The ground structure of thiourea in adduct compounds of thiourea belongs to the space group R'32/c with a ~ 15.8, c ~ 12.5 ttx. The thiourea molecules have the same shape as in the orthorhombic thiourea and their parameters are xs ----0.2995; xc = 0.414; xN = 0.444, yN = --0.014, zN = 0.086.Cyclohexane as an adduct is situated near the sulphur atoms within the canal or tube formed by the thiourea molecules.Most parts of the diffraction pattern can be assigned either to the ground substance or to the enclosed component. From the latter the canal length occupied by an enclosed molecule can be obtained. From a discussion of the entire pattern of dicyclohexylparaffin adducts it follows that within the canal the paraffin chain is lengthened or shortened compared with its normal length; this brings the cyclohexyl end rings to certain regions of the thiourea canal which can be determined from the diffraction effects.
Fur 35 Gruppen konstitutionell zusammengehorender Kohlenwasserstoffe, sekundarer Alkohole sowie Chloride, Ketone, Ather, Thioather, Ester, Fettsauren und Dicarbonsauren werden rontgenographisch die ldentitatsperioden im Harnstoff-EinschluBkanal gemessen (Tab. 1). In der Regel ist die je Molekiil beanspruchte Kanalstrecke eine lineare Funktion der Kettengliederzahl. Die Inkremente der C -C-Bindung, der C-O-Bindung, der C -S-Bindung und die in den einzelnen Fallen eingehaltenen zwischenmolekularen Abstande der Gastmolekiile werden errechnet (Tab. 2). Bei den n-Paraffinen und einigen ihrer Substitutionsprodukte entspricht das gefundene C -C-Inkrement demjenigen der maximal gestreckten, ebenen Zickzack-Kette. In den iibrigen Fallen sind die Ketten mehr oder weniger verkiirzt. Die Konformation der verkurzten Ketten ist wahrscheinlich diejenige regularer Wendeln (Abb. 1, 2). Formeln fur Verkurzung und Querschnitt der Ketten und fur die Ganghohe der Wendeln als Funktion des Verdrehungsgrades werden mitgeteilt. -Ester mit ungeradzahligem Alkohol-Rest, insbesondere Methylester, beanspruchen im Kana1 mehr Raum als isomere Ester rnit geradzahligem Alkohol-Rest, insbesondere Athylester (Abb. 3). Entgegen der Erwartung ist die Gitterenergie der dichter gepackten Addukt-Kristalle der zuletzt genannten Ester geringer als diejenige der weniger dichten. -Bei den Addukten der Dicarbonsauren ist die je Gastmolekiil beanspruchte Kanalstrecke erst von derHeptadecandisaure an annahernd proportional der Kettengliederzahl. Bei den niedrigeren Homologen ist die Funktion nicht stetig. Die beiden Carboxyl-Gruppen veranlassen Verankerung der Molekiile an bestimmten Stellen des EinschluBgitters, so daB ganzzahlige Molverhaltnisse anstatt der statistisch zu erwartenden erzwungen werden. Viele der Dicarbonsauren bilden auBer hexagonalen EinschluBverbindungen rnit Harnstoff auch Molekul-Verbindungen im Molverhaltnis 1 : 2 und 1 : 1. -Die Ketten von n-Paraffinen (C9-C14) und Cyclohexylalkanen sind in den EinschluBverbindungen rnit Thioharnstoff gegenuber denjenigen rnit Harnstoff stark verkiirzt. Fur Harnstoff-Addukte von 1.3-Diglyceriden werden Molverhailtnisse gefunden, die dem zu erwartenden Platzbedarf der gestreckten Molekiile entsprechen. The Lengths of Molecules in Inclusion Channels of Urea and ThioureaThe lengths of guest molecules in urea inclusion channels have been determined by X-ray measurements for homologous series of 35 groups of the following compounds : various types of hydrocarbons, secondary alcohols and chlorides, ketones, ethers, thioethers, esters, carboxylic and dicarboxylic acids and their esters (table 1). As a rule, the channel length occupied by a molecule is a linear function of the number of C atoms in the chain. Incre-*) Herrn Professor Dr. B. Timm zum 60. Geburtstag gewidmet.
The instable modifications a I and all (previously called y) of copper phthalocyanine are isomorphous with the stable modifications a I of 4-monochloro-copper phthalocyanine, and a of platinum phthalocyanine respectively. The latter two can be obtained as single crystals and we have determined the essential structural features of them. By isomorphy considerations it was possible to recognize the structural differences between the 8, a I and all modifications of copper phthalocyanine.These a-structures are very similar to those of the all modification of 4-monochloro phthalocyanine and of the a modification of 4-tetrachloro phthalocyanine.The essential difference between the a structures and the well-known 0 structure of copper phthalocyanine is a different type of one-dimensional molecular stacking. There are several ways of assembling the stacks into a space lattice so that different a structures are yielded.The substitution of peripheral hydrogen by chlorine (in the 4 position) increases the tendency to form a-type stacks and their stabilization. Auszug Die instabilen Modifikationen a I und all (friiher y) des Kupferphthalocyanins sind isomorph mit den stabilen Modifikationen a I des 4-Monochlor-kupferphthaloyanins bzw. a des Platinphthalocyanins. Von letzteren beiden gelingt die Herstellung von Einkristallen, deren wesentliche Strukturmerkmale bestimmt wurden.Der Umweg iiber die Isomorphiebeziehungen ermoglichte es, die Strukturunterschiede der Modifikationen 8, a I und all des Kupferphthalocyanins zu erkennen. Diesen a-Strukturen sind auch die der all-Modifikation des 4-Monochlor-und der a-Modifikation des 4-Tetraehlor-kupferphthalocyanins sehr ahnlich.
The instable modifications αI and α II (previously called γ) of copper phthalocyanine are isomorphoua with the stable modifications α I of 4-monochloro-copper phthalocyanine, and α of platinum phthalocyanine respectively. The latter two can be obtained as single crystals and we have determined the essential structural features of them.By isomorphy considerations it was possible to recognize the structural differences between the β, α I and a II modifications of copper phthalocyanine. These α-structures are very similar to those of the αΠ modification of 4-monochloro phthalocyanine and of the α modification of 4-tetrachloro phthalocyanine.The essential difference between the α structures and the well-known β structure of copper phthalocyanine is a different type of one-dimensional molecular stacking. There are several ways of assembling the stacks into a space lattice so that different α structures are yielded.The substitution of peripheral hydrogen by chlorine (in the 4 position) increases the tendency to form α-type stacks and their stabilization.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.