Aluminoborate‐Based Molecular Sieves with 18‐Octahedral‐Atom Tunnels

Abstract

A framework of AlO6 octahedra is present in the microporous aluminoborate HAl3B6O12(OH)4 (PKU‐1; see picture), which was synthesized from AlCl3 in a boric acid flux. The octahedra share two or three edges with neighboring octahedra to form a framework with 18‐ring tunnels along [001] and 10‐ring tunnels along {100}. The borate groups share vertices with the octahedra, compensating the negative charge of the octahedral framework and almost completely blocking the 10‐ring channels.

Designable Aluminum Molecular Rings: Ring Expansion and Ligand Functionalization

“…In summary,w eh ave employed the CDH strategy in the assembly of an ew family of aluminum molecular rings ranging from 8R to 16R. Based on structural information of these ring cluster compounds,t he monohydric alcohols used and synthetic conditions play crucial roles in the expansion of the rings.I ti sp ossible to tune the surface chemistry and properties through the judicious choice of functional groups of benzoate ligands.Considering the large aluminum windows already found in zeolites, [50,51] further ring expansion is predicted. In addition, these sets of rings with modifiable ligands can be used as building blocks to form large clusterbased hierarchical materials with tunable and specific properties.…”

Mullite-type Ga4B2O9: structure and order–disorder phenomenon

“…It is well known that boric acid may dehydrate stepwise and polymerizes to metaboric acid and then to boron oxide in an open vessel, while in a closed system it melts at $ 443 K and can, therefore, serve as a reaction medium at low temperature (Wells, 1975). By using a boric-acid flux method, we were able to obtain a series of new borates, including PKU-n (n = 1-8; here PKU is the abbreviation of Peking University) and rare-earth polyborates (Lu et al, 2001;Ju et al, 2003Ju et al, , 2004Yang et al, 2007;Gao et al, 2008;Li et al, 2002Li et al, , 2003. PKU-1 is an interesting aluminoborate [HAl 3 B 6 O 12 (OH) 4 ] with 18-ring tunnels constructed by AlO 6 octahedra (Ju et al, 2003).…”

Separation of 1,3‐Cyclohexanebis(methylamine) Isomers by Template Synthesis of Open‐Framework Bimetallic Phosphites

“…openings and SU-M with 30-ring mesopores [11], as well as sulfides ASU-31 with cavities 25.6 Å in diameter and ASU-32 with channels larger than 14.7 Å [12]. Another route introduces three-connected centers replacing the four-connected units, such as HOPO 3 2Ϫ , OϭPO 3 3Ϫ , SeO 3 2Ϫ , and BO 3 3Ϫ , which were successfully used to obtain large pores and low framework densities due to the reduced connectivity, for example, in borate PKU-1 [13], phosphates ICL-1 [14], MIL-46 [15], and MIL-31 [16] with 18-rings, cloverite [17], JDF-20 [18], FePO [19] and H 3 N(CH 2 ) 6 NH 3 · Zn 4 (PO 4 ) 2 (HPO 4 ) 2 · 3H 2 O [20] with 20rings and VSB-1 [21], VSB-5 [22], ND-1 [23] and NTHU-1 [24] [52] and Cr-NKU-24 [53] and 26ring channels in NTHU-5 [54]. Moreover, transition metal atoms bestow redox catalytic properties and structural versatility upon porous materials.…”