystal-to-single crystal volume transformation thus far reported (to the best of our knowledge), the system also shows conformational flexibility while maintaining robustness over several cycles in the reversible uptake and release of guest molecules switching the crystal between different metamorphic states. This material combines the robustness of inorganic materials with the flexibility of organic frameworks, thereby challenging the notion that flexible materials with robustness are mutually exclusive

Digital light processing 3D printing of polymerizable ionic liquids towards carbon capture applications

This study presents new 3D printable materials based on ad -hoc synthesized photocurable imidazolium ionic liquids (ILs) with bis(trifluoromethanesulfonyl)imide (NTf 2 ) - as counterion and two different alkyl chain 's structures at the cation, with enhanced CO 2 capture properties. The molecular structure of the synthesized ILs was confirmed through NMR technique and a polymerization study was carried out, by means of photorheological tests and FT-IR analyses, on formulations containing a crosslinking monomer (PEGDA). The study confirmed the good reactivity of the formulations that makes them suitable for digital light processing (DLP) 3D printing technique. Simple membranes were then tested through high pressure CO 2 uptake analysis to estimate their capture efficiency, comparing the results with the standard room temperature ionic liquid (RTIL) counterpart, and evidencing an increase of CO 2 absorption regardless the pressure applied. At last, complex gyroidlike structures incorporating the synthesized ILs were successfully 3D printed, showing the remarkable ability of these materials to be processed with 3D printing technology while maintaining the great CO 2 capture performances of ionic liquids. This preliminary work paves the way for the implementation of "ad -hoc " designs to create filters or devices to enhance the CO 2 capture