Telltale diamagnetism at 50 K of a coordination polymer system

Fe(iii)-carboxythiolate layered metal–organic frameworks with interest as active materials for rechargeable alkali-ion batteries

“…The reactivity of H 4 DSBDC and related ligands with a large variety of cations has been already explored, notably by the team of Z. Xu. In line with the hard and so acid and base (HSAB) theory, 20 it was found that networks comprising M(I) (M = Ag) and M(II) (M = Fe, Co, Ni, Cu, Pb) cations rely on M-S (and M-O) bonds, [21][22][23] while those based on M(III) (M = Al, Eu) and M(IV) (M = Zr) cations are based exclusively on M-O bonds. 21,[24][25][26][27][28] Nevertheless, studies on molecular complexes derived from thiosalicylic acid reveal that the formation of M-S bonds with high-charge cations (e.g.…”

“…39 The isomer shi scale is referred to a-Fe at room temperature. 23 Na MAS NMR experiments were carried out at room temperature on a Bruker Avance-200 spectrometer (B 0 = 4.7 T, Larmor frequency n 0 ( 23 Na) = 52.94 MHz). MAS spectra were obtained by using a Bruker MAS probe with a cylindrical 2.5 mm o.d.…”

“…Spinning frequencies up to 25 kHz were utilized. 23 Na NMR spectra were acquired using an echo sequence to discard the signicant contribution from the probe signal, with a p/2 pulse of 1 ms. Recycle delays of 1 s were determined to ensure quantitative measurements.…”

Nanoscaling and Heterojunction for Photocatalytic Hydrogen Evolution by Bimetallic Metal‐Organic Frameworks

“…For example, it should forgo precious metals like Pd or Pt, and it should be recyclable (as a solid‐state, heterogeneous system) and offer stable lasting performances. [ 2 ] That is why we have been drawn to a recently reported layered coordination polymer system M 2 DMBD (M: variable transition metals; as exemplified by CoNiDMBD), [ 3 ] which features robust, tunable 2D metal‐thiolate sheets intercalated with more ionic metal‐carboxyl domains (containing µ 2 ‐aqua units). The fresh sample of CoNiDMBD is a semiconductor with paramagnetic to ferromagnetic transition at low temperature; but after exposure to air, it exhibits, at ≈60 K, strong diamagnetism (suggestive of superconductivity) and negative electrical resistance (potentially associated with some ferroelectric order).…”

“…By comparison, soluble metal salts of Ni(OAc) 2 •4H 2 O and FeSO 4 •4H 2 O (in set ratios) were used for preparing thicker, aggregated platelets of Fe 2− x Ni x DMBD‐PL (PL: platelet; reaction condition: 120 °C for 48 h in DMF/H 2 O, 1:1, v/v, with CH 3 COOH as the modulator). These larger, block‐like crystallites are isostructural to the reported Ni‐dfdmt (dfdmt: 2,5‐difluoro‐3,6‐dimercaptoterephthalate) [ 3 ] or Co‐dfdmt (ccdc 2213738), so we have here used this known model to refine the Ni 2 DMBD structure based on the PXRD data ( Figure A). The layered crystal structure is triclinic ($$P\bar{1}$$), and features two crystallographically distinct metal sites (Figure S1, Supporting Information): M1 belongs to the metal‐thiolate layer, with two O atoms (each from a separate carboxyl) also bonded to the M1 site; while M2 sits between the thiolate layers and is bonded to two carboxyl O atoms, and to four µ 2 ‐aqua units, resulting in a row of edge‐sharing M2‐oxo octahedra (so it is key to have water in the reaction to forge the interlayer metal‐aqua domain).…”