Magnetic Correlation Engineering in Spin‐Sandwiched Layered Magnetic Frameworks

Abstract

The insertion of “sandwiched spins” between magnetic layers could efficiently affect the interlayer magnetic correlations, but doing so increases the complexity in the interlayer spin alignment because of competition between the inserted spin‐layer interaction JNNI and the interlayer through‐space interaction JNNNI if the magnitude of JNNI is of the same order as JNNNI with reciprocal signs of the respective interactions. Herein, systematic tuning of the magnetic phase variations by JNNI and JNNNI in two kinds of metal‐variable isostructural series of supramolecular pillared layer magnets [MCp*2][{Ru2II,II(2,3,5,6‐F4CO2)4}2(TCNQ)]⋅2 DCE (M=Co, Fe, Cr; 2,3,5,6‐F4PhCO2−=2,3,5,6‐tetrafluorobenzoate; TCNQ=7,7,8,8‐tetracyano‐p‐quinodimethane; DCE=1,2‐dichloroethane) and their DCE‐free series, in which [MCp*2]+ (Cp*=η5‐C5Me5) species with S=0, 1/2, and 3/2 for M=Co, Fe, Cr, respectively, are sandwiched between ferrimagnetic layers of [{Ru2}2(TCNQ)]−, is demonstrated. The results showed that the flexible magnetic natures of these magnets are changeable in dependence on JNNI and JNNNI, as well as on interlayer inserted spins M.

Inter-layer magnetic tuning by gas adsorption in π-stacked pillared-layer framework magnets

“…6e), or because both key exchanges of JNNNI and JNNI basically induced ferromagnetism (Fig. 6f), 3 could be considered an F with TC = 70 K. 54,72 As expected, 3N2 and 3O2 showed FCM curves similar to those of 3, and a noticeable qualitative change in TC was not observed. However, in 3CO2, TC became slightly higher (TC = 78 K, from RM, Fig.…”

“…The shape of the hysteresis loops was similar to that in 2, in which the anisotropic paramagnetic spin of [FeCp*2] + was closely associated with the sigmoidal shape of spin flipping. 54,71 In 2O2 and 1O2, the Ms values were larger than the others owing to the contributions from the paramagnetic spins of the adsorbed O2 molecules without involvement from the long-range magnetic ordering. The hysteresis loop in 2CO2 was slightly modified with MR = 0.90 NB and Hc = 1.76 T, proving that the state of the F phase in 2CO2 was different from those in 2N2 and 2O2.…”

“…S15b †). 54 Only 3O2 revealed an O2-paramagnetic character superposed in 3. In addition to pristine 3, the closest ferromagnetic interaction JNNI > 0 Please do not adjust margins Please do not adjust margins between the spin of [CrCp*2] + (S = 3/2) and the TCNQ moieties of the [Ru2]2-TCNQ ferrimagnetic layers governed long-range magnetic ordering even under the gases.…”

“…4e-4j. 54 The -stack distances (d; see Fig. 2c), defined as the distance between the centers of the 6-membered ring of TCNQ and the 5-membered ring of [CoCp*2], were found to be 3.76, 3.49, and 3.51 Å in 1CO2, 1O2, and 1N2, respectively.…”

“…2). 53,54 These compounds are composed of ferrimagnetic layers [{Ru2 II,II (2,3,5,6-F4PhCO2)4}2(TCNQ)]and sandwiched dodecamethylmetallocenium [ 2a), [55][56][57][58][59][60] which are denoted as -PLFs. The compounds have almost identical gas adsorption capabilities for common gases such as CO2 (4-6 mol mol -1 at 195 K), O2 (3-5 mol mol -1 at 120 K), and N2 (1-2 mol mol -1 at 120 K).…”