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Abstract Bis‐porphyrin nanocages (M₂BiCage, M = FeCl, Co, Zn) and their host‐guest complexes with C₆₀and C₇₀were used to examine how molecular porosity and interactions with carbon nanomaterials affect the CO₂reduction activity of metalloporphyrin electrocatalysts. The cages were found to adsorb on carbon black to provide electrocatalytic inks with excellent accessibilities of the metal sites (≈50%) even at high metal loadings (2500 nmol cm⁻²), enabling good activity for reducing CO₂to CO. A complex of C₇₀bound inside(FeCl)₂BiCageachieves high current densities for CO formation at low overpotentials (|j_CO| >7 mA cm⁻²,η= 320 mV; >13.5 mA cm⁻²,η= 520 mV) with ≥95% Faradaic efficiency (FE_CO), andCo₂BiCageachieves high turnover frequencies (≈1300 h⁻¹,η= 520 mV) with 90% FE_CO. In general, blocking the pore with C₆₀or C₇₀improves the catalytic performance of(FeCl)₂BiCageand has only small effects onCo₂BiCage, indicating that the good catalytic properties of the cages cannot be attributed to their internal pores. Neither enhanced electron transfer rates nor metal‐fullerene interactions appear to underlie the ability of C₆₀/C₇₀to improve the performance of(FeCl)₂BiCage, in contrast to effects often proposed for other carbon nanosupports. 

Abstract Affinities of six anions (mesylate, acetate, trifluoroacetate,p‐toluenecarboxylate,p‐toluenesulfonate, and perfluorooctanoate) for three related Pt²⁺‐linked porphyrin nanocages were measured to probe the influence of different noncovalent recognition motifs (e. g., hydrogen bonding, electrostatics, π bonding) on anion binding. Two new hosts of M₆L₃¹²⁺(1b) and M₄L₂⁸⁺(2) composition (M=(en)Pt²⁺, L=(3‐py)₄porphyrin) were prepared in a one‐pot synthesis and allowed comparison of hosts that differ in structure while maintaining similar N−H hydrogen‐bond donor ability. Comparisons of isostructural hosts that differ in hydrogen‐bonding ability were made between1band a related M₆L₃¹²⁺nanoprism (1a, M=(tmeda)Pt²⁺) that lacks N−H groups. Considerable variation in association constants (K₁=1.6×10³ M⁻¹to 1.3×10⁸ M⁻¹) and binding mode (exovs.endo) were found for different host–guest combinations. Strongest binding was seen betweenp‐toluenecarboxylate and1b, but surprisingly, association of this guest with1awas only slightly weaker despite the absence of NH⋅⋅⋅O interactions. The high affinity betweenp‐toluenecarboxylate and1acould be turned off by protonation, and this behavior was used to toggle between the binding of this guest and the environmental pollutant perfluorooctanoate, which otherwise has a lower affinity for the host. 

Abstract Endohedral metallofullerenes are chemically more inert compared to empty fullerenes, primarily due to their intramolecular electron transfer. In this work, we report an inverse electron demand Diels–Alder (IEDDA) reaction on M₃N@C₈₀(M=Lu, Sc), where they show significantly higher reactivity than empty fullerenes. The molecular structures of the [4+2] cycloadducts were unambiguously characterized. Moreover, the cycloadducts can fully revert to pristine M₃N@C₈₀via retro‐cycloaddition upon thermal treatment. With the unusual reactivity and reversibility, the IEDDA reaction enables an effective separation approach for metallofullerenes from their soot extracts, opening path to efficient and economical scale‐up synthesis of metallofullerenes in laboratory and industrial settings. 

Abstract The production of olefins via on‐purpose dehydrogenation of alkanes allows for a more efficient, selective and lower cost alternative to processes such as steam cracking. Silica‐supported pincer‐iridium complexes of the form [(≡SiO−^R4POCOP)Ir(CO)] (^R4POCOP=κ³‐C₆H₃‐2,6‐(OPR₂)₂) are effective for acceptorless alkane dehydrogenation, and have been shown stable up to 300 °C. However, while solution‐phase analogues of such species have demonstrated high regioselectivity for terminal olefin production under transfer dehydrogenation conditions at or below 240 °C, in open systems at 300 °C, regioselectivity under acceptorless dehydrogenation conditions is consistently low. In this work, complexes [(≡SiO−^tBu4POCOP)Ir(CO)] (1) and [(≡SiO−^iPr4PCP)Ir(CO)] (2) were synthesized via immobilization of molecular precursors. These complexes were used for gas‐phase butane transfer dehydrogenation using increasingly sterically demanding olefins, resulting in observed selectivities of up to 77 %. The results indicate that the active site is conserved upon immobilization.