The host–guest system TCNQ@Cu3BTC2 is a striking example of how semiconductivity can be introduced by guest incorporation in an otherwise insulating parent material.

Electrically conductive metal–organic frameworks (MOFs) exhibit a large potential as working medium in next-generation electronic devices where electronic transport is paired with one or more other physicochemical properties. An important pathway in introducing electronic transport in MOFs is the postsynthetic incorporation of guest molecules in the porous host structures, where resulting host–guest interactions facilitate the creation of charge transport pathways. Here, we report the in-depth analysis of the host–guest interactions in the system (TCNE) x M2TTFTB, (TTFTB4– = tetrathiafulvalene tetrabenzoate, TCNE = tetracyanoethylene), rationalizing the electrical conductivity enhancement in the isostructural MOFs Zn2TTFTB and Cd2TTFTB via TCNE. Via vibrational spectroscopy, we show that the guest-infiltrated MOFs contain a mixture of neutral TCNE0 and radical–anionic TCNE–, TTFTB0, radical–cationic TTFTB+, and dicationic TTFTB2+, which together serve as an indicator for the MOF reactivity toward guest infiltration. For (TCNE) x Zn2TTFTB, an increase of the electrical conductivity of two magnitudes is observed compared to Zn2TTFTB, while the increase of (TCNE) x Cd2TTFTB compared to Cd2TTFTB is significantly smaller due to the lower reactivity of Cd2TTFTB toward TCNE. The results highlight the power of vibrational spectroscopy as a tool for accessing the chemical nature of host–guest interactions in MOFs, a crucial aspect on the road toward design principles of MOFs with high electrical conductivities.

The bimetallic, decanuclear Ni3Ga7‐cluster of the formula [Ni3(GaTMP)3(μ2‐GaTMP)3(μ3‐GaTMP)] (1, TMP=2,2,6,6‐tetramethylpiperidinyl) reacts reversibly with dihydrogen under the formation of a series of (poly‐)hydride clusters 2. Low‐temperature 2D NMR experiments at −80 °C show that 2 consist of a mixture of a di‐ (2Di), tetra‐ (2Tetra) and hexahydride species (2Hexa). The structures of 2Di and 2Tetra are assessed by a combination of 2D NMR spectroscopy and DFT calculations. The cooperation of both metals is essential for the high hydrogen uptake of the cluster. Polyhydrides 2 are catalytically active in the semihydrogenation of 4‐octyne to 4‐octene with good selectivity. The example is the first of its kind and conceptually relates properties of molecular, atom‐precise transition metal/main group metal clusters to the respective solid‐state phase in catalysis.

Der bimetallische, dekanukleare Ni3Ga7‐Cluster [Ni3(GaTMP)3(μ2‐GaTMP)3(μ3‐GaTMP)] (1, TMP=2,2,6,6‐ Tetramethylpiperidinyl) reagiert reversibel mit Wasserstoff unter Bildung einer Reihe von (Poly‐)Hydridclustern 2. Tieftemperatur‐2D NMR‐Experimente bei −80 °C zeigen, dass 2 aus einem Gemisch von Di‐ (2Di), Tetra‐ (2Tetra) und Hexahydrid‐Spezies (2Hexa) besteht. Die Strukturen von 2Di und 2Tetra werden durch eine Kombination aus 2D NMR‐Spektroskopie und DFT‐Berechnungen untersucht. Das Zusammenspiel beider Metalle ist für die hohe Wasserstoffinkorperierung des Clusters entscheidend. Die Polyhydride 2 sind bei der Semihydrierung von 4‐Octin zu 4‐Octen bei guter Selektivität katalytisch aktiv. Bei 2 handelt es sich um die erste Spezies ihrer Art, die die Eigenschaften von molekularen, atomgenauen Übergangsmetall‐/Hauptgruppenmetallclustern konzeptionell mit der entsprechenden Festkörperphase in der Katalyse verbindet.