A fivefold UO22+ node is a path to dodecagonal quasicrystal approximants in coordination polymers

Abstract

Aperiodic formations continue to focus interest in areas ranging from advanced scientific theories to practical everyday applications. Starting from diverse and tightly bonded intermetallic compounds, this world showed an important breakthrough toward the so-called soft systems of meso/macroscale: liquid crystals, thin films, polymers, proteins, etc. This work opens a route for making bulk quasicrystals (QC) in an unprecedented but very common area, with molecular ligands. Since these systems are, to a large extent, transparent, they extend the possible areas of QC application to previously unreachable corners, e.g., photonics. We combined efficient bridging ligands with uranyl pentagonal bonding centers and, unexpectedly, brought the unique attributes of f-element coordination chemistry to an interdisciplinary area of aperiodic formations. Taking advantage of the planar coordination of uranyl ions, we were able to direct the structure expansion solely in two directions with a characteristic snub square tiling, a predicted but previously unobtainable dodecagonal approximant.

Chemical engineering of quasicrystal approximants in lanthanide-based coordination solids

“…1b, e, f ). Due to their similarities with the local structure of dodecagonal quasicrystals, crystalline phases with structure motifs of five-vertex semi-regular Archimedean tessellations (ATs) are referred to as quasicrystal approximants 9 , 12 , 18 – 20 . The appearance of approximants suggests the possibility of designing quasicrystallinity by chemical means.…”

“…Accordingly, the assembly of atomic Ce and the same ditopic ligand on a Ag(111) surface lead to the formation of a 3 2 .4.3.4 tiling 30 . Only recently, an ionic liquid-based approach led to the isolation of a bulk coordination solid containing layers of [(UO 2 )(1,2,4-triazolate) 2.5 ] (1/2)− , constituting the first example of an 3 2 .4.3.4 tiling realized through fivefold coordinated trans-{UO 2 } 2+ nodes 20 . Herein, however, the presence of a net charge of the 2D layer could impede the possibilities for further processing of this material for nanostructuring and the nonmagnetic uranyl nodes hinder the exploration of magnetic properties.…”

Pseudo-5-Fold-Symmetrical Ligand Drives Geometric Frustration in Porous Metal–Organic and Hydrogen-Bonded Frameworks

“…12,16 Several strategies exist for the introduction of C5 symmetry in organic building blocks, [17][18][19][20] as these are used for the synthesis of large cage coordination compounds, 19,[21][22][23][24] or as metal nodes for the synthesis of quasicrystal approximants. 25 As introducing C5-symmetry can be synthetically challenging, 20,26 instead we designed a pseudo-C5 symmetrical ligand based on a pyrrole core (see method section, Figure S2). The pseudo-C5 symmetric linker containing pendant carboxylic acid groups, 1,2,3,4,5-penta (4-(benzoic acid))pyrrole (pLH5; Figure 1) was reacted with copper(II) ions with the intention of creating the C4 -symmetric paddlewheel motif.…”

Aperiodic metal–organic frameworks

“…The structure, [Hmim] [(UO 2 ) 2 (1,2,4-triazolate) 5 ]$3mim (mim ¼ methylimidazole; Fig. 5b), 43 leverages the ability of the uranyl ion to coordinate to ve equatorial ligands. As quasicrystal approximants are typically found at similar compositions to their parent quasicrystals, it is possible that a quasicrystal phase lies in this system, warranting further studies.…”