Chemists of all fields currently publish about 50 000 crystal structures per year, the vast majority of which are X‐ray structures. We determined two molecular structures by employing electron rather than X‐ray diffraction. For this purpose, an EIGER hybrid pixel detector was fitted to a transmission electron microscope, yielding an electron diffractometer. The structure of a new methylene blue derivative was determined at 0.9 Å resolution from a crystal smaller than 1×2 μm 2 . Several thousand active pharmaceutical ingredients (APIs) are only available as submicrocrystalline powders. To illustrate the potential of electron crystallography for the pharmaceutical industry, we also determined the structure of an API from its pill. We demonstrate that electron crystallography complements X‐ray crystallography and is the technique of choice for all unsolved cases in which submicrometer‐sized crystals were the limiting factor.

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A strategy to implement four members of the classic coal‐tar dye family, Michler's ketone, methylene blue, rhodamine B, and crystal violet, into [Pd2L4] self‐assemblies is introduced. Chromophores were incorporated into bis‐monodentate ligands using piperazine linkers that allow to retain the auxochromic dialkyl amine functionalities required for intense colors deep in the visible spectrum. Upon palladium coordination, ligands with pyridine donors form lantern‐shaped dinuclear cages while quinoline donors lead to strongly twisted [Pd2L4] helicates in solution. In one case, single crystal X‐ray diffraction revealed rearrangement to a [Pd3L6] ring structure in the solid state. For nine examined derivatives, showing colors from yellow to deep violet, CD spectroscopy discloses different degrees of chiral induction by an enantiomerically pure guest. Ion mobility mass spectrometry allows to distinguish two binding modes. Self‐assemblies based on this new ligand class promise application in chiroptical recognition, photo‐redox catalysis and optical materials.

A series of metal-mediated cages, having multiple cavities, was synthesized from Pd cations and tris- or tetrakis-monodentate bridging ligands and characterized by NMR spectroscopy, mass spectrometry, and X-ray methods. The peanut-shaped [Pd L ] cage deriving from the tris-monodentate ligand L could be quantitatively converted into its interpenetrated [5Cl@Pd L ] dimer featuring a linear {[Pd-Cl-] Pd} stack as an unprecedented structural motif upon addition of chloride anions. Small-angle neutron scattering (SANS) experiments showed that the cigar-shaped assembly with a length of 3.7 nm aggregates into mono-layered discs of 14 nm diameter via solvophobic interactions between the hexyl sidechains. The hepta-cationic [5Cl@Pd L ] cage was found to interact with polyanionic oligonucleotide double-strands under dissolution of the aggregates in water, rendering the compound class interesting for applications based on non-covalent DNA binding.

Derzeit publizieren Chemiker aller Fachrichtungen ca. 50 000 Kristallstrukturen pro Jahr,von denen es sich bei der überwältigenden Mehrheit um Rçntgenstrukturen handelt. Wir setzen Elektronen-statt Rçntgenbeugung ein, um die Struktur zweier molekularer Verbindungen zu bestimmen. Zu diesem Zweckw urde ein EIGER-Hybridpixeldetektor an ein Transmissionselektronenmikroskop angebaut und so ein Elektronendiffraktometer konstruiert. Die Struktur eines neuen Methylenblauderivates wurde aus einem Kristall kleiner als 1 2 mm 2 mit einer Auflçsung von 0.9 bestimmt. Mehrere tausend Wirkstoffe sind nur als submikrokristallines Pulver verfügbar.Umdas Potenzial fürdie pharmazeutische Industrie zu verdeutlichen,h aben wir die Struktur eines Wirkstoffs direkt aus einer Tablette bestimmt. Wird emonstrieren, dass Elektronenkristallographie die Rçntgenkristallographie ergänzt und die Methode der Wahl ist füra lle ungelçsten Strukturen von submikrometergroßen Kristallen. Die Grçße der Kristalle ist uns hier wichtig als Kriterium fürd ie Elektronenbeugung.