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I?S, microfocus source, sc-xrd component

IμS and IμS 3.0 with Copper Radiation

Absolute configuration from light atom structures

The IμS and IμS 3.0, both equipped with HELIOS optics deliver a 2D focused beam with an unprecedented flux. The excellent beam stability guarantees high data quality allowing absolute structure determination on very small samples with no atoms heavier than oxygen.

Application - Absolute configuration of Vitamin C

I?S with Copper Radiation
IμS with Copper Radiation

Intensity data was collected on a small crystal of Vitamin C (40 μm x 100 μm x 100 μm) using an D8 QUEST with Cu radiation. Data is 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

It is possible to determine the absolute structure of chiral compounds by accurately measuring the small differences (Bijvoet anomalies) of Friedel pairs. Data has to be collected very carefully using highly performing instrumentation to allow the detection of these small differences in measured intensity data.