TY - JOUR
T1 - Circular Dichroism Imaging Microscopy
T2 - Application to Enantiomorphous Twinning in Biaxial Crystals of 1,8-Dihydroxyanthraquinone
AU - Claborn, Kacey
AU - Puklin-Faucher, Eileen
AU - Kurimoto, Miki
AU - Kaminsky, Werner
AU - Kahr, Bart
PY - 2003/12/3
Y1 - 2003/12/3
N2 - A microscope was constructed for imaging circular dichroism of heterogeneous anisotropic media. To avoid linear biases that are common with electronic circular polarization modulation, we chose a retrogressive solution: mechanical light modulation by rotating a linear polarizer with respect to a quarter wave plate continuously tuned by tilting to the operating wavelength. Our comparatively slow technique succeeds with near-perfect circular input and signal averaging using a CCD camera. We have applied the method to anomalously birefringent crystals of 1,8-dihydroxyanthraquinone that are shown to have intergrown mirror image domains, undetected by X-ray diffraction because the twinning complexity renders differences in anomalous dispersion, already small, unreliable. The origin of the anomalous birefringence and the assignment of the absolute configuration are discussed.
AB - A microscope was constructed for imaging circular dichroism of heterogeneous anisotropic media. To avoid linear biases that are common with electronic circular polarization modulation, we chose a retrogressive solution: mechanical light modulation by rotating a linear polarizer with respect to a quarter wave plate continuously tuned by tilting to the operating wavelength. Our comparatively slow technique succeeds with near-perfect circular input and signal averaging using a CCD camera. We have applied the method to anomalously birefringent crystals of 1,8-dihydroxyanthraquinone that are shown to have intergrown mirror image domains, undetected by X-ray diffraction because the twinning complexity renders differences in anomalous dispersion, already small, unreliable. The origin of the anomalous birefringence and the assignment of the absolute configuration are discussed.
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U2 - 10.1021/ja035644w
DO - 10.1021/ja035644w
M3 - Article
C2 - 14640658
AN - SCOPUS:0345724792
SN - 0002-7863
VL - 125
SP - 14825
EP - 14831
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 48
ER -