Influence of morphology and defects in crystals of porous coordination polymers on the sorption characteristics

Abstract

Porous coordination polymers [Fe 2 MO(Piv) 6 (L) x ] n (L is tris(4 pyridyl)pyridine, M = Ni (I) and Co (II); L is tris(4 pyridyl)triazine, M = Ni (III) and Co (IV); x varies from 0.7 to 1.17) are obtained. The structure of polymer I is determined by X ray diffraction analysis. The choice of the solvent (chloroform or dimethylformamide (DMF)) for the preparation of polycrystalline samples affects the morphology of the crystals. It is found for the studied samples that an increase in the average crystal size (from 1 to 20 μm) and the enhancement of the crystallinity of the samples increase the sorption capacity with respect to hydrogen from 0.7 to 0.9% (78 K, 1 atm).

$C_3$ symmetry breaking metal-insulator transitions in a flat band in the half-filled Hubbard model on the decorated honeycomb lattice

“…Many coordination polymers [15] have elaborate lattices with large geometric frustration, which often results in flat bands similar to the kagome lattice [16][17][18][19][20][21][22][23][24][25][26][27]. Coordination polymers are also often strongly correlated, displaying phenomena such as Mott insulators, Kondo physics [26,27], and unconventional superconductivity [28][29][30].…”

Multiple insulating phases due to the interplay of strong correlations and lattice geometry in a single-orbital Hubbard model

“…Decorated lattices are found in a wide range of materials, including inorganic compounds [1][2][3], organometallics [4], organic molecular crystals [5], and are especially prolific in metal-organic frameworks (MOFs) [6][7][8][9][10][11][12][13][14][15]. They consist of one or more cluster types, e.g., a molecule, linked to form a net [15,16].…”

“…1(a), vertex configuration 3.12 2 [16]), which interpolates between the honeycomb and kagome lattices. This lattice is realized in materials such as the trinuclear organometallic compounds, e.g., Mo 3 S 7 (dmit) 3 [4], in organic molecular crystals [5], in iron (III) acetates [1], in cold fermionic atoms [27], and in MOFs [12][13][14]. There are a number of theoretical studies that predict exotic phases of matter on this lattice, such as the quantum spin Hall insulator [20], quantum anomalous Hall insulator [21][22][23], topological metals [23], valence bond solids (VBS) [28][29][30][31], and quantum spin liquids [32][33][34] with non-Abelian anyons [32].…”

“…Electronic structure calculations have identified organometallic compounds that may be topological insulators [77][78][79][80]. MOFs and molecular crystals already realize the kagome-like [5,13] and honeycomb-like [4,14] regimes of the decorated honeycomb lattice. Band filling can be varied by chemical substitution [14,73,81].…”

“…MOFs and molecular crystals already realize the kagome-like [5,13] and honeycomb-like [4,14] regimes of the decorated honeycomb lattice. Band filling can be varied by chemical substitution [14,73,81]. For example, replacing Zn 2+ by Ga + in the kagome material ZnCu 3 (OH) 6 Cl 2 changes the band filling from 1 to 4/3 [73].…”