Proline-catalysed asymmetric direct aldol reaction of different aromatic aldehydes with acetone and several other ketones in the room temperature ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate achieved good yields of aldolisation products with reasonable enantioselectivities, even when just 1-5% of proline was used as the catalyst; immobilisation of the catalyst in an ionic liquid phase offers simple product isolation and reuse of the catalytical system in subsequent reactions.

While an increasing number of two-dimensional (2D) materials, including graphene and silicene, have already been realized, others have only been predicted. An interesting example is the two-dimensional form of silicon carbide (2D-SiC). Here, we present an observation of atomically thin and hexagonally bonded nanosized grains of SiC assembling temporarily in graphene oxide pores during an atomic resolution scanning transmission electron microscopy experiment. Even though these small grains do not fully represent the bulk crystal, simulations indicate that their electronic structure already approaches that of 2D-SiC. This is predicted to be flat, but some doubts have remained regarding the preference of Si for sp 3 hybridization. Exploring a number of corrugated morphologies, we find completely flat 2D-SiC to have the lowest energy. We further compute its phonon dispersion, with a Raman-active transverse optical mode, and estimate the core level binding energies. Finally, we study the chemical reactivity of 2D-SiC, suggesting it is like silicene unstable against molecular absorption or interlayer linking. Nonetheless, it can form stable van der Waals-bonded bilayers with either graphene or hexagonal boron nitride, promising to further enrich the family of two-dimensional materials once bulk synthesis is achieved.

such structures exist under ambient conditions and in total, only a few dozen 2D crystals have been successfully synthesized or exfoliated. While the unusual properties of graphene make it an interesting object of investigation itself, [1] it can also serve as a substrate to stabilize other, less obvious 2D materials. These include materials that do not by themselves form 2D phases, such as the covalent SiO 2 , [2] pseudo-ionic PbI 2 , [3] and metallic CuAu. [4] In the same spirit, layers of graphene have also been used to encapsulate materials. Metal atoms (in some cases forming nitrides [5,6] ) have been intercalated between a monocrystalline SiC surface and graphene to produce 2D metamaterials. [7][8][9] In other studies the encapsulation strategy has been applied in in situ transmission electron microscopy (TEM) observations of dynamics in liquids [10,11] and for protection of electron-beam-sensitive materials. [12,13] In addition, the inert and impermeable graphene envelope can also stabilize 2D layers of weakly bound molecules and atoms, and islands of C 60 fullerenes [14] and noble gases [15] have been Heterostructures composed of 2D materials are already opening many new possibilities in such fields of technology as electronics and magnonics, but far more could be achieved if the number and diversity of 2D materials were increased. So far, only a few dozen 2D crystals have been extracted from materials that exhibit a layered phase in ambient conditions, omitting entirely the large number of layered materials that may exist at other temperatures and pressures. This work demonstrates how such structures can be stabilized in 2D van der Waals (vdw) stacks under room temperature via growing them directly in graphene encapsulation by using graphene oxide as the template material. Specifically, an ambient stable 2D structure of copper and iodine, a material that normally only occurs in layered form at elevated temperatures between 645 and 675 K, is produced. The results establish a simple route to the production of more exotic phases of materials that would otherwise be difficult or impossible to stabilize for experiments in ambient.The ORCID identification number(s) for the author(s) of this article can be found under

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