Influence of the Primary and Secondary Coordination Spheres on Nitric Oxide Adsorption and Reactivity in Cobalt(II)–Triazolate Frameworks

Nitric oxide (NO) is an important signaling molecule in biological systems, and as such, the ability of porous materials to reversibly adsorb NO is of interest for potential medical applications....

Correction: Influence of the primary and secondary coordination spheres on nitric oxide adsorption and reactivity in cobalt(ii)–triazolate frameworks

Correction for ‘Influence of the primary and secondary coordination spheres on nitric oxide adsorption and reactivity in cobalt(ii)–triazolate frameworks’ by Julia Oktawiec et al., Chem. Sci., 2021, DOI: 10.1039/d1sc03994f.

Tuning Nitric Oxide Adsorption in Cobalt–Triazolate Frameworks

<p>Nitric oxide (NO) is an important signaling molecule in biological systems, and as such the ability of certain porous materials to reversibly adsorb NO is of interest for medical applications. Metal–organic frameworks have been explored for their ability to reversibly bind NO at coordinatively-unsaturated metal sites, however the influence of metal coordination environment on NO adsorption has yet to be studied in detail. Here, we examine NO adsorption in the frameworks Co₂Cl₂(bbta) and Co₂(OH)₂(bbta) (H₂bbta = 1<i>H</i>,5<i>H</i>-benzo(1,2-<i>d</i>:4,5-<i>d</i>′)bistriazole) via gas adsorption, infrared spectroscopy, powder X-ray diffaction, and magnetometry measurements. While NO adsorbs reversibly in Co₂Cl₂(bbta) without electron-transfer, adsorption of low pressures of NO in Co₂(OH)₂(bbta) is accompanied by charge transfer from the cobalt(II) centers to form a cobalt(III)–NO⁻ adduct, as supported by diffraction and infrared spectroscopy data. At higher pressures of NO, characterization data support additional uptake of the gas and disproportionation of the bound NO to form a cobalt(III)–nitro (NO₂⁻) species and N₂O gas, a transformation that appears to be facilitated in part by stabilizing hydrogen bonding interactions between the bound NO₂⁻ and framework hydroxo groups. This reactivity represents a rare example of reductive NO-binding in a metal–organic framework and demonstrates that NO binding can be tuned by changing the coordination environment of the framework metal centers.</p>

Tuning Nitric Oxide Adsorption in Cobalt–Triazolate Frameworks

<p>Nitric oxide (NO) is an important signaling molecule in biological systems, and as such the ability of certain porous materials to reversibly adsorb NO is of interest for medical applications. Metal–organic frameworks have been explored for their ability to reversibly bind NO at coordinatively-unsaturated metal sites, however the influence of metal coordination environment on NO adsorption has yet to be studied in detail. Here, we examine NO adsorption in the frameworks Co₂Cl₂(bbta) and Co₂(OH)₂(bbta) (H₂bbta = 1<i>H</i>,5<i>H</i>-benzo(1,2-<i>d</i>:4,5-<i>d</i>′)bistriazole) via gas adsorption, infrared spectroscopy, powder X-ray diffaction, and magnetometry measurements. While NO adsorbs reversibly in Co₂Cl₂(bbta) without electron-transfer, adsorption of low pressures of NO in Co₂(OH)₂(bbta) is accompanied by charge transfer from the cobalt(II) centers to form a cobalt(III)–NO⁻ adduct, as supported by diffraction and infrared spectroscopy data. At higher pressures of NO, characterization data support additional uptake of the gas and disproportionation of the bound NO to form a cobalt(III)–nitro (NO₂⁻) species and N₂O gas, a transformation that appears to be facilitated in part by stabilizing hydrogen bonding interactions between the bound NO₂⁻ and framework hydroxo groups. This reactivity represents a rare example of reductive NO-binding in a metal–organic framework and demonstrates that NO binding can be tuned by changing the coordination environment of the framework metal centers.</p>

MOLECULAR ADSORPTION OF NO ON WmMon (m + n≤6) CLUSTERS

Geometric and electronic properties of nitric oxide adsorption on WmMon ([Formula: see text] 6) clusters have been systematically calculated by density functional theory (DFT) at the generalized gradient approximation (GGA) level for ground-state structures. NO molecule prefers top site with nitrogen-end bridging a tungsten atom for W[Formula: see text]Mo[Formula: see text] and W3Mo2 clusters. While NO tends to locate on the hollow site for WMo5, W2Mo4 and W3Mo3 clusters, and dissociation of NO molecule happens on W3Mo, N–O bond lengths expand in accordance with the variation of adsorption energy with the increasing number of tungsten atoms, originating from metal [Formula: see text] back-donation. Electron transfer occurs among 4d state of Mo, 5d state of W, 2p state of N and 2p state of O.

Homochiral iron(ii)-based metal–organic nanotubes: metamagnetism and selective nitric oxide adsorption in a confined channel

Homochiral nanotubular metal phosphonates (R)-or (S)-[Fe(pemp)(H2O2)2] [pemp2− = (R)- or (S)-(1-phenylethylamino) methylphonate] are reported which are the first examples of metal–organic nanotubes combining chirality, metamagnetism and highly selective nitric oxide absorption in the same molecular composite.

Enhancement of the spin polarization of an Fe3O4(100) surface by nitric oxide adsorption

The spin polarization of the Fe3O4(100) surface is greatly enhanced by NO adsorption through the filling of the spin-down 2π* states.