The crystal structures of the unbound carotenoids, synthetic astaxanthin (3S,3'S:3R,3'S:3R,3'R in a 1:2:1 ratio), canthaxanthin and (3R,3'S, meso)-zeaxanthin are compared with each other and the protein bound astaxanthin molecule in the carotenoprotein, beta-crustacyanin. Three new crystal forms of astaxanthin have been obtained, using different crystallization conditions, comprising a chloroform solvate, a pyridine solvate and an unsolvated form. In each structure, the astaxanthin molecules, which are similar to one another, are centrosymmetric and adopt the 6-s-cis conformation; the end rings are bent out of the plane of the polyene chain by angles of -42.6 (5), -48.9 (5) and -50.4 (3) degrees , respectively, and are disordered, showing the presence of both R and S configurations (in a 1:1 ratio). In the crystal packing of the chloroform and pyridine solvates, the astaxanthin molecules show pair-wise end-to-end intermolecular hydrogen bonding of the adjacent 3-hydroxyl and 4-keto oxygens, whereas in the unsolvated crystal form, the hydrogen-bonding interaction is intermolecular. In addition, there are intermolecular C-H hydrogen bonds in all three structures. The canthaxanthin structure, measured at 100 and 293 K, also adopts the 6-s-cis conformation, but with disorder of one end ring only. The rotation of the end rings out of the plane of the polyene chains (ca -50 degrees for each structure) is similar to that of astaxanthin. A number of possible C-H hydrogen bonds to the keto O atoms are also observed. (3R,3'S, meso)-zeaxanthin is centrosymmetric with a C5-C6-C7-C8 torsion angle of -74.9 (3) degrees ; the molecules show pair-wise hydrogen bonding between the hydroxyl O atoms. In addition, for all the crystal structures the polyene chains were arranged one above the other, with intermolecular distances of 3.61-3.79 A, indicating the presence of pi-stacking interactions. Overall, these six crystal structures provide an ensemble of experimentally derived results that allow several key parameters, thought to influence colour tuning of the bathochromic shift of astaxanthin in crustacyanin, to be varied. The fact that the colour of each of the six crystals remains red, rather than turning blue, is therefore especially significant.

s13.m35.o4 Unravelling the chemical property of the colouration bathochromic shift in the lobster carapace; a new crystal structure of unbound astaxanthin.

layer with oxygen and La/Ba atoms is stacked by two types. One is cubic ABCABC stacking for perovskite layer and hexagonal ABAB stacking for junction slabs which is composed three octahedral with face contact. There are three positions for Ba/La ions as follows: A1 position with La and Ba is located near vacant octahedron, A2 position is located next stacking layer, and A3 position is occupied the center of perovskite layer. Structures of BaLa 4 Ti 4 O 15 substituted Ca and Sr for Ba are also analyzed. And relationship between structure and properties of them are presented.