Chem

Magnetic Properties In their Full Paper on page 16828 ff., M. Pumera et al. discuss the hydrogenation of graphene using a Birch reduction method. The choice of alkali metals and alcohols/water as quenching agents has been studied and a systematic survey of electron (Li, Na, K, Cs) and proton sources (tBuOH, iPrOH, MeOH, H₂O) has been performed to identify the optimal conditions.

A giant 3d/4f/POM tetrahedron was prepared through a one-pot self-assembly process which combines 4f and 3d/4f coordination cluster chemistry with polyoxometalate (POM) chemistry. In their Communication on page 15574 ff., M. Ibrahim, A. K. Powell et al. describe how trilacunary [GeW₉O₃₄]¹⁰⁻ POMs are used as superligands to construct the nanoscale hybrid anion [{(GeW₉O₃₄)₂Dy^III₃(µ-OH)₃(H₂O)}₆{Co^II₂Dy^III₃(µ₃-OH)₆(OH₂)₆}₄]⁵⁶⁻, which contains 30 Dy^III, 8 Co^II, and 108 W^VI metal centers, and exhibits single-molecule magnet behavior. It contains the largest number of 4f ions of any POM system reported to date.

The ionothermal synthesis, structure, and magnetic susceptibility of a novel inorganic–organic hybrid material, imidazolium vanadium(III,IV) oxyfluoride [C₃H₅N₂][V₉O₆F₂₄(H₂O)₂] (ImVOF) are presented. The structure consists of inorganic vanadium oxyfluoride slabs with kagome layers of V⁴⁺ S= ions separated by a mixed valence layer. These inorganic slabs are intercalated with imidazolium cations. Quinuclidinium (Q) and pyrazinium (Pyz) cations can also be incorporated into the hybrid structure type to give QVOF and PyzVOF analogues, respectively. The highly frustrated topology of the inorganic slabs, along with the quantum nature of the magnetism associated with V⁴⁺, means that these materials are excellent candidates to host exotic magnetic ground states, such as the highly sought quantum spin liquid. Magnetic susceptibility measurements of all samples suggest an absence of conventional long-range magnetic order down to 2 K despite considerable antiferromagnetic exchange.

All in a spin: Antiferromagnetic crystalline solids with a kagome network of

ions are desired as realizations of two-dimensional quantum spin liquids. Until recently, the few examples of these materials were all based on Cu²⁺ ions. Now, the ionothermal synthesis, structure, and magnetic properties of a family of inorganic–organic hybrid solids that contain antiferromagnetic kagome layers of

V⁴⁺ ions is presented.

By deliberately using a metastable polyanion [(NbO₂)₆P₂W₁₂O₅₆]¹²⁻ (1), which was formed in situ, we have discovered the unprecedented hexameric cluster {Mn₁₅(Nb₆P₂W₁₂O₆₂)₆} (2), in which the six polyanions [Nb₆P₂W₁₂O₆₁]¹⁰⁻ are alternately connected by four intriguing trinuclear {Mn^III₃} moieties and four {Mn^II} linkers. This discovery is the first in which the phosphoniobotungstate has been made accessible by using transition-metal ions; furthermore, polyanion 2 represents the largest niobotungstate cluster reported to date. Analysis by means of electrospray ionization mass spectrometry (ESI-MS) provides insight into the self-assembly process, and the peaks observed relate to the different charge states of the parent cluster, thus confirming the stability of 2. In addition, magnetic-susceptibility measurements reveal that each {Mn^III₃} subunit is a separate single-molecule magnet (SMM). This discovery results from the exploration of the reverse effect of metastable polyanion 1 possessing high reactivity, thereby turning a disadvantage into an advantage. This finding could define a new synthetic strategy for the design and synthesis of magnetic polyoxometalate (POM) clusters.

Turning a disadvantage into an advantage: A facile strategy for the use of {(NbO₂)₆P₂W₁₂} formed in situ with paramagnetic manganese ions has led to the discovery of the unprecedented hexameric cluster {Mn₁₅(Nb₆P₂W₁₂O₆₂)₆} (see figure), which represents the first phosphoniobotungstate-based transition-metal derivative and largest niobotungstate cluster reported to date. In addition, the title compound behaves as a single-molecule magnet (SMM).