Structural and Magnetic Study of O₂ Molecules Arranged along a Channel in a Flexible Single-Crystal Host Family

Abstract

We report the magnetic behaviors of O(2) molecules, which aligned in the channels of four types of single-crystal adsorbents, [M(2)(bza)(4)(pyz)](n) (bza = benzoate; pyz = pyrazine; M = Rh(II) (1a) and Cu(II) (1b)) and [M(2)(bza)(4)(2-mpyz)](n) (2-mpyz = 2-methylpyrazine; M = Rh(II) (2a) and Cu(II) (2b)). The X-ray single-crystal structures at various temperatures from 10 to 298 K were determined for O(2)-included crystals of 1a and 2a. All adsorbed O(2) molecules exhibited abnormal magnetic phases above 4 T in the temperature range around 55-105 K. The magnetic behaviors of adsorbed O(2) molecules between four inclusions were discussed. The existence of the metastable state, which was also suggested by hysteresis on the M-H curves, was revealed by analysis of the time course of the magnetization. Considering that the abnormal magnetic behavior occurred at relatively high temperatures and a low magnetic field, it was suggested that these behaviors were induced because of the changes of magnetic interaction of included O(2) aggregates involving transformation which is supported by the surrounding of the channels of the single-crystal hosts under the applied magnetic field.

Crystallographic studies of gas sorption in metal–organic frameworks

“…Although not formally the focus of this review it is pertinent to place the work on MOFs in a broader context and refer the reader to some examples of the growing number of crystallographic studies of gas and vapour sorption involving molecular crystals and coordination polymers. Such materials include flexible one-dimensional coordination polymers that adsorb a wide variety of gases (CO 2 , CH 4 , O 2 , H 2 , Ar, Kr, Xe) into small spaces between polymer strands (Takamizawa et al, 2003(Takamizawa et al, , 2004Takamizawa, Nakata & Akatsuka, 2006;Takamizawa, Kojima & Akatsuka, 2006;Takamizawa, Nakata, Akatsuka, Kachi-Terajima & Miyake, 2008Ueda et al, 2007;Kosaka, Yamagishi, Hori et al, 2013;Kosaka, Yamagishi, Yoshida et al, 2013;) or within cages (Coronado et al, 2013) and both metal complexes and one-dimensional coordination polymers that adsorb gases or vapours via metal coordination: SO 2 (Albrecht et al, 2000); HCl/HBr (Mínguez Espallargas et al, 2006Adams et al, 2007Adams et al, , 2010Vitó rica-Yrezá bal et al, 2011;Coronado et al, 2012); N 2 /O 2 /H 2 /CO/C 2 H 4 /NH 3 (Huang et al, 2010); alcohol (ROH) vapours (Vitó rica-Yrezá bal et al, 2013;Libri et al, 2008). Organic molecular crystals which adsorb gases have been subject to crystallographic characterization for CO 2 (Jacobs et al, 2012, 2014) and Xe (Taratula et al, 2010).…”

Hydrogen Bonds Dictate O2 Capture and Release within a Zinc Tripod

“…16 The N-C pyr distances range 1.3587(14)-1.3675(14) Å and are consistent with single-bonds where the N-H has not been deprotonated. 17 The O 2 motif (O1-O1’ = 1.4954(13) Å) is more reduced than dioxygen 18 or superoxide, 19 and comparable to main-group trans -1,2-peroxides including [O 2 (B(C 6 F 5 ) 3 ) 2 ] 2− (1.488 Å) 20 and L 2 B 2 O 2 21 (1.484 Å; L = subporphyrin). 22 Notably, the O-O distance is the same as isostructural [(L H ) 2 Cu 2 O 2 ] 2+ (1.477(5) Å), which suggests that the ligand scaffold itself may serve a key role in regulating the structure, rather than the metal.…”

Low-temperature Gas-adsorption Studies of Six Two-dimensional Microporous Porphyrin Coordination Lattices

“…Recently, microporous coordination polymers consisting of transition metal ions and organic linkers have been rapidly emerging as one unique type of porous materials due to their potential applications in adsorption, separation, catalytic properties and so on. [1][2][3] Carboxylate linkers, including dicarboxylate, tricarboxylate, and tetracarboxylate ligands, are among the most important and widely used briding ligands for constructing stable coordination polymers with permanent porosity. Particularly, when functional carboxylic acid such as catalytic activity site will be used to prepare coordination polymer, the formation of functional coordination polymer is expected.…”