New multicomponent reactions involving an isocyanide, terminal or internal alkynes, and endohedral metallofullerene (EMF) Lu 3 N@C 80 yield metallofulleroids which are characterized by mass-spectrometry, HPLC, and multiple 1D and 2D NMR techniques. Single crystal studies revealed one ketenimine metallofulleroid has ordered Lu 3 N cluster which is unusual for EMF monoadducts. Computational analysis, based on crystallographic data, confirm that the endohedral cluster motion is controlled by the position of the exohedral organic appendants. Our findings provide a new functionalization reaction for EMFs, and a potential facile approach to freeze the endohedral cluster motion at relatively high temperatures.

Molecular aggregation and crystallization during film coating play a crucial role in the realization of high‐performing organic photovoltaics. Strong intermolecular interactions and high solid‐state crystallinity are beneficial for charge transport. However, fast crystallization during thin‐film drying often limits the formation of the finely phase‐separated morphology required for efficient charge generation. Herein, the authors show that twisted acceptor‐donor‐acceptor (A‐D‐A) type compounds, containing an indacenodithiophene (IDT) electron‐rich core and two naphthalenediimide (NDI) electron‐poor units, leads to formation of mostly amorphous phases in the as‐cast film, which can be readily converted into more crystalline domains by means of thermal annealing. This design strategy solves the aforementioned conundrum, leading to an optimal morphology in terms of reduced donor/acceptor domain‐separation sizes (ca. 13 nm) and increased packing order. Solar cells based on these acceptors with a PBDB‐T polymer donor show a power conversion efficiency over 10% and stable morphology, which results from the combined properties of desirable excited‐state dynamics, high charge mobility, and optimal aggregation/crystallization characteristics. These results demonstrate that the twisted A‐D‐A motif featuring thermally‐induced crystallization behavior is indeed a promising alternative design approach toward more morphologically robust materials for efficient organic photovoltaics.

Nanocages with porphyrin walls are common, but studies of such structures hosting redox-active metals are rare. Pt2+-linked M6L3 nanoprisms with cobalt-porphyrin walls were prepared and their redox properties were evaluated...

CoII mediates electronic coupling between two N-Me-pyridinium-terpyridine ligands that are related to redox-active N,N'-dialkyl-4,4′-bipyridinium dications (viologens). Borderline Class II/III electronic delocalization imparts the cobaltoviologen complex with distinct electronic properties (e.g....

The host−guest chemistry of metal−organic nanocages is typically driven by thermodynamically favorable interactions with their guests such that uptake and release of guests can be controlled by switching this affinity on or off. Herein, we achieve this effect by reducing porphyrin-walled cationic nanoprisms 1a 12+ and 1b 12+ to zwitterionic states that rapidly uptake organometallic cations Cp* 2 Co + and Cp 2 Co + , respectively. Cp* 2 Co + binds strongly (K a = 1.3 × 10 3 M −1 ) in the neutral state 1a 0 of host 1a 12+ , which has its three porphyrin walls doubly reduced and its six (bipy)Pt 2+ linkers singly reduced (bipy = 2,2′bipyridine). The less-reduced states of the host 1a 3+ and 1a 9+ also bind Cp* 2 Co + , though with lower affinities. The smaller Cp 2 Co + cation binds strongly (K a = 1.7 × 10 3 M −1 ) in the 3e − reduced state 1b 9+ of the (tmeda)Pt 2+ -linked host 1b 12+ (tmeda = N,N,N′,N′-tetramethylethylenediamine). Upon reoxidation of the hosts with Ag + , the guests become trapped to provide unprecedented metastable cation-in-cation complexes Cp* 2 Co + @1a 12+ and Cp 2 Co + @1b 12+ that persist for >1 month. Thus, dramatic kinetic effects reveal a way to confine the guests in thermodynamically unfavorable environments. Experimental and DFT studies indicate that PF 6 − anions kinetically stabilize Cp* 2 Co + @1a 12+ through electrostatic interactions and by influencing conformational changes of the host that open and close its apertures. However, when Cp* 2 Co + @1a 12+ was prepared using ferrocenium (Fc + ) instead of Ag + to reoxidize the host, dissociation was accelerated >200× even though neither Fc + nor Fc have any observable affinity for 1a 12+ . This finding shows that metastable host−guest complexes can respond to subtler stimuli than those required to induce guest release from thermodynamically favorable complexes.