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A novel 2D layered iodoplumbate, [Ni(opd)2(acn)2]n[Pb4l10]n (1), yellow-green in color, has been synthesized, The anionic (Pb4l102-]n layer is comparable to the hexagonal Pbl2 sheet but in a lower symmetry. Although the intercalated cations contribute negligibly to the electron transition, they induce the reconstruction of the inorganic moiety, which leads to a band-gap blue shift with respect to that of Pbl2. [ABSTRACT FROM AUTHOR]

A novel Cl-decorated trinuclear-Cu cluster-based MOF ( NbU-7-Cl , NbU denotes Ningbo University) was synthesized by a stepwise synthesis strategy. Compared to one-step reactions, the strategy of combining cationic templates with single-crystal-to-single-crystal transformation provides more possibilities for the design and postsynthetic modification of multifunctional materials. Note that the chloride ions are attached to the copper ions of the planar trinuclear cluster nodes in a fully symmetric or partially asymmetric manner. The insertion of the chloride ion can alter the overall symmetry and adsorption energy in addition to occupying the appropriate asymmetric orbit and reducing the effective active sites of metal. The activated NbU-7-Cl displays improved C 2 H 2 uptake capacity and C 2 H 2 /C 2 H 4 and C 2 H 2 /CO 2 separation performance, which is proved by breakthrough experiments.

Fullerene cages are ideal hosts to encapsulate otherwise unstable metallic clusters to form endohedral metallofullerenes (EMFs). Herein, a novel Ti 2 C 2 cluster with two titanium atoms bridged by a C 2 -unit has been stabilized by three different fullerene cages to form Ti 2 C 2 @ D 3 h (5)-C 78 , Ti 2 C 2 @ C 3 v (8)-C 82 , and Ti 2 C 2 @ C s (6)-C 82 , representing the first examples of unsupported titanium carbide clusters. Crystallographic results show that the configuration of the Ti 2 C 2 cluster changes upon cage variation. In detail, the Ti 2 C 2 cluster adopts a butterfly shape in Ti 2 C 2 @ C 3 v (8)-C 82 and Ti 2 C 2 @ C s (6)-C 82 with Ti-C 2 -Ti dihedral angles of 156.35 and 147.52° and Ti-Ti distances of 3.633 and 3.860 Å, respectively. In sharp contrast, a stretched planar geometry of Ti 2 C 2 is observed in Ti 2 C 2 @ D 3 h (5)-C 78 , where a Ti-C 2 -Ti angle of 176.87° and a long Ti-Ti distance of 5.000 Å are presented. Consistently, theoretical calculations reveal that the cluster configuration is very sensitive to the cage shape which eventually determines the electronic structures of the hybrid EMF-molecules, thus adding new insights into modern coordination chemistry.

Endohedral clusterfullerenes (ECFs) are fullerene cages with various metallic clusters trapped inside. So far, the actinide-based ECFs are rather scarce with their possible structures and chemistry remaining largely unexplored. Herein, density functional theory calculations characterized that the recently synthesized U 2 O@C 76 could be U 2 O@ C s (17 490)-C 76 or U 2 O@ C 2 v (19 138)-C 76 , whose cages have two or one pentagon adjacencies (PAs) and thus both violate the isolated pentagon rule (IPR). It is noteworthy that they are the first actinide-based ECFs bearing non-IPR outer cages. They are also the first C s (17 490)- and C 2 v (19 138)-C 76 -based oxide ECFs. Moreover, U 2 O@ C 2 v (19 138)-C 76 is the first example of a hexavalent metal cluster within the C 2 v (19 138)-C 76 cage. Interestingly, although trapped by the two same-sized cages, the U 2 O unit exhibits a bent and a perfect linear configuration, respectively, indicative of the crucial role of cage shape in steering the internal cluster configuration. Their electronic structures can be formally described as (U 2 O) 6+ @C 76 6- with primary electrostatic attractions and secondary covalent interactions between cluster and cage. Significantly, bonding analyses reveal that the encaged U 2 O moiety may only features two three-center, two-electron (3c-2e) U-O-U bonds with completely absent common two-center bonds.

The reaction of 1,1,2,2-tetrakis(4-(pyridin-4-yl)phenyl)ethene (tppe) with [Fe(NCBH 3 ) 2 ] produced a two-dimensional coordination polymer [Fe(NCBH 3 ) 2 (tppe)] n ( 1 ), which was pillared in an ABAB manner through interlayer multiple [C-H δ+ ···H δ- -B] dihydrogen bonds (DHBs) to form a stable porous three-dimensional (3D) supramolecular structure that showed guest-molecule-dependent spin-crossover behaviors.

Stimulated by the recent successful synthesis and crystallographic characterization of the first diuranium carbide endohedral metallofullerene (EMF) U 2 C@ I h (7)-C 80 ( Zhang et al. Nat. Commun. ; 2018 ), density functional theory calculations were performed for a series of U 2 C@C 2 n (2 n = 60, 68, 72, 78, 80, 88, 96, and 104) analogues. The internal UCU bond angle increases from 96.9° in I h -C 60 to 180.0° in D 3 d -C 104 , exhibiting cage-size-dependent cluster configuration. However, further evidence suggests that the U 2 C shape may be also affected by the amount of charge transferred from the cluster to the outer cage with 6e and 4e favoring bent and linear, respectively. The change of the bond angle closely correlates with the charge and hybrid state of the internal atom. Significantly, besides the covalent two-center two-electron (2c-2e) U-C bonds, the U 2 C unit always features two 3c-2e bonds regardless of its size, shape, and charge state. Furthermore, for the cluster-cage interactions, besides the dominated electrostatic attractions, all these EMFs show an obvious covalent character with the substantial participation of U 5f valence orbitals.

The addition of a bulky N-heterocyclic carbene (NHC) to Sc 2 C 2 @C 3v (8)-C 82 affords two monoadducts (2a and 2b) quantitatively and regioselectively, representing the first examples of Lewis acid-base pairs of metal carbide cluster fullerenes. 2b is likely a kinetically favorable labile product that cannot be isolated from the solution. The crystallographic results of 2a unambiguously demonstrate that one polarized C-C single bond is formed between the normal carbene site C2N of the NHC and a specific [5,6,6]-carbon atom out of 17 types of nonequivalent cage carbon atoms of Sc 2 C 2 @C 3v (8)-C 82 . Theoretical calculations demonstrate that the high regioselectivity, the unexpected addition pattern, and the quantitative formation of monoadducts are synergistic results from the cage geometry and electron distribution on the cage.