Language
Search
News
- Bruker Acquires Hecus MICROcaliX(R) Product Line to Expand Product Portfolio for Small Angle X-ray Scattering (SAXS)
- Lab Report SC-XRD 46 - Higher Dimensional Crystallography
- Bruker and Lawrence Berkeley National Laboratory Collaborate on Novel Technology for Structural Biology
- 2011 Nobel Prize for Chemistry awarded for quasicrystal discovery
- Bruker Launches D8 QUEST and D8 VENTURE Crystallography Systems with Novel High Intensity X-ray Sources for Structural Biology
Upcoming Events
- Pittcon 2012
Mar 11-15, Orlando, Florida, USA - SEMICON China 2012
Mar 20-22, Shanghai, China - ARAB LAB 2012
Mar 26-29, Dubai, UAE - DPG Spring Meeting
Mar 27-29, Berlin, Germany - 2012 NUANCE-Bruker International Symposium
Apr 05, Evanston, IL, USA - ANALYTICA 2012
Apr 17-20, Munich, Germany
IμS with Copper Radiation – Absolute configuration from light atom structures
The IμS with Quazar optics delivers a 2D focused beam with an unprecedented flux of more than 5 x 109 X-rays/(s mm2). The excellent beam stability guarantees high data quality allowing absolute structure determination on very small samples with no atoms heavier than oxygen.
- Vitamin C
Absolute configuration of Vitamin C
Intensity data were collected on a small crystal of Vitamin C (40 μm x 100 μm x 100 μm) using an APEX II QUAZAR with Cu radiation. Data are 10 fold redundant and complete to 0.83 Å. The structure refines with a reliability criteria R1 of 2.25% a Flack x parameter of 0.03(15) and an Hooft y parameter of 0.04(16).
The determination of absolute configuration
Currently, the established method to determine the absolute configuration of a chiral molecule calls for the determination of the Flack x parameter. Flack, H.D. (1983). Acta Cryst. A39, 876-881. A new statistical method based on Bayesian statistics was developed by Rob Hooft et al. J. Appl. Cryst. (2008). 41, 96-103 and determines the Hooft y parameter.
It is possible to determine the absolute structure of chiral compounds by accurately measuring the small differences (Bijvoet anomalies) of Friedel pairs. Data have to be collected very carefully using highly performing instrumentation to allow the detection of these small differences in measured intensity data.
