Mali H. Rosnes

Assembly of modular asymmetric organic-inorganic polyoxometalate hybrids into anisotropic nanostructures

Three organic-inorganic hybrid Mn-Anderson polyoxometalates (POMs), with both symmetrical and asymmetrical appended groups, have been synthesized, identified using electrospray mass spectrometry, and isolated using an approach that allows the three AA, BB, and AB compounds to be structurally characterized. Investigation of the self-assembly of the hybrids on hydrophilic surfaces reveals the formation of nanofibres with characteristics that reflect the nature of the substitution of the POM yielding a route to the programmed assembly of anisotropic hybrid nanostructures.

Real-Time Observation of the Self-Assembly of Hybrid Polyoxometalates Using Mass Spectrometry**

Electrospray ionization mass spectrometry (ESI-MS) allows monitoring of the real-time, “in-solution” formation of an organic–inorganic polyoxometalate hybrid system (see picture). This has provided insight into the rearrangement involved in the formation of the manganese-Anderson cluster coordinated with tris(hydroxymethyl)aminomethane ligands, through the rearrangement of the [α-Mo8O26]4− cluster in the presence of Mn(CH3CO2)3.

3D-printed devices for continuous-flow organic chemistry

Summary We present a study in which the versatility of 3D-printing is combined with the processing advantages of flow chemistry for the synthesis of organic compounds. Robust and inexpensive 3D-printed reactionware devices are easily connected using standard fittings resulting in complex, custom-made flow systems, including multiple reactors in a series with in-line, real-time analysis using an ATR-IR flow cell. As a proof of concept, we utilized two types of organic reactions, imine syntheses and imine reductions, to show how different reactor configurations and substrates give different products.

Controllable Self-Assembly of Organic-Inorganic Amphiphiles Containing Dawson Polyoxometalate Clusters

An organic-inorganic molecular hybrid containing the Dawson polyoxometalate, ((C(4)H(9))(4)N)(5)H[P(2)V(3)W(15)O(59)(OCH(2))(3)CNHCOC(15)H(31)], was synthesized and its surfactant-like amphiphilic properties, represented by the formation of bilayer vesicles, were studied in polar solvents. The vesicle size decreases with both decreasing hybrid concentration and with increasing polarity of the solvent, independently. The self-assembly behavior of this hybrid can be controlled by introducing different counterions into the acetonitrile solutions. The addition of ZnCl(2) and NaI can cause a gradual decrease and increase of vesicular sizes, respectively. Tetraalkylammonium bromide is found to disassemble the vesicle assemblies. Moreover, the original counterions of the hybrid can be replaced with protons, resulting in pH-dependent formation of vesicles in aqueous solutions. The hybrid surfactant can further form micro-needle structures in aqueous solutions upon addition of Ca(2+) ions.

Observing the Hierarchical Self‐Assembly and Architectural Bistability of Hybrid Molecular Metal Oxides Using Ion‐Mobility Mass Spectrometry

This structural flexibility is tantalizing in terms of thepotential for real design but, given the plethora of species insolution,understandingandhencecontrollingself-assemblyisextremely demanding. In this respect we have recently beenemploying electrospray ionization mass spectrometry (ESI-MS) in the characterization of the primary, secondary, andtertiary structures of POM clusters.

Modular Inorganic Polyoxometalate Frameworks Showing Emergent Properties: Redox Alloys

Alloy, alloy: A pure cobalt-based Keggin network linked by W-O-Co interactions is “alloyed” with a pure manganese-based Keggin network, linked by W-O-Mn interactions. These isostructural alloys are solid solutions of the Co and Mn nets. The alloys are prepared by the stoichiometric mixing of the components of each discrete network, leading to a series of single-crystalline mixed transition-metal frameworks with novel redox properties.

Continuous parallel ESI-MS analysis of reactions carried out in a bespoke 3D printed device.

Summary Herein, we present an approach for the rapid, straightforward and economical preparation of a tailored reactor device using three-dimensional (3D) printing, which can be directly linked to a high-resolution electrospray ionisation mass spectrometer (ESI-MS) for real-time, in-line observations. To highlight the potential of the setup, supramolecular coordination chemistry was carried out in the device, with the product of the reactions being recorded continuously and in parallel by ESI-MS. Utilising in-house-programmed computer control, the reactant flow rates and order were carefully controlled and varied, with the changes in the pump inlets being mirrored by the recorded ESI-MS spectra.

Smart High-κ Nanodielectrics Using Solid Supported Polyoxometalate-Rich Nanostructures

Utilizing Langmuir-Blodgett deposition and scanning probe microscopy, we have investigated the extent to which cations alter the self-assembly processes of hybrid polyoxometalates (POMs) on surfaces. The well-defined 2D hexagonal nanostructures obtained were extensively characterized and their properties were studied, and this has revealed fascinating dielectric behavior and reversible capacitive properties. The nanostructures are extremely stable under ambient conditions, and yet exhibit fascinating self-patterning upon heating. These findings present POMs as effective smart nanodielectrics and open up a new field for future POM applications.

Intriguing differences in hydrogen adsorption in CPO-27 materials induced by metal substitution

An extraordinarily interesting series of metal–organic framework compounds are the isostructural microporous coordination polymers [M2(dhtp)] (CPO-27–M, M–MOF-74 or M2(dobdc)) in which a high concentration of coordinatively unsaturated metal sites results in high initial heats of adsorption for a variety of adsorbents. We present here a comparative study of hydrogen gas adsorption experiments on CPO-27–Cu and –Mn, which show significant differences in their hydrogen uptake behaviours which can be attributed to the difference in interaction between hydrogen and the respective metal cation incorporated in the framework structure. Inelastic neutron scattering and neutron diffraction experiments were carried out to gain additional insight into the adsorption processes leading to the difference in hydrogen uptake behaviour by the two compounds. On the basis of the experimental results the hydrogen uptake properties of CPO-27–Cu and –Mn are compared, and finally related to the properties of the other members of the CPO-27 series. It is found that CPO-27–Cu demonstrates the lowest isosteric heat of adsorption for H2 of all the CPO-27–M materials reported to date, where M = Ni, Co, Mg, Zn, Mn, and Fe, whereas CPO-27–Mn demonstrates the second lowest. While all the previously reported CPO-27 materials show two steps in the adsorption isotherm and two distinct values corresponding to the first and second adsorption sites in the heats of adsorption, these are not observed for CPO-27–Cu. Consequently, the open metal site and the second adsorption site are energetically equivalent, and there is no preference for the hydrogen gas at the open metal centre.

Exploring a series of isostructural dodecanuclear mixed Ni:Co clusters: toward the control of elemental composition using pH and stoichiometry.

The compositional parameter space in the formation of polynuclear clusters is probed in the synthesis of a series of dodecanuclear coordination clusters of Ni(II) and Co(II) with isostructural D(3h)-symmetric frameworks. At the core of their construction are a carbonate template and the directing ligands cis,trans-1,3,5-triaminocyclohexane and acetate at contrasting pH values. The pH and stoichiometric dependence has been mapped, and analysis by electrospray mass spectrometry reveals the cluster cores in solution. In two specific cases, site-specific occupations are eluded to by analysis of the magnetic properties, and we discuss the possibility of controlling the molecular composition of mixed metal polynuclear clusters.