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1. Gas‐Induced Electrical and Magnetic Modulation of Two‐Dimensional Conductive Metal−Organic Framework

   https://doi.org/10.1002/ange.202404290  

   Meng, Zheng; Stolz, Robert M.; De Moraes, Lygia Silva; Jones, Christopher G.; Eagleton, Aileen M.; Nelson, Hosea M.; Mirica, Katherine A. (April 2024, Angewandte Chemie)

   Controlled modulation of electronic and magnetic properties in stimuli‐responsive materials provides valuable insights for the design of magnetoelectric or multiferroic devices. This paper demonstrates the modulation of electrical and magnetic properties of a semiconductive, paramagnetic metal−organic framework Cu3(C6O6)2 with small gaseous molecules, NH3, H2S, and NO. This study merges chemiresistive and magnetic tests to reveal that the MOF undergoes simultaneous changes in electrical conductance and magnetization that are uniquely modulated by each gas. The features of response, including direction, magnitude, and kinetics, are modulated by the physicochemical properties of the gaseous molecules. This study advances the design of multifunctional materials capable of undergoing simultaneous changes in electrical and magnetic properties in response to chemical stimuli. 

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2. Advancing Pore‐Space‐Partitioned Metal–Organic Frameworks with Isoreticular Cluster Concept

   https://doi.org/10.1002/anie.202403698  

   Xiao, Yuchen; Chen, Yichong; Wang, Wei; Bu, Xianhui; Feng, Pingyun (May 2024, Angewandte Chemie International Edition)

   Abstract Trigonal planar M₃(O/OH) trimers are among the most important clusters in inorganic chemistry and are the foundational features of multiple high‐impact MOF platforms. Here we introduce a concept called isoreticular cluster series and demonstrate that M₃(O/OH), as the first member of a supertrimer series, can be combined with a higher hierarchical member (double‐deck trimer here) to advance isoreticular chemistry. We report here an isoreticular series of pore‐space‐partitioned MOFs called M₃M₆pacsmade from co‐assembly between M₃single‐deck trimer and M_3x2double‐deck trimer. Important factors were identified on this multi‐modular MOF platform to guide optimization of each module, which enables the phase selection of M₃M₆pacsby overcoming the formation of previously‐always‐observed same‐cluster phases. The newpacsmaterials exhibit high surface area and high uptake capacity for CO₂and small hydrocarbons, as well as selective adsorption properties relevant to separation of industrially important mixtures such as C₂H₂/CO₂and C₂H₂/C₂H₄. Furthermore, new M₃M₆pacsmaterials show electrocatalytic properties with high activity. 

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3. Bonding Interactions Can Drive Topological Phase Transitions in a Zintl Antiferromagnetic Insulator

   https://doi.org/10.1002/adfm.202415610  

   Berry, Tanya; Moya, Jaime M; Smiadak, David; Lee, Scott B; Aharon, Sigalit; Zevalkink, Alexandra; McQueen, Tyrel M; Schoop, Leslie M (February 2025, Advanced Functional Materials)

   Abstract While ∼30% of materials are reported to be topological, topological insulators are rare. Magnetic topological insulators (MTI) are even harder to find. Identifying crystallographic features that can host the coexistence of a topological insulating phase with magnetic order is vital for finding intrinsic MTI materials. Thus far, most materials that are investigated for the determination of an MTI are some combination of known topological insulators with a magnetic ion such as MnBi₂Te₄. Motivated by the recent success of EuIn₂As₂, the role of chemical pressure on topologically trivial insulator is investigated, Eu₅In₂Sb₆via Ga substitution. Eu₅Ga₂Sb₆is predicted to be topological but is synthetically difficult to stabilize. The intermediate compositions between Eu₅In₂Sb₆and Eu₅Ga₂Sb₆are observed through theoretical works to explore a topological phase transition and band inversion mechanism. The band inversion mechanism is attributed to changes in Eu–Sb hybridization as Ga is substituted for In due to chemical pressure. Eu₅In_4/3Ga_2/3Sb₆is also synthesized, the highest Ga concentration in Eu₅In_2‐xGa_xSb₆, and report the thermodynamic, magnetic, transport, and Hall properties. Overall, the work paints a picture of a possible MTI via band engineering and explains why Eu‐based Zintl compounds are suitable for the co‐existence of magnetism and topology. 

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4. Antiferromagnetic Ordering in A One‐Dimensional Organic Copper Chloride Hybrid Insulator

   https://doi.org/10.1002/anie.202412759  

   Islam, Md Sazedul; Comstock, Andrew; Hua, Zhenqi; Thapa, Puja; He, Yufang; Ben‐Akacha, Azza; Liu, He; Manny, Tarannuma Ferdous; Viera, Jarek; Lin, Xinsong; et al (November 2024, Angewandte Chemie International Edition)

   Abstract Low dimensional (LD) organic metal halide hybrids (OMHHs) have recently emerged as new generation functional materials with exceptional structural and property tunability. Despite the remarkable advances in the development of LD OMHHs, optical properties have been the major functionality extensively investigated for most of LD OMHHs developed to date, while other properties, such as magnetic and electronic properties, remain significantly under‐explored. Here, we report for the first time the characterization of the magnetic and electronic properties of a 1D OMHH, organic‐copper (II) chloride hybrid (C₈H₂₂N₂)Cu₂Cl₆. Owing to the antiferromagnetic coupling between Cu atoms through chloride bridges in 1D [Cu₂Cl₆²⁻]_∞chains, (C₈H₂₂N₂)Cu₂Cl₆is found to exhibit antiferromagnetic ordering with a Néel temperature of 24 K. The two‐terminal (2T) electrical measurement on a (C₈H₂₂N₂)Cu₂Cl₆single crystal reveals its insulating nature. This work shows the potential of LD OMHHs as a highly tunable quantum material platform for spintronics. 

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5. The Transport Properties of Quasi–One-Dimensional Ba3Co2O6(CO3)0.7

   https://doi.org/10.3389/fphy.2021.785801  

   Chen, Minnan; Wu, Jiangtao; Huang, Qing; Jiao, Jinlong; Dun, Zhiling; Wang, Guohua; Chen, Zhiwei; Lin, Gaoting; Rathinam, Vasudevan; Li, Cangjin; et al (December 2021, Frontiers in Physics)

   We have performed combined elastic neutron diffuse, electrical transport, specific heat, and thermal conductivity measurements on the quasi–one-dimensional Ba 3 Co 2 O 6 (CO 3 ) 0.7 single crystal to characterize its transport properties. A modulated superstructure of polyatomic CO 3 2− is formed, which not only interferes the electronic properties of this compound, but also reduces the thermal conductivity along the c-axis. Furthermore, a large magnetic entropy is observed to be contributed to the heat conduction. Our investigations reveal the influence of both structural and magnetic effects on its transport properties and suggest a theoretical improvement on the thermoelectric materials by building up superlattice with conducting ionic group. 

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