R-factors based on F 2 are statistically about twice as largeĪs those based on F, and R- factors based on ALL data will beįractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2) top Σ( F 2) is used only for calculating R-factors(gt) etc.Īnd is not relevant to the choice of reflections for refinement. R-factors R are based on F, with F set to zero for WR and goodness of fit S are based on F 2, conventional Refinement of F 2 against ALL reflections. Treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. Used when they are defined by crystal symmetry. Into account individually in the estimation of e.s.d.'s in distances, anglesĪnd torsion angles correlations between e.s.d.'s in cell parameters are only Independent reflections 13191 (Rint 0.0697).
#BRUKER APEX II FULL#
planes)Īre estimated using the full covariance matrix. A crystal with dimensions 0.400 à 0.080 à 0.050 mm3 was selected, and intensities of 82581 reflections were measured using a Bruker Apex II CCD diffractometer, lMoKa 0.71073 Ã, 1.505° £ q £ 33.728°. The azo group is not involved in any specific intermolecular interactions in any of the co-crystals studied, which is an interesting feature in the context of enhanced photoisomerization behaviour and photoactive properties of the material systems.Įxperimental. It is demonstrated that the studied halogen-bond donor molecule is a reliable tecton for assembling halogen-bonded co-crystals with potential photoresponsive behaviour. The crystal structure of the non-iodinated homologue ( E)-bis(2,3,5,6-tetrafluorophenyl)diazene, C 12H 2F 8N 2, is also reported. In order to obtain further insight into the solid-state features of halogen-bonded photoactive molecules, three halogen-bonded co-crystals containing an azobenzene-based difunctional halogen-bond donor molecule, ( E)-bis(4-iodo-2,3,5,6-tetrafluorophenyl)diazene, C 12F 8I 2N 2, have been synthesized and structurally characterized by single-crystal X-ray diffraction.
#BRUKER APEX II GENERATOR#
The combination of the sensitive APEX II detector and strong source means that very small crystals can be examined and publishable structures obtained. A Kryoflex X-ray generator with a Cu sealed tube running routinely at 1.6 kW (40 kV, 40 mA) of power output provides the X-ray radiation.Halogen bonding is emerging as a powerful non-covalent interaction in the context of supramolecular photoresponsive materials design, particularly due to its high directionality. The larger anomalous signal also allows the determination of absolute configuration ofchiral light atom molecules. The Cu radiation provides a substantial increase (4-5 fold) in intensity for experiments on smaller crystals. Thus desolvation processes and temperature dependent phase changes may be monitored during the diffraction experiment. However, the sample temperature may be varied between -173 ✬ and 123 ✬. The samples are usually cooled to -163 ✬ by an Oxford Cryostream improving the high angle diffraction and reducing thermal noise from the sample. A Kryoflex X-ray generator with a Mo sealed tube running routinely at 1.6 kW (45 kV, 35 mA) of power output provides the X-ray radiation. Poorly diffracting and various types of twinned crystals can also be examined successfully.
The Xray lab also has two single crystal Bruker APEX II CCD diffractometers.
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