title: Crystal structures of 3,3'-bis-(hy-droxy-dimethylsilan-yl)azo-benzene and 4,4'-bis-(hy-droxy-dimethyl-silane)azo-benzene.
abstract: The title compounds {systematic names (E)-[diazene-1,2-diylbis(3,1-phenyl-ene)]bis-(di-methyl-silanol) and (E)-[diazene-1,2-diylbis(4,1-phenyl-ene)]bis-(di-methyl-silanol)}, both of the sum formula C16H22N2O2Si2, were obtained by transmetallation of the respective bis-stannylated azo-benzenes with di-chloro-dimethyl-silane and esterification followed by hydrolysis. The asymmetric unit of 3,3'-diazenediylbis[dimeth-yl(phen-yl)silanol] (with the silanol functional group in ametaposition) consists of two mol-ecules, of which one occupies a general position, whereas the second is located on a centre of inversion. In 4,4'-diazenediylbis[dimeth-yl(phen-yl)silanol] (with the silanol functional group in aparaposition) likewise two mol-ecules are present in the asymmetric unit, but in this case both occupy general positions. Differences between all mol-ecules can be found in the torsions about the N=N bond, as well as in the dihedral angles between the benzene rings. In both structures, inter-molecular O-H⋯O hydrogen bonding is observed, leading to the formation of layers parallel to (01-1) for (I) and to chains parallel to theaaxis for (II).
authors.affiliation: Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität Kiel, Otto-Hahn-Platz 4, 24118 Kiel, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Strüben
authors.affiliation: Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität Kiel, Otto-Hahn-Platz 4, 24118 Kiel, Germany.
authors.forename: Jonas
authors.initials: J
authors.lastname: Hoffmann
authors.affiliation: Department of Organic and Inorganic Chemistry IUQOEM, University of Oviedo, Julián Claveria, 33006 Oviedo, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Presa-Soto
authors.affiliation: Institut für Anorganische Chemie, Christian-Albrechts-Universität Kiel, Max-Eyth-Strasse 2, 24118 Kiel, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Näther
authors.affiliation: Otto-Diels-Institut für Organische Chemie, Christian-Albrechts-Universität Kiel, Otto-Hahn-Platz 4, 24118 Kiel, Germany; Institute for Organic and Analytical Chemistry, University of Bremen, Leobener Strasse NW2 C, 28359 Bremen, Germany; MAPEX Center for Materials and Processes University of Bremen, Bibliothekstrasse 1, 28359 Bremen, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Staubitz
keywords: O—H⋯O hydrogen bonding; azo­benzene; crystal structure