Schnelle Strukturaufklärung mikrokristalliner molekularer Verbindungen durch Elektronenbeugung

Abstract

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.

Crystal structure of vyacheslavite, U(PO4)(OH), solved from natural nanocrystal: a precession electron diffraction tomography (PEDT) study and DFT calculations

“…The possibility to see a residual potential related to hydrogen among heavy atoms like uranium is not as obvious as in previous works on materials containing lighter atoms. 11,14 However, this maximum corresponds to an ideal O-H distance and the hydrogen position is also supported by the DFT computations. Because of the presence of uranium, a further renement including hydrogen is not signicant and does not provide any improvement of further information.…”

Crystal Engineering: An Outlook for the Future

“…These principles are common for all types of crystals—organic, inorganic, and metal–organic. Opportunities and new advances continue to be reported, and a notable one is the complete crystal structure determination from powder quality microcrystals using electron diffraction and cryo transmission electron microscopy (ED‐TEM) …”

“…Like much of chemistry,the subject is oceanic in scope even as it is based on as mall number of guiding principles.T hese principles are common for all types of crystals-organic,i norganic,a nd metal-organic.O pportunities and new advances continue to be reported, and anotable one is the complete crystal structure determination from powder quality microcrystals using electron diffraction and cryo transmission electron microscopy (ED-TEM). [59,60] As as ubject with av ery promising future,t he following wish list for Crystal Engineering is inspired by Lippards article from 2000 in which he made such alist for chemistry. [61] It is interesting to note that 9out of 22 items in Lippardslist have to do with interactions between molecules and how they may be used to make extended domains of matter,generally with apre-desired property.Our wish list of ten items sets out what we feel are fundamental goals of the subject over the next decade.W el eave it to the reader to link the ways in which the attainment of these fundamental goals would help achieve the practical applications to which we allude in this Viewpoint.…”

MicroED structure of the human adenosine receptor determined from a single nanocrystal in LCP

“…Microcrystal electron diffraction (MicroED) is ideally suited to study protein nanocrystals of soluble proteins (17)(18)(19), membrane proteins (20)(21)(22) and small molecules (19,(23)(24)(25). However, recent investigations attempting to extract crystals from the viscous lipid-matrix have demonstrated that traditional sample preparation methods are ill-equipped to isolate well-diffracting crystals for MicroED experiments (26,27).…”