Coding the Assembly of Polyoxotungstates with a Programmable Reaction System

Abstract

Chemical transformations are normally conducted in batch or flow mode, thereby allowing the chemistry to be temporally or spatially controlled, but these approaches are not normally combined dynamically. However, the investigation of the underlying chemistry masked by the self-assembly processes that often occur in one-pot reactions and exploitation of the potential of complex chemical systems requires control in both time and space. Additionally, maintaining the intermediate constituents of a self-assembled system “off equilibrium” and utilizing them dynamically at specific time intervals provide access to building blocks that cannot coexist under one-pot conditions and ultimately to the formation of new clusters. Herein, we implement the concept of a programmable networked reaction system, allowing us to connect discrete “one-pot” reactions that produce the building block{W11O38} ≡ {W11} under different conditions and control, in real time, the assembly of a series of polyoxometalate clusters {W12O42} ≡ {W12}, {W22O74} ≡ {W22} 1a, {W34O116} ≡ {W34} 2a, and {W36O120} ≡ {W36} 3a, using pH and ultraviolet–visible monitoring. The programmable networked reaction system reveals that is possible to assemble a range of different clusters using {W11}-based building blocks, demonstrating the relationship between the clusters within the family of iso-polyoxotungstates, with the final structural motif being entirely dependent on the building block libraries generated in each separate reaction space within the network. In total, this approach led to the isolation of five distinct inorganic clusters using a “fixed” set of reagents and using a fully automated sequence code, rather than five entirely different reaction protocols. As such, this approach allows us to discover, record, and implement complex one-pot reaction syntheses in a more general way, increasing the yield and reproducibility and potentially giving access to nonspecialists.

Rotating Magnetocaloric Effect in an Anisotropic Two-Dimensional CuII[WV(CN)8]3– Molecular Magnet with Topological Phase Transition: Experiment and Theory

“…The CVMPA method is based on a self-consistent determination of the Gibbs energy from which thermodynamic properties are subsequently derived. The Gibbs energy is given by the general formula = ⟨ ̂⟩ − G H ST (12) where ⟨H ̂⟩ is the thermodynamic mean value of the Hamiltonian (magnetic enthalpy) and S is entropy of the system. Upon averaging of the Hamiltonian given in eq 1, one arrives at the formula…”

“…Modern coordination chemistry provides a wide scope of functional metallo-organic molecular platforms revealing different coordination dimensionalities, from discrete molecules (0D) through chain (1D) and layered (2D) substructures to fully extended (3D) systems. − Apart from the fundamental role of local atomic/molecular features of interest (size, symmetry, electron transfer, chirality, electronic properties, etc. ), which are important for the desired properties, in many cases the target functionality emerges in accordance with their coordination dimensionality.…”

Unlocking Phase Diagrams for Molybdenum and Tungsten Nanoclusters and Prediction of their Formation Constants

“…However, it is becoming more and more apparent that a deeper understanding of metal-oxo speciation, and thus of the self-assembly process, is needed . Currently, different techniques are used to study POMs in solution: electronic and vibrational spectroscopy, nuclear magnetic resonance, mass-spectrometry experiments, small-angle X-ray scattering, and kinetic investigations . Despite that, the experimental determination of unstable metal-oxo equilibrium constants is proving to be difficult.…”

Cyanido-Bridged Clusters with Remote N-Oxide Groups for Branched Multimetallic Systems

“…During recent decades, unceasing interest has been devoted to polynuclear coordination assemblies, where the switching function can be implemented basing on properties that exploit binary or multiple states of matter, e.g., magnetization, spin-crossover, chirality, porosity, and structural nonrigidity. − Particular attention has centered on large discrete polynuclear systems inspired by the ideas of external manipulation on multistate single molecules, e.g., memory units in nanotransistors or magneto-cooling media. , The avalanche of studies toward nanoscale molecules, including the number of single molecule magnets (SMMs), , has resulted in appealing advanced molecular organization exemplified by the Mn 84 giant torus ( S GR = 6) and related nanotubes; high-spin ground-state Mn 19 ( S GR = 83 / 2 ), Mn 49 ( S GR = 61 / 2 ), or Mn 25 Na 4 ( S GR = 51 / 2 ) large clusters; Cr 7 Ni rings and assemblies of weakly coupled switchable (± 1 / 2 ) q-bits acting as logic gates; large Gd and Gd-(3d metal) clusters representing the materials designated as low-temperature magnetic refrigerants; , and polymetallic POM based architectures, − among many others. Along with the studies on low dimensional cyanide-bridged platforms for single molecule magnets − and single molecule photomagnets, , a notable number of 1–10 nm size range species were afforded.…”