188宝金博页面版

ORIGINAL ARTICLEA new triol host framework and the remarkable crystal structureof its DMSO inclusion complexAnne Ho¨lzel • Wilhelm Seichter • Edwin WeberReceived: 29 June 2010/Accepted: 2 December 2010/Published online: 7 January 2011? Springer Science+Business Media B.V. 2011Abstract A new trigonal host molecule 1 featuringthree 4-(9-hydroxy-9-fluorenyl)phenyl units symmetricallyattached to a benzene core was synthesized and is shown toyield a 1:3 (host:guest) crystalline inclusion compound withDMSO (1a). The crystal structure of 1a is distinguished byarare case of piedfort arrangement of host molecules and aunique hexameric cluster formation of DMSO.Keywords Hydroxy host ? DMSO guest ? Crystallineinclusion compound ? X-ray crystal structure ?Supramolecular interactionsIntroductionSymmetry, shape and functionality are important parame-ters in the design of crystal inclusion host compounds[1–5]. Using these parameters provided a great variety ofmolecular structures, many of them being efficient clath-rate formers [6]. Twofold rotational symmetry of the hostcompound has been realized a keynote in this designstrategy [1, 2]. Bulky linear [7, 8] or roof-shaped [2, 3, 9]and scissor like [2, 3, 10] geometries proved particularsuccessful guiding principles regarding the shape selectionof the host molecules. Aside from carboxylic units [3, 11,12], hydroxyl groups [2, 7, 13, 14] demonstrated highesteffectiveness from the point of functionality. Comparedwith the host molecules of this specific design, i.e. having aC 2 symmetry as a structural feature, corresponding hostcompounds involving C 3 symmetry are not just as frequentand have not been so broadly varied in the past [1, 15, 16]though the structure type of trisubstituted triazines is cur-rently very promising [17–20].Here, we report the synthesis of a new trigonal hostcompound 1 (Scheme 1) having three 9-hydroxy-9-fluore-nyl units laterally attached to a central 1,3,5-triphenylbenzene moiety. We describe preparation of a DMSOinclusion complex of 1, i.e. 1a (Scheme 1), and discuss thespecial features of this remarkable crystal structure.Results and discussionSynthesisThe host compound 1 was synthesized from 1,3,5-tris(4-bromophenyl)benzene via lithiation with n-BuLi andsubsequent reaction with fluoren-9-one. The starting com-pound 1,3,5-tris(4-bromophenyl)benzene [16] was preparedthrough SiCl 4 mediated triple condensation of 4-bromoace-tophenone [21]. The inclusion compound 1a was obtainedfrom crystallization of 1 from DMSO.X-ray structural studyThe X-ray crystal structure of the inclusion compound 1a[1?DMSO (1:3)] has been determined. Crystal data, detailsof the data collection and refinement calculations of thestructure are summarized in Table 1. Information regardingnon-covalent interactions is given in Table 2. A perspec-tive view of the molecular structure including atom label-ling and ring specification is shown in Fig. 1. Details of thepacking structure are illustrated in Figs. 2, 3, 4, and 5.The crystals of 1a belong to the rhombohedral spacegroup R-3. Since the threefold molecular symmetryA. Ho¨lzel ? W. Seichter ? E. Weber (&)Institut fu¨r Organische Chemie, TU Bergakademie Freiberg,Leipziger Straße 29, 09596 Freiberg/Sachs., Germanye-mail: edwin.weber@chemie.tu-freiberg.de123J Incl Phenom Macrocycl Chem (2011) 71:113–120DOI 10.1007/s10847-010-9914-1