X-Ray Crystallography
(Person in Charge: Linda J.W. Shimon)
The X-ray Crystallography Laboratory of the Weizmann Institute is both a service and user facility. It is well equipped for the single crystal diffraction experiments needed for structural biology and chemistry research. We apply a variety of experimental methods to these investigations.
Since each crystal is unique, we tailor each experiment to the individual sample and offer expertise in the following areas:
1. Air sensitive crystals
2. Unusually small crystals
3. Low-temperature data collection
4. Disorder or twinning
5. Absolute structure determinations, including all-light atom structures
6. Database searches
A structure determination of molecular crystals will typically involve the following:
1. Crystal Sample inspection under the polarizing microscope
2. Determination of unit cell parameters, crystal system and space group
3. Structure solution and refinement
4. Creation of tables in CIF and other formats
5. Publication-ready molecular and packing plots
The measurements of organic and organometallic materials are performed using a Nonius KappaCCD diffractometer mounted on a FR590 generator Mo radiation. Measurements may also be performed on a Nonius Mach3 Kappa diffractometer mounted on a FR590 generator with Cu radiation. Inorganic materials are measured on a Rigaku AFC5R 4 circle diffractometer mounted on a Rigaku RU300 rotating anode. Measurements may be performed at either LN or ambient temperatures Low temperature has many benefits for X-ray structure determination, including better quality data in less time than room-temperature work and the ability to handle highly reactive compounds with minimal fuss. We typically collect data at 120K, but on occasion, destructive phase transitions force data collection at higher temperatures
For the Structural Biologists, the X-ray laboratory is a user facility. Macromolecular crystallographic measurements are made on two R-Axis IV++ systems. The image plate detectors are mounted on RU-H3R Rigaku rotating anode generators equipped with Osmic confocal focusing mirrors. One of these systems is outfitted with a 2-theta stage allowing high resolution data collection. Both systems are equipped with Oxford cryostream cooling systems for LN, low-temperature measurements. Also available in the laboratory are light-microscopes for sample inspection and mounting as well as a digital camera for crystal photography.
Training is available for users, so that they can perform their own experiments.
Weizmann Institute of Science, Faculty of Chemistry
Comments & Suggestions to: tali.scherf@weizmann.ac.il
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