Dalton Transactions

doi: 10.1039/D0DT90097Dpmid: 32452504

doi: 10.1039/d0dt90097dpmid: 32452487

doi: 10.1039/D0DT90098Bpmid: 32452508

doi: 10.1039/d0dt90098bpmid: 32452488

doi: 10.1039/D0DT90099Kpmid: 32452489

doi: 10.1039/d0dt90099kpmid: 32452489

Puntoriero, Fausto; Ishitani, Osamu

doi: 10.1039/d0dt90081hpmid: 32412560

Chivers, Tristram; Laitinen, Risto S.

doi: 10.1039/d0dt00807apmid: 32342078

Early theoretical and experimental investigations of inorganic sulfur–nitrogen compounds were dominated by (a) assessments of the purported aromatic character of cyclic, binary S,N molecules and ions, (b) the unpredictable reactions of the fascinating cage compound S4N4, and (c) the unique structure and properties of the conducting polymer (SN)x. In the last few years, in addition to unexpected developments in the chemistry of well-known sulfur nitrides, the emphasis of these studies has changed to include nitrogen-rich species formed under high pressures, as well as the selenium analogues of well-known S,N compounds. Novel applications have been established or predicted for many binary S/Se,N molecules, including their use for fingerprint detection, in optoelectronic devices, as high energy-density compounds or as hydrogen-storage materials. The purpose of this perspective is to evaluate critically these new aspects of the chemistry of neutral, binary chalcogen–nitrogen molecules and to suggest experimental approaches to the synthesis of target compounds. Recently identified ternary S,N,P compounds will also be considered in light of their isoelectronic relationship with binary S,N cations.

Jiang, Yilin; Zhang, Xu; Fei, Honghan

doi: 10.1039/d0dt01022gpmid: 32301467

N-heterocyclic carbenes (NHCs) are a class of molecules with a lone pair of carbene electrons and thus, they have the ability to activate CO2 to form imidazolium carboxylates. The incorporation of activated, metal-free NHC moieties into metal–organic frameworks (MOFs) without the decomposition of metal–carboxylate coordination motifs is highly desired owing to the high CO2 affinity and versatile chemical functionalities in MOFs. Herein, we have summarized the recent in situ generation approaches to form metal-free NHC-functionalized MOFs, which are a unique class of CO2-conversion catalysts with high catalytic activity, selectivity and stability, superior to those of homogenous and other heterogeneous NHC analogues. The NHC-functionalized MOFs for catalytic CO2 reduction include reactions such as the hydroboration of CO2, hydrosilylation of CO2, N-methylation using CO2 and hydrogenation of CO2 to formic acid. Overall, the synthetic strategy of metal-free NHC-functionalized MOFs, the unique catalytic pathways of NHC-functionalized MOFs, and potentially new research directions of NHC-functionalized MOFs are discussed, which will guide researchers to attempt to design new NHC-MOFs and extend their catalytic applications in the chemical fixation of CO2.

Maldonado, Rodrigo R.; Zhang, Xuan; Hanna, Sylvia; Gong, Xinyi; Gianneschi, Nathan C.; Hupp, Joseph T.; Farha, Omar K.

doi: 10.1039/d0dt00546kpmid: 32211674

Isoreticular synthesis is a powerful tool to enhance specific attributes of a metal–organic framework (MOF). While the isoreticular expansion of MOF structure are prevalent in the literature, the compression of a topology holds great promise for separations due to the contracted pore apertures and/or cavities. Herein, we report the synthesis, characterization and Xe/Kr separation capability of a new Zr-based MOF, NU-1106, connected by the tetratopic linker 1,3,6,8-pyrene tetracarboxylate, which exhibits a compressed ftw topology compared to the extended ones reported previously. NU-1106 showed selective uptake of Xenon over Krypton, providing the potential for use for separations.