The symbolic addition procedure for phase determination for centrosymmetric and non‐centrosymmetric crystals
01 Dec 1966-Acta Crystallographica (International Union of Crystallography)-Vol. 21, Iss: 6, pp 849-859
About: This article is published in Acta Crystallographica.The article was published on 1966-12-01. It has received 442 citations till now. The article focuses on the topics: Phase (matter).
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TL;DR: The isolation, structure determination and biological activity of this new plant growth promoter, named (22R, 23R, 24S)-2α-3α,22,23-tetrahydroxy-24-methyl-6,7-s-5α-cholestano-6-7-lactone or brassinolide is reported.
Abstract: Extracts of Brassica napus L. (rape) pollen (family, Cruciferae) have been reported to produce a novel growth-promoting effect when applied to young pinto bean plants1,2. Fractions that are active in the bean second-internode assay3 give rise to both increased cell elongation and cell division4. The validity of these early reports has been questioned because biological activity was not correlated with any one pure compound5. Subsequently, we showed that isolation of the growth promoter was complicated by the presence of chromatographically similar, inactive components that were identified as 6-D-glucopyranosyl esters of long-chain fatty acids6. We now report the isolation, structure determination and biological activity of this new plant growth promoter, named (22R, 23R, 24S)-2α-3α,22,23-tetrahydroxy-24-methyl-6,7-s-5α-cholestano-6,7-lactone or brassinolide (Fig. 1).
887 citations
TL;DR: In this article, the structures of the title compounds have been established by X-ray crystal structure analysis, based on three-dimensional diffractometer data, and the thermal motion of the molecules in the crystals is discussed.
Abstract: The structures of the title compounds have been established by X-ray crystal structure analysis, based on three-dimensional diffractometer data. Bond lengths and angles are given, and the thermal motion of the molecules in the crystals is discussed. The most striking feature of all three molecules is the twist of the aniline ring out of the CNCC plane by 41–55°.
197 citations
171 citations
TL;DR: In this paper, the prediction and synthesis of new crystal structures enable the targeted preparation of materials with desired properties among porous solids, this has been achieved for metal-organic frameworks.
Abstract: The prediction and synthesis of new crystal structures enable the targeted preparation of materials with desired properties. Among porous solids, this has been achieved for metal-organic frameworks ...
148 citations
TL;DR: The structure and absolute configuration of Chaetocin, a metabolite of the fungus Chaetomium minutum with antibacterial and cytostatic activity has been elucidated by chemical and X-ray methods.
Abstract: The structure and absolute configuration of Chaetocin, a metabolite of the fungus Chaetomium minutum with antibacterial and cytostatic activity has been elucidated by chemical and X-ray methods.
144 citations